CN107422185A - A kind of insulation resistance of DC system observation circuit, system and method - Google Patents

A kind of insulation resistance of DC system observation circuit, system and method Download PDF

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Publication number
CN107422185A
CN107422185A CN201710198085.2A CN201710198085A CN107422185A CN 107422185 A CN107422185 A CN 107422185A CN 201710198085 A CN201710198085 A CN 201710198085A CN 107422185 A CN107422185 A CN 107422185A
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China
Prior art keywords
resistance
circuit
booster
voltage
resistor
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Inventor
刘群
梁树明
张伟森
柏伟杰
黄浩
许兴发
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Electrical Appliances Co Ltd That Jiangmen City Is Sweet
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Electrical Appliances Co Ltd That Jiangmen City Is Sweet
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Priority to CN201710198085.2A priority Critical patent/CN107422185A/en
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
    • G01R27/025Measuring very high resistances, e.g. isolation resistances, i.e. megohm-meters

Abstract

The invention provides a kind of insulation resistance of DC system observation circuit, including:Booster circuit, observation circuit and magnitude of voltage sample circuit;The booster circuit, it includes the first booster T1 and the second booster T2, for providing observation circuit injection PWM ripples.The voltage sampling circuit is used to sample the voltage in observation circuit, so as to calculate the insulator chain size in straight-flow system.Compared to prior art, circuit of the invention is by injecting direct current signal so as to improving accuracy of detection.Further, observation circuit of the invention can monitor the fault state of positive and negative electrode insulaion resistance in real time, and will not be to influenceing power supply quality.

Description

A kind of insulation resistance of DC system observation circuit, system and method
Technical field
The present invention relates to electric automobiles, particularly a kind of insulation resistance of DC system observation circuit;The invention further relates to A kind of monitoring system and monitoring method of the application circuit.
Background technology
The voltage of the battery bag of electric automobile typically in 300V or so, and electric automobile use environment is more severe, by Colded and heat succeed each other and the influence of electrokinetic cell corrosive liquids, gas etc. in vibration, impact, weather, its strong power part (such as power The parts such as battery bag, electric machine controller, motor and onboard charger) damaging and breaking easily occur in the insulation between car body It is bad, make decreasing insulating, power supply positive and negative electrode lead forms leakage current loop by insulating barrier and chassis, made on the current potential of chassis Rise, the not only personal safety of entail dangers to passenger, will also influence the normal work of in-car electrical equipment, accurately, detect high-voltage electrical apparatus in real time System has important meaning to vehicle chassis insulating properties, guarantee passenger safety, electrical equipment normal work and vehicle safety operation Justice.
At present, contour straightening is detected in pure electric automobile, hybrid power automobile battery group and energy-storage battery group insulaion resistance The insulaion resistance detection field of streaming system, main method have bridge balance principle method, Low frequency signal injection method.
Wherein, the specific method of balanced bridge method is as follows:
Fig. 1 a-1b are referred to, it is respectively circuit diagram of prior art balanced bridge method when switch on and off.Together When closure open K1 ", K2 ", then it is in parallel with insulaion resistance Rp, Rn respectively to access resistance R1 ", R2 ".Wherein R1 "=R2 ", sets simultaneously Standby insulaion resistance under normal circumstances, then Rp=Rn.Therefore, by judging whether U1 is equal " with U2 ", recognizes if unequal For insulaion resistance failure, U1 ", U2 " is respectively the measured value of positive and negative electrode insulaion resistance both end voltage.
The problem of balanced bridge method is present:1st, it is closed at switching K1 ", K2 ", parallel connection access resistance can reduce the exhausted of equipment Edge performance, therefore just reduce the security of personnel and equipment;2. when insulaion resistance Rp, Rn are reduced simultaneously, then can't detect Insulaion resistance failure;3. the real time monitoring function without insulaion resistance.
Referring to Fig. 2, it is the circuit diagram of Low frequency signal injection method.The Low frequency signal injection method is specific as follows:
First, fault detect is carried out to insulaion resistance, opens switch K1、K2, calculate the parallel connection of positive and negative electrode insulaion resistance Value Rpn;And by RpnWith the threshold value R of settingthCompare, come judge the insulaion resistance of equipment whether failure.
