Quanzhou Ausenist Technology Co., Ltd Operational Differences of Synchronous vs Asynchronous Motors During Inverter Auto-Tuning
According to the technical manuals of inverters (e.g., JT550, EV510A, YS820 and Y780 series), the operational differences between synchronous and asynchronous motors during motor self-identification (auto-tuning) are mainly reflected in parameter identification focus, identification result storage, and mode selection for specific models.
Below are the specific differences and operational details:
1. Differences in Core Identification Parameters
The main purpose of auto-tuning is to allow the inverter to automatically obtain the internal electrical parameters of the motor to establish an accurate mathematical control model:
- Asynchronous Motor (Induction Motor): The focus of auto-tuning is on obtaining stator resistance, rotor resistance, leakage inductance, mutual inductance and no-load current.
- Synchronous Motor (Permanent Magnet Synchronous): The focus of auto-tuning is on obtaining counter-electromotive force coefficient, stator resistance, D-axis inductance and Q-axis inductance.
2. Selection of Identification Modes
In the parameter setting group, the mode selection for both motors is often under the same function code (e.g., F1.37, P1-37 or U3-49), but with different targeting:
2.1 Static Auto-Tuning
- Motor does not rotate.
- Suitable for asynchronous motors to obtain basic parameters when unable to disconnect from load, only partial resistance and leakage inductance can be identified at this time.
- For synchronous motors, some models also support static identification of partial inductance parameters.
2.2 Dynamic/Rotating Auto-Tuning
- Motor needs to run with no load (must completely disconnect the motor from the load).
- Recommended method for obtaining high-precision control performance.
- Asynchronous Motor: Dynamic identification covers key parameters such as no-load current and mutual inductance.
- Synchronous Motor: Dynamic identification is usually used to obtain encoder A/B phase sequence and initial magnetic pole position, which are essential for vector control.
3. Differences in Operation Process
Although the basic process is similar, the specific parameter configurations are different:
- Preset Parameters: Before starting auto-tuning, the rated power, voltage, current, frequency and speed must be accurately entered according to the motor nameplate.
- Motor Type Switching: The motor type must be correctly selected through parameters (e.g., U3-32, P1-00 or U02.00) first. For example, set to 0 for asynchronous motor and 1 for permanent magnet synchronous motor.
- Execution Command:
- In JT550: Set F1.37 to 1 (static) or 2 (complete identification), then press the RUN key.
- In Y780: Set U00.15 to 1 (rotating) or 2 (static), the keyboard displays TUNE, then press the RUN key; the process lasts about 2 minutes.
- In YS820: Select 1 (static identification) or 2 (dynamic identification) via U3-49.
4. Encoder and Phase Sequence Identification
For closed-loop control with encoder (FVC mode):
- Asynchronous Motor: The encoder AB phase sequence can be automatically obtained through complete auto-tuning.
- Synchronous Motor: During dynamic identification, in addition to AB phase sequence, it may also involve automatic calibration of encoder installation angle, which is crucial for the starting torque of synchronous motors.
Summary
Auto-tuning for asynchronous motors focuses more on excitation characteristic parameters, while synchronous motors focus more on reluctance characteristics (D/Q axis) and rotor position characteristics. For optimal performance regardless of motor type, dynamic (load-disconnected) auto-tuning is recommended whenever possible.