CN108599111A - A kind of electric machine controller and its current foldback circuit - Google Patents
A kind of electric machine controller and its current foldback circuit Download PDFInfo
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- CN108599111A CN108599111A CN201810615378.0A CN201810615378A CN108599111A CN 108599111 A CN108599111 A CN 108599111A CN 201810615378 A CN201810615378 A CN 201810615378A CN 108599111 A CN108599111 A CN 108599111A
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/122—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/02—Providing protection against overload without automatic interruption of supply
- H02P29/024—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load
- H02P29/0241—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load the fault being an overvoltage
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/02—Providing protection against overload without automatic interruption of supply
- H02P29/024—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load
- H02P29/027—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load the fault being an over-current
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
Abstract
The invention belongs to electrical equipment and field of engineering technology, and in particular to a kind of electric machine controller and its current foldback circuit.It is additionally arranged assignment module and delay circuit in motor controller overcurrent protection circuit, assignment module is located at microprocessor internal, can flexibly adjust the threshold values of overcurrent protection；Delay circuit is used to provide the turn-off time interval of three upper bridge power switch tubes and three lower bridge power switch tubes；Two kinds of measures can be substantially reduced the induced potential of loop of power circuit parasitic inductance, more reliable and effective to solve the problems, such as power switch tube overcurrent damage.
Description
Technical field
The invention belongs to electrical equipment and field of engineering technology, and in particular to a kind of electric machine controller and its overcurrent protection electricity
Road.
Background technology
For general electric machine controller, such as：Frequency converter, vehicle control device etc., the power topological loop generally used
It is three phase inverter bridge, is that three-phase alternating current output voltage is run with driving motor by DC bus-bar voltage inversion, at present three-phase inversion
The power switch tube that bridge generally uses is MOSFET (Metal-Oxide-Semiconductor Field-Effect
Transistor) and IGBT (Insulated Gate Bipolar Transistor), the security reliability pair of power switch tube
Key effect is played in the safe operation of electric machine controller.During electric machine controller use, due to the insulation damages of motor, outside
The reasons such as portion's wiring short circuit can cause electric machine controller output overcurrent, excessive output current that power switch tube is caused to be generated heat, such as
Switch-off power switching tube will cause power switch tube to cross cause thermal damage to fruit not in time.
When power switch tube turns off, the parasitic inductance of loop of power circuit will generate induced potential, the size of induced potential with
The parasitic inductance amount in circuit is directly proportional, directly proportional to the current change quantity in circuit, is inversely proportional with the turn-off time of power switch tube；
The induced potential will be superimposed upon between the collector and emitter of power switch tube together with busbar voltage so that power switch tube
The voltage at collector and emitter both ends can exceed that power switch tube pressure voltage, lead to power switch tube excessive pressure damages.Generally
, the pressure resistance of MOSFET is related with the temperature of withstanding current capability with itself, and temperature is higher, and pressure resistance is higher, and withstanding current capability is got over
It is low；Temperature is lower, and pressure resistance is lower, and withstanding current capability is higher.
The major way of electric machine controller output overcurrent protection at present is sampled output current signal, and current signal is by electricity
It is sent to overcurrent comparator after the conditioning of road, and output overcurrent signal is compared with preset hardware overcurrent voltage reference, is led to
Over-current signal latches are crossed, latch output is then connected to the enabled of power switch tube gate electrode drive signals buffer
End, simultaneously turns off the six tunnel power switch tube gate electrode drive signals exported by microprocessor, specific block diagram is shown in attached drawing 1.
The method of motor controller overcurrent protection is the problem is that in electric machine controller operational process, when power returns
Road parasitic inductance is larger, and when the temperature of power module of controller is relatively low or DC bus-bar voltage is higher, power switch tube occurred
Stream, when switch-off power switching tube, it is possible to causing power switch tube excessive pressure damages.
Based on the above issues, general that power is reduced using the gate pole turn-off speed for reducing power switch tube when overcurrent occurs
The induced potential that parasitic inductance generates when switching tube turns off.But this method needs complicated circuit or cost higher special
Gate-drive chip realizes that reliability is poor or cost is higher.
Invention content
The problem of for more reliable effective solution power switch tube overcurrent damage, the present invention propose a kind of electric machine controller
Current foldback circuit and electric machine controller with the current foldback circuit.
Technical solution of the invention is to provide a kind of motor controller overcurrent protection circuit, is characterized in that：
Including on current signal sample circuit, current signal conditioning circuit, microprocessor, over-current signal latch, delay circuit, three-phase
Bridge gate electrode drive signals buffer and three-phase inversion unit under bridge gate electrode drive signals buffer, three-phase；
Above-mentioned microprocessor include overcurrent comparator, DAC converter (Digital-to-Analog Converter, below
Abbreviation DAC converter) and assignment module；Above-mentioned assignment module be used for according to the temperature of controller power module, controller it is defeated
Go out electric current or DC bus-bar voltage setting overcurrent voltage reference；The output end of assignment module is by DAC converter compared with overcurrent
The in-phase input end of device connects；
The output end of above-mentioned current signal sample circuit and the input terminal of current signal conditioning circuit connect；Above-mentioned electric current letter
The output end of number modulate circuit is connect with the inverting input of overcurrent comparator；The output end of overcurrent comparator is locked with over-current signal
The input terminal of storage connects；The output end of over-current signal latch is slow with bridge gate electrode drive signals on delay circuit and three-phase respectively
The input terminal for rushing bridge gate electrode drive signals buffer under the input terminal or three-phase of device connects, under the output end and three-phase of delay circuit
Bridge gate electrode drive signals buffer input connects on bridge gate electrode drive signals buffer input or three-phase, portal pole on three-phase
Bridge gate electrode drive signals buffer output end is defeated with three-phase inversion unit under the output end and three-phase of drive signal buffer
Enter end connection；Delay between the output signal of the output end of over-current signal latch and the output end output signal of delay circuit
Time should be longer than the time of power switch tube shutdown, while the delay time does not answer long, otherwise excessive electric current meeting too long yet
Power switch tube is caused to cross cause thermal damage.