If normal, circulation carries out fault detect, otherwise, carries out insulaion resistance calculating, then disconnecting consumers, AC signal Source, closure switch K1、K2, resistance R is measured respectively1、R2Both end voltage, calculate positive and negative electrode insulation Rp、RnValue.
This method can monitor the fault state of positive and negative electrode insulaion resistance in real time compared with balanced bridge method, and to whole negative Load does not influence;By calculating insulaion resistance Rp、RnThe size of value, to provide foundation to the fault diagnosis of whole system, to personnel And the safety of equipment is provided and ensured in real time.However, this method still has following defect:Increase the ripple of straight-flow system, Power supply quality is influenceed, and the distribution capacity of system can directly affect measurement result, reduce resolution ratio.
The content of the invention
The shortcomings that it is an object of the invention to overcome prior art and deficiency, there is provided a kind of insulation resistance of DC system prison Slowdown monitoring circuit, system and method.
The present invention is realized by following scheme:A kind of insulation resistance of DC system observation circuit, including:Booster circuit, Observation circuit and magnitude of voltage sample circuit;
The booster circuit, it includes the first booster T1 and the second booster T2;
The observation circuit, it includes the first relay contact S1, the second relay contact S2, the first diode D1, Two diode D2, first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, 7th resistance R7 and the 8th resistance R8;
Described first relay contact S1 one end is connected with the positive pole of battery bag device, the other end successively with first resistor R1,3rd resistor R3, the 5th resistance R5 and the 7th resistance R7 connections, and pass through the second relay contact S2 and battery bag device Negative pole connects;The first relay S1 and first resistor R1 tie point connects the first diode D1 negative pole, the second relay S1 and the 7th resistance R1 tie point connect the second diode D2 positive pole, the first diode D1 positive pole and second resistance R2, the Four resistance R4, the 6th resistance R5, the 8th resistance R8, the second diode D2 negative pole are sequentially connected;The 4th resistance R4 and Six resistance R6 tie point ground connection, 3rd resistor R3 and the 5th resistance R5 tie point are grounded;
The magnitude of voltage sample circuit is respectively used to 3rd resistor R3, the 5th resistance R5, the electricity of the 4th resistance R4 and the 6th Resistance R6 both end voltages are acquired;
The input of the first booster T1 receives PWM ripples, and output end is connected in parallel on second resistance R2 both ends;
The input of the second booster T2 receives PWM ripples, and output end is connected in parallel on the 8th resistance R8 both ends.
Compared to prior art, the invention provides a kind of circuit of the insulaion resistance for straight-flow systems such as electric cars, The circuit of the present invention is by injecting direct current signal so as to improving accuracy of detection.Further, observation circuit of the invention can be real-time The fault state of positive and negative electrode insulaion resistance is monitored, and will not be to influenceing power supply quality.
As a further improvement on the present invention, the size of the first resistor R1 and the 7th resistance R7 are in 45M Ω~55M Ω Between, the size of the 3rd resistor R3 and the 5th resistance R5 are between 4.7K Ω~10K Ω.
As a further improvement on the present invention, the magnitude of voltage sample circuit is provided with filter circuit, for eliminating direct current Clutter in voltage.
Present invention also offers a kind of insulation resistance of DC system monitoring system, and it includes battery bag device, insulating monitoring Device, MCU processors, battery management system and entire car controller;
The insulation monitoring and warning device is used to be monitored the insulaion resistance of battery bag device;
The MCU processors connect respectively at battery management system with insulation monitoring and warning device, for receiving battery management system The instruction of system, and the resistance size for the insulaion resistance that insulation monitoring and warning device is monitored is sent to battery management system;
The entire car controller is connected with the battery management system, the insulation monitored for receiving battery management system The resistance of resistance, and given a warning according to the resistance size of insulaion resistance;
Insulation resistance of DC system observation circuit, the insulaion resistance observation circuit bag are provided with the insulation monitoring and warning device Include:Booster circuit, observation circuit and magnitude of voltage sample circuit;
The booster circuit, it includes the first booster T1 and the second booster T2;
The observation circuit, it includes the first relay contact S1, the second relay contact S2, the first diode D1, Two diode D2, first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, 7th resistance R7 and the 8th resistance R8;
Described first relay contact S1 one end is connected with the positive pole of battery bag device, the other end successively with first resistor R1,3rd resistor R3, the 5th resistance R5 and the 7th resistance R7 connections, and pass through the second relay contact S2 and battery bag device Negative pole connects;The first relay contact S1 other ends are connected with the first diode D1 negative pole simultaneously, first diode D3 positive pole is connected with second resistance R2, the 4th resistance R4, the 6th resistance R5, the 8th resistance R8 successively, the 8th resistance R8's The other end is connected with the second diode D2 negative pole, and second diode D2 positive pole passes through the second relay contact S2 and battery The negative pole connection of bag apparatus;One end ground connection that the 4th resistance R4 and the 6th resistance R6 are connected with each other, the 3rd resistor R3 It is grounded with one end that the 5th resistance R5 is connected with each other;
The magnitude of voltage sample circuit is respectively used to 3rd resistor R3, the 5th resistance R5, the electricity of the 4th resistance R4 and the 6th Resistance R6 both end voltages are acquired;
The input of the first booster T1 receives PWM ripples, and output end is connected in parallel on second resistance R2 both ends;
The input of the second booster T2 receives PWM ripples, and output end is connected in parallel on the 8th resistance R8 both ends.
