JP2016226151A - Power supply control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply control device capable of achieving space saving and weight reduction while preventing an inrush current to a load side.SOLUTION: A power supply control device 1 provided to a vehicle, comprises: a mechanical relay 21 installed in a first route 8 for connecting a battery 3 to a load 5 and allowing connection between the battery 3 and the load 5 by opening/closing of a contact 31; a semiconductor relay 23 installed in a second route 9 for connecting the battery 3 to the load 5 and allowing connection between the battery 3 and the load 5 by a drive pulse; and a signal generation section included in an ECU for setting a duty ratio of the drive pulse to a previously set upper limit value or less on the basis of load voltage applied to the load 5 and battery voltage of the battery 3, when starting the vehicle and performing charging. The previously set upper limit value is correlated with a range within a rating current of the semiconductor relay 23.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power supply control device.

  A vehicle such as an electric car or a hybrid car is equipped with a high voltage load such as an inverter. When the vehicle is started, an inrush current may flow into the load-side smoothing capacitor. Therefore, a series circuit including a current limiting resistor and a precharge relay is connected in parallel with the main relay for energizing or cutting off the load. When the vehicle is started, the capacitor provided on the load side is charged while the amount of current is limited by passing through this series circuit.

  However, since the circuit configuration requires a main relay, a precharge relay, and a current limiting resistor, the component size increases and the overall weight increases. Thus, the circuit configuration increases the overall system size and vehicle weight.

  Therefore, by using the characteristics of the gate voltage and drain current of the semiconductor relay instead of the current limiting resistor, a pseudo high resistance state is created, the load current at the start of the vehicle is reduced, and the inrush current is prevented. (For example, refer to Patent Document 1).

JP2012-210110A

  However, since the technique described in Patent Document 1 requires a total of three various relays, sufficient space saving and weight reduction cannot be achieved.

  Therefore, the technique described in Patent Document 1 cannot achieve space saving and weight reduction while preventing inrush current to the load side.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a power supply control device capable of realizing space saving and weight reduction while preventing an inrush current to the load side. is there.

  A power supply control device according to the present invention is a power supply control device provided in a vehicle, provided in a first path connecting a battery and a load, and connecting the battery and the load by opening and closing a contact. A mechanical relay that is allowed, a semiconductor relay that is provided in a second path that connects the battery and the load, and allows the connection between the battery and the load by a drive pulse, and is charged when the vehicle is started A signal generation unit that sets a duty ratio of the drive pulse to a preset upper limit value or less based on a load voltage applied to the load and a battery voltage of the battery. The preset upper limit value is associated with a rated current range of the semiconductor relay.

  According to the power supply control device of the present invention, the load current is controlled within a range not exceeding the rated current of the semiconductor relay without separately providing a circuit for preventing the inrush current, while preventing the inrush current to the load side. , Space saving and weight reduction can be realized.

  In addition, since different types of relays such as a mechanical relay and a semiconductor relay are used, it is possible to avoid a situation where a failure occurs at the same time and to ensure safety at the time of the failure.

  In the power supply control device according to the present invention, it is preferable that the signal generator weights a coefficient determined by characteristics of the semiconductor relay when setting a duty ratio of the drive pulse.

  According to this power supply control device, by adjusting the coefficient, it is possible to cope with any circuit environment without changing the hardware. Therefore, even if the surrounding circuit environment is changed, a low-cost and safe vehicle An activation system can be constructed.

  Further, in the power supply control device according to the present invention, the signal generation unit is less than or equal to the preset upper limit value until a differential voltage between the load voltage and the battery voltage is less than or equal to a preset threshold voltage. Preferably, the drive pulse generated based on the duty ratio is output.

  According to this power supply control device, the load current is controlled within a range not exceeding the rated current of the semiconductor relay, and no extra charging operation is performed, so that the vehicle can be quickly shifted from the start state to the normal state. it can.

  According to the present invention, since the load current is controlled within a range not exceeding the rated current of the semiconductor relay without separately providing a circuit for preventing inrush current, space saving can be achieved while preventing inrush current to the load side. It is possible to provide a power supply control device that can achieve weight reduction.

It is a figure which shows the structural example of the power supply control apparatus 1 which concerns on this embodiment. It is a figure explaining the example of a production | generation of the control signal of the power supply control apparatus. 3 is a block diagram illustrating a configuration example of functions of a signal generation unit 50. FIG. It is a figure explaining the example of a setting of duty ratio. 5 is a flowchart for explaining a control example of the power supply control device 1.

  FIG. 1 is a diagram illustrating a configuration example of a power supply control device 1 according to the present embodiment. As shown in FIG. 1, the power supply control device 1 includes a mechanical relay 21, a semiconductor relay 23, an ECU, and the like, and is provided in a vehicle.

  The mechanical relay 21 is provided on the first path 8 that connects the battery 3 and the load 5. The mechanical relay 21 includes a contact 31 and a coil winding 32. The contact 31 switches the connection state between the battery 3 and the load 5 to one of an on state and an off state. The coil winding 32 controls the contact 31. The coil winding 32 is electrically insulated from the contact 31, but when the current flows, the contact 31 is operated and the contact 31 is controlled to be energized or disconnected.

  The first path 8 is a path that connects the battery 3 and the load 5, and is connected to the positive electrode side of the battery 3. Therefore, the mechanical relay 21 is provided in the first path 8 that connects the battery 3 and the load 5, and allows the connection between the battery 3 and the load 5 by opening and closing the contact 31, and the system relay 1. It functions as one.

  The semiconductor relay 23 is provided in the second path 9 that connects the battery 3 and the load 5. The semiconductor relay 23 is composed of an N-channel MOSFET, and the gate-voltage Vg generated by the drive pulse duty is controlled, whereby the drain-source voltage is controlled, and the drain-source of the semiconductor relay 23 is cut off. Transition to the energized state.

  The second path 9 is a path that connects the battery 3 and the load 5, and is connected to the negative electrode side of the battery 3. Therefore, the semiconductor relay 23 is provided in the second path 9 that connects the battery 3 and the load 5, and allows the connection between the battery 3 and the load 5 by the drive pulse duty, and is one of the system main relays. It functions.

  The battery 3 is a high-voltage power source, and includes, for example, an assembled battery to which a plurality of cells are connected, and is mounted on a vehicle. In addition, the battery 3 should just supply the stable DC voltage like a primary battery and a secondary battery.

  The load 5 is an inverter composed of six arms and a smoothing capacitor CL. Each arm is composed of an IGBT and is mounted on a vehicle. When the connection state between the load 5 and the battery 3 is changed from the cut-off state to the energized state by the mechanical relay 21 and the connection state between the battery 3 is changed from the cut-off state to the energized state by the semiconductor relay 23, 3 is driven by applying a voltage.

  The power supply control device 1 includes a voltage monitoring circuit 7a and a voltage monitoring circuit 7b. The voltage monitoring circuit 7a is provided between the battery 3 and the upstream side of the mechanical relay 21 and the semiconductor relay 23, and detects the battery voltage VB_H. The voltage monitoring circuit 7a transmits the detection result of the battery voltage VB_H to the ECU.

  The voltage monitoring circuit 7b is provided between the battery 3 and the downstream side of the mechanical relay 21 and the semiconductor relay 23, and detects the load voltage VL. The voltage monitoring circuit 7b transmits the detection result of the load voltage VL to the ECU.

  Based on the battery voltage VB_H transmitted from the voltage monitoring circuit 7a and the load voltage VL transmitted from the voltage monitoring circuit 7b, the ECU obtains an appropriate drive pulse duty, that is, an appropriate PWM signal, and generates the drive circuit 13. Output to. The PWM signal is converted into an analog signal by the drive circuit 13 and applied to the semiconductor relay 23 as the gate voltage Vg. Note that the conversion process from the PWM signal to the analog signal can also be realized by the ECU having the D / A conversion function.

  Next, a series of processes in which the load voltage VL is controlled by the drive pulse duty generated by the ECU will be described with reference to FIG. FIG. 2 is a diagram illustrating an example of generation of a control signal of the power supply control device 1. As shown in FIG. 2, the ECU includes a function including a signal generation unit 50. The signal generation unit 50 may be realized by hardware or may be realized by software.

  The signal generation unit 50 sets the duty ratio of the drive pulse duty in advance based on the load voltage VL applied to the load 5 and the battery voltage VB_H of the battery 3 when charging is performed when the vehicle is started. It is set below the upper limit value DUTY_MAX. Here, the upper limit value DUTY_MAX is associated with the rated current range of the semiconductor relay 23. Further, when setting the duty ratio of the drive pulse duty, the signal generator 50 weights the coefficient K0 determined by the characteristics of the semiconductor relay 23. The coefficient K0 is a coefficient for calculating the duty ratio, and is a value determined based on the battery voltage VB_H and the gate voltage-drain current characteristics of the semiconductor relay 23, and contributes to the charging time of the smoothing capacitor CL. Is an element.

  Specifically, the ECU obtains a differential voltage Vdiff between the load voltage VL and the battery voltage VB_H. Next, the signal generation unit 50 adds the output value duty (n−1) of the previous duty ratio to the product of the differential voltage Vdiff and the coefficient K0 to obtain an output value duty (n) of the duty ratio. The process described above is expressed by the following equation (1).

  Note that the product of the coefficient K0 and the differential voltage Vdiff is obtained by subtracting the output value duty (n−1) of the previous duty ratio from the output value duty (n) of the duty ratio from the equation (1). Derived.

  Next, the signal generator 50 obtains the drive pulse duty based on the duty ratio output value duty (n). The signal generation unit 50 outputs the obtained drive pulse duty to the drive circuit 13. The drive circuit 13 is a low-pass filter composed of a CR circuit, and outputs a gate voltage Vg to the semiconductor relay 23 according to the duty ratio included in the drive pulse duty that is a PWM signal by performing D / A conversion. The semiconductor relay 23 outputs a predetermined load current Id according to the gate voltage-drain current characteristic.

  Next, the smoothing capacitor CL is charged according to the integrated amount of the inflowing load current value Id (t) by the inflow of the load current Id. Here, the charged load voltage VL is expressed by the following equation (2).

  Next, details of the signal generation unit 50 will be described with reference to FIGS. FIG. 3 is a block diagram illustrating an exemplary functional configuration of the signal generation unit 50. FIG. 4 is a diagram for explaining an example of setting the duty ratio.

  The signal generation unit 50 has a function including a calculation unit 51, a control command unit 52, and a contact control unit 53. Furthermore, the calculation unit 51 realizes a function including an initial value setting unit 61, a differential voltage calculation unit 62, a duty ratio setting unit 63, a storage unit 64, and a differential voltage determination unit 65. Further, the signal generation unit 50 also has a function including the contact control unit 53. Each of these functions may be realized by hardware or may be realized by software.

  The contact control unit 53 outputs a relay control signal to the coil winding 32, generates a magnetic action on the coil winding 32, and operates the contact 31.

  The initial value setting unit 61 determines the duty ratio initial value duty (0) based on the gate voltage-drain current characteristic of the semiconductor relay 23 that is driven when the high voltage system is started (n = 0) and the battery voltage VB_H. Set.

  The differential voltage calculation unit 62 calculates a differential voltage Vdiff between the battery voltage VB_H and the load voltage VL. The duty ratio setting unit 63 sets the duty ratio based on Expression (1). Specifically, as shown in FIG. 4, the duty ratio increment Δduty is set to a larger value as the differential voltage Vdiff between the battery voltage VB_H and the load voltage VL increases. On the other hand, as the differential voltage Vdiff between the battery voltage VB_H and the load voltage VL decreases, Δduty, which is an increase in the duty ratio, is set to a smaller value.