The upper portal pole driving signal output end of microprocessor is connect with bridge gate electrode drive signals buffer on three-phase, micro- place
The lower portal pole driving signal output end of reason device is connect with bridge gate electrode drive signals buffer under three-phase.Bridge gate-drive on three-phase
Bridge gate electrode drive signals buffer under signal buffer and three-phase, the two internal structure having the same, while having signal defeated
Go out Enable Pin, when output Enable Pin is enabled, closing gate signal output.The power switch tube of three-phase inversion unit is according to gate pole
The high low state of level of drive signal is switched on or off.
In the program, the model TMS320F28035 of microprocessor, including internal comparator, DAC converter, comparator
Inverting input receive the signal Icur of current signal conditioning circuit output, the in-phase input end of comparator receives DAC module
The input value of output valve AREF, DAC be that software assignment DREF, DREF value can be according to the temperature of controller power module, controls
Output current or the DC bus-bar voltage adjustment (being not limited to these three conditions, designer can flexibly be designed) of device processed；
Overcurrent comparator by comparing Icur and AREF value output overcurrent signal OC.Meanwhile the microprocessor also be responsible for generate and it is defeated
Go out gate electrode drive signals to gate electrode drive signals buffer.
The present invention also provides another motor controller overcurrents to protect circuit, is characterized in that：Believe including electric current
Number sample circuit, current signal conditioning circuit, DAC converter, overcurrent comparator, microprocessor, over-current signal latch, delay
Bridge gate electrode drive signals buffer and three-phase inversion unit under bridge gate electrode drive signals buffer, three-phase on circuit, three-phase；
Above-mentioned microprocessor includes assignment module, upper portal pole driving signal output end and the portal on three-phase of microprocessor
Pole drive signal buffer connection, the lower portal pole driving signal output end and bridge gate electrode drive signals under three-phase of microprocessor are slow
Rush device connection；
Above-mentioned assignment module is used for according to the temperature of controller power module, the output current of controller or DC bus electricity
Pressure setting overcurrent voltage reference；The output end of assignment module is connect by DAC converter with the in-phase input end of overcurrent comparator；
The output end of above-mentioned current signal sample circuit and the input terminal of current signal conditioning circuit connect；Above-mentioned electric current letter
The output end of number modulate circuit is connect with the inverting input of overcurrent comparator；The output end of overcurrent comparator is locked with over-current signal
The input terminal of storage connects；The output end of over-current signal latch is slow with bridge gate electrode drive signals on delay circuit and three-phase respectively
The input terminal for rushing bridge gate electrode drive signals buffer under the input terminal or three-phase of device connects, under the output end and three-phase of delay circuit
Bridge gate electrode drive signals buffer input connects on bridge gate electrode drive signals buffer input or three-phase, portal pole on three-phase
Bridge gate electrode drive signals buffer output end is defeated with three-phase inversion unit under the output end and three-phase of drive signal buffer
Enter end connection.
Microprocessor in the program does not include overcurrent comparator and DAC module, and the external overcurrent of introducing one is needed to compare
The input value of device and DAC module, the same DAC module can flexibly be changed by assignment module.
Further, above-mentioned over-current signal latch includes rest-set flip-flop, rest-set flip-flop include two NAND gate U4A and
U4B, the output end of the set end connection overcurrent comparator of rest-set flip-flop, reset terminal is connected to the output pin of microprocessor, micro-
Processor is responsible for resetting rest-set flip-flop.
The output end of trigger respectively with bridge gate electrode drive signals under bridge gate electrode drive signals buffer on three-phase or three-phase
The Enable Pin of buffer and the input terminal connection of delay circuit；Bridge gate electrode drive signals are slow under the output end and three-phase of delay circuit
The Enable Pin for rushing bridge gate electrode drive signals buffer on device or three-phase connects, bridge gate electrode drive signals buffer and three-phase under three-phase
The output end of upper bridge gate electrode drive signals buffer respectively drives bridge power switch tube and three road bridge power switch tubes under three tunnels.
Further, above-mentioned delay circuit be RC filter circuits, including the output end of resistance R20 and capacitance C20, U4A with
One end of resistance R20 connects, and portal pole is driven on bridge gate electrode drive signals buffer or three-phase under the other end and three-phase of resistance R20
The Enable Pin connection of dynamic signal buffer；The high-pressure side of capacitance C20 is connect with the other end of resistance R20, the low-pressure end of capacitance C20
Ground connection.
Further, above-mentioned current signal sampling circuit samples output current, including current Hall sensor and signal are adopted
Sample circuit, the effect of current Hall sensor are that output current is converted to voltage signal and realizes electrical isolation, signal sampling
Circuit includes an operational amplifier, and output end connect composition voltage follower circuit with inverting input, realizes circuit
Impedance matching and the driving capability for enhancing signal.
