A Novel Phase Current Difference Construction Based Initial Rotor Position Detection Method for Surface Mounted PMSM Without Injections of High-Frequency Voltage or Pulse Sequence

The paper focuses on the initial position detection of a three-phase surface-mounted permanent magnet synchronous motor (SPMSM) in order to solve the problem of the conflict between the detection time and accuracy of the existing initial position detection methods. In the method, only six basic space voltage vectors are used to be injected into the SPMSM at standstill. The switching between adjacent space voltage vectors is achieved by using the full switched-off states as the switching buffer state. Hence, only the phase current responses are measured without using the dead-time configuration of the PWM signals. By constructing the trigonometric function related variables of the initial position angle of rotor pole, the initial rotor position can be easily detected through the calculation of inverse trigonometric function. The simulation results show that the proposed method obtains the same less than ± 5° initial position estimation error, and the time required is shortened by 50% compared with the traditional pulse sequence voltage injection method, and shortened by no less than 92.6% when compared with the high frequency voltage injection method. The proposed method does not need complex high-frequency voltage injection or pulse sequence voltage injection, pole polarity judgement and is simple to implement.