Abstract
Although general-purpose inverters have been used for variable speeds driving of AC motors, these are only for induction motor (IM) driving. Synchronous motor (SM) with permanent magnets has many advantages compared with IM; Small size, high efficiency, driving only synchronous frequency, and so on. In this paper, “general-purpose inverter for SM driving” is discussed. Following characteristics are required for the achievement of this inverter; (1) Stable driving without position sensor. (2) Performance characteristics equal to DC motor driving. (3) Robust control system with the estimating functions of motor parameters.
This paper describes practical methods that attain the above characteristics by controlling primary flux of SM. In addition, it is shown that the estimating functions of motor parameters and the inverter circuits generating voltages equal to reference are indispensable to achieve high performance over all working regions.