Current signal sample circuit specifically includes current Hall sensor and signal sample circuit；
Above-mentioned signal sample circuit includes R1C1 filter circuits, operational amplifier U1A；
The input terminal of R1C1 filter circuits and the output end of current Hall sensor connect, the output end of R1C1 filter circuits
It is connect with the in-phase input end of operational amplifier U1A, inverting input and the operational amplifier U1A of operational amplifier U1A are exported
End is connected, and operational amplifier U1A output ends connect resistance R4, and the other end of resistance R4 is connected to the reverse phase of operational amplifier U2A
Input terminal.
Further, it is unidirectional electricity that above-mentioned current signal conditioning circuit, which is used to sample obtained bidirectional current signal condition,
Signal is flowed, and is sent to overcurrent comparator after partial pressure and filtering.
Further, above-mentioned current signal conditioning circuit includes power supply VCC, the first partial pressure and filter circuit, operation amplifier
Device U1B, resistance R4, operational amplifier U2A, diode D1, operational amplifier U2B, the partial pressures of resistance R5 and second and filter circuit；
Power supply VCC is connected to the in-phase input end of operational amplifier U1B, operation amplifier by the first partial pressure with filter circuit
The inverting input of device U1B is connected with the output end of operational amplifier U1B, the output end and operation amplifier of operational amplifier U1B
The in-phase input end of device U2A connects；
The anode of the output end connection diode D1 of operational amplifier U2A, the cathode of diode D1 are connected by resistance R5
To the inverting input of U2A, inverting input is connected to the output end of operational amplifier U1A by resistance R4；
The in-phase input end of operational amplifier U2B is connect with the cathode of diode D1, the anti-phase input of operational amplifier U2B
End is connected with the output end of operational amplifier U2B；The output end of operational amplifier U2B is connect with the second partial pressure with filter circuit.
Further, above-mentioned first partial pressure and filter circuit include resistance R2, resistance R3 and capacitance C2, the resistance R2's
One end is connect with the output end of power supply VCC, the high-pressure side and operational amplifier of the other end and resistance R3, capacitance C2 of resistance R2
The in-phase input end of U1B connects, the low-pressure end ground connection of resistance R3 and capacitance C2；
Above-mentioned second partial pressure and filter circuit include resistance R6, resistance R7, resistance R8 and capacitance C3, one end of resistance R6 with
The output end of operational amplifier U2B connects, and the other end of resistance R6 is connect with one end of resistance R7, resistance R8, and resistance R8's is another
The high-pressure side of one termination capacitor C3 exports Icur signals, the low-pressure end of another termination capacitor C3 of resistance R7.
The present invention also provides a kind of electric machine controllers, are characterized in that：Including above-mentioned current foldback circuit.
The beneficial effects of the invention are as follows：
1, motor controller overcurrent protection circuit proposed by the present invention is additionally arranged assignment module and delay circuit, assignment module
Positioned at microprocessor internal, designer can flexibly adjust the threshold values of overcurrent protection；Delay circuit is for providing three
The turn-off time interval of bridge power switch tube and three lower bridge power switch tubes；Two kinds of measures can be substantially reduced loop of power circuit
The induced potential of parasitic inductance, to greatly reduce the possibility of the power switch tube excessive pressure damages caused by overcurrent；
2, the threshold values of motor controller overcurrent protection of the present invention can be according to electric machine controller temperature of power module height, direct current
The conditions such as busbar voltage size are flexibly changed by assignment module.When microprocessor detect controller temperature of power module compared with
Low, when DC bus-bar voltage is higher, corresponding power switch tube pressure resistance is relatively low, and controller overcurrent is reduced by software assignment module
Protect threshold values, controller occur overcurrent turn-off function switching tube when, cut-off current is smaller, parasitic inductance generate induced potential compared with
It is low, between being superimposed upon the collector and emitter of power switch tube together with the induced potential and busbar voltage, power switch tube collection
Electrode and the voltage at emitter both ends are relatively low, are no more than power switch tube pressure resistance, to greatly reduce the work(caused by overcurrent
The possibility of rate switching tube excessive pressure damages；
3, after electric machine controller of the present invention detects that overcurrent occurs, the order of switch-off power switching tube is to turn off three first
Upper bridge power switch tube turns off three lower bridge power switch tubes after delay；Either it is first turned off three lower bridge power switch
Pipe after delay, turns off three upper bridge power switch tubes, rather than simultaneously turns off six power switch tubes, can reduce circuit and post
The induced potential that raw inductance generates achievees the purpose that reduce the voltage stress that power switch tube is born in overcurrent turn-off function, circuit
Simply, cost is relatively low；
4, using the current signal processing circuit, the bidirectional current signal condition that sampling is obtained is unidirectional current signal,
It is sent to the inside of microprocessor, over-current signal can be realized to DAC and comparator resource of microprocessor internal
The purpose of output, cost are relatively low.