As a further improvement on the present invention, the size of the first resistor R1 and the 7th resistance R7 are in 45M Ω~55M Ω Between, the size of the 3rd resistor R3 and the 5th resistance R5 are between 4.7K Ω~10K Ω.
As a further improvement on the present invention, the magnitude of voltage sample circuit is provided with filter circuit, for eliminating direct current Clutter in voltage.
Present invention also offers a kind of detection method using above-mentioned insulation resistance of DC system detecting system, including it is following Step:
Step S1:Monitoring order is received, closing relay S1, S2, MCU do not give pwm signal, and booster circuit does not work;
Step S2:3rd resistor R3, the 5th resistance R5 voltage are sampled, calculate the positive and negative bus pair of straight-flow system Voltage U+, U- and straight-flow system total voltage U=U++U- on ground insulaion resistance, then positive and negative bus insulation against ground resistance got Dc bus total voltage intrinsic standoff ratio N=U-/U+=Rn/Rp;
S3:Work as Rn>Rp, and U, U+ and U- are in the range of presetting, and disconnect the negative of the bigger side of the partial pressure End relay S2, MCU give booster circuit pwm signal, and a direct current is produced at second resistance R2 both ends by the first booster T1 Voltage signal;If U or U+ or U- is in outside predetermined scope, alarm signal is sent, skips to step S6;
As Rn < Rp, and U, U+ and U- are in the range of presetting, and disconnect the negative terminal of the bigger side of the partial pressure Relay S1, MCU give booster circuit pwm signal, and a direct current is produced at the 8th resistance R8 both ends by the first booster T2 Press signal;If U or U+ or U- is in outside predetermined scope, alarm signal is sent, skips to step S6;
S4:Work as Rn>Rp, by the voltage Ucc for sampling to obtain in the 4th resistance R4, calculate and injected by the first booster T1 The size of DC current, while 3rd resistor R3 voltage is sampled again, calculate when anode booster circuit works, just The voltage U+ ' and the resistance Rp of insulation against ground resistance got on bus insulation against ground resistance;
Wherein, U+ '/Rp=Ucc/R4+ (U-U+ ')/Rn, with reference to intrinsic standoff ratio equation, can obtain
As Rn < Rp, by the voltage Ucc for sampling to obtain in the 6th resistance R6, calculate straight by the first booster T2 injections The size of electric current is flowed, while the 5th resistance R5 voltage is sampled again, is calculated when anode booster circuit works, positive pole The voltage U- ' and the resistance Rn of insulation against ground resistance got on line insulation against ground resistance;
Wherein, U- '/Rn=Ucc/R6+ (U-U-′)/Rp, with reference to intrinsic standoff ratio equation, can obtain
S5:Work as Rn>Rp, according to intrinsic standoff ratio N calculate negative busbar insulation against ground resistance resistance Rn, if both Rp, Rn or it One is less than setting set in advance, then sends alarm signal;
As Rn < Rp, the resistance Rp of negative busbar insulation against ground resistance is calculated according to intrinsic standoff ratio N, if both Rp, Rn or one of Less than setting set in advance, then alarm signal is sent;
S6:Relay S1, S2 is turned off, MCU give pwm signal, and booster circuit does not work, and waits monitoring next time to order.
