# Menu 5 − Motor Control

Mode: Open‑Loop

The following table shows various definitions associated with controlling the motor. In each case the paramters used and the effect are given.

Function | Parameters | Usage
Rated Current | Rated Current (05.007) | General defintion of motor rated current Motor pre-heat Injection braking level Motor thermal model
Stator resistance | Stator Resistance (05.017) | Voltage characteristic adjustment with current
Transient inductance | Transient Inductance (05.024) | Definition of rated magnetising current
Stator inductance | Stator Inductance (05.025) | Definition of rated magnetising current
Rated voltage | Rated Voltage (05.009) | Voltage characteristic
Rated frequency | Rated Frequency (05.006) | Torque to current conversion Voltage to frequency characteristic Injection braking frequency used when stopping is detected
Rated magnetising current | Rated Current (05.007) Rated Frequency (05.006) Rated Voltage (05.009) Stator Resistance (05.017) Transient Inductance (05.024) Stator Inductance (05.025) Rated Power Factor (05.010)* *Used if stator inductance is not provided. | Voltage characteristic
Rated torque producing current | Parameters used to define the rated magnetising current. | Dynamic V to F Slip frequency
Motor poles | Number Of Motor Poles (05.011) | Frequency to speed conversion Standard motion controller output conversion
Rated slip frequency | Rated Frequency (05.006) Rated Speed (05.008) Number Of Motor Poles (05.011) | Slip compensation
Maximum current limits | Parameters used to define the rated magnetising current. Symmetrical Current Limit (04.007) Motoring Current Limit (04.005) | Current limit variable maximums, i.e. VM_MOTOR1_CURRENT_LIMIT.
Motor thermal model | Motor Thermal Time Constant 1 (04.015) Thermal Protection Mode (04.016) Motor Thermal Time Constant 2 Scaling (04.038) Rated Iron Losses As Percentage Of Losses (04.039) Motor Thermal Time Constant 2 (04.037) Rated Current (05.007) Rated Frequency (05.006) |
Torque estimation | Stator Resistance (05.017) Transient Inductance (05.024) Stator Inductance (05.025) No-load core loss (04.045) Rated Core Loss (04.046) | Estimated percentage torque

Parameter | 05.001 Output Frequency
--- | ---
Short description | Displays the frequency applied to the motor
Mode | Open‑Loop
Minimum | −VM_SPEED_FREQ_REF | Maximum | VM_SPEED_FREQ_REF
Default |  | Units | Hz
Type | 32 Bit Volatile | Update Rate | 4ms write
Display Format | Standard | Decimal Places | 1
Coding | RO, FI, VM, ND, NC, PT

If Enable Frequency Slaving (03.013) = 0 the Output Frequency (05.001) is the sum of the Post Ramp Reference (02.001) and the motor slip compensation frequency. If Enable Frequency Slaving (03.013) = 1 the Output Frequency (05.001) is given directly by the Frequency Slaving Demand (03.001).

Parameter | 05.002 Output Voltage
--- | ---
Short description | Displays the r.m.s. line to line voltage at the a.c. terminals of the drive
Mode | Open‑Loop
Minimum | −VM_AC_VOLTAGE | Maximum | VM_AC_VOLTAGE
Default |  | Units | V
Type | 16 Bit Volatile | Update Rate | 4ms write
Display Format | Standard | Decimal Places | 0
Coding | RO, FI, VM, ND, NC, PT

The Output Voltage (05.002) is the r.m.s. line to line voltage at the a.c. terminals of the drive.

Parameter | 05.003 Output Power
--- | ---
Short description | Displays the power flowing via the a.c. terminals of the drive
Mode | Open‑Loop
Minimum | −VM_POWER | Maximum | VM_POWER
Default |  | Units | kW
Type | 32 Bit Volatile | Update Rate | 4ms write
Display Format | Standard | Decimal Places | 3
Coding | RO, FI, VM, ND, NC, PT

The Output Power (05.003) is the power flowing via the a.c. terminals of the drive. The power is derived as the dot product of the output voltage and current vectors, and so this is correct even if the motor parameters are incorrect and the motor model does not align the reference frame with the flux axis of a motor in RFC-A mode. For Open-loop, RFC-A and RFC-S modes a positive value of power indicates power flowing from the drive to motor. For Regen mode a positive value of power indicates power flowing from the supply to the regen drive.

Parameter | 05.004 Motor Rpm
--- | ---
Short description | Displays the estimated speed of the motor
Mode | Open‑Loop
Minimum | -180000 | Maximum | 180000
Default |  | Units | rpm
Type | 32 Bit Volatile | Update Rate | Background write
Display Format | Standard | Decimal Places | 0
Coding | RO, FI, ND, NC, PT

If Enable Frequency Slaving (03.013) = 0 (normal operation) the frequency used to derive the Motor Rpm (05.004) is the Post Ramp Reference (02.001). If Enable Frequency Slaving (03.013) = 1 (frequency slaving operation) the Frequency Slaving Demand (03.001) is used.

Motor Rpm (05.004) = 60 x Frequency / Pole pairs

where
Pole pairs = the numeric value of Number Of Motor Poles (05.011) (i.e. 3 for a 6 pole motor)

For frequency slaving operation there will be an error due to the motor slip frequency. For normal operation the result will be reasonably accurate provided that the slip compensation has been set up correctly.

Parameter | 05.005 D.c. Bus Voltage
--- | ---
Short description | Displays the voltage across the d.c. link of the drive
Mode | Open‑Loop
Minimum | −VM_DC_VOLTAGE | Maximum | VM_DC_VOLTAGE
Default |  | Units | V
Type | 16 Bit Volatile | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RO, FI, VM, ND, NC, PT

D.c. Bus Voltage (05.005) gives the voltage across the d.c. link of the drive.

