JPH0969435A - Inductance load driving bridge circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the title inductance load driving bridge circuit capable of increasing the power supply voltage impressing the inductance load while suppressing the complification of circuit composition. SOLUTION: When the switches H2, L1 of switching bridge 1 are turned off, the current generated by the voltage due to the magnetic energy of a coil 5 runs through a diode D in parallel with the switches H1, L2 to charge a capacitor 3. At this time, the charge of a battery 6 is prohibited by a diode 2 so that a capacitor 3 may be charged with higher voltage than the battery VB to be pressed on the coil 5. That is, the large power driving of the coil 5 can be realized by adding the simple circuit composition of the diode 2 and the capacitor 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inductance load driving bridge circuit.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 3-275935 proposes a method of increasing a voltage applied to a coil of a rotary solenoid in a rotary solenoid drive type intake control device as the engine speed increases.

[0003]

It is easy to increase the power supply voltage in order to increase the electric power supplied to an inductance load such as a coil of a rotary solenoid to increase the torque, for example, an on-vehicle battery or the like. It is usually difficult to increase the power supply voltage, as can be seen from the inductance load mounted on the vehicle and the like, where V is the power supply voltage.

It is possible to boost the power supply voltage by using a dedicated booster circuit such as a switching inverter and then apply it to an inductance load, but this causes a problem that the circuit configuration becomes complicated. The present invention has been made in view of the above problems, and an object thereof is to provide an inductance load drive bridge circuit capable of increasing the power supply voltage applied to the inductance load while suppressing the complexity of the circuit configuration.

The increased power supply voltage can be applied to loads other than the inductance load. Therefore, another object of the present invention is to provide an inductance load drive bridge circuit having a booster circuit with a simple circuit configuration.

[0006]

A first structure of the present invention is a switching bridge formed by connecting in parallel a plurality of inverters, each of which is formed by connecting a high side switch and a low side switch in series. Inductance loads bidirectionally energized from the output terminals of the respective inverters, and backflow prohibition means interposed between the power source and the high end of the high side switch to inhibit energization of the high side switch to the power source. An inductance load drive bridge circuit, comprising: a storage means charged from the high end and an energization control means for connecting and disconnecting the switch to control energization of the load coil.

According to the present invention, it is possible to realize an inductance load drive bridge circuit capable of increasing the power supply voltage applied to an inductance load while suppressing the complexity of the circuit configuration, or a booster circuit having a simple circuit configuration. An inductance load drive bridge circuit having a circuit can be realized. More specifically, if the high-side switch and the low-side switch of each inverter are turned on and off in order to perform bidirectional energization to the inductance load, that is, to alternately energize in the opposite directions, a high reverse load is applied to the inductance load when the energization is cut off in one direction. An electromotive force is generated, and current is circulated to the high end of the high side switch through the switch that has been turned off.

In this configuration, in particular, the power supply is prohibited from being charged from the high end of the high side switch by the backflow prohibiting means, so that the above-mentioned return current due to the magnetic energy of the inductance load is accumulated in the storage means. . The high voltage accumulated in the storage means is applied to the inductance load during the next phase period, and the energy supplied to the inductance load can be increased. As a result, it is possible to drive the inductance load at a high voltage. In addition, this high voltage can be used as a power supply voltage of the energization control means for controlling the above-mentioned switch, which requires the high voltage.

A second structure of the present invention is characterized in that, in the first structure, the switching bridge is composed of a pair of inverters for driving the inductance load composed of one coil. Third of the present invention
The configuration of 1 is further characterized in that, in the first configuration, the switching bridge is composed of three inverters that drive the inductance load composed of an AC rotating electric machine.

A fourth structure of the present invention is further characterized in that, in the first structure, the high-side switch and the low-side switch each include a transistor and a free wheeling diode connected in parallel to each other. A fifth configuration of the present invention is further characterized in that, in the first configuration, the high-side switch and the low-side switch are MOS transistors having a parasitic diode.

A sixth structure of the present invention is characterized in that, in the first structure, the backflow inhibiting means is composed of a diode. The 7th structure of this invention is the said 1st.
Further, in the above configuration, the backflow inhibiting means is composed of a transistor which is turned on only when the power source has a higher potential than the high end of the high side switch. According to this configuration, the forward potential drop of the diode of the sixth configuration can be avoided and the loss can be reduced.

An eighth structure of the present invention is the same as the first structure, further provided between the high end of the high side switch and the electric storage means to energize the electric storage means to the high end. It is characterized by having a discharge control switch for controlling. According to this configuration, the inductance load can be driven at a high voltage when desired.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the following examples.