In summary, compared to prior art, the invention provides a kind of insulated electro for straight-flow systems such as electric cars The circuit of resistance, circuit of the invention is by injecting direct current signal so as to improving accuracy of detection.Further, observation circuit of the invention The fault state of positive and negative electrode insulaion resistance can be monitored in real time, and will not be to influenceing power supply quality.
Meanwhile on the basis of based on observation circuit, present invention also offers a kind of insulation for being used to monitor straight-flow system The monitoring system of resistance, and the monitoring method using the monitoring system.
In order to more fully understand and implement, the invention will now be described in detail with reference to the accompanying drawings.
Brief description of the drawings
Fig. 1 a are circuit diagrams when switching off of prior art balanced bridge method.
Circuit diagram when Fig. 1 b are the switch closures of prior art balanced bridge method.
Fig. 2 is the circuit diagram of Low frequency signal injection method.
The circuit diagram of Fig. 3 observation circuit of the invention.
Fig. 4 is the connection block diagram of the monitoring system of the present invention.
The step flow chart of Fig. 5 monitoring method of the invention.
Embodiment
With reference to embodiments and accompanying drawing the present invention is described in further detail, but embodiments of the present invention are unlimited In this.
Caused defect during present invention is generally directed to use balanced bridge method or low frequency injection method in the prior art, there is provided A kind of insulation resistance of DC system observation circuit, detecting system and detection method, specific scheme are entered by following examples Row is introduced:
Embodiment 1
First, the invention provides a kind of observation circuit, the insulaion resistance for the straight-flow system to electric car carries out real When monitor, so as to calculate the size of the insulating resistance value of the straight-flow system.The observation circuit of the present invention is introduced in detail below Circuit is formed, referring to Fig. 3, its circuit diagram for the observation circuit of the present invention.The invention provides a kind of insulation of straight-flow system Electrical resistance monitoring circuit, including:Booster circuit, observation circuit and magnitude of voltage sample circuit.
The booster circuit, it includes the first booster T1 and the second booster T2.
The observation circuit, it includes the first relay contact S1, the second relay contact S2, the first diode D1, Two diode D2, first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, 7th resistance R7 and the 8th resistance R8.
Described first relay contact S1 one end is connected with the positive pole of battery bag device, the other end successively with first resistor R1,3rd resistor R3, the 5th resistance R5 and the 7th resistance R7 connections, and pass through the second relay contact S2 and battery bag device Negative pole connects;The first relay S1 and first resistor R1 tie point connects the first diode D1 negative pole, the second relay S1 and the 7th resistance R1 tie point connect the second diode D2 positive pole, the first diode D1 positive pole and second resistance R2, the Four resistance R4, the 6th resistance R5, the 8th resistance R8, the second diode D2 negative pole are sequentially connected;The 4th resistance R4 and Six resistance R6 tie point ground connection, 3rd resistor R3 and the 5th resistance R5 tie point are grounded.
The magnitude of voltage sample circuit is respectively used to 3rd resistor R3, the 5th resistance R5, the electricity of the 4th resistance R4 and the 6th Resistance R6 both end voltages are acquired.
The input of the first booster T1 receives PWM ripples, and output end is connected in parallel on second resistance R2 both ends.
The input of the second booster T2 receives PWM ripples, and output end is connected in parallel on the 8th resistance R8 both ends.
Further, the size of the first resistor R1 and the 7th resistance R7 are between 45M Ω~55M Ω, the 3rd electricity R3 and the 5th resistance R5 size is hindered between 4.7K Ω~10K Ω.Specifically, when for different objects progress insulaion resistance prison During survey, the resistance of different resistances can be used.
Further, because motor work makes DC voltage contain clutter, therefore the filtering such as π types is being increased on sample circuit Circuit, the data for being sampled sample resistance are more accurate, and effect is more preferable.
Embodiment 2
1 observation circuit in conjunction with the embodiments, present invention also offers the insulation resistance of DC system that one is used for electric car Monitoring system.Referring specifically to Fig. 4, it is the connection block diagram of the monitoring system of the present invention.Present invention also offers a kind of straight Streaming system insulaion resistance monitoring system, it includes battery bag device 1, insulation monitoring and warning device 2, MCU processors 3, battery management system System 4 and entire car controller 5.