Parameter | 05.006 Rated Frequency
--- | ---
Short description | Set to the rated frequency of the motor
Mode | Open‑Loop
Minimum | 0.0 | Maximum | 550.0
Default | See exceptions below | Units | Hz
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 1
Coding | RW

Region | Default Value
50Hz | 50.0
60Hz | 60.0

Rated Frequency (05.006) and Rated Voltage (05.009) define the frequency to voltage characteristic applied to the motor. See Open-loop Control Mode (05.014) for more details. Rated Frequency (05.006), Rated Speed (05.008) and Number Of Motor Poles (05.011) are used to calculate the rated slip of the motor for slip compensation.

Rated slip (Hz) = Rated Frequency (05.006) - (Pole pairs x Rated Speed (05.008) / 60)

where
Pole pairs = the numeric value of Number Of Motor Poles (05.011) (i.e. 3 for a 6 pole motor)

If slip compensation is required Rated Speed (05.008) should be set to the motor nameplate value, which should give the correct compensation for a hot motor provide the nameplate value is correct. Slip compensation can be used throughout the speed range of the motor, i.e. below base speed and in the flux weakening region, to correct the motor speed to minimise the change of speed with load. Rated Speed (05.008) can be set to a value that is higher than synchronous speed to deliberately introduce speed droop, which can be used to aid load sharing with mechanically coupled motors.

Slip compensation is disabled under the following conditions:

> 1. Rated Speed (05.008) = 0
> 2. Rated Speed (05.008) = Rated Frequency (05.006) x 60 / Pole pairs, i.e. synchronous speed.
> 3. Enable Slip Compensation (05.027) = 0

It should be noted that Rated Speed (05.008) is used to calculate the rotor time constant of the motor which is then used to determine the flux build-up time at the start of the catch a spinning motor algorithm. If spinning start is required (i.e. Catch A Spinning Motor (06.009) ≥ 1) then Rated Speed (05.008) should be set up correctly for the motor. If slip compensation is not required it can be disabled by setting Enable Slip Compensation (05.027) to 0.

Parameter | 05.007 Rated Current
--- | ---
Short description | Set to the rated current rated of the motor
Mode | Open‑Loop
Minimum | −VM_RATED_CURRENT | Maximum | VM_RATED_CURRENT
Default | 0.000 | Units | A
Type | 32 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 3
Coding | RW, VM, RA

Rated Current (05.007) is used as follows:

1. To define the rated operating conditions for motor thermal protection. See Motor Thermal Time Constant 1 (04.015).
2. To define the range of the current limits.
3. In the motor control algorithm for Open-loop and RFC-A modes.

Parameter | 05.008 Rated Speed
--- | ---
Short description | Set to the rated speed of the motor
Mode | Open‑Loop
Minimum | 0 | Maximum | 33000
Default | See exceptions below | Units | rpm
Type | 32 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

Region | Default Value
50Hz | 1500
60Hz | 1800

See Rated Frequency (05.006).

Parameter | 05.009 Rated Voltage
--- | ---
Short description | Set to the rated voltage of the motor
Mode | Open‑Loop
Minimum | −VM_AC_VOLTAGE_SET | Maximum | VM_AC_VOLTAGE_SET
Default | See exceptions below | Units | V
Type | 16 Bit User Save | Update Rate | 4ms read
Display Format | Standard | Decimal Places | 0
Coding | RW, VM, RA

Voltage | Region | Default Value
200V | All | 230
400V | 50Hz | 400
400V | 60Hz | 460
575V | All | 575
690V | All | 690

Rated Frequency (05.006) and Rated Voltage (05.009) define the frequency to voltage characteristic applied to the motor. See Open-loop Control Mode (05.014) for more details.

Parameter | 05.010 Rated Power Factor
--- | ---
Short description | Set to the rated power factor of the motor. This value can be measured by the drive during a rotating autotune.
Mode | Open‑Loop
Minimum | 0.000 | Maximum | 1.000
Default | 0.850 | Units |
Type | 16 Bit User Save | Update Rate | Background read/write
Display Format | Standard | Decimal Places | 3
Coding | RW, RA

Rated Power Factor (05.010) is the true power factor of the motor under rated conditions, i.e. the cosine of the angle between the motor voltage and current. If Stator Inductance (05.025) is set to a non-zero value then the stator inductance is used to calculate the rated magnetising current for the motor and the rated power factor can be calculated by the drive. Therefore if Stator Inductance (05.025) is non-zero Rated Power Factor (05.010) is continuously set to the calculated value of rated power factor by the drive. If Stator Inductance (05.025) is set to zero then Rated Power Factor (05.010) is used to estimate the rated magnetising current which is an approximation and not as accurate. Stator Inductance (05.025) can be measured by the drive during auto-tuning and this is the preferred option, however, if it is not possible to obtain the value for Stator Inductance (05.025) then Rated Power Factor (05.010) should be set to the motor nameplate value.

Parameter | 05.011 Number Of Motor Poles
--- | ---
Short description | Set to the number of poles of the motor
Mode | Open‑Loop
Minimum | 0 | Maximum | 240
Default | 0 | Units | PolePairs
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, BU

* The units relate to the text string of the parameter and not the numeric value.

The numeric value in Number Of Motor Poles (05.011) should be set to the number of motor pole pairs (i.e. number of motor poles / 2). The text strings associated with Number Of Motor Poles (05.011) show the number of motor poles (i.e. the parameter value x 2). If a linear position feedback device is used Number Of Motor Poles (05.011) should be set to 1 (2 Pole).

If Number Of Motor Poles (05.011) = 0 the number of motor poles are calculated automatically as given below.

Pole pairs = 60 x Rated Frequency (05.006) / Rated Speed (05.008) rounded down to the nearest integer.

