The Research On Variable Frequency Technology Of VRV Air Conditioner Compressor Variable-speed System

With the arrival of the energy source crisis worldwide, governments in many countries have been promoting the energy saving techniques actively. As the main energy consuming equipment in family ,traditional air conditioners are withdrawing from the market gradually because of its low efficiency .Owing to the advantages of high efficiency ,energy saving and more comfort, new generations of variable frequency air conditioner—VRV conditioner have become the developing trend. Compressor, as the key part of variable frequency conditioner, plays a crucial role in the whole VRV conditioner system.This paper explains the typical control methods for controlling the compressor and adopts a high performance PWM technology (SVPWM) to control the compressor. The principle of SVPWM is in-depth discussed and the regular algorithm for SVPWM is given. Furthermore, a simple way of realizing SVPWM is deduced. This method can facility the realization of SVPWM. SVPWM technique have many good qualities, such as less pulsating torque, high usage of DC bus voltage, less switching loss, better high-speed regulation performance. Aiming at the inherent problem of dead time in the common pulse width modulation, the affection of dead time on the whole system is analyzed and a new simple way of dead time compensation— —compensation based on phase angle is put forward. It isn't necessary to detect the cross zero time of the current in using this method . The principle of this way is introduced and the corresponding realization is given. It can reduce the cost and achieved better performance.According to the parameter of the compressor and new requirement on compressor motor control system, the control system is designed. As for hardware, the inverter module, protection module, control module and communication module based on TMS320LF2407 and Intelligent Power Module( IPM) is designed. As for software, using assemble language of DSP to compile the whole program, including SVPWM module, communication module and protection module. At last, some measures are adopt to reduce distortion both hardware and software. For the high precision of varying frequency, and stabilization of running, this system meets the requirement.