The insulation monitoring and warning device 2 is used to be monitored the insulaion resistance of battery bag device;
The MCU processors 3 connect respectively at battery management system with insulation monitoring and warning device, for receiving battery management system The instruction of system, and the resistance size for the insulaion resistance that insulation monitoring and warning device is monitored is sent to battery management system;
The entire car controller 5 is connected with the battery management system 4, for receive battery management system monitored it is exhausted The resistance of edge resistance, and given a warning according to the resistance size of insulaion resistance.
Provided with the insulation resistance of DC system observation circuit described in embodiment 1 in the insulation monitoring and warning device 2.It is described exhausted Edge electrical resistance monitoring circuit includes:Booster circuit, observation circuit and magnitude of voltage sample circuit.
The booster circuit, it includes the first booster T1 and the second booster T2;
The observation circuit, it includes the first relay contact S1, the second relay contact S2, the first diode D1, Two diode D2, first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, 7th resistance R7 and the 8th resistance R8;
Described first relay contact S1 one end is connected with the positive pole of battery bag device, the other end successively with first resistor R1,3rd resistor R3, the 5th resistance R5 and the 7th resistance R7 connections, and pass through the second relay contact S2 and battery bag device Negative pole connects;The first relay S1 and first resistor R1 tie point connects the first diode D1 negative pole, the second relay S1 and the 7th resistance R1 tie point connect the second diode D2 positive pole, the first diode D1 positive pole and second resistance R2, the Four resistance R4, the 6th resistance R5, the 8th resistance R8, the second diode D2 negative pole are sequentially connected;The 4th resistance R4 and Six resistance R6 tie point ground connection, 3rd resistor R3 and the 5th resistance R5 tie point are grounded.
The magnitude of voltage sample circuit is respectively used to 3rd resistor R3, the 5th resistance R5, the electricity of the 4th resistance R4 and the 6th Resistance R6 both end voltages are acquired;
The input of the first booster T1 receives PWM ripples, and output end is connected in parallel on second resistance R2 both ends;
The input of the second booster T2 receives PWM ripples, and output end is connected in parallel on the 8th resistance R8 both ends.
As a further improvement on the present invention, the size of the first resistor R1 and the 7th resistance R7 are in 45M Ω~55M Ω Between, the size of the 3rd resistor R3 and the 5th resistance R5 are between 4.7K Ω~10K Ω.
Embodiment 3
Referring to Fig. 5, its step flow chart for the monitoring method of the present invention.It is exhausted based on the straight-flow system in embodiment 2 Edge electrical resistance monitoring system, present invention also offers a kind of monitoring method using above-mentioned insulation resistance of DC system monitoring system, Comprise the following steps:
Step S1:Monitoring order is received, closing relay S1, S2, MCU do not give pwm signal, and booster circuit does not work;
Step S2:3rd resistor R3, the 5th resistance R5 voltage are sampled, calculate the positive and negative bus pair of straight-flow system Voltage U+, U- and straight-flow system total voltage U=U++U- on ground insulaion resistance, then positive and negative bus insulation against ground resistance got Dc bus total voltage intrinsic standoff ratio N=U-/U+=Rn/Rp.
S3:Work as Rn>Rp, and U, U+ and U- are in the range of presetting, and disconnect the negative of the bigger side of the partial pressure End relay S2, MCU give booster circuit pwm signal, and a direct current is produced at second resistance R2 both ends by the first booster T1 Voltage signal;If U or U+ or U- is in outside predetermined scope, alarm signal is sent, skips to step S6.
As Rn < Rp, and U, U+ and U- are in the range of presetting, and disconnect the negative terminal of the bigger side of the partial pressure Relay S1, MCU give booster circuit pwm signal, and a direct current is produced at the 8th resistance R8 both ends by the first booster T2 Press signal;If U or U+ or U- is in outside predetermined scope, alarm signal is sent, skips to step S6.
S4:Work as Rn>Rp, by the voltage Ucc for sampling to obtain in the 4th resistance R4, calculate and injected by the first booster T1 The size of DC current, while 3rd resistor R3 voltage is sampled again, calculate when anode booster circuit works, just The voltage U+ ' and the resistance Rp of insulation against ground resistance got on bus insulation against ground resistance.
Wherein, U+ '/Rp=Ucc/R4+ (U-U+ ')/Rn, with reference to intrinsic standoff ratio equation, can obtain
As Rn < Rp, by the voltage Ucc for sampling to obtain in the 6th resistance R6, calculate straight by the first booster T2 injections The size of electric current is flowed, while the 5th resistance R5 voltage is sampled again, is calculated when anode booster circuit works, positive pole The voltage U- ' and the resistance Rn of insulation against ground resistance got on line insulation against ground resistance.
