Single-phase controller design for a fault-tolerant permanent magnet generator

A simple, per-phase controller is described for a five-phase, fault-tolerant, permanent magnet generator. The power conditioning and control system for the generator comprises five independent H-bridge converters operating with sinusoidal PWM and supplying a common high-voltage DC bus. The separate controllers adjust the PWM pattern in each converter to regulate the DC bus voltage over the 3:1 machine speed range, which requires field weakening operation at high speed. Small-signal analysis is used to form a theoretical basis for the control loop design. Practical results are included from a 70 kW, five-phase prototype system to validate the analysis and illustrate the controller performance.