Abstract : This paper introduces the working principle and usage of the three-phase SPWM controller SM2001, and presents its hardware circuit and software programming application in frequency converters. Experimental results show that the output waveform of the frequency converter using SM2001 is good and its performance meets the requirements. Keywords : SPWM, integrated chip, frequency converter speed control 1 Introduction Sinusoidal pulse width modulation (SPWM) technology is the core of modern frequency converter control technology. With the continuous development of this technology, the generation and control of sinusoidal pulse width modulation signals have gradually shifted to the use of large-scale integrated circuit chips. SM2001 is an integrated chip specifically designed for the generation and control of three-phase SPWM signals. It has a wide operating frequency range, low sinusoidal harmonic distortion, accurate and convenient parameter adjustment, and comprehensive protection circuitry. It also offers two waveforms to choose from: ordinary sine wave and high-efficiency motor drive wave, making it widely applicable in AC motor frequency converter drive applications. This paper introduces the internal structure, working principle, and usage of SM2001, and presents ideal experimental results based on its application in frequency converters. [b]2 SM2001 Chip and Its Functions 2.1 Main Performance Characteristics of the Chip[/b] The SM2001 is a fully digital design and fully digital circuit. It achieves parameterized control of a single-chip microcomputer through a high-speed three-wire synchronous serial interface with a transmission rate of up to 1MHz, requiring very few microcomputer resources. The SM2001 uses double-edge regular sampling to generate PWM modulation waves with a frequency range of 200Hz (when the clock is 20MHz) and an eight-bit resolution; the carrier frequency can be selected in multiple levels, reaching a maximum of 38kHz; the dead time and narrow pulse time can also be customized, ranging from 0.05 to 25.6 s. The SM2001 uses an external clock drive and can share a crystal resonator with a single-chip microcomputer, with a maximum operating frequency of 24MHz. The three-phase PWM output level is active when the negative pulse is active and remains high when it is inactive; the pulse drive signal can reach 20mA, directly driving optocouplers, and the PWM waveform adjustment is fast, completing the conversion within one cycle. This chip has a complete multi-level protection circuit, with sensitive protection action (typical response time less than two clock cycles). [b][align=center]For details, please click: Three-phase SPWM Controller SM2001 and its Application in Frequency Inverters[/align][/b]