Wherein, U- '/Rn=Ucc/R6+ (U-U-′)/Rp, with reference to intrinsic standoff ratio equation, can obtain
S5:Work as Rn>Rp, according to intrinsic standoff ratio N calculate negative busbar insulation against ground resistance resistance Rn, if both Rp, Rn or it One is less than setting set in advance, then sends alarm signal.
As Rn < Rp, the resistance Rp of negative busbar insulation against ground resistance is calculated according to intrinsic standoff ratio N, if both Rp, Rn or one of Less than setting set in advance, then alarm signal is sent.
S6:Relay S1, S2 is turned off, MCU give pwm signal, and booster circuit does not work, and waits monitoring next time to order.
In summary, compared to prior art, the invention provides a kind of insulated electro for straight-flow systems such as electric cars The circuit of resistance, circuit of the invention is by injecting direct current signal so as to improving accuracy of detection.Further, observation circuit of the invention The fault state of positive and negative electrode insulaion resistance can be monitored in real time, and will not be to influenceing power supply quality.
Meanwhile on the basis of based on observation circuit, present invention also offers a kind of insulation for being used to monitor straight-flow system The monitoring system of resistance, and the monitoring method using the monitoring system.
Above-described embodiment is the preferable embodiment of the present invention, but embodiments of the present invention are not by above-described embodiment Limitation, other any Spirit Essences without departing from the present invention with made under principle change, modification, replacement, combine, simplification, Equivalent substitute mode is should be, is included within protection scope of the present invention.

Claims (7)

  1. A kind of 1. insulation resistance of DC system observation circuit, it is characterised in that:Including:Booster circuit, observation circuit and magnitude of voltage Sample circuit;
    The booster circuit, it includes the first booster T1 and the second booster T2;
    The observation circuit, it includes the first relay contact S1, the second relay contact S2, the first diode D1, the two or two Pole pipe D2, first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, the 7th Resistance R7 and the 8th resistance R8;
    Described first relay contact S1 one end is connected with the positive pole of battery bag device, the other end successively with first resistor R1, Three resistance R3, the 5th resistance R5 and the 7th resistance R7 connections, and pass through the second relay contact S2 and the negative pole of battery bag device Connection;The first relay S1 and first resistor R1 tie point connect the first diode D1 negative pole, the second relay S1 with 7th resistance R1 tie point connects the second diode D2 positive pole, the first diode D1 positive pole and second resistance R2, the 4th electricity Resistance R4, the 6th resistance R5, the 8th resistance R8, the second diode D2 negative pole are sequentially connected;The electricity of the 4th resistance R4 and the 6th Hinder the tie point ground connection of R6 tie point ground connection, 3rd resistor R3 and the 5th resistance R5;
    The magnitude of voltage sample circuit is respectively used to 3rd resistor R3, the 5th resistance R5, the 4th resistance R4 and the 6th resistance R6 Both end voltage is acquired;
    The input of the first booster T1 receives PWM ripples, and output end is connected in parallel on second resistance R2 both ends;
    The input of the second booster T2 receives PWM ripples, and output end is connected in parallel on the 8th resistance R8 both ends.
  2. 2. insulation resistance of DC system observation circuit according to claim 1, it is characterised in that:The magnitude of voltage sample circuit Filter circuit is provided with, for eliminating the clutter in DC voltage.
  3. 3. insulation resistance of DC system observation circuit according to claim 1, it is characterised in that:The first resistor R1 and Seven resistance R7 size between 45M Ω~55M Ω, the size of the 3rd resistor R3 and the 5th resistance R5 4.7K Ω~ Between 10K Ω.
