The solar controller can also be said to be a solar charge and discharge controller. It is a controller with two charging modes, one is MPPW charging mode and the other is PWM charging mode.

Unipolar PWM control means that the carrier only changes in one direction within a half cycle, and the resulting PWM waveform changes only in one direction. The bipolar PWM control method is the opposite of unipolarity, and he changes the carrier in two directions within a half cycle. According to whether the carrier signal and the modulation signal are kept synchronous, PWM control can be divided into synchronous modulation and asynchronous modulation. The characteristic of rectangular wave pulse width modulation is that the output pulse width column is of equal width, and only a certain number of harmonics can be controlled; the characteristic of sine wave pulse width modulation is that the output pulse width column is of unequal width, and the width changes according to the sine law, The output waveform is close to a sine wave. Sine wave pulse width modulation is also called SPWM. The key to this technology is to generate the pulse width according to the control signal. At present, the triangular wave comparison method, the hysteresis comparison method and the space voltage vector method are commonly used.