Pulse width modulation is commonly used in engineering to control the energy flow to the load by adjusting the duty cycle of pulse width modulation(PWM)for controlling the output circuit of electrical energy.However,in practical applications,if the AC and DC forms of energy are not considered when controlling the output circuit,there may be a problem where the duty cycle changes and the output of the thyristor does not change,resulting in the controlled load losing control.To solve this problem,PWM control of DC load and AC load modes were studied,and the situation of obtaining AC voltage under different PWM cycles and duty cycles was analyzed.A configuration method for the relevant parameters of PWM control thyristor circuit was proposed.Finally,the water circulation temperature control system was tested,and the test results showed that the method achieved precise and stable temperature control,which can provide reference for engineers engaged in related work in this field.