Research On Control Of A Five-phase Permanent Magnet Machine Based On Harmonic Injection

With rapid development of industries like more electric aircraft(MEA), ship propulsion and electric vehicles, requirement for performance of machines is rising higher and higher on machine torque, efficiency and fault tolerance, which leads people to do research on new special electrical machines. On the other hand, the development of control strategy, power electronics, microprocessor and sensors also makes it possible for multiphase machine to be applied to use. This article makes a research on harmonic injection into a five phase PM machine, the EMF of which is trapezoidal, and analyzes the machine torque improvement when injecting harmonics current. Main contents are as follows:First of all, the article establishes the mathematical modeling of the machine in natural coordinate system according to machine characteristics, and a multidimensional d-q model is got through external Park transform. Then the machine vector control system is established, based on which the current control method is analyzed.The second, the article analyzes SVPWM control method in motor control system, as well as the voltage space vector of five phases SVPWM, pointing out the shortcomings of traditional SVPWM method when used in five phase machine, and introduces a kind of SVPWM in multi-dimensional orthogonal vector space, through which controlling fundamental and third harmonic current in double d-q subspaces is possible, but on the other hand, this SVPWM strategy has some problems,followed by solutions given for specific problem.And then, the hardware and software designs of motor control system are introduced based on a processor TMS320F28335. Hardware circuit degisn is first introduced, including some core parts, like AD sampling, PWM output, rotor position and speed detection and so on, followed by software design, including overall control process, current coordination transform, space vector pulse width modulation and SVPWM output.At last, an experiment is done due to the motor control system designed, which verifies the rationality of motor control algorithm and system design. A set of data on current and torque of the machine is acquired by giving different ratio of fundamental and third harmonic current. And the result shows the machine current can be well controlled in the control system, and injecting third harmonic current into a five phase machine which has trapezoidal EMF can improve output torque.