CN108394297A - The protection of direct-current charging post residual voltage bleeder resistance and control method - Google Patents

Abstract

The present invention discloses protection and the control method of a kind of direct-current charging post residual voltage bleeder resistance, the heat Q received according to the assembly of bleeder resistance R_Reg, the initial maximum pulse shock power P that can bear of resistance_pulse, output capacitance voltage U_out, bleeder resistance R accumulation the constraintss such as calorific value E ' and coefficient of heat transfer K, select suitable pulse-width regulated duty ratio, the closing time of high-voltage MOS pipe Q is controlled to adjust by PWM, so that the energy released of each period bus capacitor C is no more than the energy that current period bleeder resistance R can bear, and the heat that resistance is accumulated during entirely releasing is no more than the thermal capacitance of bleeder resistance R itself.So as under the premise of ensureing the drainage function of charging pile, more effectively protect the service life of bleeder resistance R, and release under energy situation in identical system, the allowance smaller needed for also relatively directly simple switching mode is chosen to resistance rated power.

Description

The protection of direct-current charging post residual voltage bleeder resistance and control method

Technical field

The present invention relates to the technical field of direct-current charging post pressure release more particularly to a kind of direct-current charging post residual voltage bleeder resistancesProtection and control method.

Background technology

Direct-current charging post is when charging service terminates or encounter system failure stopping charging, due to having in its power moduleOutput capacitance C0, there are still certain residual high pressures.It, need to be by defined time 1S to ensure the safe operation of charging operations personnelInside rapidly the residual voltage of capacitance C0 is discharged to safe voltage.As shown in Figure of description 1, pass through switching relay or electronic cuttingThe both ends that (common with MOSFET or IGBT) makes bleeder resistance be incorporated to direct current output capacitance are closed, to by the release of the residual voltage of capacitance C0It is currently used control method to fall.

As shown in Figure of description 1, Q0 can be relay or electronic switch MOSFET, R0 are bleeder resistance, when charging takesBusiness terminates after stopping charging, and is closed Q0 and is formed into a loop bleeder resistance R0 inputs with output capacitance, thus by the residual voltage of capacitance C0It runs out of.When charging pile normally provides charging service, Q0 is disconnected, bleeder resistance R0 is exited into bleed-off circuit.

As people are shorter and shorter to the requirement of electric vehicle charging time, the capacity of charging pile is also corresponding increasing, fillsIt needs more charging power modules to compose in parallel inside electric stake, also accordingly adds to the output capacitance C0 of its internal electric source moduleGreatly, the inconsistency for adding charging vehicle cell voltage is kept when progress residual voltage is released after charging service suspension according to energyConstant rule is that the ENERGY E for being stored charging module internal capacitance C0 switchs to thermal energy consumption by resistance R and falls.Capacitance C0 is storedENERGY E=1/2CU², C0 or when U0 bigger, the energy of storage is bigger.Namely bleeder resistance R0 is interior at the same timeThe energy of required consumption is bigger, and calorific value is also accordingly with regard to bigger.It only releases with the control of simply switching in the prior artResistance R0 carries out residual voltage of releasing, and needs the abundant rated power space for staying bigger when system on the one hand being caused to choose bleeder resistance, increasesAdding system cost；On the other hand, if releasing under long-time continuous several times voltage levels, the wink of low-voltage-grade resistance is comparedBetween calorific value higher, to the impact thermal energy bigger of resistance, in some instances it may even be possible to ontology can be burnt out beyond itself thermal stress, to shadowThe security reliability of direct-current charging post system operation is rung.

Invention content

Shortcoming present in view of the above technology, the present invention, which provides one kind, can meet the stopping of charging pile charging serviceResidual voltage afterwards is released requirement, and can be to control method that bleeder resistance is protected.

In order to achieve the above object, a kind of protection of direct-current charging post residual voltage bleeder resistance of the present invention and control method, whenWhen direct-current charging post charging service stops, bleeder resistance accesses bleed-off circuit by high-voltage MOS pipe, according to the assembly of bleeder resistanceWhat voltage, the bleeder resistance of initial maximum pulse shock power, output bus capacitor that heat, the resistance received can be born were accumulated sends outHeat and coefficient of heat transfer constraints, calculated in each cycle time, the maximum turn-on time by bleeder resistance, then byMCU controls to adjust the closing time of high-voltage MOS pipe by PWM, to ensure that bus capacitor release energy when bleeder resistanceCalorific value is no more than the maximum heat that itself can be born, it is ensured that the service life of bleeder resistance.

