變頻壓縮機馬達高效率驅動模組之研製與省能技術之研究(II)

Abstract

高功因、高效率、變頻控制已成為新型電冰箱壓縮機驅動器的基本需求。發展 高效率變頻驅動器有三種主要的方法：其一是降低功率元件的開關損失；其二是提 高扭矩效率；其三是提高系統的功率因數。本計劃針對高效率電冰箱壓縮機所使用 的無刷直流馬達，進行高效率變頻驅動模組之研製，研究內容包括發展高效率可變 輸出功因修正轉換電路、無刷直流馬達的最佳扭矩控制技術、發展具有功因修正控 制的PAM高效率變頻驅動模組，達到高效率高功因的控制效果。本計畫之第一年已 完成針對高效率電冰箱壓縮機發展具有功因修正控制的PAM高效率變頻驅動器之 硬體電路設計，用脈衝振幅調變(pulse amplitude modulation, PAM)控制方式，達到 高效率高功因的控制效果。研究內容包括發展可變輸出功因修正轉換電路，高效率 換流器柔切技術，採用高頻軟開關(soft switching)方式，提高功率轉換器的效率。 本階段之研究重於發展應用於壓縮機變頻器的Nios-Based FPGA-SoPC數位控 制技術，並以前階段所發展的模組式變頻器為對象，採用先進的可程式系統晶片 (SoPC) FPGA控制器，發展數位式功率因數控制之PAM調變技術，發展壓縮機變頻 器無感測馬達啟動與速度調節控制技術，完成一個額定功率750W、最高效率達88% 的PAM變頻驅動器，速控範圍為400-4000 RPM，轉速變化率為200 rpm/sec；運轉中 具有全載變化(0-100%)的速度調控能力，在全載狀況下亦可啟動。此驅動器具有串 聯通訊介面，可由外部下達速度命令與設定控制參數，利於壓縮機變頻系統整合。 研究計畫將完成壓縮機無感測變頻器的原型製作與實驗性能量測。

High efficiency, high power factor, and variable speed control have become fundamental requirements of modern compressor drive used in high-efficiency refrigerators and cooling machines. In recent years, high efficiency permanent magnet brushless DC motors have been developed for variable speed control of compressors used in refrigerators. This project is focused on the design and implementation of a high-efficiency PAM inverter drive for compressor used in next-generation refrigerators. Single-phase AC-DC converter with power factor correction and variable output can be used to improve power quality at the same time to reduce switching losses by adopting pulse amplitude modulation (PAM) technique. An advanced digital control technique will be developed to improve the dynamic response of the VOPFC converter. FPGA-based system-on-a-programmable-chip (SoPC) solution will be developed to improve the efficiency of the PAM inverter driven compressor. A prototype of the PAM inverter will be constructed to verify the proposed control scheme. During the first year of this project, we have already accomplished the design of a bridgeless PFC converter combined with a PWM inverter to achieve the PAM control of a brushless dc motor used for high-efficiency compressor applications. Soft switching control techniques will be developed to minimize the switching losses as well as the switching stress. Digital power factor correction control technique will be developed for the bridgeless PFC converter to achieve PAM control for the brushless dc motors. In the second year of this project, we will focus on the development of SoPC-based digital control techniques for the sensorless control brushless dc motor with unit power factor correction. The constructed sensorless drive can achieve a high efficiency of 88% with a rated power of 750W. The proposed control techniques will be realized by using a FPGA-based SoPC controller. All the control functions for the senseless PAM inverter drive will be realized by using SoPC programmable digital and software control techniques. The designed PAM BLDCM drive should possess the following features: RS-232 for external serial communication, variable speed control from 400 to 4000 RPM with speed-change rate of 200 RPM/sec, good speed regulation under a full load variation, the motor can be started from zero speed at full load, and the overall efficiency should be higher than 88%.