# Menu 3 − Regen Control

Mode: Regeneration

Parameter | 03.001 Reactive Power
--- | ---
Short description |
Mode | Regeneration
Minimum | −VM_POWER | Maximum | VM_POWER
Default |  | Units | kVAr
Type | 32 Bit Volatile | Update Rate | Background write
Display Format | Standard | Decimal Places | 3
Coding | RO, FI, VM, ND, NC, PT

Output Power (05.003) and Reactive Power (03.001) are the power and VAR's respectively that flow from the supply to the drive. When Reactive Power (03.001) is positive the phase current flowing from the supply to the drive contains a component that lags the respective phase voltage, and so the regen system appears like and inductance connected to the supply and imports VARs. When Reactive Power (03.001) is negative the phase current flowing from the supply contains a component which leads the respective phase voltage, and so the regen system appears like a capacitance connected to the supply and exports VARs.

Parameter | 03.004 Regen Syncronisation Mode
--- | ---
Short description | Regen Syncronisation Mode
Mode | Regeneration
Minimum | 0 | Maximum | 3
Default | 0 | Units |
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, TE

Value | Text
0 | Re-syncronise
1 | Delayed Trip
2 | Trip
3 | Auto-synchronise

When the system is enabled it attempts to synchronise to the supply. If the supply has significant distortion then the synchronisation process may fail and cause an over-current condition to be detected. The system will automatically reset the detected over-current condition and continue to attempt to synchronise. Once the system is synchronised, then if synchronisation is subsequently lost, or an over-current condition caused by a supply transient occurs, or supply loss is detected (i.e. Supply Loss (10.015) = 1), then the action taken is defined by Regen Syncronisation Mode (03.004) as given below. (It should be noted that the over-current condition will only be reset automatically ten times in any 10s period before an OI ac trip is produced.)

0: Re-synchronise
If supply loss is detected the system will attempt to re-synchronise when the supply loss condition is no longer active. If an over-current trip occurs the system will attempt to resynchronise. If Supply Voltage Detection Mode (03.029) = 0 or 2 re-synchronisation will only begin if D.c. Bus Voltage (05.005) has stopped rising or falling. For Supply Voltage Detection Mode (03.029) = 0, this is so the supply voltage can be estimated from the level of the d.c. link voltage. If Supply Voltage Detection Mode (03.029) = 1 rapid resynchronisation is possible because the system does not wait for the d.c. link voltage to stop falling before attempting to re-synchronise.

1: Delayed Trip
The system operates in the same way as "Re-synchronise" mode except that a Line Sync trip is initiated if synchronisation takes more than 30s.

2: Immediate Trip
The system operates in the same way as "Re-synchronise" mode except that a Line Sync trip is initiated if synchronisation takes more than 30s, and Line Sync trip is produced immediately if supply loss is detected while the system is synchronised.

3: Auto-synchronise
If an over-current condition is detected then this is reset. The system will simulate the supply angle based on the supply conditions before the over-current condition and restart the system within 10ms.
If supply loss is detected the system will simulate the supply angle based on the supply conditions before supply loss was detected. This allows the inverter to remain active during the supply loss period and it is possible for reactive current to flow into the supply in the normal way, but the active current is held at zero. As the active current is held at zero the d.c. link must be held at the required level externally, therefore this mode is only suitable for an application where an external system connected to the d.c. terminals and holds the d.c. voltage at a suitable level. Regen Supply Loss a.c. Level (03.023) should be set to a level that is higher than the likely voltage seen at the inverter terminals due to any current being fed into the supply (e.g. 10% of nominal supply voltage) or else the system will attempt to synchronise to its own output voltage. If Supply Loss (10.015) remains active for more than 2.0s then an Island.2 trip is initiated. The diagram below shows the timing and minimum voltage envelope for auto-synchronisation. If the required timing and voltage for transient fault ride-through lies within this envelope then the auto-synchronisation can be used to meet the requirements.

