JP7340977B2 - Vehicle DC/DC converter system, operation instruction circuit, and control method for vehicle DC/DC converter system - Google Patents

Description

The present invention relates to a vehicular DC/DC converter system, an operation instruction circuit, and a control method for a vehicular DC/DC converter system.

BACKGROUND ART Conventionally, there is a load driving system that drives two DC/DC converters in parallel (for example, see Patent Document 1).

In such a conventional load driving system, the output current of each DC/DC converter is detected and controlled so that the output current of each DC/DC converter is shared equally.

However, in this conventional load driving system, when a short-circuit failure occurs in the output of one of the DC/DC converters connected in parallel, the output of the other DC/DC converter is There is also the problem that current flows backward from the load battery on the output side.

JP2014-183705

Therefore, in the present invention, when a short-circuit failure occurs in one output of DC/DC converters connected in parallel, the output side of the other DC/DC converter or the output side of the failed DC/DC converter is An object of the present invention is to provide a DC/DC converter system for a vehicle that can prevent current from flowing backward from a load battery.

A vehicle DC/DC converter system according to one aspect of the present invention includes:
A vehicle DC/DC converter system that uses a plurality of DC/DC converters to supply power to a vehicle load according to a load request, the system comprising:
A main DC/DC converter includes a first bridge rectifier circuit that rectifies a first voltage generated from a power supply voltage, and outputs a first output voltage from an output section based on the voltage rectified by the first bridge rectifier circuit. DC converter and
One having a second bridge rectifier circuit that rectifies a second voltage generated from the power supply voltage, and outputs a second output voltage from an output section based on the voltage rectified by the second bridge rectifier circuit. or a plurality of sub DC/DC converters,
The first bridge rectifier circuit includes:
a first rectifying element;
a first switching element connected in series to the first rectifying element,
The second bridge rectifier circuit is
a second rectifying element;
A vehicular DC/DC converter system comprising: a second switching element connected in series to the second rectifying element.

In the vehicle DC/DC converter system,
The main DC/DC converter is
If it is determined that the first rectifying element is short-circuited, the first switching element is not turned on;
The sub DC/DC converter is
If it is determined that the second rectifying element has a short-circuit failure, the second switching element is not turned on.

In the vehicle DC/DC converter system,
The main DC/DC converter is
Monitoring the current or voltage between the first rectifying element and the first switching element, and determining whether or not the first rectifying element has a short-circuit failure based on the monitoring result. Features.

In the vehicle DC/DC converter system,
The main DC/DC converter is
If the current or voltage being monitored is greater than or equal to a preset first threshold, determining that the first rectifying element has a short-circuit failure;
On the other hand, if the current or voltage being monitored is less than the first threshold, it is determined that the first rectifying element is normal.

In the vehicle DC/DC converter system,
The main DC/DC converter is
If it is determined that the first rectifying element is normal, the first switching element is brought into a state in which oscillation operation is possible in response to a load request.

In the vehicle DC/DC converter system,
The sub DC/DC converter is
Monitoring the current or voltage between the second rectifying element and the second switching element, and determining whether or not the second rectifying element has a short-circuit failure based on the monitoring result. Features.

In the vehicle DC/DC converter system,
The sub DC/DC converter is
If the monitored current or voltage is equal to or higher than a preset second threshold, it is determined that the second rectifying element has a short-circuit failure,
On the other hand, if the current or voltage being monitored is less than the second threshold, it is determined that the second rectifying element is normal.

In the vehicle DC/DC converter system,
The sub DC/DC converter is
If it is determined that the second rectifying element is normal, the second switching element is brought into a state in which oscillation operation is possible in response to a load request.

In the vehicle DC/DC converter system,
a first output fuse electrically connected between an output part of the main DC/DC converter and an output voltage terminal to which the vehicle load and the load battery are connected;
It is characterized by further comprising a second output fuse electrically connected between the output section of the sub-DC/DC converter and the output voltage terminal.

In the vehicle DC/DC converter system,
the first voltage is applied to first and second input nodes of the first bridge rectifier circuit;
The first bridge rectifier circuit includes:
a first diode, the cathode of which is one of the first rectifier elements, the vehicle load and the load battery being electrically connected to the output voltage terminal, and the anode being connected to the first input node; ,
a second diode, which is one of the first rectifier elements, whose cathode is electrically connected to the output voltage terminal and whose anode is connected to the second input node;
a first transistor, which is one of the first switch elements, whose drain is connected to the first input node and whose source is connected to a ground terminal;
a second transistor, which is one of the first switch elements, whose drain is connected to the second input node and whose source is connected to the ground terminal;
the second voltage is applied to third and fourth input nodes of the second bridge rectifier circuit;
The second bridge rectifier circuit is
a third diode, the cathode of which is one of the second rectifying elements, the vehicle load and the load battery being electrically connected to the output voltage terminal, and the anode being connected to the third input node; ,
a fourth diode, which is one of the second rectifier elements, whose cathode is electrically connected to the output voltage terminal and whose anode is connected to the fourth input node;
a third transistor, which is one of the second switch elements, whose drain is connected to the third input node and whose source is connected to a ground terminal;
and a fourth transistor, which is one of the second switching elements, whose drain is connected to the fourth input node and whose source is connected to the ground terminal.

