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High-stability flat-top pulsed magnetic field, which combines the advantages of pulsed high magnetic field and steady high magnetic field, is widely used in in the fields of physics, biology, and chemistry. The pulsed alternator-rectifier power supply, with controllable output voltage, is suitable to discharge a multicoil magnet to generate a synthetic flat-top magnetic field with high parameters. However, the coupling characteristics of coil current and the time-varying nonlinear characteristics of magnetic field system bring challenges to generate a high-stability flat-top pulsed magnetic field. This paper first adds a decoupling transformer in discharge circuit of the 50-T flat-top pulsed magnetic field system existed at the Wuhan Nation High Magnetic Field Center, Wuhan, China, and hence, the coupling effect of 50-T dual-coil magnet can be eliminated. Then, a control method of high-stability flat-top pulsed magnetic field based on the model predictive control is proposed. A prediction model of rectifier trigger angle is obtained by establishing the mathematical model of the system. A simulation model is built by MATLAB/Simulink to simulate the discharge process, and a 50-T/120-ms flat-top pulsed magnetic field with an accuracy of 400 ppm is generated. [ABSTRACT FROM AUTHOR]

At Wuhan National High Magnetic Field Center, a 100-MVA/100-MJ pulsed generator and two 67.5-MW converter modules have been installed as power supply for pulsed magnets. Long-pulsed magnetic field with 50-T/100-ms flat-top has been produced and 100-T pulse magnetic field is under commissioning by utilizing this pulsed generator converter. In this high-power occasion, the three-phase voltages undergo serious harmonics, large notches, amplitude variation, rapid frequency fluctuation, and phase jump simultaneously. Synchronization method with fast dynamics, excellent harmonics rejection, and smooth time-domain response is expected, which is difficult for the conventional synchronous reference frame phase-locked loop (SRF-PLL). Therefore, this paper presents a new synchronization method based on compensation of phase deviation. In this method, the phase of three-phase voltages, which is achieved by summing filtered phase deviation and phase of a given $d$ - $q$ rotating reference frame, is open-loop computed directly. The main attributes of the method are the fact that its dynamics is independent of the input vector amplitude, better harmonics rejection/dynamics tradeoff, and smooth time-domain response. Comparative experiments are performed between the proposed synchronization method and SRF-PLL. [ABSTRACT FROM AUTHOR]