Parameter | 05.012 Auto-tune
--- | ---
Short description | Defines the auto-tune test to be performed
Mode | Open‑Loop
Minimum | 0 | Maximum | 2
Default | 0 | Units |
Type | 8 Bit Volatile | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, NC

The following describes how an auto-tune test can be initiated and normal operation can be resumed after the test for Open-loop mode:

1. An auto-tune test cannot be initiated if the drive is tripped or the drive inverter is active, i.e. Drive Healthy (10.001) = 0 or Drive Active (10.002) = 1. The inverter can be made inactive by ensuring that the Final drive enable is inactive, or the Final drive run is inactive and Hold Zero Speed (06.008) = 0.
2. An auto-tune test is initiated by setting Auto-tune (05.012) to a non-zero value and making the Final drive enable and the Final drive run active.
3. All tests that move the motor will move the motor in the forward direction if Reverse Select (01.012) = 0 or the reverse direction if Reverse Select (01.012) = 1.
4. If the auto-tune sequence is completed successfully the Final drive enable is set to the inactive state and Auto-tune (05.012) is set to zero. The Final drive enable can only be set to the active state again by removing the enable and reapplying it. The enable can be removed by setting Drive Enable (06.015) = 0, or by setting bit 0 of the Control Word (06.042) to 0 provided Control Word Enable (06.043) = 1, or by making Hardware Enable (06.029) = 0.
5. If a trip occurs during the auto-tune sequence the drive will go into the trip state and Auto-tune (05.012) is set to zero. As in 4. above the enable must be removed and re-applied before the drive can be restarted after the trip has been reset. However, care should be taken because if the auto-tune was not completed the drive parameters that should have been measured and set up will still have their original values.
6. If the Final drive enable is made active, the Final drive run is inactive and Hold Zero Speed (06.008) = 1 the drive would normally be in the Stop state (i.e. the inverter is active, but the frequency or speed reference is 0).

The following describes the effects of the auto-tune test on the drive parameters for Open-loop mode:

1. All auto-tune tests rely on the motor being stationary when the test is initiated to give accurate results.
2. If Select Motor 2 Parameters (11.045) = 0 then the parameters associated with motor map 1 are updated as a result of the test, and if Select Motor 2 Parameters (11.045) = 1 the parameters associated with motor map 2 are updated.
3. When each stage of the test is complete the results written to the appropriate parameters and these parameters saved in the drive non-volatile memory. If Parameter Cloning (11.042) is set to 3 or 4 the parameters are also written to a non-volatile media card fitted in the drive.

The table below shows the parameters required for motor control indicating which should be set by the user and which can be measured with an auto-tune test.

Parameter | Required for | Measured in test
Rated Frequency (05.006) | Basic control |
Rated Current (05.007) | Basic control |
Rated Speed (05.008) | Slip compensation Spinning start |
Rated Voltage (05.009) | Basic control |
Rated Power Factor (05.010) | Basic control | 2
Number Of Motor Poles (05.011) | Not used |
Stator Resistance (05.017) | Ur, Ur I, Ur S and Ur Auto modes Spinning start | 1, 2
Transient Inductance (05.024) | Improved performance | 1, 2
Stator Inductance (05.025) | Improved performance | 2
Maximum Deadtime Compensation (05.059) | Basic control | 1, 2
Current At Maximum Deadtime Compensation (05.060) | Basic control | 1, 2
No-load Core Loss (04.045) | Torque feedback* | 2
Rated Core Loss (04.046) | Torque feedback* | 2

*Torque feedback is provided in Percentage Torque (04.026). The estimated value can be improved by setting up the No-load Core Loss (04.045) and Rated Core Loss (04.046) for the motor. It should be noted that the core loss characteristic for a motor is complex and depends to some extent on the switching frequency, but the drive can include an approximation to the core losses based on these two parameters. The value for the no-load core losses measured by the auto-tuning is likely to be higher than the actual value, but can be used to significantly reduce the difference that will be seen in the estimate torque between motoring and regenerating operation. If more accurate core loss compensation is required No-load Core Loss (04.045) and Rated Core Loss (04.046) must be set up based on testing the motor using a torque transducer.

Auto-tune test 1: Basic control parameters
This test measures the basic control parameters without moving the motor.

1. A stationary test is performed to measure Stator Resistance (05.017), Transient Inductance (05.024), Maximum Deadtime Compensation (05.059) and Current At Maximum Deadtime Compensation (05.060). If Enable Stator Compensation (05.049) = 1 then Stator Base Temperature (05.048) is made equal to Stator Temperature (05.046).

Auto-tune test 2: Basic control and improved performance parameters
This test measures the parameters for improved performance by rotating the motor.

1. Auto-tune test 1 is performed.
2. A rotating test is performed in which the motor is accelerated with the currently selected ramps up to a frequency of Rated Frequency (05.006) x 2/3, and the frequency is maintained at that level for 4 seconds. Stator Inductance (05.025) is measured and this value is used in conjunction with other motor parameters to calculate Rated Power Factor (05.010). The no-load motor core losses are measured and written to No-load Core Loss (04.045). It is not possible to measure the rated load motor core losses, and so Rated Core Loss (04.046) is set to zero. The motor should be unloaded for this test.

The table below shows the trips that can occur during an auto-tune test:

Trip | Reason | Trip can occur in test
Autotune Stopped | The final drive enable or the final drive run were removed before the test was completed. | All
Resistance.001 | The measured value of Stator Resistance (05.017) exceeded a value of (VFS / √2) / Full Scale Current Kc (11.061), where VFS is the full scale d.c. link voltage. | All
Resistance.002 | It has not been possible to measure the drive inverter characteristic to define Maximum Deadtime Compensation (05.059) and Current At Maximum Deadtime Compensation (05.060). | All

Parameter | 05.013 Dynamic V To F Select
--- | ---
Short description | Set to 1 to enable Dynamic V to F mode
Mode | Open‑Loop
Minimum | 0 | Maximum | 1
Default | 0 | Units |
Type | 1 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

Dynamic V to F mode is intended for applications where power loss should be kept to a minimum under low load conditions, but dynamic performance is not important. The reduction in power loss under low load conditions is achieved by increasing the rated frequency used to derive the frequency to voltage characteristic of the drive with reduced load. If Dynamic V To F Select (05.013) = 0 then Rated Frequency (05.006) is used directly to define the output voltage characteristic. If Dynamic V To F Select (05.013) = 1 then a modified value of rated frequency is used when |Percentage Load (04.020)|

rated frequency = Rated Frequency (05.006) x [2 - |Percentage Load (04.020)| / 70.0%]

For higher load levels Rated Frequency (05.006) is used directly.