  Since the correlation between the duty ratio included in the PWM signal, that is, the drive pulse duty, and the drain current of the semiconductor relay 23 is known in advance, an upper limit value DUTY_MAX is provided for the duty ratio as shown in FIG. . In this way, the duty ratio setting unit 63 can control the load current Id within a range that does not exceed the rated current of the semiconductor relay 23. The duty ratio setting unit 63 stores the output value duty (n) of the set duty ratio in the storage unit 64.

  The differential voltage determination unit 65 outputs the drive pulse duty generated based on the duty ratio that is set to the upper limit value DUTY_MAX or less until the differential voltage Vdiff becomes equal to or less than the preset threshold voltage V_CHARGE. When the initial value duty (0) of the duty ratio is set, the control command unit 52 outputs a drive pulse duty based on the initial value duty (0). Further, the control command unit 52 continuously outputs the drive pulse duty with the duty ratio suppressed to the upper limit value DUTY_MAX or less until the differential voltage Vdiff becomes the threshold voltage V_CHARGE or less.

  Next, the vehicle starting charging process will be described with reference to FIG. FIG. 5 is a flowchart for explaining a control example of the power supply control device 1.

  In step S11, the signal generator 50 sets an initial value duty (0) of the duty ratio. The count value n is initialized to 0. In step S12, the signal generation unit 50 obtains the differential voltage Vdiff by subtracting the load voltage VL from the battery voltage VB_H. In step S13, the signal generation unit 50 obtains the output value duty (n) of the duty ratio based on the equation (1), and sets the duty ratio.

  In step S14, the signal generation unit 50 determines whether or not the output value duty (n) of the duty ratio is equal to or greater than the upper limit value DUTY_MAX. If the output value duty (n) of the duty ratio is greater than or equal to the upper limit value DUTY_MAX, the process proceeds to step S15. On the other hand, if the output value duty (n) of the duty ratio is less than the upper limit value DUTY_MAX, the process proceeds to step S16.

  In step S15, the signal generation unit 50 sets the upper limit value of the duty ratio by setting the upper limit value DUTY_MAX of the output value duty (n) of the duty ratio.

  In step S16, the signal generating unit 50 stores the set duty ratio.

  In step S17, the signal generator 50 increments the count value n by 1, that is, advances by 1. In step S18, the signal generation unit 50 determines whether or not the differential voltage Vdiff is equal to or lower than the threshold voltage V_CHARGE. When the differential voltage Vdiff is equal to or less than the threshold voltage V_CHARGE, the vehicle start-up charging process is terminated. On the other hand, when the differential voltage Vdiff is larger than the threshold voltage V_CHARGE, the process returns to step S12.

  From the above description, in the present embodiment, the mechanical relay 21 is provided in the first path 8, and the semiconductor relay 23 is provided in the second path 9. Therefore, the battery 3 and the load 5 are connected by controlling the mechanical relay 21 and the semiconductor relay 23. Here, when charging is performed when the vehicle is started, if the battery 3 and the load 5 are connected as they are, the load current Id may flow into the load 5 as an inrush current in a transient state.

  Due to its structure, the mechanical relay 21 is simply in one of an on state and an off state in a certain time. Therefore, it is difficult to prevent the inrush current from flowing into the load 5 in the transient state by controlling the mechanical relay 21.

  On the other hand, since the semiconductor relay 23 can adjust the current flowing through the load by utilizing the characteristics of the gate voltage and the drain current, the load current Id flowing into the smoothing capacitor CL can be controlled in a transient state. Therefore, by controlling the semiconductor relay 23, inrush current can be prevented from flowing into the load 5 in a transient state.

  Specifically, the power supply control device 1 drives the semiconductor relay 23 based on the load voltage VL applied to the load 5 and the battery voltage VB_H of the battery 3 when charging when starting the vehicle. The duty ratio of the duty is set to be equal to or less than a preset upper limit value DUTY_MAX. Furthermore, the power supply control device 1 associates the preset upper limit value DUTY_MAX within the rated current range of the semiconductor relay 23.

  Therefore, the power supply control device 1 provides the upper limit value DUTY_MAX in the duty ratio, and the upper limit value DUTY_MAX is associated with the rated current range of the semiconductor relay 23, so that the load does not exceed the rated current of the semiconductor relay 23. The current Id can be controlled. Therefore, inrush current to the load 5 side can be prevented.