In the vehicle DC/DC converter system,
The main DC/DC converter is
a first full-bridge circuit that converts and outputs a voltage based on the power supply voltage;
further comprising a first transformer into which the voltage output by the first full-bridge circuit is input to the primary side and outputs the first voltage from the secondary side to the first bridge rectifier circuit;
The sub DC/DC converter is
a second full-bridge circuit that converts and outputs a voltage based on the power supply voltage;
It is characterized by further comprising a second transformer into which the voltage outputted by the second full-bridge circuit is input to the primary side and outputs the second voltage from the secondary side to the second bridge rectifier circuit. shall be.

In the vehicle DC/DC converter system,
The vehicular DC/DC converter system is characterized in that it is installed in an automobile equipped with an automatic driving function.

A method for controlling a vehicle DC/DC converter system according to one aspect of the present invention includes:
A vehicle DC/DC converter system that supplies power to a vehicle load using a plurality of DC/DC converters according to a load request, the system including a first bridge rectifier that rectifies a first voltage generated from a power supply voltage. a main DC/DC converter having a circuit that outputs a first output voltage from an output section based on the voltage rectified by the first bridge rectifier circuit; and a main DC/DC converter that rectifies a second voltage generated from the power supply voltage. one or more sub-DC/DC converters that have a second bridge rectifier circuit and output a second output voltage from an output section based on the voltage rectified by the second bridge rectifier circuit; A method for controlling a DC/DC converter system for a vehicle, comprising:
Controlling the driving of the main DC/DC converter and the sub DC/DC converter according to the load request,
The first bridge rectifier circuit includes:
a first rectifying element;
a first switching element connected in series to the first rectifying element,
The second bridge rectifier circuit is
a second rectifying element;
A second switching element connected in series to the second rectifying element.

An operation instruction circuit according to one aspect of the present invention includes:
A vehicle DC/DC converter system that supplies power to a vehicle load using a plurality of DC/DC converters according to a load request, the system including a first bridge rectifier that rectifies a first voltage generated from a power supply voltage. a main DC/DC converter having a circuit that outputs a first output voltage from an output section based on the voltage rectified by the first bridge rectifier circuit; and a main DC/DC converter that rectifies a second voltage generated from the power supply voltage. one or more sub-DC/DC converters that have a second bridge rectifier circuit and output a second output voltage from an output section based on the voltage rectified by the second bridge rectifier circuit; An operation instruction circuit applied to a vehicle DC/DC converter system, comprising:
The operation instruction circuit controls driving of the main DC/DC converter and the sub DC/DC converter according to the load request,
The first bridge rectifier circuit includes:
a first rectifying element;
a first switching element connected in series to the first rectifying element,
The second bridge rectifier circuit is
a second rectifying element;
A second switching element connected in series to the second rectifying element.

A vehicular DC/DC converter system according to one aspect of the present invention is a vehicular DC/DC converter system that uses a plurality of DC/DC converters to supply power to a vehicular load according to a load request, and includes: A main DC/DC that includes a first bridge rectifier circuit that rectifies a first voltage generated from a power supply voltage, and outputs a first output voltage from an output section based on the voltage rectified by the first bridge rectifier circuit. 1, which has a converter and a second bridge rectifier circuit that rectifies a second voltage generated from a power supply voltage, and outputs a second output voltage from an output section based on the voltage rectified by the second bridge rectifier circuit; one or more sub DC/DC converters.

The first bridge rectifier circuit includes a first rectifying element that rectifies the first voltage and prevents reverse current, and a first switching element connected in series to the first rectifying element.

The second bridge rectifier circuit includes a second rectifier that rectifies the second voltage and prevents reverse current, and a second switch element that is connected in series to the second rectifier.

As a result, according to the vehicle DC/DC converter system according to one aspect of the present invention, when a short-circuit failure occurs in one output of the DC/DC converters connected in parallel, the faulty DC/DC converter It is possible to prevent current from flowing backward from the other DC/DC converter or the load battery on the output side with respect to the output.

FIG. 1 is a circuit diagram showing an example of a circuit configuration of a vehicle DC/DC converter system 100 according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of a current path of the vehicle DC/DC converter system 100 shown in FIG. 1.