Description of the drawings
Fig. 1 is that motor controller overcurrent protects electrical block diagram in the prior art；
Fig. 2 is the motor controller overcurrent protection electrical block diagram of embodiment one in the present invention；
Fig. 3 is the current sampling circuit and signal conditioning circuit diagram of embodiment one in the present invention；
Fig. 4 is the microprocessor of embodiment one and gate-drive buffer circuits schematic diagram in the present invention；
Fig. 5 is the three-phase inversion element circuit schematic diagram of embodiment one in the present invention；
Fig. 6 is the motor controller overcurrent protection electrical block diagram of embodiment two in the present invention.
Specific implementation mode
Content to facilitate the understanding of the present invention is made the present invention below in conjunction with drawings and examples further detailed
Description, the following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention..
Embodiment one
Figure it is seen that the present embodiment current signal sample circuit acquires output current, current signal conditioning circuit will
The collected bidirectional current signal condition of current signal sample circuit is unidirectional current signal, and is sent to after partial pressure and filtering
Microprocessor.Microprocessor includes overcurrent comparator, assignment module and DAC, and assignment module is same by DAC and overcurrent comparator
Phase input terminal connects, and the input value that the in-phase input end of overcurrent comparator receives the output valve AREF, DAC of DAC module is assignment
Module assignment DREF, DREF value can be adjusted according to the temperature or DC bus-bar voltage of controller power module (be not limited to this two
A condition, designer can flexibly be designed, such as can also adjust DREF values according to the output current of controller)；It crosses
The inverting input for flowing comparator receives the Icur signals after current signal conditioning circuit improves.Overcurrent comparator passes through ratio
Value output overcurrent signal OC compared with Icur and AREF.Microprocessor also is responsible for generating and exporting gate electrode drive signals to gate-drive
Signal buffer, including the upper bridge gate electrode drive signals of output and the supreme bridge gate electrode drive signals buffer of lower bridge gate electrode drive signals
With lower bridge gate electrode drive signals buffer.Over-current signal OC is input to over-current signal latch by overcurrent comparator, is believed overcurrent
It number is latched, prevents repeatedly the generation of overcurrent, Latch output signal 1OE that it is slow to be connected to bridge gate electrode drive signals on three-phase
Bridge gate electrode drive signals buffer under device or three-phase is rushed, 1OE is connected to delay circuit simultaneously, and delay circuit output signal 2OE connects
It is connected under three-phase bridge gate electrode drive signals buffer on bridge gate electrode drive signals buffer or three-phase.Bridge gate-drive is believed under three-phase
Bridge gate electrode drive signals buffer receives the output of over-current signal latch or the output of delay circuit on number buffer or three-phase,
When output Enable Pin is enabled, gate signal output is closed.The power switch tube of three-phase inversion unit is according to gate electrode drive signals
The high low state of level be switched on or off.
From figure 3, it can be seen that current sampling circuit and signal conditioning circuit in the present embodiment, current sampling circuit includes electricity
Flow Hall sensor and signal sample circuit, the effect of current Hall sensor is that output current is converted to voltage signal and real
Existing electrical isolation, signal sample circuit include an operational amplifier, output end connect with inverting input form voltage with
With device circuit, realizes the impedance matching of circuit and enhance the driving capability of signal.Signal conditioning circuit includes two operation amplifiers
Device, bleeder circuit and filter circuit；It is that will sample obtained bidirectional current signal condition be unidirectional current signal, and is passed through that it, which is acted on,
It crosses partial pressure and is sent to the internal comparator of microprocessor after filtering.
Current sampling circuit and current signal conditioning circuit operation principle are as follows：
Resistance R1 receives current sampling signal, and in the present embodiment, when motor normal operation, current signal is peak-to-peak value range
For 0-5V, bias is the signal of 2.5V, and 0V corresponds to negative sense output maximum current, and 5V indicates positive output maximum current, passes through
Resistance R1 after capacitance C1 filtering, is connected to the in-phase input end of operational amplifier U1A (using double operation amplifiers in the present embodiment
Device device, model are TL3472ID), the inverting input of operational amplifier U1A is connected with its output end, forms voltage follower
Circuit plays impedance matching and improves the jamproof ability of signal, and output end connects resistance R4, and the other end of resistance R4 is connected to
The inverting input of operational amplifier U2A.
Power supply VCC is connected to the in-phase input end of operational amplifier U1B, the both ends resistance R3 by resistance R2, R3 after dividing
Shunt capacitance C2, capacitance C2 play the role of signal filtering, and the inverting input of operational amplifier U1B is connected with its output end,
Voltage follower circuit is formed, the output signal VREF of operational amplifier U1B is connected to the homophase input of operational amplifier U2A
End, VREF voltage values are equal with the bias voltage 2.5V of current signal, such as generate the bias voltage of 2.5V simultaneously using other circuits
(function can be also realized for example, by using special voltage reference chip, such as using based on device without departing from protection scope of the present invention
The voltage reference circuit of part TL431).The in-phase input end of operational amplifier U2A connects bias voltage VREF, operational amplifier
The anode of the output end connection diode D1 of U2A, the cathode of diode D1 are connected to the anti-of operational amplifier U2A by resistance R5
The value of phase input terminal, resistance R4 is equal with the value of resistance R5.When current signal voltage value is less than bias voltage VREF values, operation
Amplifier U2A exports high level, diode D1 forward conductions, resistance R4, R5, operational amplifier U2A, diode D1 composition reverse phases
Proportional amplifier, input current signal voltage 0-2.5V, corresponding output signal voltage 5-2.5V.When current signal voltage value is higher than
When bias voltage VREF values, operational amplifier U2A exports low level, and diode D1 is not turned on, input current signal voltage 2.5-
5V is equal with output signal voltage；The output of diode D1 while the in-phase input end for being connected to operational amplifier U2B, operation are put
The inverting input of big device U2B is connected with its output end, forms voltage follower circuit, the output signal of operational amplifier U2B
It is divided by resistance R6, R7, by resistance R8, microprocessor is sent into after capacitance C3 filtering.By current sampling circuit and signal
After modulate circuit, the input current signal of 0-5V is improved into the output voltage signal of 2.5-5V, and one is only needed in microprocessor
Comparator reduces the demand to microprocessor internal comparator resource it may determine that whether overcurrent occurs.