At point 'A' the fault occurs and the voltage falls below Regen Supply Loss a.c. Level (03.023). During the period from point 'A' to point 'B' the regen system does not allow either active or reactive power to flow to/from the supply. The maximum time between point 'A' and point 'B' is 8ms, but this may be shorter depending on the size of the current transient caused by the fault. If the current transient exceeds the over-current threshold then the system will take 8ms to recover, otherwise there is no delay and the regen system will remain active thoughout the fault. From point 'B' to point 'C', where the supply voltage remains below Regen Supply Loss a.c. Level (03.023) x 1.05, auto-sysnchornisation is active and it is possible to request reactive power flow either using Reactive Power Input kVAR (03.020) or Reactive Current Reference (04.008). During this period active power flow is not possible as it is disabled by the regen system. If the supply voltage remains below Regen Supply Loss a.c. Level (03.023) x 1.05 for more than 2s the regen system will trip. Once the supply voltage has risen above Regen Supply Loss a.c. Level (03.023) x 1.05 auto-synchronisation is disabled and active power flow is re-enabled. The request for reactive and active power must be made by the user during supply tranisent ride-through. It is also likely that the supply voltage recovery characteristic envelope must lie within the envelope given and that additional supply voltage monitoring will be required to take action if the required recover does not occur.

Parameter | 03.005 Voltage Set Point
--- | ---
Short description |
Mode | Regeneration
Minimum | −VM_DC_VOLTAGE_SET | Maximum | VM_DC_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 | Default Value
200V | 350
400V | 700
575V | 835
690V | 1100

The regen drive attempts to hold the d.c. bus voltage at the level specified by Voltage Set Point (03.005). The Voltage Set Point (03.005) must always be higher than the peak of the line to line supply voltage if the unit is to operate correctly. The default values can be used with most supplies giving a reasonable level of control headroom. However, with higher voltage supplies the set-point must be raised.

Parameter | 03.006 Voltage Controller Proportional Gain Kp
--- | ---
Short description |
Mode | Regeneration
Minimum | 0 | Maximum | 65535
Default | 4000 | Units |
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, BU

The d.c. bus voltage is controlled by a PI controller, which provides the reference for the real component of current from the inverter terminals to the supply. The power input parameters (Power Input 1 (03.010), Power Input 2 (03.013), Power Input 3 (03.014) or Power Input kW (03.018)) are provided to give a power feed forward term, at the output of the PI controller, from the motor drives connected to the d.c. bus. If possible the power feed forwards should be used so that the PI controller is simply providing a trim to the d.c. bus voltage. In most cases the default voltage controller gains can be used, however the effect of the gains and the response of the voltage controller is discussed below.

For the purpose of analysing the voltage controller response it is assumed that a power feed-forward term is not provided. If the power flow from the d.c. bus is increased (i.e. motor is accelerated by a motor drive connected to the d.c. bus) the d.c. bus voltage will fall, but the minimum level will be limited to just below the peak rectified level of the supply provided the maximum rating of the unit is not exceeded. If the power flow to the d.c. bus is increased (i.e. motor is decelerated by a motor drive connected to the d.c. bus) the d.c. bus voltage will rise. If the peak of the d.c. bus voltage reaches the over voltage level the regen drive will trip. A rapid transient where power into the d.c. bus is increased is shown below.

The example shown is for a very rapid load change where the torque reference of the motor drive has been changed instantly from one value to another. The peak of the resulting transient is

ΔVdc = 191680 x Pd / (vll x Kp x Kc) Volts

and the time constant of the recovery is Kp / 30520 seconds.

where:
Pd is the transient change of power flow
vll is the line to line supply voltage
Kp = Voltage Controller Proportional Gain Kp (03.006)
Kc = Full Scale Current Kc (11.061)

For example, if Pd=7.5kW, vll=400V, Kp=4000, Kc=38.222A then ΔVdc=23.5V and the time constant is 131ms.

In the example given there is a very rapid change of power flow. The transient d.c. bus voltage change can be substantially reduced by introducing a time constant into the power transient. For example a filter could be included between the speed controller and current controller in the motor drive with Current Reference Filter 1 Time Constant (04.012). A time constant of 20ms reduces the voltage transient by 25% and a time constant of 40ms reduces the voltage transient by 50%. In most cases it is not desirable to reduce the performance of the motor drive, and so as already mentioned the best solution is to use a power feed forward term from the motor drive.

So far the discussion has been related to the d.c. bus voltage controller gain, however, the controller provides the real current reference to the regen drive current controllers, and so the current controller gains affect the response of the voltage controller. If the default voltage controller gain is used and it is possible to obtain a stable response from the current controllers with their default gains then the voltage controller response will be stable. However, in some cases it will be necessary to reduce the current controller gains to make these controllers stable, in which case it is likely that the voltage controller gain will need to be reduced to make this controller stable.