Hereinafter, a DC/DC converter system for a vehicle according to the present invention will be explained with reference to the drawings.

FIG. 1 is a circuit diagram showing an example of a circuit configuration of a vehicle DC/DC converter system 100 according to an embodiment of the present invention.

[Vehicle DC/DC converter system]
The vehicle DC/DC converter system 100 shown in FIG. 1 supplies power to the vehicle load LOAD from a power supply battery BS using a plurality of DC/DC converters in accordance with the load request of the vehicle load LOAD. It has become.

This vehicular DC/DC converter system 100 is installed, for example, in a car (not shown) equipped with an automatic driving function, and is applied to supply electric power to the car, and includes a power supply battery BS and a load battery BOUT. is loaded on the vehicle. Note that this vehicular DC/DC converter system 100 can be applied not only to automobiles but also to other devices such as drones.

For example, as shown in FIG. 1, this vehicle DC/DC converter system 100 includes a main DC/DC converter (first DC/DC converter) X1, a sub DC/DC converter (second DC/DC converter) ) X2, a first output fuse FO1, a second output fuse FO2, and an operation instruction unit (operation instruction circuit) ECU.

Although one sub DC/DC converter X2 is shown in FIG. 1 as an example, the vehicle DC/DC converter system 100 may include a plurality of sub DC/DC converters X2. .

For example, as shown in FIG. 1, a vehicle load LOAD is connected between the output voltage terminal TOUT and the ground terminal TGND.

Further, for example, as shown in FIG. 1, a load battery BOUT is connected between the output voltage terminal TOUT and the ground terminal TGND.

[Main DC/DC converter]
For example, as shown in FIG. 1, the main DC/DC converter X1 is configured to be supplied with a power supply voltage VB from a power supply battery BS via first and second input parts TIN1a and TIN1b.

In the main DC/DC converter X1, the first output section TO1a is electrically connected to the output voltage terminal TOUT, and the second output section TO1b is electrically connected to the ground terminal TGND. The main DC/DC converter X1 outputs the first output voltage VO1 from the first output section TO1a.

Here, as shown in FIG. 1, the main DC/DC converter X1 includes, for example, a first fuse FI1, a first line filter circuit LF1, a first full bridge circuit FBM1, and a first transformer. MT1, a first bridge rectifier circuit FBR1, a first output choke LO1, a first output capacitor CO1, and a first control section A1.

The first fuse FI1 is connected between the first input section TIN1a and the first line filter circuit LF1.

Further, the first line filter circuit LF1 filters the power supply voltage VB supplied from the power supply battery BS via the first and second input parts TIN1a and TIN1b, and supplies the filtered power supply voltage VB to the first full bridge circuit FBM1. It is designed to be output.
Further, the first full-bridge circuit FBM1 converts a voltage based on the power supply voltage VB into alternating current and outputs the converted alternating current.

In this first full-bridge circuit FBM1, switch elements (nMOS transistors) Q1, Q2, Q3, and Q4 constituting the bridge circuit are controlled by a first control section A1.

Further, in the first transformer MT1, the voltage outputted by the first full-bridge circuit FBM1 is input to the primary side, and the first voltage VT1 is applied from the secondary side to the first and second terminals of the first bridge rectifier circuit FBR1. It is configured to output to input nodes N1 and N2.

That is, the first voltage VT1 output from the first transformer MT1 is applied to the first and second input nodes N1 and N2 of the first bridge rectifier circuit FBR1.

The first bridge rectifier circuit FBR1 rectifies the first voltage VT1.

For example, as shown in FIG. 1, the first bridge rectifier circuit FBR1 includes first rectifying elements (diodes) D1 and D2 and first switching elements (nMOS transistors) M1 and M2.

More specifically, the first bridge rectifier circuit FBR1 includes, for example, a first diode D1, which is one of the first rectifying elements D1 and D2, and a first rectifying element, as shown in FIG. A second diode D2 that is one of D1 and D2, a first transistor M1 that is one of first switch elements M1 and M2, and one of first switch elements M1 and M2. one second transistor M2.

The first diode D1 has a cathode electrically connected to the output voltage terminal TOUT via the first output choke LO1 and the first output fuse FO1, and an anode connected to the first input node N1. ing.

Further, the second diode D2 has a cathode electrically connected to the output voltage terminal TOUT via the first output choke LO1 and the first output fuse FO1, and an anode connected to the second input node N2. ing.

Further, the first transistor M1 has one end (drain) connected to the first input node N1, and the other end (source) connected to the ground terminal TGND.

The first transistor M1 is, for example, an nMOS transistor controlled by the first control unit A1, as shown in FIG.

Further, the second transistor M2 has one end (drain) connected to the second input node N2, and the other end (source) connected to the ground terminal TGND.

