SPWM (Sinusoidal Pulse Width Modulation) power modulation method and system

Abstract

The invention discloses an SPWM (Sinusoidal Pulse Width Modulation) power modulation method and system, which is applied to a controlled rectifier circuit or a semi-controlled rectifier circuit. The method comprises the following steps: determining a pulse width range, calculating the quantity of pulses according to the pulse width range, controlling an output voltage value of a rectifier circuit by adjusting a conduction angle of a controlled silicone rectifier element, and generating an equivalent sinusoidal pulse. According to the scheme, the controlled silicone rectifier element is applied, so that the changes of the quantity of the pulses and the output voltage value are realized, the changes of the quantity of the pulses and amplitude values are realized, and thus the phenomenon that a series of square wave pulses are changed according to the sine law is ensured; moreover, the situation that zero-crossing-point neighbouring square wave of a series of square wave pulses is lost is avoided, so that the defect that equivalent waveform is affected by modulation degree and carrier wave ratio in an existing SPWM modulation method is overcome.

Description

technical field [0001] The invention relates to the field of power supplies, in particular to an SPWM power supply modulation method and system. Background technique [0002] At present, the SPWM power supply modulation method mainly uses a series of square wave pulses whose width changes according to the sinusoidal law to form an equivalent sinusoidal waveform voltage. [0003] In this SPWM power modulation method, through the three-phase bridge type uncontrollable rectification circuit, the DC voltage after rectification is a fixed value Ud, so the series square wave pulse amplitude is a fixed value, and the series square wave pulse width changes according to the sinusoidal law, and then through the insulation The gate bipolar transistor IGBT is inverted into a series of square waves that change according to the sinusoidal law, thereby forming an equivalent sinusoidal voltage waveform at the primary stage of the transformer, such as figure 1 shown. [0004] figure 1 The...

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Problems solved by technology

[0006] In view of this, the present invention provides a SPWM power supply modulation method and system to solve the problem that the sine wave voltage waveform formed in the prior art is greatly affected by the modulation degree and carrier ratio. The specific scheme is as follows:

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