Background technique
In the electric-control motor ejecting system, closing motion to solenoid valve has strict requirement, because the closing motion and the driving current of solenoid valve have substantial connection, so when finishing the solenoid valve action, how to realize by accurate controlling and driving electric current, it is particularly evident that this shows in engine electromagnetic valve drives, driving current usually requires shape two-part driving current as shown in Figure 4, and solenoid valve is at T
1And T
2Finish closed action in time period, at T
3Keep closed state in time period until end.For obtaining the driving current of the type, some drive circuits have been developed, as traditional high low side driving structure: the shared cover high-end drive circuit of each solenoid valve, comprise a high-side driver power supply and a high-end pliotron, the high-side driver supply voltage adopts Vehicular accumulator cell voltage---24V more; Each solenoid valve respectively has a cover low-side driver circuitry, and the main devices of every cover low-side driver circuitry is a low side power triode, and for detecting driving current, many common ports at each solenoid valve are provided with a sampling resistor.During work, adjust the driving current size, realize selecting cylinder working by gating low side pliotron by the dutycycle that changes high-end pliotron control impuls.This driving circuit structure is simple, but its shortcoming is also apparent in view: at first, and the closed electromagnetic valve overlong time.Its reason is that the driving power voltage of 24V can't provide enough energy within a short period of time, causes driving current to rise slowly, is not enough to produce at short notice enough electromagnetic forces and closes solenoid valve.If simple dependence improves driving power voltage and reduces the closed electromagnetic valve time, will increase energy consumption greatly, this improvement project is not used usually.Secondly, control accuracy is low.For the size of driving current is adjusted to satisfactory shape, need driving current is adopted the current closed-loop feedback control.In the high low-side driver circuitry, because hardware circuit only provides the driving current value of feedback, so to sampling, the comparison of driving current and adjust control actions such as high-end pliotron control impuls dutycycle and all must rely on software to finish, this control mode is called as the software Current Feedback Control, writing of its control software is very complicated, and it is also very low to adjusting frequency of dutycycle, generally be no more than 100Hz, so low feedback control frequency must cause the current fluctuation amplitude bigger, and control accuracy is lower.As seen, traditional drive circuit all haves much room for improvement on driving force, control accuracy.
Summary of the invention
The objective of the invention is to propose a kind of motor driving circuit for electromagnetic valve.The driving force of this drive circuit is strong, can shorten the closed electromagnetic valve time, can also improve the precision of Current Control.
The present invention contains high-end drive circuit and the low-side driver circuitry that is connected to the solenoid valve two ends, it is characterized in that, also contain a signal processing circuit, described signal processing circuit receives the control impuls A that is sent by engine electronic control unit, and exports a high drive pulse A respectively
HWith a low-voltage driving pulse A
LTo described high-end drive circuit, receive simultaneously by the current signal of described low-side driver circuitry described solenoid valve sampling feedback, handle the back and regulate described low-voltage driving pulse A
LDescribed high-end drive circuit is regulated control, thereby regulate the driving current of solenoid valve, described low-side driver circuitry directly receives the pulse signal B that is sent by engine electronic control unit, and this pulse signal is identical with described control signal A.
Described high-end drive circuit contains a high-voltage power triode M by high voltage drive
HWith a low pressure and low power triode M by low voltage drive
L, described high-voltage power triode M
HGate pole receive the high drive pulse A that above-mentioned signal processing circuit is sent
H, described low pressure and low power triode M
LGate pole receive the low-voltage driving pulse A that above-mentioned signal processing circuit is sent
L, described high-voltage power triode M
HEmitter connect an end of described solenoid valve, at described low pressure and low power triode M
LEmitter and described high-voltage power triode M
HEmitter between connect a diode D who realizes buffer action
0
Described signal processing circuit receives the control impuls A that engine electronic control unit sends, and this control impuls A is through the above-mentioned high drive pulse A of a timer (1) back output
HTo above-mentioned high-end drive circuit; The control impuls A that described engine electronic control unit sends also imports a hardware feedback current close-loop feedback control circuit, and this feedback control circuit receives the current signal of above-mentioned low-side driver circuitry feedback, and this current signal is through an amplifier U
1Amplify comparator U of back input
2Compare with a reference voltage; Described control impuls A is through triode T of another timer (2) back input
1, and control this triode T
1Conducting and end described comparator U
2Reference voltage input terminal and described triode T
1Emitter between connect the resistance of the described reference voltage level of decision, by described triode T
1Conducting and end, change the resistance of described resistance, thereby make reference voltage at high level U
HWith low level U
LBetween switch this reference voltage and described amplifier U
1The current feedback signal of exporting compares trigger of back input, one of a common input of this trigger output signal and described control impuls A and a door U
3, be somebody's turn to do and door U
3Output low-voltage driving pulse A
LTo described high-end drive circuit.
