PTC power control method and device

Abstract

A PTC power control method and device provided by the embodiments of the present invention relate to the field of PTC power control, and the method includes: obtaining the first current of the previous cycle and the second current of the current cycle of the current curve of the PTC heater, Calculate the predicted current for the next cycle based on the first current and the second current, the predicted current is the current value corresponding to the minimum PWM duty cycle in the next cycle, and calculate the target PWM duty cycle output for the next cycle based on the predicted current and the target current , so that the current of the next cycle is stable as the target current. The predicted current of the next cycle is predicted by the integral calculation of the actual current of the current cycle and the actual current of the previous cycle, and the target PWM duty ratio output of the next cycle is calculated according to the difference between the predicted current and the target current, so that the PTC heater can pass through The current is more precisely close to the target current, so that the stability of the PTC heater is the target power.

Description

technical field [0001] The present invention relates to the field of PTC power control, in particular to a PTC power control method and device. Background technique [0002] With the rapid development of new energy vehicles, more and more vehicle air conditioners use positive temperature coefficient (positive temperature coefficient, PTC) for heating. For the power control of PTC, the industry mainly uses a proportional-integral-differential (ProportionIntegrationDifferentiation, PID) controller to adjust the pulse width modulation (Pulse width modulation, PWM) duty cycle to turn on the high voltage voltage applied to both ends of the PTC. The PID controller mainly adjusts the power at both ends of the PTC based on the deviation between the set power and the actual power. [0003] Since the resistance value of the PTC varies at different temperatures, the actual power of the PTC varies even with the same PWM duty cycle. When the PTC performs power control, the traditional P...

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Problems solved by technology

[0003] Since the resistance value of the PTC varies at different temperatures, the actual power of the PTC varies even with the same PWM duty cycle. When the PTC performs power control, the traditional PID control method is based on the deviation between the actual power and the set power. Calculation, this PID control method is a pure feedback control method, which is bound to have a process of oscillation and convergence, which will lead to inaccurate adjusted PTC power

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