KR102422113B1 - Bidirectional DC-DC converter with improved auxiliary power - Google Patents

Abstract

The present invention relates to a bidirectional DC-DC converter with an improved auxiliary power supply. A bidirectional DC-DC converter that performs bidirectional voltage conversion between a high voltage battery and a low voltage battery according to the present invention, and includes an improved auxiliary power supply, is a pair of switching elements that are switched to a boost mode or a buck mode in response to a switching signal a DC-DC converter unit including a high voltage switch and a low voltage switch, and an inductor connected to the high voltage switch and the low voltage switch; The power generated from the low voltage battery or the high voltage battery is adjusted to a first voltage power source and a second voltage power source through a first path or a second path, and the adjusted first voltage power supply and the second voltage power supply are used as a controller unit. It is operated through the auxiliary power supply provided and the second voltage power supplied from the auxiliary power unit, and the first voltage power supplied from the auxiliary power unit is provided as a peripheral component, and the switching signal is generated by the DC-DC converter unit, and a controller unit for determining whether to use the second path.

Description

Bidirectional DC-DC converter with improved auxiliary power

The present invention relates to a DC-DC converter, and more particularly, to a bidirectional DC-DC converter with an improved auxiliary power supply.

As 48V systems for vehicles have recently become popular, the need for a bidirectional DC-DC converter for controlling the electric flow of the existing 12V system and the 48V system has emerged. The bidirectional DC-DC switch is controlled according to a command signal, and operates in a boost mode or a buck mode. The following patent documents disclose a bidirectional DC-DC converter and a control method thereof.

In order to control the bidirectional DC-DC converter in boost mode or buck mode, auxiliary power is first supplied to the microcontroller unit (MCU), and the MCU is driven through the auxiliary power, and power is supplied to peripheral circuits (eg, sensors). should be

1 is a diagram illustrating a conventional bidirectional DC-DC converter.

Referring to FIG. 1 , in the conventional bidirectional DC-DC converter 100 , the MCU 170 controls the operation of each switch 121 and 122 to determine the operation mode of the bidirectional DC-DC converter 100 . The MCU 170 receives a 5V voltage from the first voltage regulator 141 and supplies the 5V voltage to peripheral circuits, that is, the sensors 111 , 112 , 113 , and the like. Also, the MCU 170 receives a voltage of 3.3V from the second voltage regulator 142 and uses the voltage of 3.3V as a power source of the MCU 170 . The second voltage regulator 142 receives a voltage of 5V from the first voltage regulator 141 , adjusts the voltage of 5V to a voltage of 3.3V, and provides it to the MCU 170 .

However, as shown in FIG. 1 , a required voltage is provided to the first voltage regulator 141 through the PWM IC 160 and the transformer 150 , and the first voltage regulator 141 adjusts the supplied voltage. to provide to the MCU 170 and the second voltage regulator 142 . When the principle of supplying power to the MCU 170 is described in order, when the low voltage battery 131 is activated and supplied, a PWM signal is generated from the PWM IC 160 and applied to the transformer 150 . The transformer 150 generates power having a predetermined voltage based on the PWM signal, and this power is applied to the first voltage regulator 141 . Then, the first voltage regulator 141 adjusts the power applied from the transformer 150 to a voltage of 5V and applies it to the MCU 170 and the second voltage regulator 142 . In addition, the first voltage regulator 141 adjusts the voltage of 5V to 3.3V, applies the voltage of 3.3V to the MCU 170, and the MCU 170 is driven by receiving the power of 3.3V, 1 The 5V voltage provided from the voltage regulator 141 is provided to each sensor 111 , 112 , 113 , etc. to control a component such as a sensor to be driven.

However, in order to supply power to the MCU 170 and the sensors 111 , 112 , and 113 , the conventional bidirectional DC-DC converter 100 having the PWM IC 160 reduces the heat dissipation of the PWM IC 160 . In order to prevent this, there is a problem in that the use area of the PWM IC 160 must be set wide. In addition, when the power sources 131 and 132 of the DC-DC converter need to be expanded, the PWM IC 160 or a connection line with the PWM IC 160 must be added, so that the expansion of the DC-DC converter is restricted. There are also problems.

Korean Patent Publication No. 10-2010-0115087 (published on October 27, 2010)

The present invention has been proposed to solve these conventional problems, and it is an object of the present invention to provide a bidirectional DC-DC converter that is easy to miniaturize by removing a PWM IC and has a reduced manufacturing cost.

Other objects and advantages of the present invention may be understood by the following description, and will become more clearly understood by the examples of the present invention. It will also be readily apparent that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the appended claims.