It is possible to disable the d.c. bus voltage controller by setting Voltage Controller Proportional Gain Kp (03.006) to zero. This sets both the proportional and integral gains to zero. Once the controller is disabled the flow of power through the regen drive can be defined using the power input parameters (Power Input 1 (03.010), Power Input 2 (03.013), Power Input 3 (03.014), Power Input kW (03.018)) or Active Current (04.002). This method of control can only be used if the d.c. bus voltage is defined at a voltage above the level of the rectified a.c. supply to the regen drive by another system connected to the d.c. terminals.

Parameter | 03.007 Disable Charge System / Close Contactor
--- | ---
Short description |
Mode | Regeneration
Minimum | 0 | Maximum | 1
Default |  | Units |
Type | 1 Bit Volatile | Update Rate | 4ms write
Display Format | Standard | Decimal Places | 0
Coding | RO, ND, NC, PT

In Regen mode some form of charging system must be used to limit the current taken from the supply to charge the d.c. bus capacitors when the supply is first connected to the inverter terminals (i.e. UVW). An external soft start resistor or the thyristor charging system in the drive may be used. The regen mode sequencer provides an output which should be used to disable or enable the charge system ( Disable Charge System / Close Contactor (03.007)). This should be routed to a digital output, so that when Disable Charge System / Close Contactor (03.007) = 0 the charge system is connected between the supply and the regen system, and when Disable Charge System / Close Contactor (03.007) = 1 the charge system is bypassed and the inverter terminals are connected to the supply. This is demonstrated by the simplified charge system diagram below. It should be noted that this is used to show the connections required between the charge system and the drive, and does not show a complete power circuit.

It is possible that the charge circuit could be damaged if the motor drive is active while the charge circuit has not been bypassed or disconnected. To prevent damage from occurring, the state of the charge system should be passed to Charge System Disabled / Contactor Closed (03.008) via a digital input so that the Regen system can monitor the actual charge system state. It is also necessary to pass an indication of the state of the charge system and the Regen system to the motor drive. The "synchronised" indication is used to enable the motor drive, so that it will only be enabled when the charge system is disabled and the regen system is enabled and fully synchronised.

Parameter | 03.008 Charge System Disabled / Contactor Closed
--- | ---
Short description |
Mode | Regeneration
Minimum | 0 | Maximum | 1
Default |  | Units |
Type | 1 Bit Volatile | Update Rate | 4ms read
Display Format | Standard | Decimal Places | 0
Coding | RO, ND, NC

See Disable Charge System / Close Contactor (03.007).

Parameter | 03.009 Synchronised
--- | ---
Short description | Regen system is synchronised to the supply
Mode | Regeneration
Minimum | 0 | Maximum | 1
Default |  | Units |
Type | 1 Bit Volatile | Update Rate | 4ms write
Display Format | Standard | Decimal Places | 0
Coding | RO, ND, NC, PT

See Disable Charge System / Close Contactor (03.007).

Parameter | 03.010 Power Input 1
--- | ---
Short description |
Mode | Regeneration
Minimum | -100.0 | Maximum | 100.0
Default | 0.0 | Units | %
Type | 16 Bit Volatile | Update Rate | 250µs read
Display Format | Standard | Decimal Places | 1
Coding | RW, NC

Power feed-forward compensation can be used to reduce the transient d.c. bus voltage produced when a fast load transient occurs on a drive connected to the d.c. terminals of the regen drive. If Power Output (07.033) from a motor drive is routed to an analogue output with unity scaling it will produce full scale output when the power is equal to 3 x (VM_DC_VOLTAGE[MAX] / 2√2) x Full Scale Current Kc (11.061). If this signal is connected to an analogue input on the regen drive, the input is routed to Power Input 1 (03.010) and Power Input 1 Scaling (03.015) is set to the ratio of the current scaling values for the motor drive and regen drives (i.e. Motor drive Full Scale Current Kc (11.061) / Regen drive Full Scale Current Kc (11.061)) then the correct power feed-forward term will be provided. The default value for Power Input 1 Scaling (03.015) is 1.000, and so unless the regen and motor drives are the same size this parameter will need to be adjusted.