  4. A kind of 4. insulation resistance of DC system monitoring system, it is characterised in that:Including battery bag device, insulation monitoring and warning device, MCU Processor, battery management system and entire car controller;
    The insulation monitoring and warning device is used to be monitored the insulaion resistance of battery bag device;
    The MCU processors connect respectively at battery management system with insulation monitoring and warning device, for receiving battery management system Instruction, and the resistance size for the insulaion resistance that insulation monitoring and warning device is monitored is sent to battery management system;
    The entire car controller is connected with the battery management system, the insulaion resistance monitored for receiving battery management system Resistance, and given a warning according to the resistance size of insulaion resistance;
    Insulation resistance of DC system observation circuit is provided with the insulation monitoring and warning device, the insulaion resistance observation circuit includes: Booster circuit, observation circuit and magnitude of voltage sample circuit;
    The booster circuit, it includes the first booster T1 and the second booster T2;
    The observation circuit, it includes the first relay contact S1, the second relay contact S2, the first diode D1, the two or two Pole pipe D2, first resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R4, the 5th resistance R5, the 6th resistance R6, the 7th Resistance R7 and the 8th resistance R8;
    Described first relay contact S1 one end is connected with the positive pole of battery bag device, the other end successively with first resistor R1, Three resistance R3, the 5th resistance R5 and the 7th resistance R7 connections, and pass through the second relay contact S2 and the negative pole of battery bag device Connection;The first relay contact S1 other ends are connected with the first diode D1 negative pole simultaneously, first diode D3's Positive pole is connected with second resistance R2, the 4th resistance R4, the 6th resistance R5, the 8th resistance R8 successively, and the 8th resistance R8's is another End is connected with the second diode D2 negative pole, and second diode D2 positive pole passes through the second relay contact S2 and battery packages The negative pole connection put;One end ground connection that the 4th resistance R4 and the 6th resistance R6 are connected with each other, the 3rd resistor R3 and the One end ground connection that five resistance R5 are connected with each other;
    The magnitude of voltage sample circuit is respectively used to 3rd resistor R3, the 5th resistance R5, the 4th resistance R4 and the 6th resistance R6 Both end voltage is acquired;
    The input of the first booster T1 receives PWM ripples, and output end is connected in parallel on second resistance R2 both ends;
    The input of the second booster T2 receives PWM ripples, and output end is connected in parallel on the 8th resistance R8 both ends.
  5. 5. insulation resistance of DC system monitoring system according to claim 4, it is characterised in that:The first resistor R1 and Seven resistance R7 size between 45M Ω~55M Ω, the size of the 3rd resistor R3 and the 5th resistance R5 4.7K Ω~ Between 10K Ω.
  6. 6. insulation resistance of DC system monitoring system according to claim 4, it is characterised in that:The magnitude of voltage sample circuit Filter circuit is provided with, for eliminating the clutter in DC voltage.
  7. A kind of 7. monitoring method for applying insulation resistance of DC system monitoring system as claimed in claim 3, it is characterised in that:Bag Include following steps:
    Step S1:Monitoring order is received, closing relay S1, S2, MCU controllers do not give pwm signal, and booster circuit does not work;
    Step S2:3rd resistor R3, the 5th resistance R5 voltage are sampled, it is exhausted over the ground to calculate the positive and negative bus of straight-flow system The ohmically voltage U of edge+、U-With straight-flow system total voltage U=U++U-, then positive and negative bus insulation against ground resistance got straight Flow the intrinsic standoff ratio N=U of bus total voltage-/U+=Rn/Rp
    S3:Work as Rn>Rp, and U, U+And U-In the range of presetting, the negative terminal relay of the bigger side of the partial pressure is disconnected Device S2, MCU give booster circuit pwm signal, and producing a DC voltage at second resistance R2 both ends by the first booster T1 believes Number;If U or U+Or U-Outside predetermined scope, alarm signal is sent, skips to step S6;