This second transistor M2 is, for example, an nMOS transistor controlled by the first control unit A1, as shown in FIG.

In this way, the first rectifier elements (first and second diodes) D1 and D2 are connected to rectify the first voltage VT1 and prevent backflow.

The first switching elements (first and second transistors) M1 and M2 are connected in series to the first rectifying elements D1 and D2, respectively. The first switch elements M1 and M2 are controlled by the first control section A1 to perform an oscillating operation.

In particular, by using the first and second diodes D1 and D2 on the high side of the first bridge rectifier circuit FBR1, the first switch elements (first and second transistors) M1 and M2 on the low side Even if a short-circuit failure occurs, reverse current can be prevented by the first and second diodes D1 and D2.

Further, the first output choke LO1 is connected between the cathodes of the first rectifying elements D1 and D2 and the first output section TO1a of the main DC/DC converter X1.

Further, the first output capacitor CO1 is connected between the first output section TO1a and the second output section TO1b of the main DC/DC converter X1.

The first control unit A1 also controls the operations of the first full bridge circuit FBM1 and the first bridge rectifier circuit FBR1 so that the main DC/DC converter X1 outputs a predetermined voltage, for example. It has become.

In particular, the first control unit A1 of the main DC/DC converter X1 monitors the current or voltage between the first rectifying elements D1, D2 and the first switching elements M1, M2, and Based on this, it is determined whether or not the first rectifying elements D1 and D2 have a short-circuit failure.

For example, the first control unit A1 of the main DC/DC converter When the voltage of the load battery BOUT is detected at the drains of M1 and M2), it is determined that the first rectifying elements D1 and D2 are short-circuited.

When the first control unit A1 of the main DC/DC converter X1 determines that the first rectifying elements D1 and D2 are short-circuited, it does not turn on the first switching elements M1 and M2. It looks like this.

This prevents the first switching elements (first and second transistors) M1 and M2 on the low side from being turned on even if the first and second diodes D1 and D2 on the high side have a short-circuit failure. This can prevent backflow.

On the other hand, the first control unit A1 of the main DC/DC converter (that is, there is no short-circuit failure).

When the first control unit A1 of the main DC/DC converter X1 determines that the first rectifying elements D1 and D2 are normal, the first control unit A1 switches the first switching elements M1 and M2 according to the load request. It is designed to enable oscillation operation.

As a result, if the first and second diodes D1 and D2 on the high side are not short-circuited, the first switch elements (first and second transistors) M1 and M2 on the low side are activated to oscillate. By setting it in this state, normal rectification operation can be performed.

As described above, the main DC/DC converter X1 includes the first bridge rectifier circuit FBR1 that rectifies the first voltage VT1 generated from the power supply voltage VB, and the main DC/DC converter Thus, the first output voltage VO1 is output from the first output section TO1a.

[Sub DC/DC converter]
Here, the sub DC/DC converter X2 is supplied with the power supply voltage VB from the power supply battery BS via the third and fourth input parts TIN2a and TIN2b, for example, as shown in FIG. There is.

In this sub DC/DC converter X2, the third output section TO2a is electrically connected to the output voltage terminal TOUT, and the fourth output section TO2b is electrically connected to the ground terminal TGND. The sub DC/DC converter X2 is configured to output the second output voltage VO2 from the third output section TO2a.

Further, as shown in FIG. 1, the sub DC/DC converter X2 includes, for example, a second fuse FI2, a second line filter circuit LF2, a second full bridge circuit FBM2, and a second transformer MT2. , a second bridge rectifier circuit FBR2, a second output choke LO2, a second output capacitor CO2, and a second control section A2.

The second fuse FI2 is connected between the third input section TIN2a and the third line filter circuit LF3.

Further, the second line filter circuit LF2 filters the power supply voltage VB supplied from the power supply battery BS via the third and fourth input parts TIN2a and TIN2b, and supplies the filtered power supply voltage VB to the second full bridge circuit FBM2. It is designed to be output.

Further, the second full-bridge circuit FBM2 converts a voltage based on the power supply voltage VB into alternating current and outputs the converted alternating current.

In the second full-bridge circuit FBM2, the second control unit A2 controls switch elements (nMOS transistors) Q5, Q6, Q7, and Q8 that constitute the bridge circuit.

Further, in the second transformer MT2, the voltage outputted by the second full bridge circuit FBM2 is inputted to the primary side, and the second voltage VT2 is applied from the secondary side to the third and fourth terminals of the second bridge rectifier circuit FBR2. It is designed to output to input nodes N3 and N4.

That is, the second voltage VT2 output from the second transformer MT2 is applied to the third and fourth input nodes N3 and N4 of the second bridge rectifier circuit FBR2.

The second bridge rectifier circuit FBR2 rectifies the second voltage VT2.