Fig. 4 is the microprocessor and gate-drive buffer circuits schematic diagram of the present embodiment, the model of microprocessor
TMS320F28035, internal includes hardware overcurrent comparator, and DAC module does not surpass according to external comparator and DAC module
Go out protection scope of the present invention, the output signal Icur of the inverting input receiving signal reason circuit of overcurrent comparator, same to phase
Input terminal receives the output valve of DAC module, and the input value of DAC module can flexibly be changed by assignment module.
In the present embodiment, the assignment module in microprocessor adjusts the input of DAC module according to the temperature of current controller
Value, when power switch tube temperature is relatively low, power switch tube proof voltage ability declines, and reduces overcurrent protection threshold values；Specifically, this
In embodiment, controller temperature of power module at 0~-40 DEG C, overcurrent protection threshold values from 100% linear decline to 50%, when
Temperature of power module is relatively low, when overcurrent occurs, can turn off power switch tube under smaller output current, to reduce because of parasitism
The size of induced potential caused by inductance, the voltage at power switch tube both ends when reducing shutdown, probability of damage reduce.
The comparator output overcurrent level signal OC of microprocessor, in the present embodiment, OC is that low level indicates that overcurrent occurs,
Two NAND gates U4A and U4B form rest-set flip-flop, and set end connects OC signals, and the output that reset terminal is connected to microprocessor is drawn
Foot；After OC signals are set low, rest-set flip-flop latches over-current signal, prevents repeatedly the generation of overcurrent；When the disappearance of overcurrent condition, OC signals
Height is set, microprocessor is according to Conditional reset rest-set flip-flop.
The model of upper bridge gate electrode drive signals buffer U3A and lower bridge gate electrode drive signals buffer U3B is
Output end can be set to high-impedance state by SN74HCT244NSR for enhancing gate signal driving capability, and by Enable Pin OE,
Gate electrode drive signals for switch-off power switching tube.Upper bridge gate electrode drive signals buffer U3A receives microprocessor output
Three road bridge drive signals, lower bridge gate electrode drive signals buffer U3B receive bridge drive signal under three tunnels that microprocessor exports.
The output signal 1OE of rest-set flip-flop is connected to the Enable Pin of bridge gate electrode drive signals buffer U3A, signal 2OE
It is connected to the Enable Pin of lower bridge gate electrode drive signals buffer U3B.After overcurrent occurs, the output signal 1OE of rest-set flip-flop is first
Three road bridge driving outputs are blocked, for signal 1OE after delay, signal 2OE then blocks bridge driving output under three tunnels.This implementation
In example, in order to reduce cost, provides delay using RC filter circuits and (provide delay without departing from the present invention according to other modes
Protection domain)；In the present embodiment, resistance R20 and capacitance C20 form delay circuit, when the delay of signal 1OE and signal 2OE
Between be slightly larger than power switch tube turn-off time.
The output signal DRV-UP, DRV-VP, DRV-WP of upper bridge gate electrode drive signals buffer U3A passes through gate-drive electricity
Road (not shown) respectively drives three road bridge power switch tubes, and corresponding gate signal is UP, VP, WP；Lower bridge gate-drive letter
The output signal DRV-UN, DRV-VN, DRV-WN of number buffer U3B respectively drives three tunnels by gate drive circuit (not shown)
Lower bridge power switch tube, corresponding gate signal are UN, VN, WN.
Fig. 5 is the three-phase inversion element circuit schematic diagram of the present embodiment, and power switch tube uses power MOSFET tube, direct current
Busbar has a Support Capacitor, six (group) power MOSFET tube Q1, Q2, Q3, Q4, Q5, and Q6 is connected into the structure of three phase inverter bridge, supports
There are loop of power circuit parasitic inductance Lk1 and Lk2 between capacitance and three phase inverter bridge, in universal three phase inverter bridge loop structure,
Parasitic inductance Lk1 and Lk2 are the main parasitic inductance of loop of power circuit, and the induced potential generated can be expressed from the next：Vlk=
(Lk1+Lk2) * Δs i/ Δ t, Δ i indicate that the current changing rate in parasitic inductance when power switch tube shutdown, Δ t indicate that power is opened
It the turn-off time for closing pipe, can be obtained from above formula, reduction parasitic inductance amount, which either reduces current changing rate or increases power, to be opened
Induced potential can be reduced by closing the turn-off time of pipe, reach the voltage at power switch tube both ends when reducing switch-off power switching tube,
Reduce the purpose of power switch tube excessive pressure damages probability.It is by reducing the current changing rate of parasitic inductance to reduce in the present invention
Induced potential.