In order to achieve the above object, a bidirectional DC-DC converter that performs bidirectional voltage conversion between a high voltage battery and a low voltage battery according to the present invention, and includes an improved auxiliary power supply, switches to a boost mode or a buck mode in response to a switching signal a DC-DC converter unit including a high-voltage switch and a low-voltage switch as a pair of switching elements, and an inductor connected to the high-voltage switch and the low-voltage switch; The power generated from the low voltage battery or the high voltage battery is adjusted to a first voltage power source and a second voltage power source through a first path or a second path, and the adjusted first voltage power supply and the second voltage power supply are used as a controller unit. Auxiliary power supply provided; and the second voltage power supplied from the auxiliary power supply unit, providing the first voltage power supplied from the auxiliary power supply unit as a peripheral component, generating the switching signal to the DC-DC converter unit, and generating the second path a controller unit that determines whether to use

The auxiliary power unit may include: a path change switch disposed between the low voltage battery or the high voltage battery and a voltage adjusting unit to form the first path; a photocoupler forming the second path, connected to the low voltage battery or the high voltage battery, and connected to a controller unit; a transformer that forms the second path and converts the power generated by the photocoupler to a predetermined voltage and provides it to the voltage adjuster; and the voltage adjusting unit configured to adjust the power provided from the path change switch of the first path or the transformer of the second path to the first power and the second power, and provide it to the controller unit.

The first path may be used until the controller unit operates, and the second path may be used when the controller unit is operated.

The path change switch may maintain a turned-on state when a control signal is not applied from the controller unit to provide power of the low-voltage battery or the high-voltage battery to the voltage adjuster. In addition, the controller unit, when operated by receiving power from the voltage regulator, applies a signal to the photocoupler to operate the photocoupler to control power to be supplied through a second path, and turn off the path change switch can do.

A collector of the photocoupler may be connected to the low voltage battery or the high voltage battery, an emitter of the photocoupler may be connected to the transformer, and an anode of the photocoupler may be connected to the controller unit.

The voltage regulator may include: a first voltage regulator configured to adjust the power provided through the first path or the second path to a first voltage power; and a second voltage regulator configured to receive power through the first path or the second path and adjust the power to a second voltage power source.

The present invention has the advantage of miniaturizing the bidirectional DC-DC converter and lowering the manufacturing cost by removing the PWM IC from the bidirectional DC-DC converter.

In addition, the present invention has the effect of facilitating the expansion of the bidirectional DC-DC converter by simplifying the structure of the auxiliary power unit by using a photocoupler and a switch.

The following drawings attached to the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical spirit of the present invention together with specific details for carrying out the invention, so that the present invention is described in such drawings. It should not be construed as being limited only to the matters.
1 is a diagram illustrating a conventional bidirectional DC-DC converter.
2 is a diagram illustrating a bidirectional DC-DC converter with an improved auxiliary power source according to an embodiment of the present invention.

The above objects, features and advantages will become more apparent through the following detailed description in relation to the accompanying drawings, and accordingly, those of ordinary skill in the art to which the present invention pertains can easily implement the technical idea of the present invention. There will be. In addition, in the description of the present invention, when it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram illustrating a bidirectional DC-DC converter with an improved auxiliary power source according to an embodiment of the present invention.

Referring to FIG. 2 , the bidirectional DC-DC converter 200 includes a low voltage battery 221 , a high voltage battery 222 , a plurality of voltage sensors 211 and 212 , a current sensor 213 , and a plurality of capacitors 223 and 224 . ) and a converter unit 230 for connecting the high voltage terminal and the low voltage terminal, the auxiliary power supply unit 250 and an MCU (Micro Controller Unit) 240 for controlling on/off of each switch.

The low-voltage battery 221 has a lower voltage than the high-voltage battery 222 and is a chargeable/dischargeable power supply, and a 12V battery may be employed. The low voltage battery 221 is electrically connected to the converter unit 230 to apply power to a load device using the low voltage battery 221 or to charge the high voltage battery 222 .

The high-voltage battery 222 has a higher voltage than the low-voltage battery 221 and is a chargeable/dischargeable power supply. A 48V battery may be employed, and an ultra-capacitor may be employed. The high voltage battery 222 is electrically connected to the converter unit 230 to apply power to a load device using the high voltage battery 222 or to charge the low voltage battery 221 .