This second bridge rectifier circuit FBR2 includes, for example, as shown in FIG. 1, second rectifying elements (diodes) D3 and D4 and second switching elements (nMOS transistors) M3 and M4.

More specifically, the second bridge rectifier circuit FBR2 includes, for example, a third diode D3, which is one of the second rectifying elements D3 and D4, and a second rectifying element, as shown in FIG. A fourth diode D4 that is one of D3 and D4, a third transistor M3 that is one of second switch elements M3 and M4, and one of second switch elements M3 and M4. one fourth transistor M4.

The third diode D3 has a cathode electrically connected to the output voltage terminal TOUT via the second output choke LO2 and the second output fuse FO2, and an anode connected to the third input node N3. ing.

Further, the fourth diode D4 has a cathode electrically connected to the output voltage terminal TOUT via the second output choke LO2 and the second output fuse FO2, and an anode connected to the fourth input node N4. ing.

Further, the third transistor M3 has one end (drain) connected to the third input node N3, and the other end (source) connected to the ground terminal TGND.

This third transistor M3 is, for example, an nMOS transistor controlled by the second control unit A2, as shown in FIG.

Further, the fourth transistor M4 has one end (drain) connected to the fourth input node N4, and the other end (source) connected to the ground terminal TGND.

This fourth transistor M4 is, for example, an nMOS transistor controlled by the second control unit A2, as shown in FIG. 1.

In this way, the second rectifier elements (third and fourth diodes) D3 and D4 are connected to rectify the second voltage VT2 and prevent backflow.

The second switching elements (third and fourth transistors) M3 and M4 are connected in series to the second rectifying elements D3 and D4, respectively. The second switch elements M3 and M4 are controlled by the second control section A2 to perform an oscillating operation.

In particular, by using the third and fourth diodes D3 and D4 on the high side of the second bridge rectifier circuit FBR2, the second switch elements (third and fourth transistors) M3 and M4 on the low side Even if a short-circuit failure occurs, backflow can be prevented by the third and fourth diodes D3 and D4.

Further, the second output choke LO2 is connected between the cathodes of the second rectifying elements D3 and D4 and the third output section TO2a of the sub DC/DC converter X2.

Further, the second output capacitor CO2 is connected between the third output section TO2a and the fourth output section TO2b of the sub DC/DC converter X2.

Further, the second control unit A2 controls the operations of the second full bridge circuit FBM2 and the second bridge rectifier circuit FBR2 so that the sub DC/DC converter X2 outputs a predetermined voltage, for example. It has become.

In particular, the second control unit A2 of the sub DC/DC converter X2 monitors the current or voltage between the second rectifying elements D3, D4 and the second switching elements M3, M4, and Based on this, it is determined whether or not the second rectifying elements D3 and D4 are short-circuited.

For example, when the current or voltage being monitored is equal to or higher than a preset second threshold, the second control unit A2 of the sub DC/DC converter When the voltage of the load battery BOUT is detected at the drains of M3 and M4), it is determined that the second rectifying elements D3 and D4 are short-circuited.

When the second control unit A2 of the sub DC/DC converter X2 determines that the second rectifying elements D3 and D4 are short-circuited, it does not turn on the second switching elements M3 and M4. It looks like this.

This prevents the second switch elements (third and fourth transistors) M3 and M4 on the low side from being turned on even if the third and fourth diodes D3 and D4 on the high side have a short-circuit failure. This can prevent backflow.

On the other hand, the second control unit A2 of the sub-DC/DC converter It is determined that there is a short-circuit failure (that is, there is no short-circuit failure).

Then, when the second control unit A2 of the sub DC/DC converter X2 determines that the second rectifying elements D3 and D4 are normal, the second control unit A2 switches the second switching elements M3 and M4 according to the load request. It is designed to enable oscillation operation.

As a result, if the third and fourth diodes D3 and D4 on the high side are not short-circuited, the second switch elements (third and fourth transistors) M3 and M4 on the low side are activated to oscillate. By setting it in this state, normal rectification operation can be performed.

As described above, the sub DC/DC converter X2 has the second bridge rectifier circuit FBR2 that rectifies the second voltage VT2 generated from the power supply voltage VB, and the voltage rectified by the second bridge rectifier circuit FBR2 Based on this, the second output voltage VO2 is output from the second output section TO2a.

[First and second output fuses]
Further, the first output fuse FO1 is electrically connected between the first output section TO1a of the main DC/DC converter X1 and the output voltage terminal TOUT to which the vehicle load LOAD and the load battery BOUT are connected. has been done. Further, the second output fuse FO2 is electrically connected between the third output section TO2a of the sub DC/DC converter X2 and the output voltage terminal TOUT.

