Briefly introduction of the resolver encoder in the motor

Briefly introduction of the resolver encoder in the motor

Mounting position

Structure and Principle:

The rotary transformer is mainly composed of an excitation coil (coil A), a sine coil (coil B), a cosine coil (coil C), and an irregularly shaped metal rotor. The excitation coil is the input coil, while the sine and cosine coils are output coils distributed at 90° in space. The metal rotor is fixed on the drive motor shaft.

The motor controller (MCU) is responsible for monitoring the signals of the rotary transformer. Based on the output sine (SINE) and cosine (COSINE) signals, after being parsed by the internal rotary transformer encoder, the current rotor position of the drive motor can be obtained. When the ignition switch is in the ON position, the MCU outputs an alternating current and a certain frequency excitation signal to the excitation coil (the alternating voltage varies for different vehicle models). After the excitation coil receives the excitation signal, it generates a magnetic field surrounding the sine coil, cosine coil, and the irregularly shaped rotor.

The MCU monitors the sine coil and cosine coil to generate sine and cosine signals respectively. By comparing these two signals, the MCU can determine the rotation angle, speed and rotation direction (forward or reverse) of the drive motor rotor. If the rotary transformer signal fails or is lost, the vehicle will not be able to power on and move.

Resistance measurement:

Waveform detection:

1.    Excitation waveform detection:

2.    Sine waveform detection:

3.    Cosine waveform detection: