JP2018085804A - Power controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power controller that performs PWM control over a contactor and that opens the contactor serenely and also reduces a power consumption in opening the contactor.SOLUTION: A power controller comprises a drive circuit which drives a circuit breaker by supplying a drive current to an exciting coil L, a voltage monitoring unit 3 which detects the voltage of a dedicated power supply Vcc, and a control unit 4 which performs PWM control over the drive circuit 2, and also generates an opening control signal decreasing in ON period of one cycle with time by a certain quantity at each time when switching the circuit breaker from a closed state to an opened stage, and the control part 4 makes, based upon a detection result of the voltage monitoring unit 3, a period of input of the opening control signal to the drive circuit 2 shorter as the voltage of the dedicated power supply Vcc is lower.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power supply control device.

  Conventionally, a switch called a contactor is installed in a vehicle between a battery and a vehicle load. This contactor includes an exciting coil, and the on / off state is switched by displacing the movable piece by the action of magnetic force generated by energizing the exciting coil.

  Since such a contactor needs to energize an exciting coil, generally it consumes electric power in order to maintain an ON state. Patent Document 1 discloses a configuration in which power consumption in a contactor is suppressed by performing PWM control of the contactor and discretely performing power supply in a period in which the contactor is kept on.

JP-A-9-62385

  By the way, in the case of PWM control of the contactor, after the contactor OFF command is input, the ON period of one cycle of the PWM control signal (hereinafter referred to as ON duty ratio) is decreased step by step by a certain amount over time. When the ON period is reduced to a certain period, the contactor can be quietly released by completely turning it OFF.

  However, the voltage of the power source that supplies power to the exciting coil of the contactor varies depending on the state of charge of the power source. For this reason, if the on-duty ratio for always turning off the contactor is constant, it is necessary to set the on-duty ratio for turning off the power supply voltage assuming that the power supply voltage is the highest. However, in such a case, there may occur a period in which the excitation coil continues to be energized even though the power supply voltage is low and the quiet release is already possible, and power is wasted in the excitation coil. There is a possibility that.

  The present invention has been made in view of the above-described problems, and is a power supply control device that performs PWM control of a contactor, and an object thereof is to reduce power consumption when the contactor is opened while quietly opening the contactor.

  As a means for solving the above problems, the present invention provides a power supply control device for controlling a switch that opens and closes when a drive current is supplied from a switch power supply to the excitation coil, and the drive current is supplied to the excitation coil. A drive circuit that drives the switch by energizing the switch, a voltage detector that detects the voltage of the switch power supply, and PWM control of the drive circuit, and when the switch is switched from a closed state to an open state A control unit that generates an open control signal in which an ON period in one cycle decreases by a certain amount with time, and the control unit determines the voltage of the switch power source based on the detection result of the voltage detection unit. The lower the input signal, the shorter the input period of the open control signal to the drive circuit.

  According to the present invention, when the switch is PWM-controlled by PWM control of the drive circuit, and the switch is switched from the closed state to the open state, the on-period in one cycle decreases by a certain amount over time. Is generated. For this reason, a switch (contactor) can be opened calmly. Further, according to the present invention, the lower the voltage of the switch power supply, the shorter the input period to the drive circuit for the control signal in which the ON period in one cycle decreases by a certain amount with time. For this reason, the power supply to the exciting coil after the switch can be quietly opened can be suppressed, and the power consumption when the contactor is opened can be reduced. Therefore, according to this invention, it is a power supply control apparatus which carries out PWM control of a contactor, Comprising: It becomes possible to reduce the power consumption at the time of a contactor open | release, opening a contactor quietly.

(A) is a circuit diagram which shows schematic structure of the power supply control apparatus in one Embodiment of this invention, (b) is a timing chart for demonstrating the contactor open | release operation of the power supply control apparatus in one Embodiment of this invention. is there.

  Hereinafter, an embodiment of a power supply control device according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

  FIG. 1A is a circuit diagram showing a schematic configuration of the power supply control device 1 of the present embodiment. The power supply control device 1 of this embodiment controls a contactor (switch) installed between a battery mounted on a vehicle and a vehicle load such as a motor. As shown in FIG. A circuit 2, a voltage monitoring unit 3 (voltage detection unit), and a control unit 4 are provided.

  The drive circuit 2 is a circuit that drives the contactor including the exciting coil L by changing the energization state of the exciting coil L of the contactor. The drive circuit 2 generates a drive current that is passed through the exciting coil L based on a control signal input from the control unit 4. As shown in FIG. 1A, such a drive circuit 2 includes a first resistor 2a, a second resistor 2b, and a drive transistor 2c.

  The drive circuit 2 outputs a predetermined positive voltage (plus voltage) from the high potential side output terminal, and supplies power from a dedicated power source Vcc (switch power source) whose low potential side output terminal is connected to GND (ground potential). Act upon. Further, one end of the exciting coil L to be driven by the driving circuit 2 is connected to a dedicated power source Vcc (high potential side output terminal).

  One end of the first resistor 2a is connected to the output end of the drive circuit 2, and the other end is connected to one end of the second resistor 2b and the gate terminal of the drive transistor 2c. The second resistor 2b has one end connected to the other end of the first resistor 2a and the gate terminal of the drive transistor 2c, and the other end connected to GND (ground potential).

  The driving transistor 2c is an N-channel MOS field effect transistor as shown in the figure, and has a gate terminal (control terminal) connected to the other end of the first resistor 2a and one end of the second resistor 2b, and a drain terminal (input). Terminal) is connected to the other end of the exciting coil L, and a source terminal (output terminal) is connected to GND (ground potential).