When following analysis U phases export generation short circuit (other phase short circuit analytic processes are identical) overcurrent with V phases, using the present invention
Bridge power switch tube separates the course of work and advantageous effect of time delayed turn-off above and below middle three-phase.
In the present embodiment, if Q1 and Q4 is opened simultaneously, (the power switch tube opening state in the present embodiment is power switch
The situation of both end voltage stress maximum when pipe cut-off current, other opening states can similarly be analyzed by the analysis
Conclusion), short circuit current circuit is the circuits S1 as shown in the figure, and bus capacitor is positive --- outside parasitic inductance Lk1--- switching tubes Q1---
Portion's short-circuit line --- switching tube Q4--- parasitic inductance Lk2--- bus capacitor cathode；Under the action of busbar voltage, on short-circuit line
Electric current Isc rapid increases, until reaching overcurrent threshold values, circuit switch-off power switching tube；In the present embodiment, three road portal poles
Driving turns off first, and power switch tube Q1 shutdowns, short circuit current circuit is the circuits S2 as shown in the figure, and the outsides switching tube Q2--- are short
Electric current on route --- switching tube Q4, parasitic inductance Lk1 and Lk2 is within the turn-off time of power switch tube Q1, from short circuit current
Isc is reduced to 0, then the induced potential generated on parasitic inductance Lk1 and Lk2：Vlk=(Lk1+Lk2) * Isc/ Δ t, the electricity of inducting
Barrier layer is added in the both ends of power switch tube Q1.After delay, external short circuit line current is Isc1, and more smaller than Isc values (value is big
It is small related with delay time and S2 loop reactances), bridge gate-drive seals wave under three-phase, lower bridge power switch tube Q2 and Q4 shutdown,
Short circuit current circuit is the circuits S3 as shown in the figure, bus capacitor cathode --- two pole of parasitic inductance Lk2--- switching tube Q2 inverse parallels
Pipe --- external short circuit line --- switching tube Q3 anti-paralleled diodes --- parasitic inductance Lk1--- bus capacitor anodes；Parasitic inductance
Electric current on Lk1 and Lk2 is within the turn-off time of power switch tube Q2, and it is Isc1 that short circuit current increases from 0, then parasitic inductance
The induced potential generated on Lk1 and Lk2：Vlk=(Lk1+Lk2) * Isc1/ Δ t, the induced potential are superimposed upon power switch tube Q4
Both ends.
It can be obtained from the above analysis, the maximum induced potential generated on parasitic inductance Lk1 and Lk2 is Vlk=(Lk1+Lk2) *
Isc/ Δ t simultaneously turn off six power switch tubes, in the shutdown of power switch tube if not using the method in the present invention
Between in Δ t, the current changing rate in parasitic inductance is 2*Isc, and the maximum induced potential of generation is Vlk=(Lk1+Lk2) * 2*
Isc/ Δ t, the induced potential than the method for the present invention is big, is superimposed upon power switch tube both ends, increases power switch tube overvoltage
The probability of damage.
A phase current sampling, two-phase or three-phase current sampling and overcurrent protection are only listed in the present embodiment only to be needed to repeat to make
It can be realized with the circuit in the present invention.
Embodiment two
From fig. 6, it can be seen that the present embodiment is not what is different from the first embodiment is that the microprocessor of the present embodiment includes overcurrent
Comparator, the microprocessor in the embodiment is only responsible for generating and output gate electrode drive signals are to gate electrode drive signals buffer.
Therefore, further include an external overcurrent comparator and DAC module in the embodiment, the input value of the same DAC module can pass through
Assignment module in microprocessor is flexibly changed.
Assignment module is set according to the adjustment of the temperature of controller power module, the output current of controller or DC bus-bar voltage
Determine overcurrent voltage reference；The output end of assignment module is connect by DAC converter with the in-phase input end of overcurrent comparator；Electric current
The output end of signal sample circuit and the input terminal of current signal conditioning circuit connect；The output end of current signal conditioning circuit with
The inverting input of overcurrent comparator connects；The output end of overcurrent comparator is connect with the input terminal of over-current signal latch.
Embodiment of above is merely to illustrate the present invention, and not limitation of the present invention, one or more in the present invention
Item method or circuit all belong to the scope of protection of the present invention；Those of ordinary skill in technical field is not departing from the present invention
Spirit and scope in the case of, can also make a variety of changes and modification, therefore all equivalent technical solutions also belong to this
The scope of invention, scope of patent protection of the invention should be defined by the claims.
Claims (10)
1. a kind of motor controller overcurrent protects circuit, it is characterised in that：It is improved including current signal sample circuit, current signal
Circuit, microprocessor, over-current signal latch, delay circuit, portal pole under bridge gate electrode drive signals buffer, three-phase on three-phase
Drive signal buffer and three-phase inversion unit；
The microprocessor includes overcurrent comparator, DAC converter and assignment module；The assignment module is used for according to controller
The temperature of power module, the output current of controller or DC bus-bar voltage set overcurrent voltage reference；The output of assignment module
End is connect by DAC converter with the in-phase input end of overcurrent comparator；
The output end of the current signal sample circuit and the input terminal of current signal conditioning circuit connect；The current signal tune
The output end of reason circuit is connect with the inverting input of overcurrent comparator；The output end of overcurrent comparator and over-current signal latch
Input terminal connection；The output end of over-current signal latch respectively with bridge gate electrode drive signals buffer on delay circuit and three-phase
Input terminal or three-phase under bridge gate electrode drive signals buffer input terminal connection, portal under the output end and three-phase of delay circuit
Bridge gate electrode drive signals buffer input connects on pole drive signal buffer input or three-phase, bridge gate-drive on three-phase
Input terminal of the bridge gate electrode drive signals buffer output end with three-phase inversion unit under the output end and three-phase of signal buffer
Connection；
The upper portal pole driving signal output end of microprocessor is connect with bridge gate electrode drive signals buffer on three-phase, microprocessor
Lower portal pole driving signal output end connect with bridge gate electrode drive signals buffer under three-phase.