Wherein, the specific control process of MCU is as follows：

S1, judge whether charging service stops, if needing to start residual voltage control of releasing；If it is not, then directly exiting return；

If S2, charging service stop, maximum calorific value Q can be born according to bleeder resistance_Reg, resistance can bear it is initialMaximum impulse percussion power P_pulse, output bus capacitor voltage U_out, bleeder resistance accumulation calorific value E ' and coefficient of heat transferK constraintss calculate the conducting dutycycle Ton that current period T allows；

S3, according to conducting dutycycle Ton is calculated, the closing time of high-voltage MOS pipe is controlled, to putting into back bleeder resistanceRoad consumes the residual voltage energy of bus capacitor；

After the completion of S4, this controlling cycle T, judge whether the residual voltage of bus capacitor reaches safe voltage value or less；

If safe voltage value S5, has not yet been reached hereinafter, judging entirely to release total time whether exceeded the defined time again；

If S6, entire total time of releasing not yet exceed the defined time, continues to return to S2~S5 steps, continue next periodRelease and calculate Ton and control；

If S7, judging that the residual voltage of bus capacitor has dropped to safe voltage value, control of releasing is exited；

If the residual voltage of S8, bus capacitor safe voltage has not yet been reached hereinafter, and release control exceeded regulation total timeTime in, show that bleed-off circuit in system breaks down, reporting fault alarm signal simultaneously returns.

Wherein, the specific calculating process of conducting dutycycle Ton is as follows in S2：

S21, determine that bleeder resistance can bear maximum calorific value, its be referred to as resistance thermal capacitance Q_Reg；

S22, the initial maximum pulse shock power P that bleeder resistance can be born is determined_pulse；

S23, during releasing, a certain period through heat Δ EReg caused by bleeder resistance be equivalent to this period motherThe energy Δ E that line capacitance is released out_C, i.e.,

Wherein, Δ U is the voltage difference before this period bus capacitor is released and after releasing, and R is bleeder resistance resistance value,ForDuty ratio is controlled, when controlling cycle T is sufficiently small, Δ U can be approximately busbar voltage U at that time_out, therefore, above formula can be reduced to

S24, the energy Δ w to be radiated when period bleeder resistance are that natural heat dissipation or cold wind are forced to dissipate according to bleeder resistanceHeat selects its coefficient of heat transfer K, and according to formula Δ w=Δs E_Reg* K calculates the energy Δ w that bleeder resistance is radiated；

The calorific value E ' that S25, bleeder resistance are accumulated is the sum of the calorific value of n controlling cycle, that is to say that each period releasesThe energy that resistance generates and the sum of the radiated energy for subtracting each period, therefore, the calorific value E ' of bleeder resistance accumulation can be calculated as：

S26, often pass through releasing for a cycle due to bleeder resistance, bleeder resistance generates certain heat, therefore currentThe pulse shock power that its maximum of period can be born

Wherein, Q_RegFor the maximum thermal capacitance of resistance, E ' is to accumulate heat caused by resistance during front is released, firstRelease the period when, E '=0, therefore, first period bleeder resistance maximum can bear most in percussion power P '_pulse=1*P_pulse；WhenE′>When 0,Therefore the percussion power that its maximum is born is reduced with the increase of calorific value；

It is S27, last, to protect bleeder resistance, prevents percussion power excessively high and lead to thermal stress and damage bleeder resistance, oftenThe energy of one controlling cycle bus capacitor should not exceed power P that resistance current period can bear '_pulse, namely

Substitution can obtain：

The beneficial effects of the invention are as follows：

Compared with prior art, the heat Q that the present invention is received according to the assembly of bleeder resistance_Reg, resistance can bear it is initial mostBig pulse shock power P_pulse, output capacitance voltage U_out, bleeder resistance accumulation calorific value E ' and coefficient of heat transfer K etc. aboutBeam condition selects suitable pulse-width regulated duty ratio, the closing time of high-voltage MOS pipe is controlled to adjust by PWM so that each periodThe energy that bus capacitor is released is no more than the energy that can bear of current period bleeder resistance, and resistance during entirely releasingThe heat of accumulation is no more than the thermal capacitance of bleeder resistance itself.So as to ensure charging pile drainage function under the premise of, moreIt is effectively protected the service life of bleeder resistance, and is released under energy situation in identical system, to resistance rated powerChoose the allowance smaller needed for also relatively directly simple switching mode.

Description of the drawings

Fig. 1 is the circuit theory schematic diagram that direct-current charging post residual voltage is released in the prior art；

Fig. 2 is the circuit theory schematic diagram that direct-current charging post residual voltage of the present invention is released；

Fig. 3 is protection and the control method flow diagram of direct-current charging post residual voltage bleeder resistance of the present invention.

Specific implementation mode

In order to more clearly state the present invention, the present invention is further described below in conjunction with the accompanying drawings.

