CN113809918A - Bidirectional DC-DC converter - Google Patents

Bidirectional DC-DC converter Download PDF

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Publication number
CN113809918A
CN113809918A CN202010555318.1A CN202010555318A CN113809918A CN 113809918 A CN113809918 A CN 113809918A CN 202010555318 A CN202010555318 A CN 202010555318A CN 113809918 A CN113809918 A CN 113809918A
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China
Prior art keywords
mos
power supply
resistor
bidirectional
circuit
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CN202010555318.1A
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Chinese (zh)
Inventor
宋平
李屏山
詹群峰
阙友桥
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Xiamen Hongfa Automotive Electronics Co Ltd
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Xiamen Hongfa Automotive Electronics Co Ltd
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Priority to CN202010555318.1A priority Critical patent/CN113809918A/en
Publication of CN113809918A publication Critical patent/CN113809918A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H02M3/1584—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load with a plurality of power processing stages connected in parallel
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H11/00—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result
    • H02H11/002—Emergency protective circuit arrangements for preventing the switching-on in case an undesired electric working condition might result in case of inverted polarity or connection; with switching for obtaining correct connection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/44—Circuits or arrangements for compensating for electromagnetic interference in converters or inverters

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The invention discloses a bidirectional DC-DC converter, which is used for being connected between a first power supply and a second power supply and comprises an MCU control module, a first voltage acquisition circuit and a power unit, wherein the output of the first voltage acquisition circuit is connected to the MCU control module; the power unit comprises a power module or at least two power modules connected in parallel, the power module comprises a multiphase bidirectional current controller, a power control circuit, a current acquisition circuit and a second voltage acquisition circuit, the power control circuit is connected with a first power supply, the current acquisition circuit is connected with a second power supply, the power control circuit is connected with the current acquisition circuit, the output ends of the current acquisition circuit and the second voltage acquisition circuit are respectively connected with the analog quantity acquisition end of the multiphase bidirectional current controller, the driving output end of the multiphase bidirectional current controller is connected with the input end of the power control circuit, and the enabling end and the programmable configuration end are respectively connected with the output end of the MCU control module. The circuit of the invention has the advantages of simple design, clear principle, few discrete components and high reliability.