Described low-side driver circuitry contains and is connected solenoid valve one end, and the low side pliotron that number is consistent with described solenoid valve number, the gate pole of described each low side pliotron receives the pulse signal B identical with above-mentioned control impuls that a route engine electronic control unit sends, sampling resistor R of the common connection of the emitter of described low side pliotron
S, the collector electrode of described low side pliotron connects an end of described each solenoid valve respectively; Between the emitter of described low side pliotron and solenoid valve and a end that described high-end drive circuit is connected, also be connected with a sustained diode
1
Described high-voltage power triode M
HDriving voltage be 100V ± 50V.Described low pressure and low power triode M
LDriving voltage be the output voltage of Vehicular accumulator cell.
Experiment showed, that compared with prior art beneficial effect of the present invention is: 1. shortened the closed electromagnetic valve time.Realized in this drive circuit that two voltage timesharing drive, its high drive source voltage can provide enough energy to solenoid valve at short notice at 100V ± 50V, improves driving current rapidly, finishes the closed electromagnetic valve action.2. Current Control precision height.This drive circuit has been realized the hardware Current Feedback Control.To the sampling of driving current, amplification, relatively the generation that reaches the PWM pulse-width modulation control signal of low pressure and low power triode is all finished automatically by hardware, do not need software intervention, so adjusting frequency of this control circuit is higher, can reach about 20Khz, the wave range that this greatly reduces driving current has improved the control accuracy to current waveform.3. control software is simple.The required input control signal of this control circuit is extremely simple, only needs two sections high level pulses inputs, and the centre no longer needs to carry out the PWM pulsewidth modulation, and this will reduce the complexity of control software greatly.
Embodiment
Describe physical circuit of the present invention and working procedure in detail below in conjunction with embodiment and accompanying drawing.
See Fig. 1, the present invention mainly comprises high-end drive circuit, low-side driver circuitry and signal processing circuit three parts.To drive six way solenoid valves is example, and high-end drive circuit is positioned at solenoid valve L
1-L
6(L
2-L
5Do not mark among the figure) end, comprise that two overlap independently driving power and pliotron, a cover comprises high drive power supply U
HWith high-voltage power triode M
H(model is IRFB61N15D), wherein, the high drive supply voltage is at 100V ± 50V, general desirable 100V, high-voltage power triode M
HA by signal processing circuit output
HPulse signal control.The another set of low-voltage driving power supply U that comprises
LWith low pressure and low power triode M
L(model is IRFB61N15D), two pliotron M
HAnd M
LBetween adopt diode D
0(60CTQ150) realize insulation blocking, wherein, the low-voltage driving power supply directly uses 24V Vehicular accumulator cell power supply, low pressure and low power triode M
LA by signal processing circuit output
LPulse signal control.
Low-side driver circuitry is positioned at solenoid valve L
1-L
6(L
2-L
5Do not mark among the figure) the other end, comprise six pliotron M
1-M
6(IRFB61N15D) (M
2-M
5Do not mark among the figure), its number should equal the engine electromagnetic valve number, and these pliotrons are connected respectively to each solenoid valve, its control signal B
1-B
6Directly being sent by engine electronic control unit (ECU), all is one section high level pulse.Emitter common port at each low side pliotron is provided with sampling resistor R
SAnd sustained diode
1(60CTQ150).
The input control signal of signal processing circuit is the A pulse, its waveform and low-side driver circuitry control signal B
1-B
6Pulse is in full accord, is also directly sent by engine electronic control unit (ECU).
See Fig. 2, signal processing circuit comprise timer 1 (74LS123), timer 2 (74LS123), triode T1 (9013), amplifier U1 (AD8051), comparator U2 (LM193), with parts such as a door U3 (74F08), trigger (adopting d type flip flop 74LS74) and clock circuit.The input control signal of whole signal processing circuit is the A pulse, its waveform and low-side driver circuitry control signal B
1-B
6Pulse is in full accord, is also directly sent by engine electronic control unit (ECU).In the output control signal, the pulse signal that timer 1 produces is control signal A
H, rest parts has been formed hardware feedback current closed control circuit, produces A
LControl signal.In this hardware feedback current closed control circuit, amplifier U1 is responsible for amplifying the sampled voltage signal on the sampling resistor Rs.Comparator U2 delivers to trigger as input with the comparative result of reference voltage and feedback voltage, and along with the difference of comparative result, trigger will produce pwm control signal under the triggering of CLK clock.The pulse signal that timer 2 sent is one section high level pulse, and its high-low level can open and close triode T1 respectively, thereby obtains to have the reference voltage of two kinds of level of height, wherein, and high level V
HEqual peak drive current I
HVoltage after sampling resistor transforms, low level V
LEqual to keep electric current I
LVoltage after conversion.
