JP7056135B2 - Load drive - Google Patents

Description

The present invention relates to a load drive device.

Some solenoid valves driven by a DC power source such as a battery recover energy to a booster circuit after the energization is completed, and regenerative control to the battery is performed so that the voltage of the capacitor in the booster circuit does not rise too much. In this case, the start of the regenerative control is determined by an overboost voltage threshold value different from the control threshold value of the booster circuit.

Therefore, in the regenerative control as described above, the overboost control threshold value set higher than the boost control threshold value of the booster circuit is used. Therefore, if the regenerative control is delayed, overshoot occurs due to the regenerative current. The margin for the device withstand voltage was not small.

Japanese Unexamined Patent Publication No. 2012-145119

The present invention has been made in consideration of the above circumstances, and an object thereof is that it is not necessary to set the overboost control threshold value at the time of regeneration to the booster circuit to be larger than the booster control threshold value of the booster operation, and there is a margin for the element withstand voltage. It is an object of the present invention to provide a load drive device capable of having a load drive device.

The load drive device according to claim 1 is a load drive device that drives a first load and a second load, and includes a booster circuit that boosts a DC power supply and charges a capacitor connected to an output terminal, and a first load drive device. The control circuit that supplies the boost power generated by the booster circuit to the first load according to the drive signal and supplies the DC power supply to the second load according to the second drive signal, and the charge of the capacitor are described. The control circuit includes a regenerative switch element for regenerating the DC power supply and a capacitor for regeneration connected in the forward direction between the downstream terminal of the second load and the output terminal of the booster circuit. The regenerative switch element is driven to regenerate the charge of the capacitor to the DC power supply in the non-driving state of the first load and after the drive control of the second load is completed.

By adopting the above configuration, the control circuit feeds the first load from the booster circuit, and when the terminal voltage of the capacitor of the booster circuit drops, the output voltage is adjusted to be within a predetermined range by the booster operation. On the other hand, when the control circuit supplies power to the second load, a DC power supply is used, so that the capacitor of the booster circuit does not discharge when the first load is not supplied, so that the terminal voltage does not fluctuate. Therefore, when the power supply to the second load is stopped, the control circuit drives the regenerative switch element to regenerate to the DC power supply side.

At this time, since the booster circuit does not perform the booster operation, it is not necessary to set the regeneration threshold voltage to be equal to or higher than the threshold for controlling the output voltage of the booster circuit. Therefore, the regenerative operation from the second load can be performed by the regenerative threshold voltage so that the overvoltage is not applied to the capacitor of the booster circuit, and the margin for the element withstand voltage can be maintained.

Electrical configuration diagram showing the first embodiment Flow chart of regenerative control processing Time chart Electrical configuration diagram showing the second embodiment Electrical configuration diagram showing a third embodiment Flow chart of regenerative control processing

(First Embodiment)
Hereinafter, the first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
The load drive device of the present embodiment drives and controls a load such as an injector and a fuel pump used for fuel injection of a vehicle engine. In FIG. 1, which shows the entire electrical configuration, the first load 1 and the second load 2, which are the objects to be driven, are driven and controlled by the load driving device 3.

In FIG. 1, two injectors 1a and 1b are shown as the inductive load as the first load 1, but they can be provided in parallel according to the number of cylinders. The second load 2 is a fuel pump provided in the engine and is an inductive load. One terminal of the injectors 1a and 1b is commonly connected to the output terminal A of the load drive device 3. The other terminals of the injectors 1a and 1b are connected to the output terminals B and C of the load drive device 3, respectively. Both terminals of the second load 2 are connected between the output terminals D and E of the load drive device 3.

The load drive device 3 includes a control unit 4, a booster circuit 5, and a drive unit 6. The load drive device 3 is given drive command signals S1 and S2 from an externally provided microcomputer 10. The drive command signal S1 is a drive command for the first load 1. The drive command signal S1 is a signal for driving a plurality of injectors 1a and 1b. The drive command signal S2 is a drive command for the second load 2. The load drive device 3 operates by a DC voltage supplied from the vehicle-mounted battery to the power supply terminal VB.

