Research On The Combined Single Phase Inverter For The Calibration Of Extra High Voltage Current Transformer

Current transformers as high voltage electricity network metering, monitoring and protection of critical equipment, its performance is directly related to energy measurement, detection accuracy. The presence of long-running aging transformer remanence phenomenon, require regular check them. At present, the current transformer calibrating power supply commonly used conventional electrical power regulation accuracy is poor, a large volume of power, big experiment site labor intensity. Power supply regulation accuracy and portability requirements with the increase of high-voltage current transformer calibrating rating requirements, traditional power can not fully meet the current UHV transformer calibrating.This article regulation accuracy and low light and poor against the current of UHV transformer calibrating power exists, proposes a digital, high-capacity, wide-voltage, high-precision modular single-phase inverter power parity program, check the power supply using a high-power single-phase digital power inverter and a low-power single-phase digital power inverter series arrangement to meet the special high-voltage current transformer calibrating voltage power supply regulation accuracy and portability requirements.This paper introduces the transformer calibrating power supply development and status of numerical control technology and power inverter. Next to the common single-phase inverter topology analysis, in order to increase the power output voltage regulation accuracy check is designed to both single-phase full-bridge inverter series modular digital power parity structure of the program. We discuss several common SPWM pulse width modulation SPWM wave generation and methods to determine the modular digital power unipolar SPWM frequency doubling technology and asymmetric regular sampling method for generating SPWM wave.Then check for the combined power of a single inverter power control strategy, it introduced single-phase inverter topology, and established an equivalent mathematical model. In its open-loop characteristics on the basis of the analysis, the main theme of the power supply and trim are made of double-loop PI control strategy in detail about the pole assignment method to determine the double-loop PI controller parameters design process, and through MATLAB based simulation. To achieve modular parity power supply and the main theme of power in trimming work in tandem, this article focuses on the combined power supply and check the power of melody series trimming power control strategies, mainly related to the switching judging conditions, the main theme of the power switch two working lock mode switching and switching and other issues.Finally, according to the above design concept, based on a design of a 150 kVA single-phase inverter and a 5kVA single phase inverter in series of ultra-high voltage current transformer calibrating combined with single-phase inverter power system. The hardware design includes the main power circuit, drive circuit, the main circuit design of the filter circuit and to TMS320F28335 and EPM3512AQC208 dual core control circuit design. And the overall control system software program portion, dual loop control algorithm, and the main theme of the power switching algorithm design. Through experiments and waveform data analysis shows that the power supply to meet the power regulating transformer calibrating precision and capacity requirements, design and selection of design parameters is reasonable and reliable.