Special features of torque production in self-controlled permanent-magnet (PM) synchronous motor drives with rectangular current excitation have been investigated. Addressed issues include the generation of undesired torque pulsations at low speeds and system operating locus limits imposed at high speeds by saturation of the current regulator. Attention is limited to motors in which sources of reluctance torque are suppressed by surface-mounting of the rotor magnets and skewing of the stator slots. Results from the low-speed investigation indicate that the pulsating torque can be minimized by a combination of steps including proper adjustment of the rotor magnet pole atc and effective use of rotor speed feedback compensation. High-speed saturated-regulator performance is significantly influenced by the 120 electrical degree inverter switch conduction intervals inherent with rectangular current excitation. The system torque-speed operating envelope can be expanded by several means, including on-line adjustment of the converter excitation phase angle a, but resulting performance trade-offs require careful scrutiny. A 15-kW prototype PM synchronous motor drive system has been used to confirm key analytical results.

Torque Production in Permanent-Magnet Synchronous Motor Drives with Rectangular Current Excitation

The time-varying topology created by the switch-mode operation of power semiconductor devices in energy conversion systems presents difficulties in analysis. Presently available methods for simulating the behavior of these systems include the use of the digital computer, the conventional analog computer, and the breadboard. A new philosophically distinct technique called "parity simulation" produces a topologically isomorphic transformation of the system under study; that is, it exhibits a 1:1 correspondence, or parity, with the structure of the actual network. A parity simulator utilizes terminal equivalent representations of network elements. The microcomputer based interface is highly user oriented. Nonlinear or time-varying element parameters are easily incorporated. Several simulation examples are presented.

Simulating power electronic systems&#8212;A new approach

A Digital Simulation of Converter Circuits

A General Digital Computer Simulation Programme for Thyristor Static Converters (Programme SACSO) Application Examples

Kinestatic refers to those energy conversion systems employing kinetic as well as static components. A comparative analysis of presently available techniques for modeling such systems is presented. These techniques include the digital computer, the analog computer, the breadboard, and specialized hybrid computers producing a topologically invariant transformation of the system to be studied. The emphasis is on illuminating the strengths and weaknesses of each and identifying the contexts in which each is best employed.

H. Foch

Papers

Complete simulation of a static convertor by digital and analogue methods