Function extension:
Rastmomente from Synchronous motors can have an undesirable effect on the drive behavior (cogging effect).
The effects can now be displayed with the function Rastmoment-compensation reduce. To do this, certain parameters must be determined via an associated identification run.
Prerequisites ffor the identification run:
- The pole position of the synchronous motor (pole position) must be known and valid.
- The current and speed controllers should be set to the desired power.
- 0x2C16:002: Enter the number of commutation angle periods to be analyzed. The compensation signal is calculated as the average of the disturbances of the selected number of periods.
Identification run of Rastmoment compensation:
- Enable the PMSM in low RPM/speed mode, as described above (0x2C16:003).
- 0x2822:044: Identify start command cogging compensation.
- The progress is displayed under 0x2823 and the status under 0x2C16:005.
The identified 10 points of the compensation curve (amplitude and phase) are displayed under 0x2C16:006 to :025.
0x2C16:001: Enable/disable compensation.
The effect of the compensation can be observed by activating and deactivating it.
Note: This function is not suitable for asynchronous motors (ASM).
Included in which products?
Servo-Inverter i950 FW: from V01.09.01
Application:
For applications with synchronous motors where maximum concentricity or position accuracy is required. position accuracy, e.g. linear motors in printing machines.
Background:
For synchronous motors with permanent magnets (SM, PSM), the so-called cogging effect has an impact on the drive behavior.
BEven in the de-energized state, it can be observed that the rotor ato certain positions, driven by more or less pronounced rest moments.
During operation, these cogging torques, together with other sources of interference such as current detection errors, lead to a torque ripple that can also affect the speed and position curve, depending on the respective drive configuration.
The effects on the drive behavior depend on the position and are greater at lower speeds.
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