The control unit 4 includes a first load drive unit 41, a second load drive unit 42, a step-up regeneration control circuit 43, and a regeneration determination circuit 44. It should be noted that these configurations can be configured by hardware, or similar functions can be performed by using software by a CPU and a program. The first load drive unit 41 and the second load drive unit 42 output control signals to the drive unit 6 in response to the drive command signals S1 and S2 given from the microcomputer 10, respectively, of the first load 1 and the second load 2. Drive control is performed.

The boost regeneration control circuit 43 performs boost operation control and regeneration control operation by the boost circuit 5. In this case, the regeneration determination circuit 44 determines the execution of regeneration based on the two drive command signals S1 and S2 input from the microcomputer 10, and outputs the determination to the boost regeneration control circuit 43. The boost regeneration control circuit 43 controls the regeneration operation in the boost circuit 5 based on the determination signal from the regeneration determination circuit 44.

In the booster circuit 5, a series circuit of the booster coil 51, the MOSFET 52 and the current detection resistor 53 is connected between the power supply terminal VB and the ground. A series circuit of the MOSFET 54 and the capacitor 55 is connected between the drain and the source of the MOSFET 52. The common connection point between the MOSFET 54 and the capacitor 55 is an output terminal that outputs a boosted output voltage VH. Diodes 52a and 54a are connected in parallel to the MOSFETs 52 and 54, respectively. The current Ia flowing through the MOSFET 52 is detected as the terminal voltage of the current detection resistor 53. The current Ib flowing through the MOSFET 54 is "positive" in the direction of the arrow in the figure, that is, in the direction of flowing toward the output terminal A, and "negative" in the direction of flowing toward the boost coil 515.

In the drive unit 6, the power supply system to the first load 1 is configured as follows. The output terminal (feeding terminal of the output voltage VH) of the booster circuit 5 is connected to the output terminal A via the MOSFET 61 as a regenerative switch element. Further, the power supply terminal VB is connected to the output terminal A via the MOSFET 62. The output terminal A is connected to the ground via the diode 63 in the opposite direction. The output terminal B is connected to the ground via a series circuit of the MOSFET 64 and the current detection resistor 65. The output terminal C is connected to the ground via a series circuit of the MOSFET 66 and the current detection resistor 65.

The current I1 flowing through the injectors 1a and 1b of the first load 1 is detected as the terminal voltage of the current detection resistor 65 at the time of feeding. Further, the output terminals B and C are connected to the output terminal of the booster circuit 5 via the regenerative diodes 67 and 68, respectively. Further, diodes 61a, 62a, 64a and 66a are connected in antiparallel to each of the MOSFETs 61, 62, 64 and 66.

The power supply system to the second load 2 is connected as follows. The power supply terminal VB is connected to the output terminal D via the MOSFET 69. The output terminal D is connected to the ground via the diode 70 in the opposite direction. The output terminal E is connected to the ground via a series circuit of the MOSFET 71 and the current detection resistor 72. Further, the output terminal E is connected to the output terminal of the booster circuit 5 via a regenerative diode 73. Diodes 69a and 71a are connected in antiparallel to each of the MOSFETs 69 and 71. The current I2 flowing through the second load 2 is detected as the terminal voltage of the current detection resistor 72 at the time of feeding.

The first load drive unit 41 of the control unit 4 outputs a drive signal to the gates of the MOSFETs 61, 62, 64 and 66 of the drive unit 6 to control on / off in order to drive the first load 1. The second load drive unit 42 of the drive unit 4 outputs a drive signal to the gates of the MOSFETs 69 and 71 of the drive unit 6 to control on / off in order to drive the second load.

