Study On Independent Power Supply System Of Single-Phase Digital Generation

Traditional small-scale generators, usually use a low-speed engine to drive a generator with power frequency, outputting electric energy without any adjustment. These kinds of generators are low-speed, bulky, and Difficult to be portable. When under different work conditions, output voltage/current is unstable, thus not can’t meet higher power quality requirements. With the power electronics and information electronics industry’s rapid development, digital power system started appearing. Due to greatly improvement in overall performance, a very broad market was created for portable power generation equipment. Meanwhile, requirements such as miniaturization, reliability, and higher power quality for portable power generation equipment are proposed by great demand.Digital power system consists of gasoline (diesel) generator set and power electronic converter. Using rectification and inversion technology to improve output power quality. Traditional digital power system usually contains“AC-DC-AC”two succeeding steps transformations: the front consists of uncontrollable diode rectifierF, backward stage uses a voltage source inverter, and intermediate link is an impedance converter or a DC-DCconverter. According to the power situation of the stator winding, or the output voltage from the inverter, a electronic speed governor is designed, which controls stepper motor to adjust the nozzle opening and change fuel quantity. Then with the power electronic converter, Digital power system can output high quality electric energy.The digital power system has made considerable progress, but still many problems need be studied. From the perspective of electronic control, problems contains: (1) the structure of power electronic converters and algorithms need to be improved; (2) the efficiency of the generator and mechanical properties need to be improved; (3) For high reliability, power generating end and using power terminal should be decoupled, etc.Based on the above considerations, this article focuses on a 1.0kW small gasoline generator system and designed power electronic converters with new control algorithms, expecting to improve system performances.1. The structure of power electronic converters in a small gasoline generator system was presented and analyzed. The feasibility of the circuit and the resulting benefits included that the sine wave form current in stator can improve the mechanical properties of the generator. Further the context of research and objectives of each part was determined, which is to design a rated power of 1.0kW, output single-phase AC220V/50Hz voltage source;2. The paper analyzed two-state interleaved Boost PFC with OCC algorithm, and verified the feasibility with MATLAB/SIMULINK simulation platform. After that the paper brought up a control algorithm, which is free from detection of input ACvoltage, for single-phase active PFC circuit and also verified the strategy with simulation program. Then according to the basic principle and physical significance of PFC, a new direct control algorithm is derived in theory and verified by simulation analysis and experimental research. The experiment circuit is designed with DSP TMS320F2808, expanding corresponding external circuit (detection circuit, control circuit, driver and protection circuits, etc.) and the outcome shows good control performance of the direct control algorithm.3. Then the paper analyzed the non-phase-shift modulation algorithm and the phase-shift modulation algorithm for inverter part within the full-bridge inverter full-bridge rectifier DC-DCconverter. As an intermediate converter, DC-DC Boost link can adjust the voltage between the front rectifier and the backward inverter, as a result, increasing the practicability of digital generator system; theoretically analyzed two-state interleaved Boost PFC with OCC algorithm, and verified the feasibility with MATLAB/SIMULINK simulation platform.4. After that a single-phase voltage source inverter with OCC control algorithm was carefully studied analyzed and verified the algorithm with simulation, which manifested that, with the OCC algorithm, voltage source inverter can get better output voltage waveform and greater load capacity.5. At last the paper focused on the digital electronic speed governor of a small gasoline digital power system, analysis including the entire control system structure (electronic control parts and mechanical parts), design of PID control parameter, the theoretical basis of the parameter selection.