  Furthermore, since the control of the load current Id is realized by utilizing the characteristics of the gate voltage-drain current of the semiconductor relay 23, it is not necessary to separately provide a circuit for preventing an inrush current. Therefore, space saving and weight reduction can be realized.

  Therefore, the power supply control device 1 controls the load current Id by the gate voltage control using the PWM signal of the semiconductor relay 23 when charging at the time of starting the vehicle, and the upper limit provided in the duty ratio for generating the PWM signal. By associating the value DUTY_MAX within the range of the rated current of the semiconductor relay 23, the load current Id is controlled within a range not exceeding the rated current of the semiconductor relay 23 without separately providing a circuit for preventing inrush current. Space saving and weight reduction can be realized while preventing inrush current.

  Further, the power supply control device 1 uses a different type of relay when charging at the start of the vehicle by providing a mechanical relay 21 on the first path 8 and providing a semiconductor relay 23 on the second path 9. ing. The mechanical relay 21 and the semiconductor relay 23 are structurally different in characteristics and are unlikely to fail at the same time. Therefore, even if the semiconductor relay 23 breaks down due to some cause and the semiconductor relay 23 becomes uncontrollable, the high voltage circuit as the load 5 can be cut off by the mechanical relay 21. Safety can be ensured.

  Therefore, since the power supply control device 1 uses different types of relays such as the mechanical relay 21 and the semiconductor relay 23 to avoid the situation of simultaneous failure, it is possible to ensure safety at the time of failure.

  Further, when setting the duty ratio, the power supply control device 1 weights the coefficient K0 determined by the characteristics of the semiconductor relay 23. The coefficient K0 is a coefficient for calculating the duty ratio, and is a value determined by the battery voltage VB_H of the battery 3 and the gate voltage-drain current characteristics of the semiconductor relay 23, and is an element that contributes to the charging time of the smoothing capacitor CL. It is. Therefore, by adjusting the coefficient K0, all kinds of semiconductor relays 23, the battery voltage VB_H, and the capacity of the load 5 can be handled.

  Therefore, since the power supply control device 1 can adapt to any circuit environment without changing the hardware by adjusting the coefficient K0, even if the surrounding circuit environment is changed, the power supply control device 1 is low-cost and safe. A vehicle activation system can be constructed.

  Further, the power supply control device 1 suppresses the load current Id within the range of the rated current of the semiconductor relay 23 until the differential voltage Vdiff between the load voltage VL and the battery voltage VB_H becomes equal to or lower than a preset threshold voltage V_CHARGE. Continue to control the load current in the

  Therefore, since the power supply control device 1 controls the load current Id within a range not exceeding the rated current of the semiconductor relay 23 and does not perform an extra charging operation, the power supply control device 1 promptly shifts from the start state of the vehicle to the normal state. be able to.

  As described above, the power supply control device 1 according to the first embodiment is a power supply control device 1 provided in a vehicle, provided in the first path 8 that connects the battery 3 and the load 5, and opens and closes the contact 31. Are provided in the second path 9 for connecting the battery 3 and the load 5 to the mechanical relay 21 that permits the connection between the battery 3 and the load 5, and the battery 3 and the load 5 are connected by the drive pulse duty. The duty ratio of the drive pulse duty is preliminarily determined based on the semiconductor relay 23 that permits connection, the load voltage VL applied to the load 5 and the battery voltage VB_H of the battery 3 when charging is performed at the start of the vehicle. A signal generation unit 50 that is set to be equal to or lower than the set upper limit value DUTY_MAX, and the preset upper limit value DUTY_MAX is associated with the rated current range of the semiconductor relay 23. And those are.

  With such a configuration, the power supply control device 1 controls the load current Id within a range not exceeding the rated current of the semiconductor relay 23 without separately providing a circuit for preventing inrush current. While preventing, space saving and weight reduction can be realized.