  Such a driving transistor 2c is turned off (opened) or turned on (closed) based on a first control signal input to the gate terminal via the first resistor 2a. Switch between energization / non-energization. That is, the drive transistor 2c is turned off (open state) when the control signal is at L (low) potential, and is turned on (closed state) when the control signal is at H (high) potential. When the signal is at the H (high) potential, the drive current is passed through the excitation coil L, and when the control signal is at the L (low) potential, the drive current is stopped from passing through the excitation coil L.

  The voltage monitoring unit 3 is connected to the dedicated power source Vcc, monitors the voltage at the output terminal of the dedicated power source Vcc, and inputs a signal indicating the voltage value at the output terminal of the dedicated power source Vcc to the control unit 4. That is, the voltage monitoring unit 3 detects the voltage of the dedicated power supply Vcc and inputs the detection result to the control unit 4. The control unit 4 generates a control signal for PWM control of the drive transistor 2c based on a command signal input from the outside.

  Further, in the present embodiment, when a command signal for turning the contactor from the on state to the off state is input, the control unit 4 controls the control signal (hereinafter, referred to as “step signal”) in which the on period in one cycle gradually decreases by a certain amount over time. (Referred to as an open control signal). That is, when the command signal for turning the contactor from the on state to the off state is input, the control unit 4 generates an opening control signal that gradually decreases the on-duty ratio.

  In the present embodiment, the control unit 4 sets an on-duty ratio (hereinafter referred to as a stop on-duty ratio) for stopping the input of the open control signal based on the voltage of the dedicated power supply Vcc input from the voltage monitoring unit 3. Then, when the on-duty ratio of the open control signal becomes the stop on-duty ratio, the input of the open control signal to the drive transistor 2c is stopped, and a control signal of L (low) potential is continuously generated to drive the drive transistor. Enter in 2c. That is, in the present embodiment, the control unit 4 makes the input period relatively longer as the voltage of the dedicated power supply Vcc is higher, and relatively shortens the input period as the voltage of the dedicated power supply Vcc is lower.

For example, when obtaining the input period, the control unit 4 obtains the stop on-duty ratio using the following equation. In the following formula, the contactor open-circuit voltage indicates an applied voltage to the excitation coil L that is separated from a state in which the magnetic force of the excitation coil L is weakened in the contactor and the movable piece is in contact with the pair of contacts.
[Stop duty ratio] = [Contactor open voltage] / [Dedicated power supply voltage] x 100%

  For example, when the contactor open-circuit voltage is 5 (V) and the dedicated power supply voltage is 14 (V), the stop on-duty ratio is about 35%. For this reason, the control unit 4 stops the input of the open control signal to the drive transistor 2c when the on-duty ratio of the open control signal, which gradually decreases by a certain amount, reaches 35%.

  Further, for example, when the contactor open voltage is 5 (V) and the dedicated power supply voltage is 24 (V), the stop on-duty ratio is about 20%. For this reason, the control unit 4 stops the input of the opening control signal to the drive transistor 2c when the on-duty ratio of the opening control signal that decreases step by step by a certain amount reaches 20%.

  Further, for example, when the contactor open voltage is 5 (V) and the dedicated power supply voltage is 7 (V), the stop on-duty ratio is about 71%. For this reason, the control unit 4 stops the input of the open control signal to the drive transistor 2c when the on-duty ratio of the open control signal, which gradually decreases by a certain amount, reaches 71%.

  The smaller the value of the stop on-duty ratio, the longer the input period of the release control signal. In other words, in the present embodiment, the higher the dedicated power supply voltage, the longer the input period of the open control signal, and the lower the dedicated power supply voltage, the shorter the input period of the open control signal. That is, as shown in the timing chart of FIG. 1A, when the dedicated power supply voltage is high, the contactor is turned off after the on-duty ratio becomes small as shown by the phantom line. When it is low, as shown by a solid line, the contactor can be turned off without waiting until the on-duty ratio becomes the same.

  According to the power supply control device 1 of the present embodiment, when the contactor is PWM-controlled by PWM control of the drive circuit 2, and the contactor is switched from the closed state to the open state, the ON period in one cycle is a constant amount over time. A control signal (open control signal) that decreases gradually is generated. For this reason, a contactor can be opened calmly. Further, according to the power supply control device 1 of the present embodiment, the lower the voltage of the dedicated power supply Vcc, the shorter the input period of the open control signal to the drive circuit 2. For this reason, power supply to the exciting coil L after the contactor can be quietly opened can be suppressed, and power consumption when the contactor is opened can be reduced. Therefore, according to the power supply control device 1 of the present embodiment, it is possible to reduce the power consumption when the contactor is opened while quietly opening the contactor.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 1 Power supply control device, 2 Drive circuit, 2a 1st resistor, 2b 2nd resistor, 2c Drive transistor, 3 Voltage monitoring part (voltage detection part), 4 Control part, L Excitation coil, Vcc Dedicated power supply (Switch power supply )

Claims (1)

A power supply control device that controls a switch that opens and closes when a drive current is applied to an exciting coil from a switch power supply,
A drive circuit for driving the switch by energizing the excitation coil with the drive current;
A voltage detector for detecting the voltage of the switch power supply;
A PWM control of the drive circuit, and when the switch is switched from a closed state to an open state, a control unit that generates an open control signal in which an ON period in one cycle decreases by a certain amount with time, and
The control unit shortens the input period of the open control signal to the drive circuit as the voltage of the switch power supply is lower based on the detection result of the voltage detection unit.

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