[0014]

【Example】

(Embodiment 1) An embodiment of an inductance load drive bridge circuit of the present invention will be described below with reference to FIG. This circuit is a circuit for driving the coil 5 of the rotary solenoid that drives the intake flow control valve, and is an NMOS
An H-bridge circuit (switching bridge) 1 composed of transistors, a diode (backflow inhibiting means) 2, a capacitor (storage means) 3, high-side switches H1 and H2 and low-side switches L1 and L of the H-bridge circuit 1.
It is composed of a drive circuit (energization control circuit) 4 for forming a gate voltage of 2, a diode 31 and a capacitor 32.

As is well known, the H bridge circuit 1 has an inverter having a high side switch H1 and a low side switch L1 connected in series, and an inverter having a high side switch H2 and a low side switch L2 connected in series. A coil 5, which is an inductance load, is connected between the output terminals of both inverters. The diode 2 is interposed between the high-side ends of the high-side switches H1 and H2 and the high-side end of the battery (power supply) 6 to prevent backflow from the high-side switches H1 and H2 to the battery 6, and as a result, , While the potentials of the high-side switches H1 and H2 and the capacitor 3 do not drop more than the potential of the battery 6-the forward potential drop of the diode 2,
Power is not supplied to the bridge circuit 1.

The drive circuit 4 is driven by the capacitor 32 as a power source, and PWM-controls the gate voltages V1 to V4 input to the H-bridge circuit 1 in accordance with the input signal voltage corresponding to the command intake flow rate. is there. PWM
Control Since control itself is well known, its description is omitted.
The diode 31 charges the capacitor 32 through the resistor 34, and the charging voltage of the capacitor 32 is converted to a constant voltage by the Zener diode 33 and supplied to the drive circuit 4 as a power supply voltage. In this way, the drive circuit 4 can apply a high power supply voltage to the high side switches H1 and H2 composed of nMOS transistors.

Next, the operation of this circuit will be described with reference to the timing chart of FIG. VH1 is the gate voltage of the high side switch H1, VH2 is the gate voltage of the high side switch H2, VL1 is the gate voltage of the low side switch L1, and VL2 is the gate voltage of the low side switch L2. First, the switches H2, L1
Is on and the switches H1 and L2 are off.
When the valve opening command is input at time t1, first, the switches H1 and L2 are turned on and the switches H2 and L1 are turned off. When the switches H2 and L1 are turned off, the stored magnetic energy is discharged in the form of an induced voltage in an attempt to keep the current -i flowing in the coil 5, and the regenerative current due to this induced voltage is connected in parallel with the switches H1 and L2. The high-side switch H is supplied through the free-wheeling diode (in this embodiment, a parasitic diode of the MOS transistor) D.
1 is transmitted to the high end of H2, and the capacitor 3 is charged. At this time, the diode 2 outputs this regenerative current to the battery 6
Prevent it from returning to.

After that, such an operation is performed by the switch H.
1 and L2 and the switches H2 and L1 are switched, and as a result, the induced voltage is the battery voltage V _B -O. 75
If higher than V, a large voltage is applied to the coil 5,
As a result, the current also increases, a large valve starting torque can be obtained, and high-speed operation is realized. After that, at time t2, the switch H1 is turned on and off, the switch L2 is constantly turned on, the switches H2 and L1 are turned off, and the PWM is performed at a predetermined duty ratio.
The coil 5 is controlled and the required average current is applied to the coil 5. By doing so, the valve rotates to the valve opening degree according to the on-duty of the switch H1. However, in this case, since the switch L2 is turned on when the switch H1 is turned off, the regenerative current is circulated through the switch L2, the ground wire, and the diode D in parallel with the switch L1, and the high-side switches H1 and H2 are powered. No increase in voltage occurs.

Further, in this embodiment, the battery 6 does not have to absorb the regenerative current that changes abruptly, so that the charging efficiency thereof and the battery life are not reduced. The result of one experiment is shown in FIG. In FIG. 3, reference numeral 100 indicates a response state when the valve is opened from the valve fully closed state to a predetermined valve opening degree by the circuit configuration of the present application, and 101 is a diode 2
The capacitor 3 is omitted, and the drive circuit 4 shows a response state at the time of valve opening from a valve fully closed state to a predetermined valve opening degree when a power supply voltage is supplied from a special high voltage circuit as a comparative example, 103 is a coil 5 in the circuit configuration of the present application
Of the coil 5 in the above conventional configuration.
And 105 indicates the terminal voltage of the capacitor 3 (high-side voltage of the high-side switches H1 and H2). From this experimental result, it was found that the circuit of the present embodiment (100) was accelerated by about 1 mS as compared with the conventional circuit.

