Research On Hysteresis Current Control Strategy Of Three-Phase To Single-Phase Matrix Converter

The rapid growth of economy is accompanied by the consumption of a large number of mineral resources,and the exploration of mineral resources is imminent.As an important resource detection method,transient electromagnetic method has been widely applied.At present,the internal and external transient electromagnetic transmitter adopts the indirect intersection topology structure of the AC direct intersection,which has complex structure and low work efficiency.Diode rectifier is adopted,and the input side power factor is low.The transmitter needs larger capacity generator.The volume and weight of reactor in DC link are large,resulting in low power density of transmitter.At the same time,the mineral resources are located in the remote areas,and the working conditions of the instrument are bad,which pose a higher challenge to the design of the transmitter.It is of great significance to further improve the working efficiency,power density and field portability of the transient electromagnetic transmitter.The three-phase to single-phase matrix converter has the advantages of directly realizing the AC to AC transformation,bidirectional power flow,the input side unit power factor and without the energy storage reactance of the DC link.In this paper,a new type of transient electromagnetic transmitter is studied by using the three-phase to single-phase matrix converter instead of the traditional AC to DC to AC topology to overcome the shortcomings of the traditional transient electromagnetic transmitter.Aiming at its output characteristics,the hysteresis loop control strategy of output current is mainly studied.It provides a new idea for the design of electromagnetic detection instrument,and has accumulated experience for the popularization and application of three-phase single-phase matrix converter.The main contents of this paper are as follows.(1)In view of the problem of the traditional transient electromagnetic transmitter,a new transient electromagnetic emission system based on the topology of three-phase to single phase matrix converter is presented,and its basic principle is introduced.The equivalent model and 10 effective switching vectors of two parallel three-phase rectifiers are analyzed in detail.(2)In view of the requirements of the output current of 0,up,steady,and down four states of the bipolar trapezoid wave,the subsection hysteresis current control strategy is studied.In the 0 stage of current,all switch tubes are closed;In the stage of current rising and falling,the method of unidirectional current hysteresis control is adopted to speed up the current rising and falling time;In the steady flow stage,the two way current hysteresis control method with fixed ring width is adopted to reduce the ripple.(3)Matlab is used to simulate the hysteresis current control strategy.The simulation model of three-phase to single-phase matrix converter is established,and the hysteresis control strategy of the output current of different amplitude,frequency,ring width and load is simulated and analyzed.(4)A prototype of three-phase to single-phase matrix converter system based on hysteresis current control is developed.The main circuit of a three-phase to signal-phase matrix converter with no middle type is built by using common-emitter structure bi-directional switches.And the peripheral circuits,such as LC filtering,signal acquisition and isolation drive,are designed.The implementation of control strategy is based on DSP control system,and input voltage output current sampling,current hysteresis control strategy and bidirectional switches commutation strategy are programmed.The results of many experiments show that the output current tracking ability is strong,the descent time is less than 100μs,the dynamic response is fast and the output current waveform is consistent with the simulation results.The feasibility of using current hysteresis control strategy to control the output bipolar trapezoidal wave current of three-phase to single-phase matrix converter is verified.