Design And Research Of Matrix Converter Applied To HIRFL Magnet Power Supply

During the development process of particle accelerator, superconducting magnet and power technology are crucial for the system of magnetic fields system. At present, the problems of low power factor and serious harmonic in the grid side exist in accelerator magnet power supply. Therefore, a low cost and high efficiency solution need to be obtained. Moreover, for superconducting power supply, how to feedback energy to grid is also need to carry out related research.Matrix converter appeared in recent years, whose grid side power factor could be adjusted even being close to unit,can realize rectifier, inverter, chopper, inverter and other power converter when using different modulation strategy. Frequency transformation can be implemented in a single stage. Consequently the converter is a kind of both environmental and commonly used converter.In this paper, matrix converter is intended to be select to be a solution of topology of the main circuit of superconducting power and the feasibility of solution was discussed in this study. The adjustable power factor of matrix converter could achieve sinusoidal input current and the harmonic pollution can be effectively reduced. As the energy can flow bidirectional freely via matrix converter, extra energy of superconducting magnet could be feedback to power grid. Without large capacitance, the volume of power supply equipment can be reduced, as well as dynamic performance improved; a variety of power conversion functions can be achieved due to the generality of MC topology, making it suitable for accelerator power supply in various applications.As DC current mode and pulsed mode are often employed in accelerator power, in this paper, the topology of matrix converter of DC power is study. Firstly, the working principle of bidirectional and high-performance electrical power transformation of matrix converter is studied from the bidirectional switch and commutation strategy perspective. As to modulation strategy of matrix converter, in this study, the control strategy of bidirectional current of accelerator power is presented. While the frequency instability of hysteresis current control is further studied and some constructive results are obtained. Secondly, three topologies of matrix rectifier(MR) of accelerator power, direct type MR, magnetic coupling type MR and pre-stage voltage regulating type MR, are presented. The difference of first two matrix rectifiers is connection between bidirectional switch matrix and load. Matrix rectifier is employed in pre-stage voltage regulating type MR and generates stabilized direct voltage, which is applied in pre-stage of H-bridge. Then combining the control of H-bridge, DC current or pulse current can be generated.For further studying the topology and performance of matrix rectifier, three different powers which are constructed by three diverse topologies are designed. The principle models of main circuit topology and control strategy are established for simulation study. The experiment results show that the proposed three kinds of topology structure can realize the steady DC output, and input power factor is ideal.In this study, an experimental prototype of matrix rectifier is built according to the design scheme and compatible interfaces of experiment platform for software and hardware system are reserved, which are appropriate for three design solutions. Via the experimental prototype, our solutions are validated. From the experiment results of experimental prototype, the stabilized DC could be robustly output with high power factor in the grid side, while the experiment for pulse current is carried out to some extent with helpful results. The experiment results of experimental prototype conform to the results of simulation experiment, which fully suggest that the proposed scheme can be applied to the accelerator dc power supply and lay a good foundation for the following research of application to the pulse power.Because of the complex control strategy of matrix converter, its practical research is extremely limited. Limited to time, this paper mainly focus on the grid-side power factor, for the issue of energy feedback problem, it is hoped to be continuously researched in the following work.Through the research of this paper, we can draw the following conclusion: matrix converter is a viable option of accelerator power and has a good prospect for research.