Abstract : This paper introduces the principle and programming characteristics of the SA8281 sinusoidal pulse width modulation (SPWM) wave generator, as well as the hardware and software design of a frequency converter based on the SA8281 and 89C52 microcontroller. Keywords : SA8281; 89C52 microcontroller; frequency converter; sinusoidal pulse width modulation[b][align=center]Principle of SPW M wave generator SA8281 and its application in frequency converter YANG Qing-hua (Institute of Telcommunication Engineering,Air Fowe Engineering Unwersity,Xi"an 710077,China)[/align][/b] Abstract: The principle and programming features of wave generator SA828 1 of sine pulse-width modulation (SPWM) are described, and the design of software/hardware for the frequency converter based on SA828 1 and sigle-chip microcomputer 89C52 is presented. Key words : SA8281; 89C52; frequency conve~er; sine pulse-width modulation 1 Introduction Pulse width modulation (PWM) technology controls the switching of elements according to a certain pattern to obtain a set of rectangular pulse waveforms with equal amplitude but unequal width, which are used to approximate a sinusoidal voltage waveform. The application of PWM technology in inverters has greatly promoted the development of modern power electronics technology and modern speed control systems. In recent years, due to the continuous emergence of field-controlled self-turn-off devices, the corresponding high-frequency SPWM (sinusoidal pulse width modulation) technology has been widely used in motor speed control. SA8281 is an integrated circuit launched by MITEL for three-phase SPWM waveform generation and control. It is easy to connect to a microprocessor, has a built-in waveform ROM and corresponding control logic, and can independently generate three-phase PWM waveforms after setting. Microprocessor intervention is only required when the output frequency or amplitude needs to be changed. The microprocessor controls it in a very short time, thus enabling it to perform detection, protection, and control of the entire system. Inverters based on SA8281 and 89C52 have advantages such as simple circuitry, complete functions, high performance-price ratio, and good reliability. [b][align=center]For more details, please click: SA8281 SPWM The principle of wave generators and their application in frequency converters.