PWM Speed ​​Regulation of Brushless DC Pump

The brushless DC water pump has the same power principle as the brushless DC motor and can have PWM speed control function. What is PWM speed regulation?

The working principle of PWM The control method is to control the on and off of the inverter circuit development device, so that the output terminal gets a series of pulses of equal amplitude, and these pulses are used to replace the sine wave or the required waveform. That is, multiple pulses are generated in the half cycle of the output waveform, so that the equivalent voltage of each pulse is a sinusoidal waveform, and the obtained output is smooth and has less low-order harmonics. By modulating the width of each pulse according to certain rules, the output voltage of the circuit can be changed, and the output frequency can also be changed. In the PWM waveform, the amplitude of each pulse is equal. To change the amplitude of the equivalent output sine wave, you only need to change the width of each pulse according to the same proportional coefficient. Therefore, in the AC-DC-AC inverter, The pulse voltage output by the PWM inverter circuit is the amplitude of the DC side voltage. According to the above principle, after the sine wave frequency, amplitude and the number of pulses in a half cycle are given, the width and interval of each pulse of the PWM waveform can be accurately calculated. According to the calculation result, the on-off of each switching device in the circuit is controlled, and the required PWM waveform can be obtained. PWM (Pluse Width Modulation) control-pulse width modulation technology, by modulating the width of a series of pulses to equivalently obtain the desired waveform (including shape and amplitude) PWM control technology is the most widely used in inverter circuits Most of the inverter circuits used are of the PWM type, and the PWM control technology depends on its application in the inverter circuit to determine its important position in the power electronics technology.