Parameter | 05.014 Open-loop Control Mode
--- | ---
Short description | Defines the drive output mode, which can either be a voltage mode or a current mode
Mode | Open‑Loop
Minimum | 0 | Maximum | 6
Default | 4 | Units |
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, TE

Value | Text
0 | Ur S
1 | Ur
2 | Fixed
3 | Ur Auto
4 | Ur I
5 | Square

Open-loop Control Mode (05.014) defines the drive output mode, which can either be a voltage mode or a current mode as given below. It should be noted that the maximum output voltage of the drive is limited to a level just below D.c. Bus Voltage (05.005) / √2. Therefore, if the drive is being supplied via its own rectifier input stage the output voltage is limited to a level just below that of the supply voltage. If the drive is operating in voltage mode the output voltage is limited to Rated Voltage (05.009) or the maximum possible output voltage whichever is the lowest. (If Quasi-square Enable (05.020) = 1 the maximum possible output voltage can be increased. See Quasi-square Enable (05.020) for details.)

0: Ur S (Resistance compensation, stator resistance measured at each start)
Resistance compensation is a form of stator flux oriented sensorless motor control. A linear frequency to voltage characteristic is used where the drive output voltage is increased from 0V to Rated Voltage (05.009). as the |Output Frequency (05.001)| increases from 0Hz to Rated Frequency (05.006). When the |Output Frequency (05.001)| is above Rated Frequency (05.006) the output voltage is limited to Rated Voltage (05.009). Vector based stator resistance compensation is applied below Rated Frequency (05.006)/4 and then this is tapered out from Rated Frequency (05.006)/4 to Rated Frequency (05.006)/2. This method controls the flux level correctly in the motor in the steady state provided the correct value of Stator Resistance (05.017) is used.

The Stator Resistance (05.017) is measured each time the drive is started. This test can only be done with a stationary motor where the flux has decayed to zero. Therefore this mode should only be used if the motor is guaranteed to be stationary each time the drive is enabled. To ensure that the measurement is not carried out before the flux has decayed, there is a period of one second after the inverter has been disabled during which the test is not carried out if the drive is re-started. The Stator Resistance (05.017) is not automatically saved in non-volatile memory after each test.

1: Ur (Resistance compensation with no stator resistance measurement)
Resistance compensation is used as in Ur S mode, but the Stator Resistance (05.017) is not measured.

2: Fixed (Fixed boost with linear characteristic)
A fixed frequency to voltage characteristic is used as shown below where the voltage at 0Hz is defined by Low Frequency Voltage Boost (05.015).

3: Ur Auto (Resistance compensation, stator resistance measured on first start)
Resistance compensation is used as in Ur S mode, but the Stator Resistance (05.017) is only measured once when the drive is first enabled. After the test has been completed successfully the mode is changed to Ur mode and Stator Resistance (05.017) is saved to non-volatile memory. If Parameter Cloning (11.042) is set to 3 or 4 the Stator Resistance (05.017) is also written to a non-volatile media card fitted in the drive. If the test fails the mode is changed to Ur mode, but Stator Resistance (05.017) is not updated.

4: Ur I (Resistance compensation, stator resistance measured at power-up)
Resistance compensation is used as in Ur S mode, but the Stator Resistance (05.017) is only measured when the drive is enabled for the first time after each power-up.

5: Square (Fixed boost with square characteristic)
A fixed square frequency to voltage characteristic is used as shown below. When the |Output Frequency (05.001)| is below Rated Frequency (05.006) the Output Voltage (05.002) is given by:

Output Voltage (05.002) = Low Frequency Voltage Boost (05.015) + [Rated Voltage (05.009) - Low Frequency Voltage Boost (05.015)] x (Output Frequency (05.001) / Rated Frequency (05.006))2]

6: Current 1P (Single phase current output)
If this mode is selected it overrides all the normal control system for Open-loop mode and is used to produce a single phase square wave current output using the system shown below.

The load should be connected between the U and V phases as shown. The drive attempts to produces a square wave of output current at the frequency defined by the Post Ramp Reference (02.001). The magnitude of the current is controlled by the Torque Reference (04.008) as a percentage of the Rated Current (05.007). Iq, Torque Producing Current (04.002) shows the magnitude of the output current, which for a square wave is the same as the r.m.s. value of current. The following should be noted about this control mode:

> 1. Id, Magnetising Current (04.017) remains at zero, and Current Magnitude (04.001) = Iq, Torque Producing Current (04.002).
> 2. Output Power (05.003) shows the correct magnitude of output power flowing from the drive, but this will always be positive whatever the phase relationship between the output current and voltage.
> 3. The maximum possible output voltage from the drive is a square wave with a magnitude approximately equal to the D.c. Bus Voltage (05.005).
> 4. High performance current controller mode is used and the current controller gains should be set up based on the load impedance for this mode as defined in the description of Current Controller Kp Gain (04.013) for RFC-A and RFC-S modes.
> 5. The drive thermal model will provide protection for the drive as though the output frequency is 0Hz whatever the value of the Post Ramp Reference (02.001). This should be taken into account because the thermal capabilities of the drive in this mode are the same as other modes when the motor is at standstill.

