Zhang Housheng

Research on a Novel Digital Photovoltaic Array Simulator

In order to make the design and optimization of solar energy systems convenient, it is very essential to choose the suitable engineering mathematic model of solar cells. A convenient and practicable engineering mathematic model of silicon solar cell is offered in this paper, which is based on photovoltaic array output I-U characteristic curve. Piecewise curve fitting method is also presented to simulate the photovoltaic array characteristic curves. A new digital photovoltaic array simulator with Buck converter is designed in detail. The designed simulator uses dual-loop control with PI regulator, which greatly enhances the systems dynamic performance and steady-state accuracy. The feasibility and rationality of the design are verified by the results of simulation and experiment. It can be used in replacement of actual photovoltaic arrays to provide a controllable environment for research and design of photovoltaic inverters and control systems.

Research on maximum power point tracker based on solar cells simulator

The output power of solar cells varies with variable temperature, light intensity and loads. In order to solve the shortcomings such as long time and high cost of using solar cells to experiment, this paper successfully uses a DC power supply and a variable resistor to simulate the solar cells output characteristic curve, its feasibility is analyzed theoretically. The basic principle of the maximum power point tracking (MPPT) is described in detail. An improved disturbance method with variable voltage step is introduced, it inherits the advantages of traditional disturbance voltage method, overcomes the shortcoming of slow response of traditional method, reduces the power loss caused by maximum power point due to continuous disturbance, and realizes the maximum power point tracking for solar cells. The proposed method improves the systems speed and efficiency. The experimental results show that the system can track the maximum power point accurately and quickly.

Research on MPPT for Solar Cells Based on Flyback Converter

A voltage source and rheostat are successfully used to simulate the solar cells character in this paper. Its feasibility is analyzed theoretically. The basic principle of the maximum power point tracking (MPPT) is described. An improved disturbance method with variable-voltage step is introduced. It inherits the advantages of traditional disturbance voltage method, overcomes the shortcomings of slow response of traditional method, reduces the power loss caused by maximum power point due to continuous disturbance, and realizes the maximum power point tracking for solar cells. The proposed method improves the systems speed and efficiency. The experimental results show that the system can track the maximum power point accurately and quickly.

Design of three-phase intermediate frequency aviation power based on single chip microcomputer

A three-phase intermediate frequency aviation inverter power with single chip microcomputer and SA8282 as its main controller is designed in this paper. The overall structure of the proposed system is given. The working principle and design method of the main circuit are presented in detail. Among the control circuit design process, the generation of SPWM waveforms, the main parameters design of SA8282, the digital PI regulation and the software design process are analyzed. The proposed control strategy has been implemented on a 9KVA, 400Hz three-phase power supply. Experimental results show that the three-phase output voltage waveforms are quite good, the performance of the supply meets the demand.

Maximum power point tracker for solar cells based on boost converter

In order to overcome the shortcomings such as long time and high cost of using solar cells to experiment, this paper successfully used a DC power supply and a variable resistor to simulate the solar cells output characteristic curve, its feasibility is analyzed theoretically. The basic principle of the maximum power point tracking (MPPT) was described in detail. Aiming at the normal maximum power point tracker algorithms some deficiencies in low tracking and concussion near the maximum power point, a new MPPT method—beeline approximation method combined with perturbation method with changing perturbation step is presented. Experimental results show that the system can track the maximum power point accurately and quickly, and the proposed method can eliminate the power oscillation at maximum power point.

Single phase photovoltaic grid-connected inverse power system based on DSP

As the energy crisis and the pollution are serious, the exploitation of solar has received more and more attentions. The configuration and principle of photovoltaic grid-connected power system are analyzed in detail. The method of maximum power point tracking is designed and the control principle of voltage and current double closed-loop is analyzed in this paper. At the same time an improved phase locked tracking method combined with software and hardware is presented. The experimental results show that the current waveform of grid-connected inverter has the same frequency and phase angle with the grid voltage, the power factor of grid-connected inverter is 0.999, which meets the design requirement entirely.

Development of a Novel Large Capacity Charger for Aircraft Battery

This paper presents a novel large capacity charger for aircraft battery, which can be used as maintainable equipment for lead-acid and cadmium-nickel batteries. The circuit scheme, control principle, software design, charger failure detection and protection circuit are also designed in detail. The main circuit of the proposed charger uses half-bridge DC-DC converter. The control circuit, which uses voltage and current double closed-loop control, takes the ADμC812 chip with A/D transformation as its core. It can control the charger in a state of constant current or trickle charge. Simultaneously, the battery charger’s soft start circuit, over-current protection circuit, over-temperature protection circuit as well as the polarity detection circuit are also designed. A prototype with ADμC812 is developed, which can control the current of the charger in the state of constant current and trickle charge. Its superiority performance such as electric separation, simple frame, high efficiency, small volume, light weight is verified by experimental results.