# Menu 5 − Motor Control

Mode: Open‑Loop

The drive can operate under Open Loop and RFC modes with respect to frequency and current control and can drive asynchronous machines. The open loop asynchronous control is further broken down into vector and fixed boost modes.

Open-loop mode

RFC operation

Parameter | 05.001 Output Frequency
--- | ---
Short description | Displays the output frequency of the drive
Mode | Open‑Loop
Minimum | −VM_SPEED_FREQ_REF | Maximum | VM_SPEED_FREQ_REF
Default |  | Units | Hz
Type | 32 Bit Volatile | Update Rate | 16ms
Display Format | Standard | Decimal Places | 2
Coding | RO, FI, VM, ND, NC, PT

Open loop mode
The Output Frequency (05.001) is the sum of the Post Ramp Reference (02.001) and the motor slip compensation frequency.

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 | 16ms
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 | 16ms
Display Format | Standard | Decimal Places | 2
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. A positive value of power indicates power flowing from the drive to the motor.

The maximum power is VM_POWER[MAX] = √3 x VM_AC_VOLTAGE[MAX] x Full Scale Current Kc (11.061) / 1000

Parameter | 05.004 Motor Rpm
--- | ---
Short description | Displays the Final Demand Reference in units of rpm
Mode | Open‑Loop
Minimum | -80000 | Maximum | 80000
Default |  | Units | rpm
Type | 32 Bit Volatile | Update Rate | Background write
Display Format | Standard | Decimal Places | 0
Coding | RO, FI, ND, NC, PT

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

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

The frequency used to derive the Motor Rpm (05.004) is the Final Demand Reference (03.001). The maximum and minimum values allow for a 10% over-shoot of the speed.

Parameter | 05.005 D.c. Link 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 | 16ms
Display Format | Standard | Decimal Places | 0
Coding | RO, FI, VM, ND, NC, PT

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

Parameter | 05.006 Motor Rated Frequency
--- | ---
Short description | Set to the rated frequency of the motor
Mode | Open‑Loop
Minimum | 0.00 | Maximum | 550.00
Default | See exceptions below | Units | Hz
Type | 32 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 2
Coding | RW

Region | Default Value
50Hz | 50.00
60Hz | 60.00

Motor Rated Frequency (05.006) and Motor Rated Voltage (05.009) define the frequency to voltage characteristic applied to the motor. See Control Mode (05.014) for more details. Motor Rated Frequency (05.006), Motor 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) = Motor Rated Frequency (05.006) - (Pole pairs x Motor 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 Motor 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. Motor 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. Motor Rated Speed (05.008) = 0
2. Motor Rated Speed (05.008) = Motor Rated Frequency (05.006) x 60 / Pole pairs, i.e. synchronous speed.
3. Slip Compensation Level (05.027) = 0.0%

It should be noted that Motor 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 Motor Rated Speed (05.008) should be set up correctly for the motor. If slip compensation is not required, it can be disabled by setting Slip Compensation Level (05.027) to 0.0%.

Parameter | 05.007 Motor 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 | 0.00 | Units | A
Type | 32 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 2
Coding | RW, VM, RA

Motor Rated Current is used as follows:

1. To define the rated operating conditions for motor thermal protection. See Thermal Protection Mode (04.016).
2. To define the range of the current limits.
3. In the motor control algorithm for Open-loop and Closed Loop asynchronous modes.

Parameter | 05.008 Motor Rated Speed
--- | ---
Short description | Set to the rated speed of the motor
Mode | Open‑Loop
Minimum | 0.0 | Maximum | 80000.0
Default | See exceptions below | Units | rpm
Type | 32 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 1
Coding | RW

Region | Default Value
50Hz | 1500.0
60Hz | 1800.0

See Motor Rated Frequency (05.006).