A modification of the circuit of this embodiment will be described below. For the high side switches H1 and H2 and the low side switches L1 and L2, diodes other than the parasitic diode of the MOS transistor may be connected in parallel with the MOS transistor. Further, the MOS transistor may be replaced with another transistor such as a bipolar transistor.

In the case of having the above-mentioned diode D for circulating the regenerative current, for example, even when the switches H2 and L1 are turned off, even if the other switches H1 and L2 are not turned on, a diode connected in parallel with them is used. Capacitor 3
Can be charged. On the other hand, the high side switch H1,
A configuration in which the diode D for regenerative current circulation is not provided in parallel with H2 and the low-side switches L1 and L2 is also possible,
In this case, the switches H2 and L1 may be turned on when the switches H1 and L2 are off, and the switches H1 and L2 may be turned on when the switches H2 and L1 are off.

Further, in the above embodiment, as shown in FIG. 2, the low side switch L2 is always turned on, and the high side switch H1 is PWM-controlled to control the average energizing current of the coil 5. Of course, the operating method of can also be applied. For example, when the valve is open, the switch H1,
PWM control of both L2 and switches H2, L when the valve is closed.
Both 1 can be PWM controlled. At this time, the valve is 50% when the energizing current is 0 due to its detent torque.
It is preferable to set the opening degree. According to this PWM control method, when the coil is disconnected, the valve is driven by the detent torque of 50
There is an advantage that it can be maintained at% opening.

In addition, in a predetermined odd period, the switch H2,
L1 is turned on and the switches H1 and L2 are turned off, and the switches H2 and L1 are turned off and the switch H is turned on in the next even period.
It is also possible to perform PWM control so that 1 and L2 are turned on. In this case, if the odd period and the even period are equal, the energization current of the coil 5 is substantially 0, and at this time, it is preferable that the valve has a 50% opening due to the detent torque. Then, the valve may be closed as the odd period is longer than the even period, and the valve may be opened as the odd period is shorter than the even period. According to this PWM control system, there is an advantage that the valve can be maintained at 50% opening due to the detent torque when the coil is broken.

(Embodiment 2) Another embodiment will be described with reference to FIG. This example is the same as Example 1 (FIG. 1).
High side switches H1 and H2 high end and capacitor 3
A MOS transistor (discharge control switch) 7 is provided between the high-level end of the MOS transistor and the high-end terminal. In this embodiment, the diode 71 connected in parallel with the MOS transistor 7 is a MOS
It is a parasitic diode of the transistor 7.

With this configuration, when the switches H1 and L2 are turned off, or when the switches H2 and L1 are turned off, the high voltage generated at the high end of the high side switches H1 and H2 causes
The charging current charges the capacitor 3 through the diode 71. Then, when the MOS transistor 7 is turned on for a desired period, the capacitor 3 is switched to the high side switch H1.
It is possible to discharge to the high end of H2. That is, in the present embodiment, high voltage driving can be performed at the time of starting when a desired large torque is required.

FIG. 5 shows a timing chart of one example of the operation, and one experimental result is shown in FIG. In FIG. 6, 20
0 indicates the response state when the valve is opened from the valve fully closed state to the predetermined valve opening according to the circuit configuration of the present application, 201 omits the diode 2 and the capacitor 3, and the drive circuit 4 has a special high level as a comparative example. A response state when the valve is opened from the valve fully closed state to a predetermined valve opening degree when the power supply voltage is supplied from the voltage circuit, 203 indicates a current of the coil 5 in the circuit configuration of the present application, and 204 indicates in the above conventional configuration. The current of the coil 5 is shown, and 205 is the terminal voltage of the capacitor 3 (high-side voltage of the high-side switches H1 and H2). From this experimental result, it was found that the circuit of the present embodiment (100) was accelerated by about 2 mS as compared with the conventional circuit.

(Embodiment 3) Another embodiment will be described with reference to FIG. In this embodiment, the diode 2 in the first embodiment (see FIG. 1) is replaced with a MOS transistor 22 driven by a comparator 21. Reference numeral 23 is a parasitic diode of the MOS transistor 22.

