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Experiment using SiC Device-Based AC-DC-AC Converter to Drive a PM Motor with Sensorless Control

Fig. 1. Structure of experimental platform.
This paper introduces a testbed for a new SiC device based AC-DC-AC converter with an axial flux permanent magnet (AFPM) motor. As shown in Figure 1 The AC-DC-AC converter is built with a Vienna-type rectifier and s two-level VSI structure with SiC JFETs and SiC Schottky diodes. The AFPM motor is based on PCB winding, and it is connected to the load machine driven by a back-to-back motor drive (shown in Figure 2). A control strategy for the AC-DC-AC converter is introduced. The AFPM motor is started with open-loop control, and is then switched to sensorless vector control (shown in Figure 3). An obvious transient appears at the switching time. This paper analyzes the principle of this transient, and an improved start-up procedure is introduced to solve the problem (shown in Figure 4). Then the steady-state and dynamic performance of the AC-DC-AC converter with the AFPM motor is tested and the performance of the AC-DC-AC converter with motor is verified by experiment (shown in Figure 5).

Fig. 2. Motor-generator connection in the experiment.
Fig. 3. Sensorless control method.

Fig. 4. Improved start-up process for sensorless control.
Fig. 5. Testing Results.