The boost regenerative control circuit 43 of the control unit 4 outputs a drive signal to the gates of the MOSFETs 52 and 54 of the boost circuit 5 to control on / off. Further, the booster regeneration control circuit 43 detects the current flowing through the MOSFET 52 from the terminal voltage of the current detection resistor 53, and also detects the voltage VH of the output terminal of the booster circuit 5.

Next, the operation of the above configuration will be described with reference to FIGS. 2 and 3.
The drive control of the first load 1 and the second load 2 by the load drive device 3 is generally described because it is a normal operation, and here, it occurs in a state where the second load 2 is driven and controlled independently. The regenerative control process for the regenerative current will be described in detail.

The control unit 4 performs the regenerative control process shown in FIG. 2 in a state where the first load 1 and the second load 2 are driven and controlled. In the regeneration control process, the control unit 4 performs the determination process B and the regeneration process C. As the determination process B, the control unit 4 determines in step A1 that the drive command signal S1 of the first load 1 from the microcomputer 10 is in the off state by the regeneration determination circuit 44, and in the subsequent step A2, the second load 2 It is determined whether or not the drive command signal S2 of is off-edge.

When both the control unit 4 becomes YES in steps A1 and A2, the control unit 4 ends the determination process B and executes the regeneration control C. In this determination process B, as will be described later, the time point at which the first load 1 is not driven and the second load 2 is driven and then stopped is determined. Then, at this timing, the regenerative current from the second load 2 flows into the booster circuit 5.

As the regeneration control C, the control unit 4 stops the boost control by the boost circuit 5 by the boost regeneration control circuit 43 in step A3. After that, the control unit 4 turns on the MOSFET 54 as the regenerative switch element in step A4, and supplies the current Ix regenerated from the second load 2 to the booster circuit 5 via the diode 73 via the MOSFET 54 and the booster coil 51. It is regenerated to the in-vehicle battery by flowing it to the terminal VB side.

The boost regeneration control circuit 43 is in an ON state of the MOSFET 54 when the terminal voltage of the capacitor 55, that is, the output voltage VH exceeds the upper limit value Vtha of the threshold voltage which is the regeneration stop voltage due to the current Ix flowing from the second load 2 to the boost circuit 5. To continue regeneration to the power supply terminal VB. After that, when the current Ix from the second load 2 drops and the output voltage VH becomes equal to or less than the upper limit value Vtha, the control unit 4 determines YES in step A5, proceeds to step A6, and turns off the MOSFET 54.

Next, the drive of the first load 1 and the second load 2 by the load drive device 3 will be described with reference to FIG. 3, and the regenerative control process will also be described. The load drive device 3 drives the first load 1 in response to the drive command signal S1 from the microcomputer 10, and drives the second load 2 in response to the drive command signal S2. Further, since the drive command signal S1 is a signal for driving and controlling a plurality of injectors such as the injectors 1a and 1b of the first load 1 over a plurality of times, it is continuous over the driving period of the first load 1. It is kept on.

First, when the power is turned on, the boost regeneration control circuit 43 of the control unit 4 controls the MOSFET 52 of the boost circuit 5 on and off by PWM control or the like. As a result, the capacitor 55 is charged through the MOSFET 54 by the high voltage induced voltage generated by energizing the boost coil 51.

The boost regeneration control circuit 43 detects the terminal voltage of the capacitor 55, that is, the output voltage VH, stops the boosting operation when the upper limit value Vtha of the threshold voltage is reached, and starts the boosting operation when the output voltage VH drops to the lower limit value Vthb. .. As a result, the output voltage VH of the booster circuit 5 is held between the upper limit value Vtha and the lower limit value Vthb of the threshold voltage even when the first load 1 is energized by the drive unit 6.

Next, when the drive command signal S1 is given from the microcomputer 10 at time t0, the control unit 4 of the load drive device 3 turns on the MOSFETs 61 and 64 in order to energize the injector 1a, for example, by the first load drive unit 41. Make it work. As a result, the injector 1a of the first load 1 is driven by applying a high voltage output voltage VH from the booster circuit 5 and flowing a current I1 as shown in FIG. 3A.