Parameter | 05.015 Low Frequency Voltage Boost
--- | ---
Short description | Defines the level of voltage boost at 0Hz when using a fixed V to F relationship
Mode | Open‑Loop
Minimum | 0.0 | Maximum | 25.0
Default | 3.0 | Units | %
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 1
Coding | RW, BU

The default value for this parameter depends on the frame size of the drive as follows:

- 3.0% up to frame size 06 drives,
- 2.0% for frame size 07and frame size 08 drives
- 1.0% for larger sizes

See Open-loop Control Mode (05.014).

Parameter | 05.017 Stator Resistance
--- | ---
Short description | Defines the resistance of the motor stator
Mode | Open‑Loop
Minimum | 0.000000 | Maximum | 1000.000000
Default | 0.000000 | Units | Ω
Type | 32 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 6
Coding | RW, RA

The Stator Resistance (05.017), Transient Inductance (05.024) and Stator Inductance (05.025) are derived from the star connected per phase equivalent circuit of an induction motor shown below.

The steady state parameters are converted to equivalent transient model parameters:

Rs = R1

Lm = Lm

Ls = L1 + Lm

Lr = L2 + Lm

σLs = Ls - (Lm2 / Lr)

The equivalent drive parameters are:

Stator Resistance (05.017) = Rs

Transient Inductance (05.024) = σLs

Stator Inductance (05.025) = Ls

Parameter | 05.018 Maximum Switching Frequency
--- | ---
Short description | Defines the maximum switching frequency that can be used by the drive
Mode | Open‑Loop
Minimum | 0 | Maximum | VM_SWITCHING_FREQUENCY
Default | 1 | Units | kHz
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, TE, VM, RA

Value | Text
0 | 2
1 | 3
2 | 4
3 | 6
4 | 8
5 | 12
6 | 16

Maximum Switching Frequency (05.018) should be set to the required PWM switching frequency. The drive inverter will operate at this frequency unless the inverter temperature becomes too hot. Under these conditions the drive will reduce the switching frequency in an attempt to avoid tripping (see Auto-switching Frequency Change (05.035) ). The actual switching frequency is shown in Switching Frequency (05.037). The switching frequency has a direct effect on the sample rate for the current controllers (see Current Controller Kp Gain (04.013)). All other control tasks are at a fixed rate.

Task |
Speed controller (RFC-A, RFC-S) | 250μs
D.c. link voltage controller | 1ms
Flux controller (RFC-A, RFC-S) | 1ms

Parameter | 05.019 High Stability Space Vector Modulation
--- | ---
Short description | Set to 1 to enable High Stability Space Vector Modulation
Mode | Open‑Loop
Minimum | 0 | Maximum | 1
Default | 0 | Units |
Type | 1 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

If High Stability Space Vector Modulation (05.019) = 0 standard space vector modulation is used to derive the inverter control signals. If High Stability Space Vector Modulation (05.019) = 1 a modified form of space vector modulation is selected which can give the following advantages:

1. With some motors instability can occur when operating below Rated Frequency (05.006) / 2 especially with light loads and high switching frequency. The preferred method to solve this problem is to use RFC-A mode without position feedback. However, if Open-loop mode is required, the instability can sometimes be reduced by selecting high stability space vector modulation.
2. As the output voltage approaches the maximum available from the drive pulse deletion occurs. This can cause unstable operation with a lightly or fully loaded motor. High stability space vector modulation will reduce this effect.

The disadvantages of using high stability space vector modulation are:

1. Increased acoustic noise from the motor.
2. A reduction in the thermal capability of the drive at low output frequencies.

Parameter | 05.020 Quasi-square Enable
--- | ---
Short description | Set to 1 to change the output voltage to a quasi-square wave
Mode | Open‑Loop
Minimum | 0 | Maximum | 1
Default | 0 | Units |
Type | 1 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

If Quasi-square Enable (05.020) = 0 then the output of the drive is limited to a modulation index of unity, which limits the output voltage to a level just below D.c. Bus Voltage (05.005) / √2. Therefore, if the drive is being supplied via its own rectifier input stage the output voltage is limited to a level just below that of the supply voltage or Rated Voltage (05.009) whichever is lower.

If Quasi-square Enable (05.020) = 1 then the limit imposed by Quasi-square Enable (05.020) is ignored and the modulation index is allowed to increase beyond unity. As the output voltage increases the output voltage changes through trapezoidal waveforms to a quasi-square wave output. This mode is useful where the ratio between the switching frequency and the fundamental output frequency is less than 12, as it removes any sub-harmonic effects that occur. However, it does produce significant multiple odd harmonics of the output frequency in the output currents which cause acoustic noise, torque ripple and motor heating.

Parameter | 05.023 D.c. Bus Voltage High Range
--- | ---
Short description | Displays the d.c. bus level but with a higher range
Mode | Open‑Loop
Minimum | −VM_HIGH_DC_VOLTAGE | Maximum | VM_HIGH_DC_VOLTAGE
Default |  | Units | V
Type | 16 Bit Volatile | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RO, FI, VM, ND, NC, PT

D.c. Bus Voltage High Range (05.023) provides voltage feedback that has lower resolution and a higher range than D.c. Bus Voltage (05.005), and so it is possible to determine the d.c. link voltage even if this exceeds the level of the over-voltage trip. It should be noted that due to tolerances, D.c. Bus Voltage High Range (05.023) may not correspond exactly with the level given by D.c. Bus Voltage (05.005). In a system with parallel power modules where the control pod is remote from any of the power modules, this parameter always shows zero.

Parameter | 05.024 Transient Inductance
--- | ---
Short description | Defines the inducatance of the transient components in the motor stator
Mode | Open‑Loop
Minimum | 0.000 | Maximum | 500.000
Default | 0.000 | Units | mH
Type | 32 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 3
Coding | RW, RA

See Stator Resistance (05.017).