The voltage sensors 211 and 212 are connected to each of the high-voltage battery 222 and the low-voltage battery 221 to measure the input/output voltage of the high-voltage battery 222 or the input/output voltage of the low-voltage battery 221, and this The measured voltage value is transmitted to the MCU 240 . That is, the voltage sensors 211 and 212 connected to the high voltage battery 222 sense the input voltage or the output voltage of the high voltage battery 222 , and transmit the sensed result to the MCU 240 , and the low voltage battery 221 . ) connected to the voltage sensors 211 and 212 sense an input voltage or an output voltage generated from the low voltage battery 221 , and transmit the sensed result to the MCU 240 .

The current sensor 213 senses the current generated by the DC-DC converter unit 230 and transmits it to the MCU 240 .

Each of the sensors 211 , 212 , and 213 receives power through the MCU 240 .

The capacitors 223 and 224 are respectively connected to the high voltage battery 222 and the low voltage battery 221 , and an output smoothing capacitor may be used.

The converter unit 230 includes an inductor 233 and a pair of switches 231 and 232 complementary to each other.

A pair of switches 231 and 232 included in the converter unit 230 is divided into a high voltage switch 231 and a low voltage switch 232 , and each switch 231 and 232 turns according to the control of the MCU 240 . turned on or turned off. Preferably, the switches 231 and 232 are turned on or off based on the PWM (Pulse Width Modulation) generated by the MCU 240 . In particular, the low voltage switch 232 and the high voltage switch 231 operate complementary to each other. That is, when the low voltage switch 232 is turned on, the high voltage switch 231 is turned off, and when the high voltage switch 231 is turned on, the low voltage switch 232 is turned off.

On the other hand, when current is transferred from the low-voltage battery 221 to the high-voltage battery 222 , the low-voltage switch 232 operates as a main switch, and conversely, when the current moves from the high-voltage battery 222 to the low-voltage battery 221 . , the high voltage switch 231 operates as a main switch. Each of the switches 231 and 232 may use a MOSFET (Metal Oxide Semiconductor Field Effect) transistor as a semiconductor switch, and in this case, a gate terminal may be connected to the MCU 240 .

The inductor 233 accumulates energy when current flows, and the current sensor 213 senses the output current generated by the inductor 233 and transmits it to the MCU 240 . The current sensor 213 is a sensor capable of measuring a bidirectional current, and may sense a positive current or a negative current according to a current flow direction. For example, the current sensor 213 may sense a positive current in the buck mode and, conversely, sense a negative current in the boost mode. When a reverse current (ie, a negative current) is sensed, the current sensor 213 transmits a current sensed value representing the negative current to the MCU 240 . A Hall sensor may be employed as the current sensor 213 .

The MCU 240 is a controller unit, and supplies power to the peripheral circuits of the bidirectional DC-DC converter 200 such as each sensor 211 , 212 , 213 , and applies a switching signal to the converter unit 230 to convert the converter unit. Controls the states of the switches 231 and 232 included in the 230, and also controls the state of the path change switch 254. The MCU 240 monitors the sensed values received from the respective sensors 211, 212, and 213, and controls the bidirectional DC-DC converter 200 such as mode control based on the sensed values, and also detects errors. . In addition, the MCU 240 is connected to the voltage adjuster 251 of the auxiliary power unit 250 and receives the second voltage power (eg, 3.3V power) from the second voltage adjuster 251b to power the MCU 240 . and receives a first voltage power (eg, 5V power) from the first voltage regulator 251a and supplies the first voltage power to a peripheral circuit such as a sensor.

In particular, the MCU 240 is connected to the anode of the photocoupler 252 and is also connected to the path change switch 254 . In addition, the MCU 240 outputs a PWM signal to the photocoupler 252 to operate the photocoupler 252 , and the PWM signal generated from the photocoupler 252 is supplied to the transformer 253 to generate a predetermined voltage. make it

On the other hand, when the MCU 240 generates a PWM signal to the photocoupler 252, it controls the path change switch 254 to be turned off, so that the second path instead of the first path, that is, the photocoupler 252 and the transformer ( 253) to control power to be supplied to the first voltage regulator 251a.

The auxiliary power supply unit 250 includes a path change switch 254 forming a first path, a photocoupler 252 and a transformer 253 forming a second path, and also includes a voltage adjusting unit 251 .

The voltage adjusting unit 251 receives power through a first path or a second path, and adjusts this power to a first voltage power supply (eg, 5V power) and a second voltage power supply (eg, 3.3V power), respectively. It is supplied to the MCU 240 . The voltage regulator 251 includes a first voltage regulator 251a for adjusting the supplied power to a first voltage power source and a second voltage regulator 251b for adjusting the supplied power to a second voltage power source.

