The Design Of Air-conditioner Power Supply For Diesel Locomotive

With the development of work coziness, air-conditioning equipment has been installed on the railway locomotive to improve the working environment of the staff. The air conditioner power supply is the power of the equipment, and it involves the electrical drive technology, power electronics technology, micro-electronics technology and intelligent control theory. The research on air conditioner power supple began in the early 1990s, though there are some achievements, but still some shortcomings. The old power supply was settled respectively out of the air conditioning motors, generating single motor working frequency, as well as offering the poor reliability, and causing the difficulty to control. Based on the technical requirements for locomotive air-conditioning supply, this paper designed a novel power supply. Compared with the original one, the new power supply is smaller, lighter, more convenient to control, more comfortable, cheaper and easier to be maintained.Considering the air conditioner supply of locomotive, this paper is divided into the following parts:Part1 introduces the present railway locomotive air-conditioning system, along with the principle, technical parameters, and features of its power supply.Part2 gives out the design blue print of the system, including the main circuit and control circuit design. It also gives the control strategy of the power supply. The air-condition system provides automatic control mode and manual control mode.Part3 introduces the main circuit and control circuit design of the DC-DC converter. The structure of the main circuit is Boost Converter. The control circuit includes PWM pulse generating circuit and negative feedback control circuit.Part4 introduced the main circuit and control circuit design of the DC-AC converter. The structure of its main circuit is three-phase full-bridge circuit, The Sunplus MCU as the core processor is used in the control circuit. The Voltage modulation method is sinusoidal pulse width modulation technology (SPWM) ,realizing Motor soft-start, variable frequency operation, overload protection, and other functions.Part5 introduces the communication system of the power supply. To fix the design of air conditioner's communication system, after comparing several field bus which are used in the industrial fields. After that, in this part is made a detailed introduction to the field bus controllers, which are used in such cases and a detailed program on communication system hardware design is then brought up. In the communication system, several measures are taken to ensure the excellent work of the bus communication system. The software flow charts of the communication system's program are also given.Part6 introduces the auxiliary control circuit of the power supply system. The auxiliary control circuit comprises the upper microcomputer human-machine interface, temperature detection circuit, voltage (current) signal detection, signal conditioning circuits, boot buffer circuits, etc. Then in this part are introduced the circuit structure and core chips. At last it introduces the anti-interference measures of the circuit hardware.Part7 supplies the experimental results, including the conditions of the hardware experiment and related test waveforms. Then a conclusion is made to the work of the paper.