Parameter | 05.009 Motor 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 | 16ms
Display Format | Standard | Decimal Places | 0
Coding | RW, VM, RA

Voltage | Region | Default Value
110V | All | 230
200V | All | 230
400V | 50Hz | 400
400V | 60Hz | 460
575V | All | 575
690V | All | 690

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

Parameter | 05.010 Motor 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 | 0.00 | Maximum | 1.00
Default | 0.85 | Units |
Type | 16 Bit User Save | Update Rate | Background read/write
Display Format | Standard | Decimal Places | 2
Coding | RW, RA

Motor 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 Motor 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 Motor 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 Motor 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 | 16
Default | 0 | Units | PolePairs
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, BU

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

Pole pairs = 60 x Motor Rated Frequency (05.006) / Motor 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, Closed 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 (see Menu 06), or the Final drive run (see Menu 06) is inactive and Hold Zero Frequency (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. It should be noted that the motor may jump by up to half an electrical revolution in either direction at the start of auto-tuning test 1 in Synchronous mode whatever the value of Reverse Select (01.012), but after the initial jump the remainder of the test will be carried out in the correct direction.
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 = 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 Frequency (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). However, the transition from the Disable state to the Stop state cannot be made in closed loop mode if Auto-tune (05.012) is non-zero. This is intended to prevent the drive entering the Stop state when an auto-tune test is required, but the enable is applied before the run as the control of the motor may rely on position estimation.

The following describes the effects of the auto-tune test on the drive :

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. Only when the whole test is completed, are 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 on the drive.

Open-loop mode
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
Motor Rated Frequency (05.006) | Basic control |
Motor Rated Current (05.007) | Basic control |
Motor Rated Speed (05.008) | Slip compensation Catch a spinning motor |
Motor Rated Voltage (05.009) | Basic control |
Motor 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 Catch a spinning motor | 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

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).

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 Motor 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 Motor Rated Power Factor (05.010). 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 occure in test
Autotune Stopped | The final drive enable or the final drive run were removed before the test was completed. | All
Resistance | The measured value of Stator Resistance (05.017) exceeded the range of the parameter. | 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 | 8 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 Flux Optimisation Select, Dynamic V To F Select (05.013) = 0 then Motor Rated Frequency (05.006) is used directly to define the output voltage characteristic. If Flux Optimisation Select, Dynamic V To F Select (05.013) = 1 then a modified value of motor rated frequency is used:

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

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

Parameter | 05.014 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 | Description
0 | Ur.S | Stator resistance and voltage offset measured at each start
1 | Ur | No measurements
2 | Fd | Fixed boost mode.
3 | Ur.Auto | Stator resistance and voltage offset measured at first drive enable
4 | Ur.I | Stator resistance and voltage offset measured at each power-up
5 | SrE | Square law characteristic
6 | Fd.tap | Fixed boost with zero slip at zero reference

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

The 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. Link 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 Motor Rated Voltage (05.009) or the maximum possible output voltage whichever is the lowest (also refer to Over Modulation Enable (05.020)).

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 Motor Rated Voltage (05.009). as the |Output Frequency (05.001)| increases from 0Hz to Motor Rated Frequency (05.006). When the |Output Frequency (05.001)| is above Motor Rated Frequency (05.006) the output voltage is limited to Motor Rated Voltage (05.009). Vector based stator resistance compensation is applied below Motor Rated Frequency (05.006) / 4 and then this is tapered off from Motor Rated Frequency (05.006) / 4 to Motor 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 above where the voltage at 0Hz is defined by Low Frequency Voltage Boost (05.015). The voltage characteristic moves linearly with output frequency passing through three points determined by [Boost End Voltage (05.074) and Boost End Frequency (05.075)], [Second Point Voltage (05.076) and Second Point Frequency (05.077)] and [Motor Rated Voltage (05.009) and Motor Rated Frequency (05.006)].

By default Boost End Frequency (05.075) is set to half the Motor Rated Frequency (05.006) and Second Point Frequency (05.077) is set to three quarters.By default Boost End Voltage (05.074) is set at half the Motor Rated Voltage (05.009) and Second Point Voltage (05.076) is set to three quarters.This is to produce the SK curve by default.