Up to 3 motor drives connected to the regen drive d.c. terminals can use this system to provide power feed-forward as each of the power inputs are summed to give the final power feed-forward term. (It should be noted that a maximum of two analogue inputs are provided on the drive with 250us update rate. If the third input is used the update rate is 4ms, and so this should only be used for a motor drive with limited dynamic performance.) If more motor drives are connected to the d.c. terminals of the regen drive, or a digital power feed-forward system is required, then Power Input kW (03.018) should be used. The power in kW can be transferred from each motor drive using fast synchronous communications to an application module in the regen drive. The total power in kW should be calculated by the applications module and then written to the Power Input kW (03.018). For the power feed-forward to be effective data should be transferred every 250μs with the minimum delay (i.e. 500μs) and the total power written to Power Input kW (03.018) every 250μs.

It should be noted that the polarity of all the power feed-forward parameters is that positive values cause power to flow from the supply and negative values cause power to flow into the supply.

Parameter | 03.011 Current Trim Mode
--- | ---
Short description |
Mode | Regeneration
Minimum | 0 | Maximum | 1
Default | 0 | Units |
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

A current feedback trimming routine runs before the regen drive is enabled to minimise offsets in the current feedback. If Current Trim Mode (03.011) = 0 the current offset trim is only carried out once when the drive comes out of the under voltage state and is not repeated unless the supply is removed and reapplied. The current offset trim is only carried out when the charge system is enabled (contactor open) as this minimises current flowing into the inverter terminals due to noise on the supply that may disturb the current offset trimming.

Current Trim Mode (03.011) should be set to one if the current offset trim is required each time when the regen drive is enabled. To ensure that the current offset trim is not disturbed by noise on the supply, the charge system is enabled before the current offset trim and then disabled again before the regen drive goes into its active state. This causes the charge system contactors to switch each time the regen drive is enabled.

Parameter | 03.012 Power Input Mode
--- | ---
Short description |
Mode | Regeneration
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 Power Input Mode (03.012) = 0 the power feed-forward is provided by the parameters that are intended for use with analogue inputs. If Power Input Mode (03.012) = 1 the power feed-forward is provided by Power Input kW (03.018).

Parameter | 03.013 Power Input 2
--- | ---
Short description |
Mode | Regeneration
Minimum | -100.0 | Maximum | 100.0
Default | 0.0 | Units | %
Type | 16 Bit Volatile | Update Rate | 250µs read
Display Format | Standard | Decimal Places | 1
Coding | RW, NC

See Power Input 1 (03.010).

Parameter | 03.014 Power Input 3
--- | ---
Short description |
Mode | Regeneration
Minimum | -100.0 | Maximum | 100.0
Default | 0.0 | Units | %
Type | 16 Bit Volatile | Update Rate | 250µs read
Display Format | Standard | Decimal Places | 1
Coding | RW, NC

See Power Input 1 (03.010).

Parameter | 03.015 Power Input 1 Scaling
--- | ---
Short description |
Mode | Regeneration
Minimum | 0.000 | Maximum | 4.000
Default | 1.000 | Units |
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 3
Coding | RW

See Power Input 1 (03.010).

Parameter | 03.016 Power Input 2 Scaling
--- | ---
Short description |
Mode | Regeneration
Minimum | 0.000 | Maximum | 4.000
Default | 1.000 | Units |
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 3
Coding | RW

See Power Input 1 (03.010).

Parameter | 03.017 Power Input 3 Scaling
--- | ---
Short description |
Mode | Regeneration
Minimum | 0.000 | Maximum | 4.000
Default | 1.000 | Units |
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 3
Coding | RW

See Power Input 1 (03.010).

Parameter | 03.018 Power Input kW
--- | ---
Short description |
Mode | Regeneration
Minimum | −VM_POWER | Maximum | VM_POWER
Default | 0.000 | Units | kW
Type | 32 Bit Volatile | Update Rate | 250µs read
Display Format | Standard | Decimal Places | 3
Coding | RW, VM, RA, NC

See Power Input 1 (03.010).

Parameter | 03.019 Reactive Power Input Mode
--- | ---
Short description |
Mode | Regeneration
Minimum | 0 | Maximum | 1
Default | 0 | Units |
Type | 1 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

It is possible to control the reactive component of current from the a.c. terminals of the regen drive. When this component is positive the reactive current flowing from the supply to the regen drive lags the voltage. When this component is negative the reactive current flowing from the supply to the regen drive leads the voltage. Reactive component control can be used even if the d.c. bus voltage controller is active, because the voltage controller only affects the real current component. If Reactive Power Input Mode (03.019) = 0 the reactive current can be defined with Reactive Current Reference (04.008). If Reactive Power Input Mode (03.019) = 1 the reactive kVAR can be specified with Reactive Power Input kVAR (03.020).

