Close-loop Control And Commutation Of Power Supply Based On Reduced Matrix-type Rectifier For Ion Accelerator

Ion accelerator has broad application prospects in engineering physics and medical field,which the key device is excitation power. The traditional excitation power supplies have some drawbacks such as low power factor, large harmonic pollution, and unidirectional power flow and other issues. The new accelerator proposes a higher demand for excitation power accuracy in terms of dynamic response and waveform shape,so it is imperative to find a "green"excitation power supply with high regulation accuracy and fast dynamic response in order to solve the above problems.As the Reduced Matrix Converter (RMC) has excellent input and output performance, low conversion stage and high power density. Therefore, RMC is used as the accelerator magnet excitation power in this paper, deducing the working principle of RMC and the bipolar current space (B-C-SVM). On this basis, aiming at the accelerator performance requirement and the change rule of the excitation current,? and ? quadrant RMC topology with bi-directional energy flow and ? and ? quadrant RMC topology with energy feedback are proposed, and the coordination control methods for front and back stage circuits are given respectively.Aiming at RMC commutation problems, the four step commutation strategy of voltage and current are also analyzed, and a reduced three-step commutation with zero vector mixed commutation strategy is verified. The commutation strategy requires no additional detection circuit, and can effectively eliminate the peak voltage that occurs in commutation, which can ensure its safty and reliability. Finally, the RMC with current closed-loop control scheme is given, which uses single neuron adaptive PID controller, and the simulation results compared with the traditional PID shows single neuron adaptive PID controller has faster dynamic response.An experiment prototype with DSP+CPLD as the controller is set up, designing the hardware and software of the system. Commutation strategy and current closed-loop scheme and power experiment verification of RMC were completed on the prototype. The experiments of I and IV quadrant RMC topology with bi-directional energy flow and I and II quadrant RMC topology with energy feedback were completed.The correctness and feasibility of the proposed solutions are verified. Result shows that the RMC converter has excellent Grid-side and output performance, and better dynamic response. The modified RMC can achieve bi-directional energy transfer, which can meet the performance requirement for the magnet power supply of ion accelerator.