Thereby, in the event of an arm short-circuit failure, the first and second output fuses FO1 and FO2 melt, thereby preventing backflow from the external load battery BOUT or the other DC/DC converter.

[Operation instruction section]
Further, the operation instruction unit (operation instruction circuit) ECU is configured to control a vehicle (automobile) in which the vehicle DC/DC converter system 100 is loaded.

In particular, this operation instruction unit ECU sets the output voltage in the first control unit A1 of the main DC/DC converter X1 and the second control unit A2 of the sub DC/DC converter X2 according to the load request. The control signal is output to control the driving of the main DC/DC converter X1 and the sub DC/DC converter X2.

For example, when the load request is a light load, the operation instruction unit ECU stops the main DC/DC converter X1 and controls the first output voltage VO1 and the first output voltage VO1 so as to drive the sub DC/DC converter X2. The second output voltage VO2 is adjusted.

On the other hand, when the load request is heavy, the operation instruction unit ECU outputs a first output voltage VO1 and a second output voltage so as to drive the main DC/DC converter X1 and the sub DC/DC converter X2. It is designed to adjust VO2.

Note that, when the load request is a light load, the operation instruction unit ECU may drive the main DC/DC converter X1 and stop the sub DC/DC converter X2. The operation instruction unit ECU may drive the main DC/DC converter X1 and the sub DC/DC converter X2 when the load request is heavy.

Next, an example of a method of controlling the vehicle DC/DC converter system 100 having the above configuration will be described.

FIG. 2 is a diagram showing an example of a current path of the vehicle DC/DC converter system 100 shown in FIG. 1.

First, for example, as shown in FIG. 2, by setting the high side of the first bridge rectifier circuit FBR1 to the first and second diodes D1, D2, the first switch elements (first, Even if a short-circuit failure occurs in the second transistors M1 and M2, reverse current can be prevented by the first and second diodes D1 and D2.

For example, as shown in FIG. 2, by setting the high side of the second bridge rectifier circuit FBR2 to the third and fourth diodes D3 and D4, the second switch elements on the low side (the third, Even if the fourth transistor (M3, M4) has a short-circuit failure, reverse current can be prevented by the third and fourth diodes D3, D4.

For example, the first control unit A1 of the main DC/DC converter It is determined that there is a short-circuit failure.

When the first control unit A1 of the main DC/DC converter X1 determines that the first rectifying elements D1 and D2 are short-circuited, it does not turn on the first switching elements M1 and M2. .

This prevents the first switching elements (first and second transistors) M1 and M2 on the low side from being turned on even if the first and second diodes D1 and D2 on the high side have a short-circuit failure. This can prevent backflow (Figure 2).

On the other hand, the first control unit A1 of the main DC/DC converter (that is, there is no short-circuit failure).

When the first control unit A1 of the main DC/DC converter X1 determines that the first rectifying elements D1 and D2 are normal, the first control unit A1 switches the first switching elements M1 and M2 according to the load request. Make oscillation possible.

As a result, if the first and second diodes D1 and D2 on the high side are not short-circuited, the first switch elements (first and second transistors) M1 and M2 on the low side are activated to oscillate. By setting it in this state, normal rectification operation can be performed.

Similarly, the second control unit A2 of the sub-DC/DC converter It is determined that there is a short-circuit failure.

When the second control unit A2 of the sub DC/DC converter X2 determines that the second rectifying elements D3 and D4 are short-circuited, it does not turn on the second switching elements M3 and M4. .

This prevents the second switch elements (third and fourth transistors) M3 and M4 on the low side from being turned on even if the third and fourth diodes D3 and D4 on the high side have a short-circuit failure. This can prevent backflow.

On the other hand, the second control unit A2 of the sub-DC/DC converter It is determined that there is a short-circuit failure (that is, there is no short-circuit failure).

Then, when the second control unit A2 of the sub DC/DC converter X2 determines that the second rectifying elements D3 and D4 are normal, the second control unit A2 switches the second switching elements M3 and M4 according to the load request. Make oscillation possible.

As a result, if the third and fourth diodes D3 and D4 on the high side are not short-circuited, the second switch elements (third and fourth transistors) M3 and M4 on the low side are activated to oscillate. By setting it in this state, normal rectification operation can be performed.

Note that in the event of an arm short-circuit failure, the first and second output fuses FO1 and FO2 are blown, thereby preventing backflow from the external load battery BOUT or the other DC/DC converter.

As described above, the vehicular DC/DC converter system according to one aspect of the present invention uses a plurality of DC/DC converters to supply power to the vehicular load according to the load request. The system includes a first bridge rectifier circuit that rectifies a first voltage generated from a power supply voltage, and outputs a first output voltage from an output section based on the voltage rectified by the first bridge rectifier circuit. The main DC/DC converter has a main DC/DC converter, and a second bridge rectifier circuit rectifies a second voltage generated from the power supply voltage, and outputs a second output voltage based on the voltage rectified by the second bridge rectifier circuit. one or more sub DC/DC converters output from the section.

