Emerson unidrive m200 - Over Modulation Enable; Transient Inductance; Stator Inductance; Slip Compensation Level

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 to set the level of slip compensation or droop control.
A value of 100.0% gives rated slip compensation as defined in MotorRatedFrequency (05.006).
Negative values can be used to introduce droop control.
A value of 0.0% disables slip compensation.
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Unidrive M200 Parameter Reference Guide
Issue: 01.05.00.10