Be example to drive the first cylinder solenoid valve below, the working procedure of this drive circuit be described:
At first, after definite solenoid valve type, should match Control Parameter I in the drive current waveform as shown in Figure 4 according to requirements such as solenoid closure time, closed electromagnetic power sizes
H, I
L, T
1And T
2, and Control Parameter T
3Should adjust in real time according to engine operating condition by engine electronic control unit (ECU).
This drive circuit works process as shown in Figure 3, t1 constantly, engine electronic control unit (ECU) sends A pulse and B
1Pulse, its high level period is calculated according to engine operating condition by the engine management program.Wherein, the A rising edge of a pulse will trigger timer 1 and timer 2, produce one section high level pulse after both are triggered at once.The pulse that timer 1 produces will be directly as A
HHigh-voltage power triode M is opened in pulse output
HB
1Pulse also will be opened the pliotron M of low side
1, two pliotrons of opening make solenoid valve L
1Drive circuit is connected, high drive power supply U
HFast lifting solenoid valve L
1Driving current produces enough big electromagnetic force to close solenoid valve L
1Simultaneously, timer 2 also produces one section high level pulse after by the A pulse triggering, and this pulse will be opened triode T1, and this makes reference voltage by R1 and the decision of R2 dividing potential drop, and the resistance value by coupling R1 and R2 can obtain peak drive current I
HCorresponding high voltage V
HBecause this moment, driving current did not reach this reference voltage, so the result of comparator is a height, this result device that is triggered latchs, and makes trigger be output as height.Because this moment, the A pulse still was a high level, the output of trigger and A pulse carry out still being height with the result of computing that this high level signal will be as A
LControl impuls is opened low pressure and low power triode M
L, but since this moment high-voltage driving circuit work, so low-voltage driving power supply U
LWill protected diode D
0Isolate, do not participate in solenoid valve L
1Drive.
In the t2 moment, the high level pulse that timer 1 sends finishes, pliotron M
HWill be closed high drive power supply U
HWith solenoid valve L
1Disconnect.At this moment, driving current is not as reaching the Peak current I of setting as yet
H, low pressure and low power triode M
LStill be on state, this makes protects diode D
0Be switched on low-voltage driving power supply U
LBe communicated with driving circuit for electromagnetic valve and promote driving current.
In the t3 moment, driving current rises to I
H, the driving current sampled signal of feedback will be higher than reference voltage V
H, comparator results is low, trigger output after the CLK clock of clock circuit triggers also is low.This will close low pressure and low power triode M
L, make solenoid valve L
1The energy of not reentrying input, driving current begin to descend.After dropping to below the reference voltage, comparator results is high, will open low pressure and low power triode M
L, low-voltage driving circuit promotes driving current once more, because the effect of latching of trigger, this process will continue a clock cycle, and this makes driving current surpass I again
H, will cause low-voltage driving circuit no longer to be worked, driving current descends.Again because the decline of driving current causes low-voltage driving circuit work, driving current rises afterwards.So repeatedly, form the situation of low-voltage driving circuit interruption work, driving current is fluctuateed within the specific limits.And A
LThe situation that the pulse high-low level alternately occurs has then formed the PWM pulse-width signal.
Generally speaking, should pass through rational Match high drive power supply U
HVoltage and A
HIt is short as far as possible to be carved into t3 interval constantly when pulse width makes t2, promptly requires to make high drive power supply U
HDirectly driving current is promoted to I
H, low-voltage driving power supply U
LBe not operated in the driving current pattern that promotes.In this case, drive current waveform Control Parameter T
1Can think the A that direct corresponding timer 1 produces
HThe high level pulse cycle of control impuls is at different solenoid valves, Control Parameter T
1Adjustment can realize by the adjustment resistance that changes timer 1.
T4 constantly, the high level pulse that timer 2 sends finishes, triode T1 closes, reference voltage by R2 and R3 polyphone after again with the R1 dividing potential drop, can obtain V by coupling
LLevel.The reduction of reference level will make low-voltage driving circuit no longer work in the short time, and driving current drops to the maintenance stage.As seen, driving current Control Parameter T
1+ T
2Can determine by the lasting cycle of reference voltage high level, and the reference voltage cycle is determined by timer 2, so, at different solenoid valves, Control Parameter T
2Adjustment can realize by the adjustment resistance that changes timer 2.
The t5 moment is when driving current drops to I
LThe time, reference voltage is higher than the feedback driving current signal, and low-voltage driving circuit work promotes driving current, thereby makes A
LPulse enters the PWM stage of modulating once more, and driving current is maintained in certain wave range.
In the t6 moment, the A end-of-pulsing makes A by U3 with door
LThe pulse step-down is closed low pressure and low power triode M
LSimultaneously, B
1Pulse also finishes, and will close low side pliotron M
1Afterwards, driving current is by sustained diode 1 afterflow, and its energy is consumed in a large number, can drop to zero fast, and whole driving process finishes.