Parameter | 03.020 Reactive Power Input kVAR
--- | ---
Short description |
Mode | Regeneration
Minimum | −VM_POWER | Maximum | VM_POWER
Default | 0.000 | Units | kVAr
Type | 32 Bit User Save | Update Rate | 250µs read
Display Format | Standard | Decimal Places | 3
Coding | RW, VM, RA, NC

See Reactive Power Input Mode (03.019).

Parameter | 03.021 Harmonic Reduction Enable
--- | ---
Short description | Harmonic Reduction Enable
Mode | Regeneration
Minimum | 0 | Maximum | 2
Default | 1 | Units |
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, TE

Value | Text
0 | Disabled
1 | Imbalance Only
2 | All

Even with the optimum d.c. bus voltage and current controller set-up it is possible for supply voltage distortion to cause harmonic distortion in the a.c. currents between the supply and the regen drive. The regen drive includes an additional system to reduce imbalance, 5th harmonics and 7th harmonics in the a.c. currents. Harmonic Reduction Enable (03.021) defines the type of distortion reduction required. It should be noted that the regen system intput filter will absorb 5th and 7th harmonic currents if there is 5th or 7th harmonic supply voltage distortion. The regen drive cannot reduce this current, but can minimise the 5th and 7th harmonic current due to 5th and 7th harmonic voltage distortion between the supply and the inverter.

Harmonic Reduction Enable (03.021) | Distortion reduced
0 | None
1 | Due to voltage imbalance
2 | Due to voltage imbalance, 5th and 7th harmonics

If Harmonic Reduction Enable (03.021) > 0 then Phase Loss (10.081) is set if Negative Phase Sequence Volts (03.038) > Positive Phase Sequence Volts (03.037) / 2 for more than 100ms. It should be noted that Phase Loss (10.081) is only set when the regen drive is active, so if the transient caused by an asymmetrical fault causes the system to trip then Phase Loss (10.081) is not set.

Each of the additional controllers used to minimise currents due to imbalance, 5th and 7th harmonic distortion have an integral controller similar to the controller for normal supply frequency currents. The gains for the 5th and 7th harmonic current control are at a fixed low level, however, the gain for minimisation of currents due to imbalance can be adjusted by the user with Negative Phase Sequence Current Gain (03.039). The default value is low, and so the response due to a change in supply imbalance is relatively slow. For most applications the gain can be left at the default level, but where a fast response is required, i.e. contiued operation in the presence of an asymmetrical fault, the level should be increased. Negative Phase Sequence Current Gain (03.039) defines the gain used for control of currents due to imbalance as a proportion of Current Controller Ki Gain (04.014). Care should be taken when increasing this value as the system stabilty may be reduced particularly with a weak supply.

Parameter | 03.022 Voltage Ramp Time
--- | ---
Short description |
Mode | Regeneration
Minimum | 0.1 | Maximum | 100.0
Default | 1.0 | Units | V/ms
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 1
Coding | RW

When a regen drive is enabled and has synchronised to the supply, the d.c. bus voltage is at a level equal to the peak line to line voltage. The voltage controller is then enabled and attempts to raise the d.c. bus voltage to the set-point defined by Voltage Set Point (03.005). The voltage reference is ramped up to the requried level at a rate defined by Voltage Ramp Time (03.022) in V/ms. The default value of 1.0V/ms ensures limited over-shoot when the d.c. link voltage reaches the required level. If a shorter synchronisation time is requried then the ramp rate can be increased, however care must be taken to avoid over-voltage trips particularly if a high level is used for the d.c. link voltage set-point. If a faster ramp rate and high set-point are required it may be necessary the increase Voltage Controller Proportional Gain Kp (03.006) to minimise over-shoot.

Parameter | 03.023 Regen Supply Loss a.c. Level
--- | ---
Short description |
Mode | Regeneration
Minimum | −VM_AC_VOLTAGE_SET | Maximum | VM_AC_VOLTAGE_SET
Default | See exceptions below | Units | V
Type | 16 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, VM, RA

Voltage | Default Value
200V | 75
400V | 150
575V | 225
690V | 225

If the supply voltage falls below Regen Supply Loss a.c. Level (03.023) x 0.95 then supply loss is detected and Supply Loss (10.015) is set to one. The supply voltage must rise above Regen Supply Loss a.c. Level (03.023) x 1.05 to remove the supply loss condition and for Supply Loss (10.015) to be reset to zero. When the system is not synchronised Estimated Supply Voltage (03.036) is used to represent the supply voltage, but when the system is synchronised the output of the inverter (Output Voltage (05.002)) is used.