Referring to Fig.2, protection and the control method of a kind of direct-current charging post residual voltage bleeder resistance of the present invention, work as direct-current charging postWhen charging service stops, bleeder resistance R accesses bleed-off circuit, the heat received according to the assembly of bleeder resistance R by high-voltage MOS pipe QThe voltage of initial maximum pulse shock power, output bus capacitor C that amount, resistance can be born, the calorific value of bleeder resistance R accumulationsAnd coefficient of heat transfer constraints, it calculates in each cycle time, then the maximum turn-on time by bleeder resistance R is led to by MCUCross the closing time that PWM controls to adjust high-voltage MOS pipe Q, to ensure that bus capacitor C release energy when bleeder resistance feverAmount is no more than the maximum heat that itself can be born, it is ensured that the service life of bleeder resistance.

Compared to the prior art, the heat Q that the present invention is received according to the assembly of bleeder resistance R_Reg, resistance can bear it is initialMaximum impulse percussion power P_pulse, output capacitance voltage U_out, bleeder resistance R accumulation calorific value E ＇ and coefficient of heat transfer K etc.Constraints selects suitable pulse-width regulated duty ratio, and the closing time of high-voltage MOS pipe Q is controlled to adjust by PWM so that eachThe energy that period bus capacitor C releases is no more than the energy that current period bleeder resistance R can bear, and process of entirely releasingThe heat of middle resistance accumulation is no more than the thermal capacitance of bleeder resistance R itself.So as to before the drainage function for ensureing charging pileIt puts, the service life of bleeder resistance R is more effectively protected, and release under energy situation in identical system, to resistanceRated power chooses the allowance smaller needed for also relatively directly simple switching mode.

Fig. 3 is further regarded to, the specific control process of MCU is as follows：

S1, judge whether charging service stops, if needing to start residual voltage control of releasing；If it is not, then directly exiting return；

If S2, charging service stop, maximum calorific value Q can be born according to bleeder resistance R_Reg, resistance can bear it is initialMaximum impulse percussion power P_pulse, output bus capacitor C voltage U_out, bleeder resistance R accumulation calorific value E ＇ and heat dissipation systemNumber K constraintss calculate the conducting dutycycle Ton that current period T allows；

S3, according to calculating conducting dutycycle Ton, the closing time of control high-voltage MOS pipe Q, to put into bleeder resistance RCircuit consumes the residual voltage energy of bus capacitor C；

After the completion of S4, this controlling cycle T, judge whether the residual voltage of bus capacitor C reaches safe voltage value or less；

If safe voltage value S5, has not yet been reached hereinafter, judging entirely to release total time whether exceeded the defined time again；

If S6, entire total time of releasing not yet exceed the defined time, continues to return to S2~S5 steps, continue next periodRelease and calculate Ton and control；

If S7, judging that the residual voltage of bus capacitor C has dropped to safe voltage value, control of releasing is exited；

If the residual voltage of S8, bus capacitor C safe voltage has not yet been reached hereinafter, and release control exceeded regulation total timeTime in, show that bleed-off circuit in system breaks down, reporting fault alarm signal simultaneously returns.

In the present embodiment, the specific calculating process of conducting dutycycle Ton is as follows in S2：

S21, determine that bleeder resistance R can bear maximum calorific value, its be referred to as resistance thermal capacitance Q_Reg；

S22, the initial maximum pulse shock power P that bleeder resistance R can be born is determined_pulse；

S23, during releasing, a certain period is through heat Δ E caused by bleeder resistance R_RegIt is equivalent to this period motherThe energy Δ E that line capacitance C releases out_C, i.e.,

Wherein, Δ U is the voltage difference before this period bus capacitor C releases and after releasing, and R is bleeder resistance R resistance values,Duty ratio in order to control, when controlling cycle T is sufficiently small, Δ U can be approximately busbar voltage U at that time_out, therefore, above formula can simplifyFor

S24, the energy Δ w to be radiated as period bleeder resistance R are that natural heat dissipation or cold wind are forced according to bleeder resistance RHeat dissipation, selects its coefficient of heat transfer K, and according to formula Δ w=Δs E_Reg* K calculates the energy Δ w that bleeder resistance R is radiated；

The calorific value E ' that S25, bleeder resistance R accumulate is the sum of the calorific value of n controlling cycle, that is to say that each period releasesThe energy that resistance R is generated and the sum of the radiated energy for subtracting each period, therefore, the calorific value E ＇ of bleeder resistance R accumulations can calculateFor：

S26, it a cycle is often passed through due to bleeder resistance R releasing, bleeder resistance R generates certain heat, therefore work asThe pulse shock power that its maximum of preceding period can be born

Wherein, Q_RegFor the maximum thermal capacitance of resistance, E ＇ are to accumulate heat caused by resistance during front is released, firstRelease the period when, E '=0, therefore, first period bleeder resistance R maximums can bear most in percussion power P '_pulse=1*P_pulse；As E '>When 0,Therefore the percussion power that its maximum is born is reduced with the increase of calorific value；

It is S27, last, to protect bleeder resistance R, prevents percussion power excessively high and lead to thermal stress and damage bleeder resistance R,The energy of each controlling cycle bus capacitor C should not exceed power P that resistance current period can bear '_pulse, namely

Substitution can obtain：

Disclosed above is only several specific embodiments of the present invention, but the present invention is not limited to this, any abilityWhat the technical staff in domain can think variation should all fall into protection scope of the present invention.