Description

Bidirectional DC-DC converter
Technical Field
The invention relates to the technical field of converters, in particular to a bidirectional DC-DC converter.
Background
At present, the bidirectional DC-DC converter in the prior art generally comprises an MCU control module and a power unit connected with an MUC control module, and because the circuit structure design of the power unit is complex and the number of discrete components is large, the integral volume is large, and the reliability and the efficiency are low.
Disclosure of Invention
The present invention provides a bidirectional DC-DC converter capable of simplifying a circuit structure of a power unit, in view of technical problems in the prior art.
The technical scheme adopted by the invention for solving the technical problems is as follows: a bidirectional DC-DC converter is used for being connected between a first power supply and a second power supply with unequal voltages and comprises an MCU control module, a first voltage acquisition circuit and a power unit, wherein the first voltage acquisition circuit is used for acquiring a first power supply voltage and a second power supply voltage; the power unit comprises a power module or at least two power modules connected in parallel, the power module comprises a multiphase bidirectional current controller, a power control circuit, a current acquisition circuit and a second voltage acquisition circuit for acquiring a first power supply voltage and a second power supply voltage, the power control circuit is connected with the current acquisition circuit, the power control circuit is connected with a first power supply, and the current acquisition circuit is connected with a second power supply; the output end of the current acquisition circuit and the output end of the second voltage acquisition circuit are respectively connected with the analog quantity acquisition end of the multiphase bidirectional current controller, and the driving output end of the multiphase bidirectional current controller is connected with the input end of the power control circuit; the multi-phase bidirectional current controller enabling end and the programmable configuration end are respectively connected with the MCU control module.
The power control circuit further comprises a first bidirectional anti-reverse-connection electric isolating switch and a second bidirectional anti-reverse-connection electric isolating switch, wherein the first bidirectional anti-reverse-connection electric isolating switch is connected between the power control circuit and the first power supply; the second bidirectional anti-reverse and electric isolation switch is connected between the current acquisition module and the second power supply; the enabling control end of the first bidirectional anti-reverse-connection electric isolating switch and the enabling control end of the second bidirectional anti-reverse-connection electric isolating switch are respectively connected with the output end of the MCU control module.
The first filter circuit is connected between the first bidirectional anti-reverse-connection-prevention and electric isolation switch and the first power supply; a second filter circuit is connected between the second bidirectional anti-reverse-blocking electrical isolation switch and the second power supply.
Further, the power control circuit comprises a MOS transistor Q1 and a MOS transistor Q2, a drain of the MOS transistor Q1 is connected to the anode of the first power supply after passing through the first bidirectional anti-reverse and electrical isolation switch, a source of the MOS transistor Q1 is connected to the drain of the MOS transistor Q2 and to the input end of the current acquisition circuit, and a source of the MOS transistor Q2 is connected to the cathode of the first power supply after passing through the first bidirectional anti-reverse and electrical isolation switch; the drive output end of the multiphase bidirectional current controller comprises a high-side gate drive output end and a low-side gate drive output end, the high-side gate drive output end is connected with the grid electrode of the MOS transistor Q1, and the low-side gate drive output end is connected with the grid electrode of the MOS transistor Q2.
Further, the current collecting circuit comprises a resistor R1, one end of the resistor R1 is connected to the source of the MOS transistor Q1 and the drain of the MOS transistor Q2, the other end of the resistor R1 is connected to the anode of the second power supply after passing through the second bidirectional anti-reverse and electrical isolation switch, and both ends of the resistor R1 are connected to the first analog quantity collecting end of the multiphase bidirectional current controller.
Further, the power module further comprises a capacitor C1, a capacitor C2 and an inductor L1, the capacitor C1 is connected between the positive electrode and the negative electrode of the first power supply passing through the first bidirectional anti-reverse-connection electric isolating switch, the capacitor C2 is connected between the positive electrode and the negative electrode of the second power supply passing through the second bidirectional anti-reverse-connection electric isolating switch, one end of an inductor L1 is connected with one end of the resistor R1, and the other end of the inductor L1 is connected with the source electrode of the MOS transistor Q1 and the drain electrode of the MOS transistor Q2.
Further, the second voltage acquisition circuit comprises a resistor R2, a resistor R3, a resistor R4 and a resistor R5, one end of the resistor R2 is connected with one end of the resistor R3, the other end of the resistor R2 and the other end of the resistor R3 are respectively connected with the anode and the cathode of the first power supply which passes through the first bidirectional anti-reverse-reaching electric isolating switch, and the connection end of the resistor R2 and the resistor R3 is connected with the second analog quantity acquisition end of the multiphase bidirectional current controller; one end of the resistor R4 is connected with one end of the resistor R5, the other end of the resistor R4 and the other end of the resistor R5 are respectively connected with the anode and the cathode of a second power supply passing through the second bidirectional anti-reverse-connection electric isolating switch, and the connecting end of the resistor R4 and the resistor R5 is connected with a third analog quantity acquisition end of the multi-phase bidirectional current controller.