If Supply Voltage Detection Mode (03.029) = 0 (Measured) then Estimated Supply Voltage (03.036) is derived from the d.c. link voltage. When the system is not synchronised Estimated Supply Voltage (03.036) is set up with a derived value, but only after the d.c. link voltage has stopped rising or falling. This ensures a correct estimate because the supply voltage has stopped causing the d.c. link voltage to rise and the d.c. link voltage is not still falling because the system was previously active. When the system synchronises Estimated Supply Voltage (03.036) is left at the value derived before synchronisation and will only be modified again when the system is not synchronised and the d.c. link voltage is stable. It should be noted that if the supply is removed and then re-applied before the d.c. link voltage falls below the under-voltage threshold, it is possible for the transient caused by re-applying the supply to give an indication that the d.c. link voltage is stable. If this occurs the measured d.c. link supply voltage may be higher than the acutal supply voltage. As the accuracy of measured supply voltage is not critical in setting up the current controllers etc. this will not generally cause a problem. If it is a problem then Supply Voltage Detection Mode (03.029) should be set to a value other than zero, so that the estimated supply voltage can be defined by the user.

If Supply Voltage Detection Mode (03.029) = 1 (User) then Estimated Supply Voltage (03.036) is set directly from Supply Voltage (03.028). This can either be set to a fixed value or it can be controlled from voltage magnitude feedback via an analogue input. When this setting is used the system does not wait for the d.c. link voltage to stop rising or falling, and so resynchronisation is quicker when the supply is restored after a short supply loss, or the system is disabled and then re-enabled rapidly. However, the system will continuously attempt to resysnchronise after the supply is removed. It is likely that some transient voltages will occur at the inverter terminals as the d.c. link voltage decays.

If Supply Voltage Detection Mode (03.029) = 2 (User Delayed) the system operates in the same way as when Supply Voltage Detection Mode (03.029) = 1 (User) except that resynchronisation when the supply is restored after supply loss, or when the system is enabled, does not start until the d.c. link voltage has stopped rising or falling.

As well as being used to give the supply loss condition, Estimated Supply Voltage (03.036) is also used to pre-set the current controllers during synchronisation and after the system has automatically reset an over-current condition when synchronised (i.e. when Regen Syncronisation Mode (03.004) = 3). During synchronisation the full value of Estimated Supply Voltage (03.036) is used to give the minimum current transient. After automatic reset of an over-current condition then Estimated Supply Voltage (03.036) / 2 is used because this mode can be used to ride through supply short circuits and the supply voltage may change rapidly between the normal supply voltage and zero. By using half the nominal supply voltage the current transient is minimised for either condition.

Parameter | 03.024 Regen Minimum Frequency
--- | ---
Short description |
Mode | Regeneration
Minimum | 10 | Maximum | 200
Default | See exceptions below | Units | Hz
Type | 8 Bit User Save | Update Rate | 4ms read
Display Format | Standard | Decimal Places | 0
Coding | RW, BU

Region | Default Value
50Hz | 40
60Hz | 50

Frequency limits defined by Regen Minimum Frequency (03.024) and Regen Maximum Frequency (03.025) are applied to the Regen system output. A margin of 5Hz or more should be allowed outside the likely supply frequency range to enable the Regen system to operate. If the Regen system supply frequency is within approximately 5Hz of either limit for 100ms the system will not remain synchronised and will attempt to re-synchronise.While the supply frequency remains within approximately 5Hz of either limit the system will not be able to synchronise successfully. The frequency limits are important if the supply is removed when the Regen system is active, as the system could remain active, particularly if energy is fed into the d.c. link, with an uncontrolled output frequency and voltage.

Parameter | 03.025 Regen Maximum Frequency
--- | ---
Short description |
Mode | Regeneration
Minimum | 10 | Maximum | 200
Default | See exceptions below | Units | Hz
Type | 8 Bit User Save | Update Rate | 4ms read
Display Format | Standard | Decimal Places | 0
Coding | RW, BU

Region | Default Value
50Hz | 60
60Hz | 70

See Regen Minimum Frequency (03.024).