The characteristic operation of this circuit will be described below. If the battery voltage V _B is lower than the voltage Vc of the capacitor 3, the comparator 21 becomes low level and the MOS
The transistor 22 is turned off to prevent the battery voltage V _B from being charged. On the other hand, if the battery voltage V _B is higher than the voltage Vc of the capacitor 3, the comparator 21 goes to high level to turn on the MOS transistor 22, and the battery 6 drives the coil 5.

In this way, the junction forward bias voltage drop due to the diode 2 can be eliminated. (Embodiment 4) Another embodiment will be described with reference to FIG. In this embodiment, the rotary solenoid coil shown in FIG. 7 is replaced with a three-phase AC motor 7 for an electric vehicle, for example, and the switching bridge 1 is replaced with a three-phase inverter 8.

The three-phase inverter 8 is composed of high-side switches 81-83 and low-side switches 84-86 which are MOS transistors, and are alternately controlled by the gate control signal voltage from the drive circuit 9, whereby the three-phase AC voltage Va. , Vb, Vc are formed. Normally, the high side switches 81 to 83 are turned on in order, and the low side switches 84 to 86 are turned on in order. Naturally, the high-side switch and the low-side switch of the same phase are not turned on at the same time.

In this way, if the high side switch 81 and the low side switch 85 which are on are turned off, for example, a high voltage is applied to the capacitor 3 through the diodes connected in parallel to the high side switch 82 and the low side switch 84, respectively. Is applied. Therefore, as in the first to third embodiments, the capacitor 3 can be charged with a high voltage, the average three-phase AC voltages Va, Vb, Vc applied to the three-phase AC motor 7 can be increased, and the battery 6 The charging burden is also reduced. Of course, in this embodiment, the three-phase AC motor 7 can also be operated to generate electricity during vehicle braking, in which case braking energy is stored in the capacitor 3. Of course, if the charging voltage of the capacitor 3 exceeds a predetermined threshold value, the MOS transistor 22
Can be turned on to prevent excessive voltage storage in the capacitor 3.

Of course, in FIGS. 7 and 8, the comparator 21 and the MOS transistor 22 can be integrated with the switching bridge 1 or the three-phase inverter 8.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a circuit of a first embodiment.

FIG. 2 is a timing chart showing a potential change in each part of the circuit of FIG.

FIG. 3 is a timing chart showing a potential change of each part in an experiment using the circuit of FIG.

FIG. 4 is a circuit diagram showing a circuit of a second embodiment.

5 is a timing chart showing a potential change in each part of the circuit of FIG.

6 is a timing chart showing a potential change in each part in an experiment using the circuit of FIG.

FIG. 7 is a circuit diagram showing a circuit of Example 3;

FIG. 8 is a circuit diagram illustrating a circuit according to a fourth exemplary embodiment.

[Explanation of symbols]

H1 and H2 are high side switches, L1 and L2 are low side switches, 1 is a switching bridge, 2 is a diode (backflow inhibiting means), 3 is a capacitor (storage means),
4 is a drive circuit (energization control means) and 5 is a coil (inductance load).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H02P 7/63 302 H02P 7/63 302C

Claims (8)

[Claims] 1. A switching bridge formed by connecting in parallel a plurality of inverters each configured by connecting a high-side switch and a low-side switch in series, an inductance load bidirectionally energized from an output end of each inverter, and a power supply. And a high-side end of the high-side switch interposed between the high-side switch and the high-side switch to inhibit energization to the power source, a power storage means charged from the high-side end, the switch is intermittently connected. And an energization control means for controlling energization of the load coil. 2. The inductance load drive bridge circuit according to claim 1, wherein the switching bridge comprises a pair of inverters for driving the inductance load formed of one coil. 3. The inductance load drive bridge circuit according to claim 1, wherein the switching bridge includes three inverters that drive the inductance load formed of an AC rotating electric machine. 4. The inductance load drive bridge circuit according to claim 1, wherein the high-side switch and the low-side switch each include a transistor and a freewheeling diode connected in parallel with each other. 5. The inductance load drive bridge circuit according to claim 1, wherein each of the high-side switch and the low-side switch is a MOS transistor having a parasitic diode. 6. The inductance load drive bridge circuit according to claim 1, wherein said backflow inhibiting means comprises a diode. 7. The inductance load drive bridge circuit according to claim 1, wherein said backflow inhibiting means comprises a transistor which is turned on only when said power source is at a higher potential than the high end of said high side switch. 8. A discharge control switch provided between the high end of the high-side switch and the power storage means to control the energization from the power storage means to the high end.
Inductance load drive bridge circuit described.