2. a kind of motor controller overcurrent protects circuit, it is characterised in that：It is improved including current signal sample circuit, current signal
Circuit, DAC converter, overcurrent comparator, microprocessor, over-current signal latch, delay circuit, bridge gate-drive letter on three-phase
Bridge gate electrode drive signals buffer and three-phase inversion unit under number buffer, three-phase；
The microprocessor includes assignment module, and upper portal pole driving signal output end and the portal pole on three-phase of microprocessor are driven
Dynamic signal buffer connection, lower portal pole driving signal output end and the bridge gate electrode drive signals buffer under three-phase of microprocessor
Connection；
The assignment module according to the temperature of controller power module, the output current of controller or DC bus-bar voltage for setting
Determine overcurrent voltage reference；The output end of assignment module is connect by DAC converter with the in-phase input end of overcurrent comparator；
The output end of the current signal sample circuit and the input terminal of current signal conditioning circuit connect；The current signal tune
The output end of reason circuit is connect with the inverting input of overcurrent comparator；The output end of overcurrent comparator and over-current signal latch
Input terminal connection；The output end of over-current signal latch respectively with bridge gate electrode drive signals buffer on delay circuit and three-phase
Input terminal or three-phase under bridge gate electrode drive signals buffer input terminal connection, portal under the output end and three-phase of delay circuit
Bridge gate electrode drive signals buffer input connects on pole drive signal buffer input or three-phase, bridge gate-drive on three-phase
Input terminal of the bridge gate electrode drive signals buffer output end with three-phase inversion unit under the output end and three-phase of signal buffer
Connection.
3. motor controller overcurrent according to claim 1 or 2 protects circuit, it is characterised in that：
The over-current signal latch includes rest-set flip-flop, and rest-set flip-flop includes two NAND gates U4A and U4B, rest-set flip-flop
Set end connects the output end of overcurrent comparator, and reset terminal is connected to the output pin of microprocessor；
The output end of trigger is buffered with bridge gate electrode drive signals under bridge gate electrode drive signals buffer on three-phase or three-phase respectively
The Enable Pin of device and the input terminal connection of delay circuit；Bridge gate electrode drive signals buffer under the output end and three-phase of delay circuit
Or on three-phase bridge gate electrode drive signals buffer Enable Pin connection, bridge on bridge gate electrode drive signals buffer and three-phase under three-phase
The output end of gate electrode drive signals buffer respectively drives bridge power switch tube and three road bridge power switch tubes under three tunnels.
4. motor controller overcurrent according to claim 3 protects circuit, it is characterised in that：
The delay circuit is RC filter circuits, includes one end of the output end and resistance R20 of resistance R20 and capacitance C20, U4A
Connection, bridge gate electrode drive signals buffer on bridge gate electrode drive signals buffer or three-phase under the other end and three-phase of resistance R20
Enable Pin connection；The high-pressure side of capacitance C20 is connect with the other end of resistance R20, the low-pressure end ground connection of capacitance C20.
5. motor controller overcurrent according to claim 4 protects circuit, it is characterised in that：The current signal sampling electricity
Road includes current Hall sensor and signal sample circuit；
The signal sample circuit includes R1C1 filter circuits and operational amplifier U1A；
The input terminal of R1C1 filter circuits and the output end of current Hall sensor connect, the output end and fortune of R1C1 filter circuits
Calculate the in-phase input end connection of amplifier U1A, inverting input and the operational amplifier U1A output end phases of operational amplifier U1A
Even, operational amplifier U1A output ends connect resistance R4, and the other end of resistance R4 is connected to the anti-phase input of operational amplifier U2A
End.
6. motor controller overcurrent according to claim 1 or 2 protects circuit, it is characterised in that：The current signal tune
It is unidirectional current signal that reason circuit, which is used to sample obtained bidirectional current signal condition, and is sent to after partial pressure and filtering
Flow comparator.
7. motor controller overcurrent according to claim 6 protects circuit, it is characterised in that：The current signal conditioning electricity
Road include power supply VCC, first partial pressure with filter circuit, operational amplifier U1B, resistance R4, operational amplifier U2A, diode D1,
Operational amplifier U2B, resistance R5 and the second partial pressure and filter circuit；
Power supply VCC is connected to the in-phase input end of operational amplifier U1B, operational amplifier by the first partial pressure with filter circuit
The inverting input of U1B is connected with its output end, the homophase input of the output end and operational amplifier U2A of operational amplifier U1B
End connection；
The anode of the output end connection diode D1 of operational amplifier U2A, the cathode of diode D1 are connected to U2A by resistance R5
Inverting input, inverting input is connected to the output end of operational amplifier U1A by resistance R4；
The in-phase input end of operational amplifier U2B is connect with the cathode of diode D1, the inverting input of operational amplifier U2B with
The output end of operational amplifier U2B is connected；The output end of operational amplifier U2B is connect with the second partial pressure with filter circuit；
The value of resistance R5 is equal with the value of resistance R4.