    Work as Rn< Rp, and U, U+And U-In the range of presetting, the negative terminal relay of the bigger side of the partial pressure is disconnected S1, MCU controller give booster circuit pwm signal, and a direct current is produced at the 8th resistance R8 both ends by the first booster T2 Press signal;If U or U+Or U-Outside predetermined scope, alarm signal is sent, skips to step S6;
    S4:Work as Rn>Rp, pass through the voltage U for sampling to obtain in the 4th resistance R4cc, calculate and direct current injected by the first booster T1 The size of stream, while 3rd resistor R3 voltage is sampled again, calculate when anode booster circuit works, positive bus-bar pair The voltage U got on ground insulaion resistance+' resistance the R with insulation against ground resistancep
    Wherein, U+′/Rp=Ucc/R4+ (U-U+′)/Rn, with reference to intrinsic standoff ratio equation, can obtain
    <mrow> <msub> <mi>R</mi> <mi>p</mi> </msub> <mo>=</mo> <mfrac> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <mfrac> <mn>1</mn> <mi>N</mi> </mfrac> <mo>)</mo> <msub> <mi>R</mi> <mn>4</mn> </msub> <mo>&amp;CenterDot;</mo> <msubsup> <mi>U</mi> <mo>+</mo> <mo>&amp;prime;</mo> </msubsup> </mrow> <msub> <mi>U</mi> <mrow> <mi>c</mi> <mi>c</mi> </mrow> </msub> </mfrac> <mo>-</mo> <mfrac> <mrow> <msub> <mi>R</mi> <mn>4</mn> </msub> <mo>&amp;CenterDot;</mo> <mi>U</mi> </mrow> <mrow> <msub> <mi>NU</mi> <mrow> <mi>c</mi> <mi>c</mi> </mrow> </msub> </mrow> </mfrac> <mo>;</mo> </mrow>
    Work as Rn< Rp, pass through the voltage U for sampling to obtain in the 6th resistance R6cc, calculate and DC current injected by the first booster T2 Size, while the 5th resistance R5 voltage is sampled again, calculated when anode booster circuit works, positive bus-bar is over the ground The voltage U got on insulaion resistance-' resistance the R with insulation against ground resistancen
    Wherein, U-′/Rn=Ucc/R6+ (U-U-′)/Rp, with reference to intrinsic standoff ratio equation, can obtain
    <mrow> <msub> <mi>R</mi> <mi>n</mi> </msub> <mo>=</mo> <mfrac> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <mi>N</mi> <mo>)</mo> <msub> <mi>R</mi> <mn>6</mn> </msub> <mo>&amp;CenterDot;</mo> <msubsup> <mi>U</mi> <mo>-</mo> <mo>&amp;prime;</mo> </msubsup> <mo>-</mo> <msub> <mi>NUR</mi> <mn>6</mn> </msub> </mrow> <msub> <mi>U</mi> <mrow> <mi>c</mi> <mi>c</mi> </mrow> </msub> </mfrac> <mo>;</mo> </mrow>
    S5:Work as Rn>Rp, according to the resistance R of intrinsic standoff ratio N calculating negative busbar insulation against ground resistancenIf Rp、RnBoth or one of be less than Setting set in advance, then send alarm signal;
    Work as Rn< Rp, according to the resistance R of intrinsic standoff ratio N calculating negative busbar insulation against ground resistancepIf Rp、RnBoth or one of be less than it is pre- The setting first set, then send alarm signal;
    S6:Relay S1, S2 are turned off, MCU controllers do not give pwm signal, and booster circuit does not work, and wait monitoring life next time Order.
CN201710198085.2A 2017-03-29 2017-03-29 A kind of insulation resistance of DC system observation circuit, system and method Pending CN107422185A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108957342A (en) * 2018-07-24 2018-12-07 欣旺达电动汽车电池有限公司 A kind of detection circuit and detection method of high-voltage battery system total voltage
CN108957135A (en) * 2018-06-26 2018-12-07 顺科新能源技术股份有限公司 A kind of electric automobile insulation resistance on-line measurement system and its method
CN109324231A (en) * 2018-12-03 2019-02-12 苏州共元自控技术有限公司 A kind of batteries of electric automobile group direct current insulation against ground resistor detecting device and method
CN109521277A (en) * 2018-12-03 2019-03-26 欣旺达电子股份有限公司 Insulating properties detection circuit and detection method
CN111103476A (en) * 2018-10-29 2020-05-05 李尔公司 Apparatus and method for asymmetric isolation monitor failure detection

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108957135A (en) * 2018-06-26 2018-12-07 顺科新能源技术股份有限公司 A kind of electric automobile insulation resistance on-line measurement system and its method
CN108957342A (en) * 2018-07-24 2018-12-07 欣旺达电动汽车电池有限公司 A kind of detection circuit and detection method of high-voltage battery system total voltage
CN111103476A (en) * 2018-10-29 2020-05-05 李尔公司 Apparatus and method for asymmetric isolation monitor failure detection
CN109324231A (en) * 2018-12-03 2019-02-12 苏州共元自控技术有限公司 A kind of batteries of electric automobile group direct current insulation against ground resistor detecting device and method
CN109521277A (en) * 2018-12-03 2019-03-26 欣旺达电子股份有限公司 Insulating properties detection circuit and detection method

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