Parameter | 05.025 Stator Inductance
--- | ---
Short description | Defines the inductance of the motor stator
Mode | Open‑Loop
Minimum | 0.00 | Maximum | 5000.00
Default | 0.00 | Units | mH
Type | 32 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 2
Coding | RW, RA

See Stator Resistance (05.017).

Parameter | 05.027 Enable Slip Compensation
--- | ---
Short description | Set to 1 to enable slip compensation
Mode | Open‑Loop
Minimum | 0 | Maximum | 1
Default | 1 | Units |
Type | 1 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, BU

See Rated Frequency (05.006).

Parameter | 05.031 Voltage Controller Gain
--- | ---
Short description | Defines the proportional gain of the d.c. link voltage controller
Mode | Open‑Loop
Minimum | 1 | Maximum | 30
Default | 1 | Units |
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

Voltage Controller Gain (05.031) can be used to modify the proportional gain of the d.c. link voltage controller used for standard ramp and supply loss control.

Parameter | 05.035 Auto-switching Frequency Change
--- | ---
Short description | Defines auto-switching frequency control with thermal model
Mode | Open‑Loop
Minimum | 0 | Maximum | 2
Default | 0 | Units |
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, TE

Value | Text
0 | Enabled
1 | Disabled
2 | No Ripple Detect

The drive inverter can be damaged if the temperature is too high. The inverter can also be damaged or the lifetime of the power devices reduced, if the temperature ripple of the devices is too high. Auto-switching Frequency Change (05.035) defines the action taken if the drive inverter becomes too hot or the temperature ripple becomes too high.

Enabled:
If the inverter becomes too hot or the ripple temperature is higher than the level defined by Maximum Inverter Temperature Ripple (05.039) the switching frequency is reduced in an attempt to prevent tripping.

Disabled:
The switching frequency is not reduced, and so the drive will trip if the inverter is too hot or the temperature ripple is too high.

No Ripple Detect:
The switching frequency is reduced if the inverter temperature, but not the temperature ripple is too high. If the temperature ripple exceeds the level defined by Maximum Inverter Temperature Ripple (05.039) then the drive will trip.

The switching frequency is changed in steps defined by Auto-switching Frequency Step Size (05.036). For example with a switching frequency of 16kHz and a step size of two, the frequency will be reduced to 8kHz, then 4kHz etc. Minimum Switching Frequency (05.038) defines the minimum switching frequency that the system will attempt to use. If the switching frequency needs to switch to a lower level, then the drive will trip. If Minimum Switching Frequency is changed the new value will only become active when Switching Frequency is at or above the minimum value.

Parameter | 05.036 Auto-switching Frequency Step Size
--- | ---
Short description | Auto-switching frequency redcution step size
Mode | Open‑Loop
Minimum | 1 | Maximum | 2
Default | 2 | Units |
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

See Auto-switching Frequency Change (05.035).

Parameter | 05.037 Switching Frequency
--- | ---
Short description | Displays the current switching frequency used by the drive
Mode | Open‑Loop
Minimum | 0 | Maximum | 6
Default |  | Units | kHz
Type | 8 Bit Volatile | Update Rate | Background write
Display Format | Standard | Decimal Places | 0
Coding | RO, TE, ND, NC, PT

Value | Text
0 | 2
1 | 3
2 | 4
3 | 6
4 | 8
5 | 12
6 | 16

Shows the actual inverter switching frequency after the auto-change function.

Parameter | 05.038 Minimum Switching Frequency
--- | ---
Short description | Minuimum Switching Frequency
Mode | Open‑Loop
Minimum | 0 | Maximum | VM_MIN_SWITCHING_FREQUENCY
Default | 0 | Units | kHz
Type | 8 Bit User Save | Update Rate | Background Read
Display Format | Standard | Decimal Places | 0
Coding | RW, TE, VM

Value | Text
0 | 2
1 | 3
2 | 4
3 | 6
4 | 8
5 | 12
6 | 16

See Auto-switching Frequency Change (05.035).

Parameter | 05.039 Maximum Inverter Temperature Ripple
--- | ---
Short description | Maximum Inverter Temperature Ripple
Mode | Open‑Loop
Minimum | 20 | Maximum | 60
Default | 60 | Units | °C
Type | 8 Bit User Save | Update Rate | Background Read
Display Format | Standard | Decimal Places | 0
Coding | RW

Maximum Inverter Temperature Ripple (05.039) defines the maximum inverter temperature ripple allowed before the switching frequency is reduced. See Auto-switching Frequency Change (05.035).

Parameter | 05.040 Spin Start Boost
--- | ---
Short description | Defines the level of spin start boost used by the algorithm that detects the speed of a spinning motor
Mode | Open‑Loop
Minimum | 0.0 | Maximum | 10.0
Default | 1.0 | Units |
Type | 8 Bit User Save | Update Rate | Background Read
Display Format | Standard | Decimal Places | 1
Coding | RW

Spin Start Boost (05.040) is used by the algorithm that detects the speed of a spinning motor when the drive is enabled and Catch A Spinning Motor (06.009) ≥ 1. For most motors Spin Start Boost (05.040) does not need to be changed from the default value, but for some larger motors Spin Start Boost (05.040) may need to be increased. If Spin Start Boost (05.040) is too small the drive will detect zero speed whatever the speed of the motor, and if Spin Start Boost (05.040) is too large the motor may accelerate away from standstill when the drive is enabled.

Parameter | 05.042 Reverse Output Phase Sequence
--- | ---
Short description | Set to 1 to reverse the sequence on the output phases
Mode | Open‑Loop
Minimum | 0 | Maximum | 1
Default | 0 | Units |
Type | 1 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

If Reverse Output Phase Sequence (05.042) = 0 the output phase sequence is U-V-W when Output Frequency (05.001) is positive and W-V-U when Output Frequency (05.001) is negative. If Reverse Output Phase Sequence (05.042) = 1 the output phase sequence is reversed so that the phase sequence in W-V-U for positive frequencies and U-V-W for negative frequencies.