Parameter | 03.026 Regen Minimum Voltage
--- | ---
Short description |
Mode | Regeneration
Minimum | −VM_AC_VOLTAGE | Maximum | VM_AC_VOLTAGE
Default | 0 | Units | V
Type | 16 Bit User Save | Update Rate | 4ms read
Display Format | Standard | Decimal Places | 0
Coding | RW, VM, RA

Supply voltage range detection can be provided. If Regen Maximum Voltage (03.027) is set to its default of zero, then additional supply voltage checking is disabled. If Regen Minimum Voltage (03.026) is set to any other value and the supply voltage is outside the range defined by Regen Maximum Voltage (03.027) and Regen Minimum Voltage (03.026) for more than 100ms a Voltage Range trip is initiated with sub-trip 1 for a voltage below the minimum threshold or sub-trip 2 for voltage above the maximum threshold. If Regen Maximum Voltage (03.027) ≤ Regen Minimum Voltage (03.026) then the trip is initated repeatedly.

Parameter | 03.027 Regen Maximum Voltage
--- | ---
Short description |
Mode | Regeneration
Minimum | −VM_AC_VOLTAGE | Maximum | VM_AC_VOLTAGE
Default | 0 | Units | V
Type | 16 Bit User Save | Update Rate | 4ms read
Display Format | Standard | Decimal Places | 0
Coding | RW, VM, RA

See Regen Minimum Voltage (03.026).

Parameter | 03.028 Supply Voltage
--- | ---
Short description |
Mode | Regeneration
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

See Regen Supply Loss a.c. Level (03.023).

Parameter | 03.029 Supply Voltage Detection Mode
--- | ---
Short description | Supply Voltage Detection Mode
Mode | Regeneration
Minimum | 0 | Maximum | 2
Default | 2 | Units |
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW, TE, BU

Value | Text
0 | Measured
1 | User
2 | User Delayed

See Regen Supply Loss a.c. Level (03.023).

Parameter | 03.030 Island Detection Enable
--- | ---
Short description |
Mode | Regeneration
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 Island Detection Enable (03.030) is set to one then the detection system is enabled and injects a test current with a frequency defined by Island Detection Injection Frequency (03.031). The Island Detection Level (03.032) shows the detection level with respect to the threshold, and if the level reaches 100% an Island.1 trip is initiated.

The following should be noted:

1. It is possible that high levels of active current that contain components similar to the injection frequency may cause false detection of an island condition and this is more likely the higher the injection frequency.
2. The detection system will detect an island condition in a time from 3 to 4 cycles of the injection frequency, therefore a higher injection frequency gives faster detection.
3. Changing Island Detection Injection Frequency (03.031) while the system is running may cause an Island.1 trip.

The injection frequency used by the island detection system affects the maximum island detection time as given in the table below:

Injection frequency | Maximum detection time
1Hz | 4s
2Hz | 2s
4Hz | 1s

For the island detection system to comply with IEEE 1547 the detection time must be 2s or less, and so an injection frequency of 2 or 4Hz must be used. For the island detection system to comply with VDE 0126-1-1 the detection time must be 5s or less, and so any of the injection frequencies may be used.

Parameter | 03.031 Island Detection Injection Frequency
--- | ---
Short description |
Mode | Regeneration
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 | 1Hz
1 | 2Hz
2 | 4Hz

See Island Detection Enable (03.030).

Parameter | 03.032 Island Detection Level
--- | ---
Short description |
Mode | Regeneration
Minimum | 0 | Maximum | 100
Default |  | Units | %
Type | 8 Bit Volatile | Update Rate | Background write
Display Format | Standard | Decimal Places | 0
Coding | RO, ND, NC, PT

See Island Detection Enable (03.030).

Parameter | 03.033 Island Detection Synchronisation Source Select
--- | ---
Short description | Island Detection Synchronisation Source Select
Mode | Regeneration
Minimum | 0 | Maximum | 4
Default | 0 | Units |
Type | 8 Bit User Save | Update Rate | Background Read
Display Format | Standard | Decimal Places | 0
Coding | RW, TE

Value | Text
0 | Disabled
1 | Slot 1
2 | Slot 2
3 | Slot 3
4 | Slot 4

If Island Detection Synchronisation Source Select (03.033) is set to its default value of zero then the frequency of the current injected to detect an island condition is defined by the Regen system. If Island Detection Synchronisation Source Select (03.033) is set to a non-zero value to select an option module, and the option module provides a suitable clock, then the injected current is synchronised to the clock. This allows the injected current from a number of Regen systems to be synchronised to a master clock. If the option module does not provide a suitable clock then the frequency is defined by the Regen system. The source being used is given in Island Detect Synchronisation Source (03.034).

