Protection and control method of DC charging pile residual pressure discharge resistor

Abstract

The invention discloses a protection and control method for the residual voltage discharge resistor of a DC charging pile. According to the total heat Q of the discharge resistor R Reg , The initial maximum pulse impact power P that the resistance can withstand pulse , the output capacitor voltage U out , the accumulated calorific value E′ of the bleed resistor R and the heat dissipation coefficient K, etc., select an appropriate pulse width to adjust the duty cycle, and adjust the closing time of the high-voltage MOS transistor Q through PWM control, so that the bus capacitor C in each cycle is discharged The energy does not exceed the energy that the discharge resistor R can withstand in the current cycle, and the heat accumulated by the resistor during the entire discharge process does not exceed the heat capacity of the discharge resistor R itself. Therefore, on the premise of ensuring the discharge function of the charging pile, the service life of the discharge resistor R can be more effectively protected, and in the case of the same system discharge energy, the selection of the rated power of the resistor is also more direct and simple. way requires less margin.

Description

Technical field [0001] The present invention relates to a technical field pile DC charging pressure relief, particularly to a method of controlling the DC resistance and charging protection pile residual pressure relief. Background technique [0002] DC charging pile at the end of a system failure or stop charging charging service, since its output capacitance C0 power module, there is still a residual high pressure. To ensure safe operation of the charging operator, time basis having predetermined capacitance C0 is rapidly released to the residual pressure within safe voltage 1S. The manual attachment Figure 1 , By switching a relay or an electronic switch (MOSFET or a common IGBT) so that both ends of a bleeder resistor incorporated DC output capacitor, the capacitor C0 so as to relieve residual pressure control method is used. [0003] The manual attachment Figure 1 Shown, Q0 can be a relay or an electronic switch the MOSFET, R0 is a bleeder resistor, when the charging service...

AI Technical Summary

Problems solved by technology

In the existing technology, the residual voltage is released by simply switching and controlling the bleeder resistor R0. On the one hand, the system needs to reserve a larger rated power space when selecting the bleeder resistor, which increases the system cost; on the other hand, if the long Continuous discharge at high voltage level for many times, compared with low voltage level resistance, the instantaneous heat generation is higher, and the impact heat energy on the resistance is greater, and may even exceed its own thermal stress and burn out the body, thus affecting the DC Safety and reliability of charging pile system operation

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