Study On Mining Three Phase Digital Power Supply With High Stability And Intrinsic Safety Uninterruptible Dc Power Device With Large Capacity

The project in this thesis is one important part of the National Key Technology R&D Program of China during the Eleventh Five-year Plan Period (serial number:2007BAK29B05; 2007BAB13B01). The work is proposed in accordance with the problems, such as:fluctuations of power grid voltage and poor quality and discontinuousness of power supply, would affect personnel safety and equipments'operation in underground coal mine. In addition, monitoring the gas concentration of the coal mine uninterruptedly is a precondition to avoid latent dangers of the major accident and ensure safety production. Currently, the mature intrinsic safety switching power supply in application features lower capacity, and doesn't have the function of uninterruptible power supply. So the work develops a full-digital High Stability Power Supply (HSPS) and a high-capacity Intrinsic safety Uninterruptible Power Supply (IUPS). The main contents of this thesis are as follows:After investigation of developing tendency at home and abroad, the performance requirements and technical specifications of the project have been analyzed in detail. And then the system's whole structure has been seriously determined; the system's design plan has been deliberately made.According to the system's design plan, the topological structures and operating principle of the high-power rectifier circuit in HSPS has been analyzed. Combined with control strategies and the digital design plan, the equivalent mathematical model has been established; a double loop rectifier current control strategy that is DC side voltage of the outer and AC current of the inner with direct current control has been skillfully designed. After analyzing the topological structures and operating principle of the main inverter circuit in HSPS, a double loop control strategy that is voltage RMS outer and voltage instantaneous value inner has been designed. Equivalent theories of the PWM pulse width and the irregular sampling modulation strategy and digital realization process of the SPWM have been analyzed. The influence of the dead-time to the inverter's output waveform has been studied; solution plans how to judge the half dead-time based on the direction of inductor's current.Considering theories and control strategies of two core modules of the rectifier and inverter, the hardware circuits has been developed. Lab experiments have shown that the circuits feature simple structure and reliable operation and strong anti-interference ability.The control programs have been compiled in terms of HSPS system's design plan which has been developed. They include several parts such as the main program of the rectifier system, external interrupt service routine and so on. It has been verified programs'efficiency and accuracy by the debugging.Aimed to the requirements of IUPS, the high accurate switching power supply based on TL494 and the double strategy of protecting over current and over power based on MAX4211 has been designed. It has also been achieved that using CPU controls the battery charging by a constant current and protected under the situations of over-charging and over-discharging.The entire debugging has been made on the experiments platform which has been established. Analyzing the experiments waveform and running data about main circuits and control circuits have made conclusions that HSPS and IUPS have reasonable structures and reliable operation condition.