Claims (3)

1. protection and the control method of a kind of direct-current charging post residual voltage bleeder resistance, which is characterized in that when direct-current charging post chargesWhen service stopping, bleeder resistance accesses bleed-off circuit, the heat received according to the assembly of bleeder resistance, resistance by high-voltage MOS pipeThe calorific value and heat dissipation that the initial maximum pulse shock power that can be born, the voltage, the bleeder resistance that export bus capacitor are accumulatedRestricted coefficients of equation condition calculated in each cycle time, then the maximum turn-on time by bleeder resistance is controlled by MCU by PWMThe closing time of high-voltage MOS pipe is adjusted, bus capacitor is released energy.

2. protection and the control method of direct-current charging post residual voltage bleeder resistance according to claim 1, which is characterized in thatThe specific control process of MCU is as follows：

S1, judge whether charging service stops, if needing to start residual voltage control of releasing；If it is not, then directly exiting return；

If S2, charging service stop, maximum calorific value Q can be born according to bleeder resistance_Reg, the initial maximum that can bear of resistancePulse shock power P_pulse, output bus capacitor voltage U_out, bleeder resistance accumulation calorific value E ' and coefficient of heat transfer K aboutBeam condition calculates the conducting dutycycle Ton that current period T allows；

S3, according to calculate conducting dutycycle Ton, control the closing time of high-voltage MOS pipe, to by bleeder resistance put into circuit pairThe residual voltage energy of bus capacitor is consumed；

After the completion of S4, this controlling cycle T, judge whether the residual voltage of bus capacitor reaches safe voltage value or less；

If safe voltage value S5, has not yet been reached hereinafter, judging entirely to release total time whether exceeded the defined time again；

If S6, entire total time of releasing not yet exceed the defined time, continues to return to S2~S5 steps, continue letting out for next periodIt puts and calculates Ton and control；

If S7, judging that the residual voltage of bus capacitor has dropped to safe voltage value, control of releasing is exited；

If safe voltage has not yet been reached hereinafter, and releasing control when total time having exceeded defined in the residual voltage of S8, bus capacitorIn, show that the bleed-off circuit in system breaks down, reporting fault alarm signal simultaneously returns.

3. protection and the control method of direct-current charging post residual voltage bleeder resistance according to claim 2, which is characterized in thatThe specific calculating process of conducting dutycycle Ton is as follows in S2：

S21, determine that bleeder resistance can bear maximum calorific value, its be referred to as resistance thermal capacitance Q_Reg；

S22, the initial maximum pulse shock power P that bleeder resistance can be born is determined_pulse；

S23, during releasing, a certain period is through heat Δ E caused by bleeder resistance_RegIt is equivalent to this period busbar electricityHold the energy Δ E to release out_C, i.e.,

Wherein, Δ U is the voltage difference before this period bus capacitor is released and after releasing, and R is bleeder resistance resistance value,In order to controlDuty ratio, when controlling cycle T is sufficiently small, Δ U can be approximately busbar voltage U at that time_out, therefore, above formula can be reduced to

S24, the energy Δ w to be radiated when period bleeder resistance are natural heat dissipation or cold wind forced heat radiation, choosing according to bleeder resistanceIts coefficient of heat transfer K is selected, and according to formula Δ w=Δs E_Reg* K calculates the energy Δ w that bleeder resistance is radiated；

The calorific value E ' that S25, bleeder resistance are accumulated is the sum of the calorific value of n controlling cycle, that is to say each period bleeder resistanceThe energy of generation and the sum of the radiated energy for subtracting each period, therefore, the calorific value E ' of bleeder resistance accumulation can be calculated as：

S26, it a cycle is often passed through due to bleeder resistance releasing, bleeder resistance generates certain heat, therefore current periodThe pulse shock power that its maximum can be born

Wherein, Q_RegFor the maximum thermal capacitance of resistance, E ' is to accumulate heat caused by resistance during front is released, first to releaseWhen the period, E '=0, therefore, first period bleeder resistance maximum can bear most in percussion power P '_pluse=1*P_pulse；As E '>0When,Therefore the percussion power that its maximum is born is reduced with the increase of calorific value；

It is S27, last, to protect bleeder resistance, prevents percussion power excessively high and lead to thermal stress and damage bleeder resistance, each controlThe energy of period bus capacitor processed should not exceed power P that resistance current period can bear '_pulse, namely

Substitution can obtain：