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 Motor Rated Frequency (05.006) the Output Voltage (05.002) is given by:

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

6: Fixed boost with tapered slip limit
A fixed boost frequency to voltage characteristic is used with:

> · the (Post Ramp Reference (02.001) +Slip) direction clamp removed, and

> · the slip limit tapering to zero at zero Post Ramp Reference (02.001) starting from a frequency determined by Low Frequency Estimator Threshold, Low Frequency Slip Boost (05.084) (as a 0.1% of the rated frequency.)

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 | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 1
Coding | RW, BU

* 3.0% up to Size D, 2.0% for Size 7 and 8, and 1.0% for larger sizes

See Control Mode (05.014).

During auto-tune test 2 the drive uses the Open-loop mode control strategy with fixed voltage boost. Low Frequency Voltage Boost (05.015) is used to define the level of low voltage boost used during the test. See Control Mode (05.014) in Open-loop mode for more details.

Parameter | 05.017 Stator Resistance
--- | ---
Short description | Defines the resistance of the motor stator
Mode | Open‑Loop
Minimum | 0.0000 | Maximum | 99.9999
Default | 0.0000 | Units | Ω
Type | 32 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 4
Coding | RW, RA

Asynchronous machines:
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_MAX_SWITCHING_FREQUENCY
Default | 3 | Units | kHz
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, TE, VM, RA

Value | Text | Description
0 | 0.667 | 667Hz switching frequency
1 | 1 | 1kHz switching frequency
2 | 2 | 2kHz switching frequency
3 | 3 | 3kHz switching frequency
4 | 4 | 4kHz switching frequency
5 | 6 | 6kHz switching frequency
6 | 8 | 8kHz switching frequency
7 | 12 | 12kHz switching frequency
8 | 16 | 16kHz switching frequency

Maximum Switching Frequency (05.018) should be set to the required PWM switching frequency. The drive inverter will operate at this frequency unless Auto-switching Frequency Change Disable (05.035) = 0 and the inverter temperature exceeds the threshold for automatic switching frequency reduction (see Inverter Temperature (07.034)). 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 of 1ms.

Note: 0.667kHz and 1KHz switching frequencies are not supported in RFC-A mode.

As default Auto-switching Frequency Change Disable (05.035) = 0 and the system described above is always active. If Auto-switching Frequency Change Disable (05.035) = 1 then the automatic switching frequency changing system is disabled. If Auto-switching Frequency Change Disable (05.035) = 2 the system is active, but does not take into account the device temperature at low output frequencies.

We recommend that a minimum ratio of 12:1 for the switching frequency compared to the output frequency is used.

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 Motor 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. 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 Over Modulation Enable
--- | ---
Short description | Set to 1 to enable over 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

The maximum modulation level of the drive is normally limited to unity giving an output voltage equivalent to the drive input voltage minus voltage drops within the drive. If the motor rated voltage is set at the same level as the supply voltage some pulse deletion will occur as the drive output voltage approaches the motor rated voltage level. If Over Modulation Enable (05.020) is set to 1 the modulator will allow over modulation, so that as the output frequency increases beyond the motor rated frequency the voltage continues to increase above the motor rated voltage. The modulation depth will increase beyond unity producing trapezoidal waveforms. This can be used for example to get slightly better performance above motor rated frequency. The disadvantage is that the machine current will be distorted as the modulation depth increases above unity, and will contain a significant amount of low order odd harmonics of the fundamental output frequency.

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 Slip Compensation Level
--- | ---
Short description | Defines the gain of slip compensation
Mode | Open‑Loop
Minimum | -150.0 | Maximum | 150.0
Default | 100.0 | Units | %
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 1
Coding | RW

See Motor Rated Frequency (05.006).

Used in open loop mode to set the level of slip compensation or droop control.

A value of 100.0% gives standard slip compensation.

A value of 0.0% disable slip compensation.

Parameter | 05.028 Flux Control Compensation Disable
--- | ---
Short description | Set to 1 to disable Flux Control 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

If Flux Control Compensation Disable (05.028) = 0 the conversion from the Final Torque Reference (04.003) to Final Current Reference (04.004) uses the estimated level of motor flux. This is the preferred method of control as it ensures that the gain of the system remains constant in speed control mode and it gives the correct relationship between torque and current in torque control modes. However, it is possible to get instability in speed control mode when flux weakening is active at high speed if the Motor Rated Speed (05.008) is set to an incorrect value. If Flux Control Compensation Disable (05.028) = 1 the compensation for flux level is disabled which can sometimes prevent instability under these conditions.