When the injector 1a is supplied with power from the booster circuit 5 for a certain period of time and the time t1 is reached, the first load drive unit 41 turns off the MOSFET 61 and then turns the MOSFET 62 on and off. As a result, the injector 1a is in a state where the voltage of the vehicle-mounted battery is applied from the power supply terminal VB and the current I1 to the extent that the driving state is maintained flows.

When the injection period by the injector 1a ends, the first load drive unit 41 turns off the MOSFETs 62 and 64 of the drive unit 6. When driving the injector 1b, the first load driving unit 41 of the control unit 4 drives and controls the MOSFET 66 instead of the MOSFET 64 during the above operation.

When the first load 1 is fed from the booster circuit 5 as described above, the electric charge of the capacitor 55 is discharged, so that the output voltage VH is lowered. As shown in FIG. 3D, for example, when the output voltage VH reaches the lower limit value Vthb of the threshold voltage at time t1, the booster regeneration control circuit 43 detects this and alternately drives and controls the MOSFETs 52 and 54. By charging the capacitor 55, the output voltage VH is boosted to the upper limit value Vtha.

In this case, the step-up regeneration control circuit 43 turns on the MOSFET 52 first at time t1, and as a result, as shown in FIG. 3 (e), from the power supply terminal VB via the step-up coil 51, the MOSFET 52, and the current detection resistor 53. A rapidly increasing current Ia flows. Next, the step-up regeneration control circuit 43 turns off the MOSFET 52 at time t2, and turns on the MOSFET 54 instead, as shown in FIG. 3 (g).

As a result, as shown in FIG. 3 (f), the current Ib flows into the capacitor 55 through the MOSFET 54 due to the induced voltage generated in the boost coil 51. As the current Ib flows into the capacitor 55, the output voltage VH of the booster circuit 5 gradually increases as shown in FIG. 3D.

Hereinafter, in the same manner as described above, the step-up regeneration control circuit 43 alternately drives the MOSFETs 52 and 54 on and off, for example, when the output voltage VH reaches the upper limit value Vtha by the third on operation of the MOSFET 54 from time t4. The boost regeneration control circuit 43 stops the boost operation.

Next, when the drive command signal S2 is given from the microcomputer 10, the control unit 4 of the load drive device 3 causes the second load drive unit 42 to control the MOSFETs 69 and 71 on and off. As a result, as shown in FIG. 3B, the voltage of the vehicle-mounted battery is applied to the second load 2 from the power supply terminal VB, and the current I2 flows.

When the drive command signal S2 is turned off at time ta, the second load drive unit 42 turns off the MOSFETs 69 and 71. As a result, the second load 2 is stopped from supplying power from the power supply terminal VB, but the current I2 tends to continue to flow due to the induced voltage generated immediately after the power supply terminal VB is turned off. Therefore, as shown in FIG. 3C, the current Ix flows from the diode 70 to the capacitor 55 from the path via the second load 2 and the diode 73 to be charged.

At this time, in a state where the drive command signal S1 is given and the first load 1 is driven, the booster circuit 5 feeds the first load 1 so that the output voltage VH, that is, the terminal voltage of the capacitor 55 is the threshold voltage. Since it is lower than the upper limit value Vtha, a boosting operation is performed. Therefore, the current Ix flowing from the second load 2 to the booster circuit 5 is applied to the charging of the capacitor 55, and even during the period when the MOSFET 54 is turned on, the current Ib from the booster coil 51 side is applied to the capacitor 55 together with the current Ib. It's flowing.

On the other hand, at the off timing of the second load 2, the output voltage VH of the booster circuit 5 is shown in FIG. As shown in 3 (d), the upper limit value Vtha of the threshold voltage is substantially maintained except for discharge such as leakage of the capacitor 55. Therefore, when the current Ix regenerated from the second load 2 to the booster circuit 5 flows into the capacitor 55 after time t7, the output voltage VH exceeds the upper limit value Vtha as shown by the broken line in FIG. 3 (d). ..