The first bridge rectifier circuit includes a first rectifying element that rectifies the first voltage and prevents reverse current, and a first switching element connected in series to the first rectifying element.

The second bridge rectifier circuit includes a second rectifier that rectifies the second voltage and prevents reverse current, and a second switch element that is connected in series to the second rectifier.

As a result, according to the vehicle DC/DC converter system according to one aspect of the present invention, when a short-circuit failure occurs in one output of the DC/DC converters connected in parallel, the faulty DC/DC converter It is possible to prevent current from flowing backward from the other DC/DC converter or the load battery on the output side with respect to the output.

Although several embodiments of the invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention as well as within the scope of the invention described in the claims and its equivalents.

100 Vehicle DC/DC converter system X1 Main DC/DC converter X2 Sub DC/DC converter FO1 First output fuse FO2 Second output fuse ECU Operation instruction section (operation instruction circuit)
BS Power supply battery TOUT Output voltage terminal TGND Ground terminal TIN1a First input section TIN1b Second input section TO1a First output section TO1b Second output section FI1 First fuse LF1 First line filter circuit FBM1 First Full-bridge circuit MT1 First transformer FBR1 First bridge rectifier circuit LO1 First output choke CO1 First output capacitor A1 First control section TIN2a Third input section TIN2b Fourth input section TO2a Third Output section TO2b Fourth output section FI2 Second fuse LF2 Second line filter circuit FBM2 Second full bridge circuit MT2 Second transformer FBR2 Second bridge rectifier circuit LO2 Second output choke CO2 Second output Capacitor A2 Second control unit LOAD Vehicle load BOUT Load battery

Claims (13)