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 | 05.032 Torque Per Amp
--- | ---
Short description | Displays the calculated value of kt for the attached motor
Mode | Open‑Loop
Minimum | 0.00 | Maximum | 500.00
Default |  | Units | Nm/A
Type | 16 Bit Volatile | Update Rate | Background write
Display Format | Standard | Decimal Places | 2
Coding | RO, ND, NC, PT, BU

Torque Per Amp (05.032) is automatically calculated from the motor parameters assuming a motor efficiency of 90%.

Torque Per Amp (05.032) = Estimated rated shaft power / [((Motor Rated Speed x 2π) / 60) x ITRated]

where

ITrated is the rated torque producing current and

Estimated rated shaft power = √3 x Motor Rated Voltage (05.009) x Motor Rated Current (05.007) x Motor Rated Power Factor (05.010) x 0.9

Torque Per Amp (05.032) is used in the automatic calculation of the speed controller gains.

Parameter | 05.033 Slip Compensation Limit
--- | ---
Short description | Defines the limit for slip compensation
Mode | Open‑Loop
Minimum | 0.00 | Maximum | 10.00
Default | 10.00 | Units | Hz
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 2
Coding | RW

See Slip Compensation Level (05.027).

Symmetrical maximum of the slip compensation frequency.

Parameter | 05.035 Auto-switching Frequency Change Disable
--- | ---
Short description | Set to 1 to prevent the drive from changing between switching frequencies
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

See Maximum Switching Frequency (05.018).

Parameter | 05.036 Slip Compensation Filter
--- | ---
Short description | Defines the time constant of the filter used for slip compensation
Mode | Open‑Loop
Minimum | 0 | Maximum | 3
Default | 1 | Units | ms
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, TE

Value | Text
0 | 64
1 | 128
2 | 256
3 | 512

See Slip Compensation Level (05.027).

Time constant for the slip compensation filter.

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

Value | Text | Description
0 | 0.667 | 667Hz switching frequency
1 | 1 | 1kHz switching frequency
2 | 2 | 2kHz switching frequency
3 | 3 | 3kHz switching frequency
4 | 4 | 4kHz switching frequency
5 | 6 | 6kHz switching frequency
6 | 8 | 8kHz switching frequency
7 | 12 | 12kHz switching frequency
8 | 16 | 16kHz switching frequency

See Maximum Switching Frequency (05.018).

Parameter | 05.038 Minimum Switching Frequency
--- | ---
Short description | Defines the minimum switching frequency that can be used by the drive
Mode | Open‑Loop
Minimum | 0 | Maximum | VM_MAX_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, RA

Value | Text | Description
0 | 0.667 | 667Hz switching frequency
1 | 1 | 1kHz switching frequency
2 | 2 | 2kHz switching frequency
3 | 3 | 3kHz switching frequency
4 | 4 | 4kHz switching frequency
5 | 6 | 6kHz switching frequency
6 | 8 | 8kHz switching frequency
7 | 12 | 12kHz switching frequency
8 | 16 | 16kHz switching frequency

Minimum Switching Frequency (05.038) defines the minimum frequency limit used if the inverter thermal model is actively reducing the switching frequency due to temperature.
Note that parameter Maximum Switching Frequency (05.018) takes priority over parameter Minimum Switching Frequency (05.038) so is not limited by parameter Minimum Switching Frequency (05.038). The actual minimum switching frequency limit used is the lower of Maximum Switching Frequency (05.018) and Minimum Switching Frequency (05.038).

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 write
Display Format | Standard | Decimal Places | 1
Coding | RW

Spin Start Boost (05.040) is used by the algorithm that detects the frequency of a spinning motor when the drive is enabled and Catch A Spinning Motor (06.009) ≥ 1. For smaller motors the default value of 1.0 is suitable, but for 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 frequency 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 | 05.059 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 dead-time compensation is disabled. 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).