In order to avoid this, the step-up regeneration control circuit 43 determines the condition according to the flow shown in FIG. 2, and during the period in which the output voltage VH exceeds the upper limit value Vtha of the threshold voltage by steps A4 and A5 (from t7). In t8), the MOSFET 54 is turned on in step A4. As a result, as shown in FIG. 3 (f), the current Ix flowing into the capacitor 55 becomes a current in the opposite direction via the MOSFET 54 and the step-up coil 51, and is regenerated from the power supply terminal VB to the vehicle-mounted battery. As a result, it becomes possible to prevent the output voltage VH of the booster circuit 5 from rising beyond the upper limit value Vtha of the threshold voltage which is the regenerative stop voltage.

According to the present embodiment as described above, the drive unit 4 determines the off timing of the first load 1 and the second load 2 in the off state, and the current Ix regenerated from the second load 2 is transmitted via the MOSFET 54. The power terminal is regenerated to the VB side. As a result, it is possible to avoid setting the overboost control threshold value exceeding the upper limit value of the boost for regeneration in the capacitor 55, and it is possible to maintain a margin between the withstand voltage of the element.

In the above embodiment, the terminal voltage of the capacitor 55, that is, the output voltage VH of the booster circuit 5 stops regenerating as a condition for turning on the MOSFET 54 in order to recover the current Ix regenerated from the second load 2 to the power supply terminal VB side. The case where the upper limit value Vtha of the threshold voltage, which is a voltage, is exceeded, but the case is not limited to this, and the case where the lower limit value Vthb is exceeded may also be used. Similarly, it can be set to a value between the upper limit value Vtha and the lower limit value Vthb of the threshold voltage.

Further, when the regenerative stop voltage is set to the upper limit value Vtha or the lower limit value Vthb of the threshold voltage, it is not necessary to provide a circuit for separately setting the threshold value or to set a program, which makes it easy to carry out. There are advantages.

(Second Embodiment)
FIG. 4 shows the second embodiment, and the parts different from the first embodiment will be described below. In this embodiment, the load drive device 300 is configured to provide the control unit 4A instead of the control unit 4.

In FIG. 4, the control unit 4A is not provided with the regeneration determination circuit 44. Instead of this, the microcomputer 100 is provided with a regeneration determination circuit 102. The regeneration determination circuit 102 executes the determination process B of FIG. 2 determined by the regeneration determination circuit 44 in the first embodiment, and outputs a signal of the determination result to the boost regeneration control circuit 43 of the control unit 4A.

As a result, in the control unit 4A, the boost regeneration control circuit 43 similarly turns on the MOSFET 54 in the off state of the first load 1 and at the off timing of the second load 2, thereby causing the second load 2 to operate. The current Ix regenerated from can be regenerated to the power supply terminal VB side via the MOSFET 54.
Therefore, the same effect as that of the first embodiment can be obtained by such a second embodiment.

(Third Embodiment)
5 and 6 show the third embodiment, and the parts different from the second embodiment will be described below. In this embodiment, the microcomputer 100a is provided with a regeneration determination circuit 102a so as to capture an accelerator opening signal Sa as a vehicle signal. The accelerator opening signal Sa is a signal indicating a depressed state of the accelerator, and fuel injection is performed according to this signal level, so that the first load 1 is driven. Therefore, when the accelerator opening signal Sa is "zero", it is a state in which the accelerator is not stepped on, that is, a state in which fuel injection by the first load 1 is not performed.

Therefore, in the above-described embodiment, it can be used as a state in which the drive command signal S1 of the first load 1 is off. In FIG. 6, the determination process Ba is performed by the regeneration determination circuit 102a of the microcomputer 100a, and as step A1a, it is determined whether or not the accelerator opening degree by the accelerator opening degree signal Sa is “zero”. ..