Parameter | 05.044 Stator Temperature Source
--- | ---
Short description | Defines the source of the stator temperature
Mode | Open‑Loop
Minimum | 0 | Maximum | 6
Default | 0 | Units |
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, TE

Value | Text
0 | An In 3
1 | User
2 | P1 Drive
3 | P1 Slot1
4 | P1 Slot2
5 | P1 Slot3
6 | P1 Slot4

The stator temperature can be used to compensate for changes in stator resistance. See Stator Temperature Coefficient (05.047). Stator Temperature Source (05.044) is used to select the source for the stator temperature measurement.

Stator Temperature Source (05.044) | Source | Comments
0 | Analog Input 3 Thermistor Temperature (07.050) | Analog input 3 must be set up for the correct temperature feedback device
1 | User Stator Temperature (05.045) | The user can provide a stator temperature value. If an alternative feedback device is to be used or the user provides an algorithm to model the stator temperature.
2 | P1 Thermistor Temperature (03.122) | P1 position feedback interface must be set up for the correct temperature feedback device
3-6 | Option slot P1 Thermistor Temperature (xx.080) | A position feedback category option module must be fitted and the P1 position feedback must be set up for the correct temperature feedback device

Parameter | 05.045 User Stator Temperature
--- | ---
Short description | Defines the stator temperature as set by the user
Mode | Open‑Loop
Minimum | -50 | Maximum | 300
Default | 0 | Units | °C
Type | 16 Bit Volatile | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

See Stator Temperature Source (05.044).

Parameter | 05.046 Stator Temperature
--- | ---
Short description | Displays the temperature of the motor stator
Mode | Open‑Loop
Minimum | -50 | Maximum | 300
Default |  | Units | °C
Type | 16 Bit Volatile | Update Rate | Background write
Display Format | Standard | Decimal Places | 0
Coding | RO, ND, NC, PT

See Stator Temperature Source (05.044).

Parameter | 05.047 Stator Temperature Coefficient
--- | ---
Short description | Defines the coefficient used to calculate the temperature of the motor stator
Mode | Open‑Loop
Minimum | 0.00000 | Maximum | 0.10000
Default | 0.00390 | Units | 1/°C
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 5
Coding | RW

Temperature Compensated Stator Resistance (05.050) shows the stator resistance from the active motor that is being used by the drive for motor control. If Enable Stator Compensation (05.049) = 0 and motor 1 is selected then Temperature Compensated Stator Resistance (05.050) is equal to Stator Resistance (05.017). If Enable Stator Compensation (05.049) = 1 the value of Stator Resistance (05.017) is not changed, but Temperature Compensated Stator Resistance (05.050) is derived as follows:

Temperature Compensated Stator Resistance (05.050) = Stator Resistance (05.017) x [1 + ((Stator Temperature (05.046) – Stator Base Temperature (05.048)) x Stator Temperature Coefficient (05.047))]

Stator Resistance (05.017) and Stator Base Temperature (05.048) can be set up by the user with the stator resistance at a given temperature. The preferred method is for the Stator Resistance (05.017) to be measured and set up using the auto-tuning system (See Auto-tune (05.012)). If Enable Stator Compensation (05.049) = 1 when the auto-tuning is carried out the Stator Base Temperature (05.048) will be updated automatically with Stator Temperature (05.046).

The temperature compensation system can only function correctly if the Stator Temperature Coefficient (05.047) is set up correctly. The default value is suitable for copper or aluminium windings and should not need to be adjusted for these materials provided the temperature measurement is a reasonable measure of the winding temperature. If the temperature measurement is not closely coupled to the winding it may be necessary to adjust Stator Temperature Coefficient (05.047) for correct compensation.

Parameter | 05.048 Stator Base Temperature
--- | ---
Short description | Defines the base temperature used to calculate the temperature of the motor stator
Mode | Open‑Loop
Minimum | -50 | Maximum | 300
Default | 0 | Units | °C
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

See Stator Temperature Coefficient (05.047).

Parameter | 05.049 Enable Stator Compensation
--- | ---
Short description | Set to 1 to enable stator compensation
Mode | Open‑Loop
Minimum | 0 | Maximum | 1
Default | 0 | Units |
Type | 1 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

See Stator Temperature Coefficient (05.047).

Parameter | 05.050 Temperature Compensated Stator Resistance
--- | ---
Short description | Final stator resistance value used by the drive including temperature compensation
Mode | Open‑Loop
Minimum | 0.000000 | Maximum | 1000.000000
Default |  | Units | Ω
Type | 32 Bit Volatile | Update Rate | Background write
Display Format | Standard | Decimal Places | 6
Coding | RO, ND, NC, PT

Temperature Compensated Stator Resistance (05.050) shows the stator resistance value for the active motor that is being used by the drive including the effect of temperature compensation.

Parameter | 05.051 Rotor Temperature Source
--- | ---
Short description | Defines the source of the rotor temperature
Mode | Open‑Loop
Minimum | 0 | Maximum | 6
Default | 0 | Units |
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, TE

Value | Text
0 | An In 3
1 | User
2 | P1 Drive
3 | P1 Slot1
4 | P1 Slot2
5 | P1 Slot3
6 | P1 Slot4

The rotor temperature can be used to compensate for changes in rotor resistance that affects the motor slip and hence the rated speed in Open-loop or RFC-A mode, or the magnet flux that affects motor torque in RFC-S mode. See Rotor Temperature Coefficient (05.054) for details. Rotor Temperature Source (05.051) is used to select the source for the rotor temperature measurement.