The path change switch 254 is disposed between the low voltage battery 221 and the first voltage regulator 251a of the voltage regulator 251 to form a first path, and is turned on when the MCU 240 is not operated. , connect between the low voltage battery 221 and the voltage adjuster 251 . That is, the path change switch 254 is turned on when the MCU 240 is not operated, and provides power (ie, the power of the low voltage battery) to the first voltage regulator 251a through the first path.

Meanwhile, when the MCU 240 is operated and a control signal is generated, the path change switch 254 is turned off to close the first path, and induces the power of the low voltage battery 221 to pass through the second path.

In the embodiment shown in FIG. 2 , it has been described that a PNP transistor is used as the path change switch 254 , but the present invention is not limited thereto. Make it clear that it is not restricted and that it is acceptable. When the path change switch 254 is a PNP transistor, the base of the path change switch 254 is connected to the MCU 240 , the emitter of the path change switch 254 is connected to the low voltage battery 221 , and the path change The collector of the switch 254 is connected to the first voltage regulator 251a.

The photocoupler 252 forms a second path, and consists of a light emitting unit and a light receiving unit. The light emitting unit converts an electrical signal (ie, a PWM signal) into an optical signal, and the light receiving unit converts the optical signal of the light emitting unit back into an electrical signal (that is, PWM signal), and the thus converted PWM signal is supplied to the transformer 253 . To this end, in the photocoupler 252 , the collector is electrically connected to the low voltage battery 221 , and the emitter is electrically connected to the transformer 253 . Also, the anode of the photocoupler 252 is connected to the MCU 240 . When the MCU 240 generates a PWM signal by this connection structure, the photocoupler 252 converts the PWM signal into an optical signal, and then converts the optical signal into a PWM signal, so that the converted PWM signal is It is supplied to the transformer 253 .

The transformer 253 forms a second path and changes the voltage of the PWM signal supplied from the photocoupler 252 to generate power having a predetermined voltage. The power generated by the transformer is provided to the first voltage regulator 251a.

The first voltage regulator 251a adjusts the voltage of the power supplied through the transformer 253 or the path change switch 254 to a first voltage, and the adjusted first voltage is the second voltage regulator 251b and MCU 240 , respectively. The first voltage power (eg, 5V power) provided from the first voltage regulator 251a to the MCU 240 is used as a power source of an auxiliary circuit such as a sensor.

The second voltage regulator 251b adjusts the first voltage power supplied from the first voltage regulator 251a to the second voltage power, and provides the adjusted second voltage to the MCU 240 . The second voltage power (eg, 3.3V power) provided from the first voltage regulator 251a to the MCU 240 is used by the MCU 240 itself. That is, the second voltage power supply is used as the power supply of the MCU 240 .

In the bidirectional DC-DC converter 200 having the above-described structure, the flow in which the auxiliary power supply unit 250 supplies power to the MCU 240 will be described.

In a state in which the MCU 240 is not operated (that is, power is not supplied to the MCU), power is initially applied from the low-voltage battery 221 or a relay connected between the low-voltage battery 211 and the converter unit 230 ( If not shown in the figure) is initially driven, the path change switch 254 maintains a turned-on state. That is, if the path change switch 254 does not receive a switching signal from the MCU 240 , it maintains a turned-on state so that power flows through the first path. When the path change switch 254 is turned on in this way, the power of the low voltage battery 221 is supplied to the first voltage regulator 251a through the path change switch 254 .

Then, the first voltage regulator 251a adjusts the power of the low-voltage battery (eg, 12V power supply) to be the first voltage power supply (eg, 5V power supply), and converts the adjusted first voltage power supply to the second voltage regulator 251b ) and MCU 240 , respectively. In addition, the second voltage regulator 251b adjusts the first voltage power (eg, 5V power) supplied from the first voltage regulator 251a to the second voltage power (eg, 3.3V power), and thus adjusted The second voltage power is supplied to the MCU 240 . In this way, the MCU 240 receiving the first voltage power and the second voltage power from each of the first voltage regulator 251a and the second voltage regulator 251b operates using the second voltage power as the MCU power, and The first voltage power is supplied to peripheral circuits such as each of the sensors 211 , 212 and 213 to operate the peripheral circuits. When the MCU 240 is operated in this way, the MCU 240 generates a PWM signal to the anode of the photocoupler 252 to operate the photocoupler 252 . In addition, when the MCU 240 is operated, it turns off the path change switch 254 to control that power is not supplied to the voltage adjuster 251 through the first path, and power is supplied through the second path as will be described later. control to be supplied.