As a result, in the control unit 4A of the load drive device 300, the boost regenerative control circuit 43 can determine the state corresponding to the off state of the first load 1 as in the second embodiment, and the off timing of the second load 2 can be determined. Then, the MOSFET 54 is turned on, whereby the regenerative current Ix from the second load 2 can be regenerated to the power supply terminal VB side via the MOSFET 54.
Therefore, the same effect as that of the second embodiment can be obtained by such a third embodiment.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof, and can be modified or extended as follows, for example.

In the first embodiment, the regeneration determination circuit 102a shown in the third embodiment is provided in place of the regeneration determination circuit 44, and the accelerator opening signal Sa is taken in as a vehicle signal to obtain the same effect. be able to.

Further, in each of the above embodiments, the current Ix regenerated from the second load 2 is collected on the power supply terminal VB side connected to the in-vehicle battery, but the present invention is not limited to this, and the power supply terminal is a DC / DC converter or the like. It may be used as a power supply terminal for supplying the voltage generated by the above.

Further, in each of the above embodiments, the example in which one second load 2 is provided is shown, but the present invention is not limited to this, and a plurality of those fed from the power supply terminal VB may be provided.
The present disclosure has been described in accordance with the examples, but it is understood that the present disclosure is not limited to the examples and structures. The present disclosure also includes various variations and variations within a uniform range. In addition, various combinations and forms, as well as other combinations and forms that include only one element, more, or less, are within the scope and scope of the present disclosure.

In the drawing, 1 is the first load, 1a and 1b are the injectors, 2 is the second load, 3, 300 is the load drive device, 4, 4A is the control unit (control circuit), 5 is the booster circuit, and 6 is the drive unit. 10 is a microcomputer, 41 is a first load drive unit, 42 is a second load drive unit, 43 is a boost regeneration control circuit, 44, 102, 102a are regeneration determination circuits, 51 is a boost coil, and 54 is a MOSFET (regeneration switch element). , 55 are capacitors, and S1 and S2 are drive command signals.

Claims (6)

A load driving device that drives the first load (1, 1a, 1b) and the second load (2).
A booster circuit (5) that boosts the DC power supply and charges the capacitor (55) connected to the output terminal .
With the control circuit (4, 4A) that supplies the boost power generated by the booster circuit to the first load according to the first drive signal and supplies the DC power supply to the second load according to the second drive signal. ,
A regenerative switch element (54) for regenerating the electric charge of the capacitor to the DC power supply, and
A regenerative diode (73) connected in the forward direction between the downstream terminal of the second load and the output terminal of the booster circuit, and
Equipped with
The control circuit is a load drive device that drives the regenerative switch element to regenerate the electric charge of the capacitor to the DC power supply in the non-drive state of the first load and after the drive control of the second load is completed. The control circuit (4, 4A) determines the non-drive state of the first load by the fact that the first drive signal is off, and terminates the drive control of the second load at the off-edge of the second drive signal. The load drive device according to claim 1. The control circuit (4, 4A) stops the regeneration of the electric charge of the capacitor to the DC power supply by turning off the regenerative switch element when the terminal voltage of the capacitor drops to the regeneration stop voltage. The load drive device according to claim 1 or 2, wherein the regenerative stop voltage is set between an upper limit value for stopping the boosting operation of the boosting circuit and a lower limit value for starting the boosting operation. The load drive device according to claim 3, wherein the regenerative stop voltage is set to the upper limit value. The load drive device according to claim 3, wherein the regenerative stop voltage is set to the lower limit value. A load drive device in which an injector provided in a fuel injection device of an internal combustion engine is used as the first load and a pump is used as the second load.
The load drive device according to any one of claims 1 to 5, wherein the non-drive state of the first load is determined based on a state in which an accelerator opening signal is input and the accelerator opening is zero.

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