A vehicle DC/DC converter system that uses a plurality of DC/DC converters to supply power to a vehicle load according to a load request, the system comprising:
A main DC/DC converter includes a first bridge rectifier circuit that rectifies a first voltage generated from a power supply voltage, and outputs a first output voltage from an output section based on the voltage rectified by the first bridge rectifier circuit. DC converter and
One having a second bridge rectifier circuit that rectifies a second voltage generated from the power supply voltage, and outputs a second output voltage from an output section based on the voltage rectified by the second bridge rectifier circuit. or a plurality of sub DC/DC converters,
The first bridge rectifier circuit includes:
a first rectifying element;
a first switching element connected in series to the first rectifying element,
The second bridge rectifier circuit is
a second rectifying element;
a second switching element connected in series to the second rectifying element ,
The main DC/DC converter is
If it is determined that the first rectifying element is short-circuited, the first switching element is not turned on;
The sub DC/DC converter is
If it is determined that the second rectifying element has a short-circuit failure, the second switching element is not turned on.
A vehicle DC/DC converter system characterized by the following. The main DC/DC converter is
A current or voltage at a node between the first rectifying element and the first switching element to which the first voltage is applied is monitored, and based on the monitoring result, the first rectifying element is short-circuited. The vehicular DC/DC converter system according to claim 1, further comprising determining whether or not there is a failure. The main DC/DC converter is
If the current or voltage being monitored is greater than or equal to a preset first threshold, determining that the first rectifying element has a short-circuit failure;
On the other hand, when the current or voltage being monitored is less than the first threshold value, it is determined that the first rectifying element is normal. /DC converter system. The main DC/DC converter is
Any one of claims 1 to 3 , characterized in that, when it is determined that the first rectifying element is normal, the first switching element is brought into a state in which oscillation operation is possible in response to a load request. The vehicle DC/DC converter system according to item 1. The sub DC/DC converter is
A current or voltage at a node to which the second voltage is applied between the second rectifying element and the second switching element is monitored, and based on the monitoring result, the second rectifying element is short-circuited. The vehicular DC/DC converter system according to any one of claims 1 to 4 , characterized in that it is determined whether or not there is a failure. The sub DC/DC converter is
If the monitored current or voltage is equal to or higher than a preset second threshold, it is determined that the second rectifying element has a short-circuit failure,
On the other hand, if the current or voltage being monitored is less than the second threshold, it is determined that the second rectifying element is normal. /DC converter system. The sub DC/DC converter is
Any one of claims 1 to 6 , characterized in that, when it is determined that the second rectifying element is normal, the second switching element is brought into a state in which oscillation operation is possible according to a load request. The vehicle DC/DC converter system according to item 1. a first output fuse electrically connected between an output part of the main DC/DC converter and an output voltage terminal to which the vehicle load and the load battery are connected;
Any one of claims 1 to 7 , further comprising a second output fuse electrically connected between the output section of the sub DC/DC converter and the output voltage terminal. The vehicle DC/DC converter system described in . the first voltage is applied to first and second input nodes of the first bridge rectifier circuit;
The first bridge rectifier circuit includes:
a first diode, the cathode of which is one of the first rectifier elements, the vehicle load and the load battery being electrically connected to the output voltage terminal, and the anode being connected to the first input node; ,
a second diode, which is one of the first rectifier elements, whose cathode is electrically connected to the output voltage terminal and whose anode is connected to the second input node;
a first transistor, which is one of the first switch elements, whose drain is connected to the first input node and whose source is connected to a ground terminal;
a second transistor, which is one of the first switch elements, whose drain is connected to the second input node and whose source is connected to the ground terminal;
the second voltage is applied to third and fourth input nodes of the second bridge rectifier circuit;
The second bridge rectifier circuit is
a third diode, the cathode of which is one of the second rectifying elements, the vehicle load and the load battery being electrically connected to the output voltage terminal, and the anode being connected to the third input node; ,
a fourth diode, which is one of the second rectifier elements, whose cathode is electrically connected to the output voltage terminal and whose anode is connected to the fourth input node;
a third transistor, which is one of the second switch elements, whose drain is connected to the third input node and whose source is connected to a ground terminal;
a fourth transistor that is one of the second switching elements, the drain of which is connected to the fourth input node, and the source of which is connected to the ground terminal. 8. The vehicular DC/DC converter system according to any one of 8 . The main DC/DC converter is
a first full-bridge circuit that converts and outputs a voltage based on the power supply voltage;
further comprising a first transformer into which the voltage output by the first full-bridge circuit is input to the primary side and outputs the first voltage from the secondary side to the first bridge rectifier circuit;
The sub DC/DC converter is
a second full-bridge circuit that converts and outputs a voltage based on the power supply voltage;
It is characterized by further comprising a second transformer into which the voltage outputted by the second full-bridge circuit is input to the primary side and outputs the second voltage from the secondary side to the second bridge rectifier circuit. The vehicle DC/DC converter system according to any one of claims 1 to 9 . The vehicular DC/DC converter system according to any one of claims 1 to 10 , wherein the vehicular DC/DC converter system is installed in an automobile equipped with an automatic driving function. A vehicle DC/DC converter system that supplies power to a vehicle load using a plurality of DC/DC converters according to a load request, the system including a first bridge rectifier that rectifies a first voltage generated from a power supply voltage. a main DC/DC converter having a circuit that outputs a first output voltage from an output section based on the voltage rectified by the first bridge rectifier circuit; and a main DC/DC converter that rectifies a second voltage generated from the power supply voltage. one or more sub-DC/DC converters that have a second bridge rectifier circuit and output a second output voltage from an output section based on the voltage rectified by the second bridge rectifier circuit. A method for controlling a DC/DC converter system for a vehicle, comprising:
Controlling the driving of the main DC/DC converter and the sub DC/DC converter according to the load request,
The first bridge rectifier circuit includes:
a first rectifying element;
a first switching element connected in series to the first rectifying element,
The second bridge rectifier circuit includes:
a second rectifying element;
a second switching element connected in series to the second rectifying element ,
The main DC/DC converter is
If it is determined that the first rectifying element is short-circuited, the first switching element is not turned on;
The sub DC/DC converter is
If it is determined that the second rectifying element is short-circuited, the second switching element is not turned on.
A method for controlling a DC/DC converter system for a vehicle, characterized in that: A vehicle DC/DC converter system that supplies power to a vehicle load using a plurality of DC/DC converters according to a load request, the system including a first bridge rectifier that rectifies a first voltage generated from a power supply voltage. a main DC/DC converter having a circuit that outputs a first output voltage from an output section based on the voltage rectified by the first bridge rectifier circuit; and a main DC/DC converter that rectifies a second voltage generated from the power supply voltage. one or more sub-DC/DC converters that have a second bridge rectifier circuit and output a second output voltage from an output section based on the voltage rectified by the second bridge rectifier circuit; An operation instruction circuit applied to a vehicle DC/DC converter system, comprising:
The operation instruction circuit controls driving of the main DC/DC converter and the sub DC/DC converter according to the load request,
The first bridge rectifier circuit includes:
a first rectifying element;
a first switching element connected in series to the first rectifying element,
The second bridge rectifier circuit is
a second rectifying element;
a second switching element connected in series to the second rectifying element ,
The main DC/DC converter is
If it is determined that the first rectifying element is short-circuited, the first switching element is not turned on;
The sub DC/DC converter is
If it is determined that the second rectifying element has a short-circuit failure, the second switching element is not turned on.
An operation instruction circuit characterized by:

Images