Parameter | 05.074 Boost End Voltage
--- | ---
Short description | Defines the boost end voltage
Mode | Open‑Loop
Minimum | 0.0 | Maximum | 100.0
Default | 50.0 | Units | %
Type | 16 Bit User Save | Update Rate | 16ms
Display Format | Standard | Decimal Places | 1
Coding | RW

See Control Mode (05.014).

Multiple point V to F characteristic.

A fixed frequency to voltage characteristic is used as shown above where the voltage at 0Hz is defined by Low Frequency Voltage Boost (05.015). The voltage characteristic moves linearly with output frequency passing through three points determined by [Boost End Voltage (05.074) and Boost End Frequency (05.075)], [Second Point Voltage (05.076) and Second Point Frequency (05.077)] and [Motor Rated Voltage (05.009) and Motor Rated Frequency (05.006)].

By default Boost End Frequency (05.075) is set to 50.0% of the Motor Rated Frequency (05.006), Second Point Frequency (05.077) is set to 55.0% and Third point frequency (05.079) is set to 75.0%.

By default Boost End Voltage (05.074) is set to 50.0% of the Motor Rated Voltage (05.009), Second Point Voltage (05.076) is set to 55.0% and Third point voltage (05.078) is set to 75.0%.

This is to produce the SK curve by default and the percentage method results in the curve naturally.

Parameter | 05.075 Boost End Frequency
--- | ---
Short description | Defines the boost end frequency
Mode | Open‑Loop
Minimum | 0.0 | Maximum | 100.0
Default | 50.0 | Units | %
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 1
Coding | RW

See Control Mode (05.014).

Parameter | 05.076 Second Point Voltage
--- | ---
Short description | Defines the second point voltage
Mode | Open‑Loop
Minimum | 0.0 | Maximum | 100.0
Default | 55.0 | Units | %
Type | 16 Bit User Save | Update Rate | 16ms
Display Format | Standard | Decimal Places | 1
Coding | RW

See Control Mode (05.014).

Parameter | 05.077 Second Point Frequency
--- | ---
Short description | Defines the second point frequency
Mode | Open‑Loop
Minimum | 0.0 | Maximum | 100.0
Default | 55.0 | Units | %
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 1
Coding | RW

See Control Mode (05.014).

Parameter | 05.078 Third point voltage
--- | ---
Short description | Defines the third point voltage
Mode | Open‑Loop
Minimum | 0.0 | Maximum | 100.0
Default | 75.0 | Units | %
Type | 16 Bit User Save | Update Rate | 16ms
Display Format | Standard | Decimal Places | 1
Coding | RW

See Control Mode (05.014).

Parameter | 05.079 Third point frequency
--- | ---
Short description | Defines the third point frequency
Mode | Open‑Loop
Minimum | 0.0 | Maximum | 100.0
Default | 75.0 | Units | %
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 1
Coding | RW

See Control Mode (05.014).

Parameter | 05.080 Low acoustic noise enable
--- | ---
Short description | Set to 1 to change the modulation to reduce the switching frequency noise
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

Open loop modes only. User set maximum switching frequencies 2kHz to 6kHz only.

When this parameter is one, the modulation scheme is modified to reduce the fundamental switching frequency acoustic noise.

When this mode is enabled, the effect of the switching frequency fundamental in the output voltage is reduced by moving the switching points of the output phases in each PWM switching period by the same randomly weighted offset. This reduces the level of noise from the switching frequency but will introduce noise at lower and higher frequencies at a lower level. The maximum offset reduces as the output voltage increases if the dc bus voltage level remains constant.

Parameter | 05.081 Change to maximum drive switching frequency at low output current
--- | ---
Short description | Change to maximum drive switching frequency at low output current
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

Open-loop and RFC modes. User set maximum switching frequencies 2kHz to 6kHz only.

Swaps to 16kHz if the output current magnitude is less than 30% (Frame sizes 1-4) and 20% (Frame sizes 5 and above) drive OI.AC limit for longer than 100ms.