Parameter | 03.034 Island Detect Synchronisation Source
--- | ---
Short description | Island Detect Synchronisation Source
Mode | Regeneration
Minimum | 0 | Maximum | 4
Default |  | Units |
Type | 8 Bit Volatile | Update Rate | Background Write
Display Format | Standard | Decimal Places | 0
Coding | RO, TE, ND, NC, PT

Value | Text
0 | Disabled
1 | Slot 1
2 | Slot 2
3 | Slot 3
4 | Slot 4

See Island Detection Synchronisation Source Select (03.033).

Parameter | 03.035 Synchronisation Headroom
--- | ---
Short description | Synchronisation Headroom
Mode | Regeneration
Minimum | 0.0 | Maximum | 25.0
Default | 5.0 | Units | %
Type | 8 Bit User Save | Update Rate | Background Read
Display Format | Standard | Decimal Places | 1
Coding | RW, BU

Each time a synchronisation attempt is made the d.c. link voltage is increased because of current that is built up in the inductors connected between the supply and the regen system. As the current decays energy is transferred from the supply to the d.c. link capacitors, and the energy stored in the inductors is also transferred to the d.c. link capcacitors. To prevent an over-voltage trip during synchronisation or re-synchronisation the system will prevent this process from starting if the d.c. link voltage is above the level defined by Maximum d.c. link voltage x Synchronisation Headroom (03.035). For example the full scale d.c. link voltage for a 400V drive is 830V, so with the default setting of 5% the d.c. link voltage must be less than 830V x 95% = 788.5V before the synchronisation process will begin. If the recommended components are connected between the supply and the regen system the rise in the d.c. link voltage during synchronisation requires less than 5% headroom. If alternative inductors are used that are significanlty larger than the recommended values or the supply inductance is very high it may be necessary to increase the headroom.

Parameter | 03.036 Estimated Supply Voltage
--- | ---
Short description | Estimated Supply Voltage
Mode | Regeneration
Minimum | −VM_AC_VOLTAGE | Maximum | VM_AC_VOLTAGE
Default |  | Units | V
Type | 16 Bit Volatile | Update Rate | 2ms Write (During Synchronisation)
Display Format | Standard | Decimal Places | 0
Coding | RO, VM, ND, NC, PT

See Regen Supply Loss a.c. Level (03.023).

Parameter | 03.037 Positive Phase Sequence Volts
--- | ---
Short description | Positive Phase Sequence Volts
Mode | Regeneration
Minimum | −VM_AC_VOLTAGE | Maximum | VM_AC_VOLTAGE
Default |  | Units | V
Type | 16 Bit Volatile | Update Rate | 1ms Write
Display Format | Standard | Decimal Places | 0
Coding | RO, FI, VM, ND, NC, PT

The supply voltage at its fundamental frequency can be represented as a combination of positive, negative and zero sequence components. The regen system supply voltage cannot contain any zero sequence components because there is no neutral connection. The negative phase sequence component is an indication of the level of supply imbalance. Positive Phase Sequence Volts (03.037) and Negative Phase Sequence Volts (03.038) show the positive and negative phase sequence components of voltage at the inverter terminals in r.m.s. line to line Volts. Note that Negative Phase Sequence Volts (03.038) is zero unless Harmonic Reduction Enable (03.021) > 0.

Parameter | 03.038 Negative Phase Sequence Volts
--- | ---
Short description | Negative Phase Sequence Volts
Mode | Regeneration
Minimum | −VM_AC_VOLTAGE | Maximum | VM_AC_VOLTAGE
Default |  | Units | V
Type | 16 Bit Volatile | Update Rate | 1ms Write
Display Format | Standard | Decimal Places | 0
Coding | RO, FI, VM, ND, NC, PT

See Positive Phase Sequence Volts (03.037).

Parameter | 03.039 Negative Phase Sequence Current Gain
--- | ---
Short description | Negative Phase Sequence Current Gain
Mode | Regeneration
Minimum | 0.00 | Maximum | 1.00
Default | 0.05 | Units |
Type | 16 Bit User Save | Update Rate | Background Read
Display Format | Standard | Decimal Places | 2
Coding | RW

See Harmonic Reduction Enable (03.021).