When the photocoupler 252 is operated, a PWM signal is generated through the photocoupler 252 , and the PMW signal is supplied to the transformer 253 . The transformer 253 converts the PWM signal into power having a predetermined voltage, and supplies the changed power to the first voltage regulator 251a. In other words, when the MCU 240 is operated, power is supplied to the first voltage regulator 251a through the second path.

The first voltage regulator 251a adjusts the power supplied from the transformer 253 to be a first voltage power (eg, 5V power), and converts the adjusted first voltage power to the second voltage regulator 251b, MCU ( 240) are supplied separately. In addition, the second voltage regulator 251b adjusts the first voltage power (eg, 5V power) supplied from the first voltage regulator 251a to the second voltage power (eg, 3.3V power), and thus adjusted The second voltage power is provided to the MCU 240 .

Meanwhile, in the above description, although it has been described that the path change switch 254 and the photocoupler 252 are connected to the low voltage battery 221 , the path change switch 254 and the photocoupler 252 are connected to the high voltage battery 222 . ) may be associated with That is, the collector of the photocoupler 252 may be connected to the high voltage battery 222 , and the path change switch 254 may also be connected to the high voltage battery 222 . In this case, the power of the high voltage battery 222 is provided to the photocoupler 252 and the path change switch 254 .

The present invention described above, for those of ordinary skill in the art to which the present invention pertains, various substitutions, modifications and changes are possible without departing from the technical spirit of the present invention. It is not limited by the drawings.

200: bidirectional DC-DC converter
211, 212: voltage sensor
213: current sensor
221, 222: battery
230: DC-DC converter unit
240: MCU
250: auxiliary power unit
251: voltage regulator

Claims (8)

A bidirectional DC-DC converter that performs bidirectional voltage conversion between a high voltage battery and a low voltage battery and includes an improved auxiliary power source, the bidirectional DC-DC converter comprising:
a DC-DC converter unit including a high voltage switch and a low voltage switch as a pair of switching elements switched to a boost mode or a buck mode in response to a switching signal, and an inductor connected to the high voltage switch and the low voltage switch;
The power generated from the low-voltage battery or the high-voltage battery is adjusted to a first voltage power supply and a second voltage power supply via a first path or a second path, and the adjusted first voltage power supply and the second voltage power supply are used as a controller unit. Auxiliary power supply provided; and
It operates through the second voltage power supplied from the auxiliary power unit, provides the first voltage power supplied from the auxiliary power unit to the auxiliary circuit, generates the switching signal with the DC-DC converter unit, and Bidirectional DC-DC converter comprising; a controller unit for determining whether to use. The method of claim 1,
The auxiliary power unit,
a path change switch disposed between the low voltage battery or the high voltage battery and a voltage regulator to form the first path;
a photocoupler forming the second path, connected to the low voltage battery or the high voltage battery, and connected to a controller unit;
a transformer that forms the second path and converts the power generated by the photocoupler to a predetermined voltage and provides it to the voltage adjuster; and
Bidirectional DC-DC converter comprising a; the voltage adjusting unit for adjusting the power supplied from the transformer of the first path or the transformer of the second path to the first power and the second power supply to the controller unit; 3. The method of claim 2,
The first path is used until the controller unit is operated, and the second path is used when the controller unit is operated. 4. The method of claim 3,
The path change switch maintains a turn-on state when no control signal is applied from the controller unit to provide the power of the low-voltage battery or the high-voltage battery to the voltage adjuster,
The controller unit, when operated by receiving power from the voltage regulator, applies a signal to the photocoupler to operate the photocoupler to control power to be supplied through a second path, and turn off the path change switch Bidirectional DC-DC converter, characterized in that. 3. The method of claim 2,
wherein the path change switch is a PNP transistor, a base is connected to the controller unit, an emitter is connected to the low voltage battery or the high voltage battery, and a collector is connected to the voltage regulator. 3. The method of claim 2,
Bidirectional DC-DC converter, characterized in that the collector of the photocoupler is connected to the low voltage battery or the high voltage battery, the emitter of the photocoupler is connected to the transformer, and the anode of the photocoupler is connected to the controller unit. . 7. The method of claim 6,
The controller unit is
Bidirectional DC-DC converter, characterized in that by generating a PWM signal to the anode to operate the photocoupler. 3. The method of claim 2,
The voltage regulator,
a first voltage regulator for adjusting the power provided through the first path or the second path to a first voltage power; and
and a second voltage regulator configured to receive power through the first path or the second path and adjust the power to a second voltage power source.

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