Swaps back immediately if the output current magnitude is greater than 15% drive OI.AC limit.

The original switching frequency may still be under the control of the inverter thermal model. This feature is disabled if the thermal model or user have changed the switching frequency within the last 10 seconds.

Parameter | 05.083 Voltage Shelving Disable
--- | ---
Short description | Set to 1 to only measure the d.c. link voltage when the inverter is active
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

When this parameter is one, the DC link voltage will only be measured when the inverter is inactive.

Open loop mode only.

A 128ms filtered version of the Vdc measurement is sampled only when the inverter stack is inactive.

The sampled filtered version of the vdc measurement is limited to between +/-10% of the actual measured vdc while the drive inverter is inactive. This sampled level for the Vdc is used instead of the actual measurement when the demand voltage is converted to a modulation index to be used by the inverter.

This removes the dc bus voltage forward compensation. It will also removed the effects of “oscillation” experienced when the drive is supplied by an extremely soft supply of through a high inductance filter.

Parameter | 05.084 Low Frequency Slip Boost
--- | ---
Short description | Controls the boost level of the slip frequency when the output frequency is below one third of the rated frequency.
Mode | Open‑Loop
Minimum | 0.0 | Maximum | 100.0
Default | 0.0 | Units | %
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 1
Coding | RW

Open-Loop mode:
In resistor compensation open loop modes (Control Mode (05.014) set to 0, 1, 3, and 4):

If the rated slip frequency is non-zero, the rated slip frequency (see Motor Rated Frequency (05.006) can be modified when the output frequency is below one third of the motor rate frequency to provide a torque boost.
The modification consists of an addition to the calculated slip frequency controlled by the user parameter Low Frequency Estimator Threshold, Low Frequency Slip Boost (05.084).The addition is equal to Low Frequency Estimator Threshold, Low Frequency Slip Boost (05.084) at zero Hz falling linearly to 0.0% at one third of the motor rated frequency.

If the rated slip frequency is zero, the amount of stator resistor compensation can be modified when the output frequency is below one tenth of the motor rate frequency to provide a torque boost. The modification consists of an addition to the calculated stator resistor compensation controlled by the user parameter Low Frequency Estimator Threshold, Low Frequency Slip Boost (05.084).The addition is equal to Low Frequency Estimator Threshold, Low Frequency Slip Boost (05.084). at zero Hz falling linearly to 0.0% at one tenth of the motor rated frequency.

In fixed boost tapered open loop control (Control Mode (05.014) set to 6):

Low Frequency Estimator Threshold, Low Frequency Slip Boost (05.084) sets the frequency at which the taper of the slip begins. This is expressed in Low Frequency Estimator Threshold, Low Frequency Slip Boost (05.084) as a percentage of the motor rated frequency, Motor Rated Frequency (05.006) . See #5.014 = 6.

RFC-A mode:

If Low Frequency Estimator Threshold, Low Frequency Slip Boost (05.084) = 0.0% (default) the RFC-A speed estimator is used when the ramp output is greater than the rated motor frequency divided by 64.
If Low Frequency Estimator Threshold, Low Frequency Slip Boost (05.084) > 0.0% , the RFC-A speed estimator is used when the ramp output is greater than the rated motor frequency divided by 128.

Parameter | 05.088 Ur Mode Pre-Flux delay
--- | ---
Short description | The delay begins as the motor starts to run and during the pre-flux delay the torque axis voltage compensation is held at zero.
Mode | Open‑Loop
Minimum | 0.0 | Maximum | 0.7
Default | 0.5 | Units | s
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 1
Coding | RW

Setting Ur Mode Pre-Flux delay to a value from 0.0s to 0.7s will configure the Ur mode pre-flux delay. The delay begins as the motor starts to run and during the pre-flux delay the torque axis voltage compensation is held at zero. The delay is provides time for the flux to build up to reduce the risk of unstable behaviour during motor starting. The user configurable delay function has been added for use with the brake macro, where the mechanical brake is holding the shaft while the motor is started. The delay can be set depending on the motor and the system.