MODELING, SIMULATION, AND ANALYSIS OF VARIABLE-SPEED CONSTANT FREQUENCY POWER CONVERSION SCHEME WITH A PERMANENT-MAGNET BRUSHLESS DC GENERATOR

Variable-speed constant-frequency (VSCF) power conversion schemes use wound rotor induction or synchronous machines for power generation. With the advent of high-power density permanent magnets (PM's) and the feasibility of superconductors at higher temperatures, their use in large synchronous machines is almost a certainty in the future to improve efficiency and power density. The PM and superconducting synchronous generators will find applications in large windmill, aircraft, and naval on-board ship power systems. Such applications involve modeling, analysis, and experimental verification of the VSCF power conversion scheme with PM synchronous generators (PMSG's). The present study describes the VSCF power conversion scheme with trapezoidal PMSG's known as PMDC brushless generators, modeling of the subsystems in the scheme in steady state, derivation of its performance equations, harmonics and their magnitudes, and finally, an experimental verification of the scheme with the full-wave line-commutated converter. The VSCF power conversion scheme has simplicity of control and uses reliable and proven subsystems for the realization of the VSCF power conversion. Recommendations for future study to reduce the harmonics and to improve line power factor are given. © 1990 IEEE