8. motor controller overcurrent according to claim 7 protects circuit, it is characterised in that：First partial pressure and filtering
Circuit includes that resistance R2, resistance R3 and capacitance C2, one end of the resistance R2 are connect with the output end of power supply VCC, resistance R2's
The other end is connect with the in-phase input end of resistance R3, the high-pressure side of capacitance C2 and operational amplifier U1B, resistance R3 and capacitance C2's
Low-pressure end is grounded；
Second partial pressure and filter circuit include resistance R6, resistance R7, resistance R8 and capacitance C3, one end of the resistance R6 with
The output end of operational amplifier U2B connects, and the other end of resistance R6 is connect with one end of resistance R7, resistance R8, and resistance R8's is another
The high-pressure side of one termination capacitor C3 exports Icur signals, the low-pressure end of another termination capacitor C3 of resistance R7.
9. motor controller overcurrent according to claim 1 protects circuit, it is characterised in that：The model of the microprocessor
For TMS320F28035.
10. a kind of electric machine controller, it is characterised in that：Including any current foldback circuits of claim 1-9.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810615378.0A CN108599111A (en) | 2018-06-14 | 2018-06-14 | A kind of electric machine controller and its current foldback circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810615378.0A CN108599111A (en) | 2018-06-14 | 2018-06-14 | A kind of electric machine controller and its current foldback circuit |
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| CN108599111A true CN108599111A (en) | 2018-09-28 |
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| CN201810615378.0A Pending CN108599111A (en) | 2018-06-14 | 2018-06-14 | A kind of electric machine controller and its current foldback circuit |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109347059A (en) * | 2018-11-05 | 2019-02-15 | 武汉精能电子技术有限公司 | A kind of hardware over-current protection method and system for bidirectional current output |
| CN109462359A (en) * | 2018-11-15 | 2019-03-12 | 江苏开璇智能科技有限公司 | A kind of current-limiting protection controller of motor |
| CN110350494A (en) * | 2019-06-28 | 2019-10-18 | 深圳市明信测试设备有限公司 | A kind of direct current protecting method of adjustable protective range |
| CN110460018A (en) * | 2019-08-29 | 2019-11-15 | 合肥阳光电动力科技有限公司 | A kind of electric machine controller and its alternate protection circuit |
| CN110676815A (en) * | 2019-09-23 | 2020-01-10 | 南京越博电驱动***有限公司 | Vehicle, motor controller and overcurrent protection circuit |
| CN111490528A (en) * | 2020-04-23 | 2020-08-04 | 国电南瑞科技股份有限公司 | Overcurrent protection device suitable for wide bandgap power device |
| CN112187025A (en) * | 2020-09-30 | 2021-01-05 | 深圳市英威腾电动汽车驱动技术有限公司 | IGBT gate resistance regulating circuit, motor controller and electric automobile |
| CN112202388A (en) * | 2020-09-27 | 2021-01-08 | 台安科技(无锡)有限公司 | Multistage series H bridge power unit protection device of high-voltage frequency converter |
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2018
- 2018-06-14 CN CN201810615378.0A patent/CN108599111A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109347059A (en) * | 2018-11-05 | 2019-02-15 | 武汉精能电子技术有限公司 | A kind of hardware over-current protection method and system for bidirectional current output |
| CN109462359A (en) * | 2018-11-15 | 2019-03-12 | 江苏开璇智能科技有限公司 | A kind of current-limiting protection controller of motor |
| CN110350494A (en) * | 2019-06-28 | 2019-10-18 | 深圳市明信测试设备有限公司 | A kind of direct current protecting method of adjustable protective range |
| CN110460018A (en) * | 2019-08-29 | 2019-11-15 | 合肥阳光电动力科技有限公司 | A kind of electric machine controller and its alternate protection circuit |
| CN110676815A (en) * | 2019-09-23 | 2020-01-10 | 南京越博电驱动***有限公司 | Vehicle, motor controller and overcurrent protection circuit |
| CN111490528A (en) * | 2020-04-23 | 2020-08-04 | 国电南瑞科技股份有限公司 | Overcurrent protection device suitable for wide bandgap power device |
| CN111490528B (en) * | 2020-04-23 | 2022-06-07 | 国电南瑞科技股份有限公司 | Overcurrent protection device suitable for wide bandgap power device |
| CN112202388A (en) * | 2020-09-27 | 2021-01-08 | 台安科技(无锡)有限公司 | Multistage series H bridge power unit protection device of high-voltage frequency converter |
| CN112187025A (en) * | 2020-09-30 | 2021-01-05 | 深圳市英威腾电动汽车驱动技术有限公司 | IGBT gate resistance regulating circuit, motor controller and electric automobile |
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Effective date of registration: 20190715 Address after: 710118 Third Floor of Auxiliary Building of Oukai Pioneering Town, 25 Xiliu Street Development Avenue, Xi'an High-tech Zone, Shaanxi Province Applicant after: Xi'an Haige Electrical Technology Co., Ltd. Address before: 710077 Xionghua Science Park Complex Building, 72 Jinye Road, Yanta District, Xi'an City, Shaanxi Province, 3rd Floor Applicant before: Xie Hongpu |