  In addition, with such a configuration, the power supply control device 1 uses different types of relays, that is, the mechanical relay 21 and the semiconductor relay 23. Therefore, it is possible to avoid the situation of failure at the same time and to ensure safety at the time of failure. .

  Further, in the power supply control device 1 according to the present embodiment, the signal generator 50 weights the coefficient K0 determined by the characteristics of the semiconductor relay 23 when setting the duty ratio of the drive pulse duty.

  With such a configuration, the power supply control device 1 can adapt to any circuit environment without changing the hardware by adjusting the coefficient K0. Therefore, even if the surrounding circuit environment is changed, the power control device 1 is low. A cost-effective and safe vehicle activation system can be constructed.

  In the power supply control device 1 according to the present embodiment, the signal generation unit 50 is set in advance until the differential voltage Vdiff between the load voltage VL and the battery voltage VB_H is equal to or lower than a preset threshold voltage V_CHARGE. The drive pulse duty generated based on the duty ratio which is set to the upper limit value DUTY_MAX or less is output.

  With such a configuration, the power supply control device 1 controls the load current Id within a range that does not exceed the rated current of the semiconductor relay 23 and does not perform an extra charging operation. It can be transferred quickly.

  As described above, the present invention has been described based on the embodiment, but the present invention is not limited to the above embodiment, and may be modified without departing from the gist of the present invention.

  For example, although an example in which the load 5 is an inverter having six arms has been described in the present embodiment, the present invention is not limited thereto, and other high-voltage loads 5 may be used. For example, the number of arms may be an inverter other than six, or a circuit configuration other than the inverter may be used.

  In addition, although an example in which the semiconductor relay 23 is an N-channel MOSFET has been described in the present embodiment, the present invention is not limited thereto, and may be a P-channel MOSFET or an IGBT.

  Further, the semiconductor relay 23 described in the present embodiment is not particularly limited, but may be formed of a wide band gap semiconductor.

  Moreover, in this embodiment, although the semiconductor relay 23 was arrange | positioned at the negative electrode side of the high voltage battery 3, and the mechanical relay 21 was arrange | positioned at the positive electrode side of the high voltage battery 3, an example was demonstrated, but it is limited especially. Instead, the circuit configuration may be such that the semiconductor relay 23 is disposed on the positive electrode side of the high-voltage battery 3 and the mechanical relay 21 is disposed on the negative electrode side of the high-voltage battery 3.

  In addition, although an example in which the various parameters described in the present embodiment, for example, the count value n is incremented by 1 has been described, the present invention is not limited to this, and the parameter is incremented at intervals different from 1, such as by 2. Or may be decremented.

1: Power supply control device 3: Battery 5: Load 7, 7 a, 7 b: Voltage monitoring circuit 8: First path 9: Second path 13: Drive circuit 21: Mechanical relay 31: Contact 32: Coil winding 23 : Semiconductor relay 50: Signal generation unit 51: Calculation unit 52: Control command unit 53: Contact control unit 61: Initial value setting unit 62: Difference voltage calculation unit 63: Duty ratio setting unit 64: Storage unit 65: Difference voltage determination unit

Claims (3)

A power supply control device provided in a vehicle,
A mechanical relay that is provided in a first path that connects the battery and the load, and that allows connection between the battery and the load by opening and closing a contact;
A semiconductor relay provided in a second path connecting the battery and the load, and allowing a connection between the battery and the load by a drive pulse;
A signal for setting the duty ratio of the drive pulse to a preset upper limit value or less based on the load voltage applied to the load and the battery voltage of the battery when charging is performed at the start of the vehicle A generator,
The power supply control device, wherein the preset upper limit value is associated with a range of a rated current of the semiconductor relay. The signal generator is
The power supply control device according to claim 1, wherein, when setting the duty ratio of the drive pulse, a coefficient determined by characteristics of the semiconductor relay is weighted. The signal generator is
The drive pulse generated based on the duty ratio set to the preset upper limit value or less is output until the differential voltage between the load voltage and the battery voltage is equal to or less than the preset threshold voltage. The power supply control device according to claim 1, wherein the power supply control device is a power supply control device.