Rotor Temperature Source (05.051) | Source | Comments
0 | Analog Input 3 Thermistor Temperature (07.050) | Analog input 3 must be set up for the correct temperature feedback device
1 | User Rotor Temperature (05.052) | The user can provide a rotor temperature value if an alternative feedback device is to be used or the user provides an algorithm to model the rotor temperature
2 | P1 Thermistor Temperature (03.122) | P1 position feedback interface must be set up for the correct temperature feedback device
3-6 | Option Slot P1 Thermistor Temperature (xx.080) | A position feedback category option module must be fitted and the P1 position feedback must be set up for the correct temperature feedback device

Parameter | 05.052 User Rotor Temperature
--- | ---
Short description | Defines the temperature of the motor as set by the user
Mode | Open‑Loop
Minimum | -50 | Maximum | 300
Default | 0 | Units | °C
Type | 16 Bit Volatile | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

See Rotor Temperature Source (05.051).

Parameter | 05.053 Rotor Temperature
--- | ---
Short description | Displays the temperature of the motor rotor
Mode | Open‑Loop
Minimum | -50 | Maximum | 300
Default |  | Units | °C
Type | 16 Bit Volatile | Update Rate | Background write
Display Format | Standard | Decimal Places | 0
Coding | RO, ND, NC, PT

See Rotor Temperature Source (05.051).

Parameter | 05.054 Rotor Temperature Coefficient
--- | ---
Short description | Defines the coefficient used to calculate the temperature of the rotor
Mode | Open‑Loop
Minimum | 0.00000 | Maximum | 0.10000
Default | 0.00390 | Units | 1/°C
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 5
Coding | RW

The slip of an induction motor is proportional to the rotor resistance, and so as the motor becomes hotter the slip increases. Therefore the rated speed used to derive the slip compensation should be changed with rotor temperature to remove the motor speed variation caused by the change of rotor temperature. Temperature compensated rated speed (05.057) shows the rated speed from the active motor that is used to derive the slip compensation. If Enable Rotor Compensation (05.056) = 0 and motor 1 is selected (i.e. Motor 2 Active (21.015) = 0) then Temperature compensated rated speed (05.057) is equal to Rated Speed (05.008) and the rated slip used for slip compensation is based on Rated Frequency (05.006) and Rated Speed (05.008). If Enable Rotor Compensation (05.056) = 1 then Temperature compensated rated speed (05.057) is calculated as follows:

Temperature compensated rated speed (05.057) = Rated Speed (05.008) x [1 + ((Rotor Temperature (05.053) – Rotor Base Temperature (05.055)) x Rotor Temperature Coefficient (05.054))]

Rated Speed (05.008) should be the rated speed of the motor with Rotor Temperature (05.053) equal to Rotor Base Temperature (05.055). These values should be set up by the user. It is likely that the available temperature measurement will give the temperature of the stator windings. The default value of Rotor Temperature Coefficient (05.054) is the temperature coefficient for aluminium or copper as one of these materials is normally used for the rotor bars of an induction motor. However, if the thermal coupling between the rotor and the temperature measuring device is poor it may be necessary to adjust Rotor Temperature Coefficient (05.054) to give better compensation.

Parameter | 05.055 Rotor Base Temperature
--- | ---
Short description | Defines the base temperature used to calculate the temperature of the rotor
Mode | Open‑Loop
Minimum | -50 | Maximum | 300
Default | 0 | Units | °C
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

See Rotor Temperature Coefficient (05.054).

Parameter | 05.056 Enable Rotor Compensation
--- | ---
Short description | Set to 1 to enable rotor compensation
Mode | Open‑Loop
Minimum | 0 | Maximum | 1
Default | 0 | Units |
Type | 1 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

See Rotor Temperature Coefficient (05.054).

Parameter | 05.057 Temperature compensated rated speed
--- | ---
Short description | Final rated speed value used by the drive including temperature compensation
Mode | Open‑Loop
Minimum | 0.00 | Maximum | 18000.00
Default |  | Units | rpm
Type | 32 Bit Volatile | Update Rate | Background
Display Format | Standard | Decimal Places | 2
Coding | RO, ND, NC, PT

Temperature compensated rated speed (05.057) shows the rated speed value for the active motor that is being used by the drive including the effect of temperature compensation.

Parameter | 05.059 Maximum Deadtime Compensation
--- | ---
Short description | Maximum Deadtime Compensation
Mode | Open‑Loop
Minimum | 0.000 | Maximum | 10.000
Default | 0.000 | Units | µs
Type | 16 Bit User Save | Update Rate | Background Read
Display Format | Standard | Decimal Places | 3
Coding | RO, NC, PT

Maximum Deadtime Compensation (05.059) is the deadtime compensation used to compensate for dead-time effects in the inverter. This level of compensation is used when the drive output current is above Current At Maximum Deadtime Compensation (05.060). Both of these values related to dead-time compensation are measured during auto-tuning and cannot be set by the user. It should be noted that if the auto-tuning test is not performed and Maximum Deadtime Compensation (05.059) = 0 then a factory defined value is used for dead-time compensation. Although it is not recommended, it is possible to disable dead-time compensation by setting Disable Deadtime Compensation (05.061) = 1.

Parameter | 05.060 Current At Maximum Deadtime Compensation
--- | ---
Short description | Current at which maximum deadtime compensation is applied
Mode | Open‑Loop
Minimum | 0.00 | Maximum | 100.00
Default | 0.00 | Units | %
Type | 16 Bit User Save | Update Rate | Background Read
Display Format | Standard | Decimal Places | 2
Coding | RO, NC, PT

See Maximum Deadtime Compensation (05.059).

Parameter | 05.061 Disable Deadtime Compensation
--- | ---
Short description | Disable Deadtime Compensation
Mode | Open‑Loop
Minimum | 0 | Maximum | 1
Default | 0 | Units |
Type | 1 Bit User Save | Update Rate | Background Read
Display Format | Standard | Decimal Places | 0
Coding | RW

See Maximum Deadtime Compensation (05.059).