Further, the first bidirectional anti-reverse-connection and electrical isolation switch comprises a MOS driver U1, a diode D1, a diode D2, a capacitor C3, a capacitor C4, a resistor R6, a resistor R7 and a first MOS unit, wherein the first MOS unit comprises a MOS component or at least two MOS components connected in parallel, the MOS component comprises two MOS transistors, and the sources of the two MOS transistors are connected together and connected with an input pin of an under-voltage locking comparator of the MOS driver U1; the anode of the diode D1, the drain of one of the MOS tubes of the MOS component and one end of the capacitor C3 are connected together and connected with the anode of the first power supply filtered by the first filter circuit, the cathode of the diode D1 is connected with the power supply input pin of the MOS driver U1, and the gate of one of the MOS tubes of the MOS component is connected with the overvoltage protection comparator input pin of the MOS driver U1; the anode of the diode D2, the drain of the other MOS tube of the MOS component and one end of the capacitor C4 are connected together and connected with the power control circuit, and the cathode of the diode D2 is connected with the output voltage detection pin of the MOS driver U1; the resistor R6 is connected between the undervoltage locking comparator input pin and the overvoltage protection comparator input pin of the MOS driver U1, and the resistor R7 is connected between the grounding pin and the undervoltage locking comparator input pin of the MOS driver U1; the other end of the capacitor C3, the other end of the capacitor C4 and a grounding pin of the MOS driver U1 are connected together and connected with the cathode of the first power supply filtered by the first filter circuit; an enabling input pin of the MOS driver U1 is connected with the output end of the MCU control module;
the second bidirectional anti-reverse-connection and electric isolation switch comprises a MOS driver U2, a diode D3, a diode D4, a capacitor C5, a capacitor C6, a resistor R8, a resistor R9 and a second MOS unit, wherein the second MOS unit comprises a MOS component or at least two MOS components connected in parallel, the MOS component comprises two MOS tubes, and the sources of the two MOS tubes are connected together and are connected with an input pin of an under-voltage locking comparator of the MOS driver U2; the anode of the diode D3, the drain of one of the MOS tubes of the MOS component and one end of the capacitor C5 are connected together and are connected with the current acquisition circuit, the cathode of the diode D3 is connected with the power supply input pin of the MOS driver U2, and the gate of one of the MOS tubes of the MOS component is connected with the overvoltage protection comparator input pin of the MOS driver U2; the anode of the diode D4, the drain of the other MOS transistor of the MOS component and one end of the capacitor C6 are connected together and connected with the anode of the second power supply filtered by the second filter circuit, and the cathode of the diode D4 is connected with the output voltage detection pin of the MOS driver U2; the resistor R8 is connected between the undervoltage locking comparator input pin and the overvoltage protection comparator input pin of the MOS driver U2, and the resistor R9 is connected between the grounding pin and the undervoltage locking comparator input pin of the MOS driver U2; the other end of the capacitor C5, the other end of the capacitor C6 and a grounding pin of the MOS driver U2 are connected together and connected with the cathode of the second power supply filtered by the second filter circuit; an enabling input pin of the MOS driver U2 is connected with the output end of the MCU control module.
The MCU control module is used for controlling the MCU control module to control the power supply of the power supply to be charged, and further comprises a first pre-charging circuit for pre-charging the first power supply and a second pre-charging circuit for pre-charging the second power supply, wherein the input end of the first pre-charging circuit and the input end of the second pre-charging circuit are respectively connected with the output end of the MCU control module; the MCU power supply device further comprises a host machine ECM and a power supply module, wherein the host machine ECM is connected with the MCU control module, the input end of the power supply module is connected with the host machine ECM, and the output end of the power supply module is connected with the input end of the MCU control module.
Furthermore, the temperature signal output end of the multiphase bidirectional current controller is connected with the input end of the MCU control module; the first power supply is a 48V battery and the second power supply is a 12V battery.
Compared with the prior art, the invention has the following beneficial effects:
1. because the power unit comprises a power module or at least two power modules connected in parallel, and the power module comprises the multiphase bidirectional current controller, the power control circuit, the current acquisition circuit and the second voltage acquisition circuit, the power unit has the advantages of simple circuit design, clear principle, few discrete components and high reliability.
2. The power module realizes modular design, is directly used in parallel, has flexible power configuration and can cover a plurality of power levels, such as 1.8kW/3 kW; the current loop and the switch loop are made to be minimum, the zero-voltage current cross point switch is made, the lossless switch is made, the efficiency is improved, the generation of high-frequency noise is obviously reduced, the EMI performance is good, the switching frequency of the circuit can be improved, the size of a power inductor is reduced, higher power density and efficiency are achieved, and the overall solution is optimized.
3. The first bidirectional anti-reverse-connection electric isolating switch and the second bidirectional anti-reverse-connection electric isolating switch are arranged, so that the bidirectional anti-reverse-connection circuit realizes the bidirectional anti-reverse function of the circuit and the switchable control function between the power unit and the power supply end.
The invention is further explained in detail with the accompanying drawings and the embodiments; a bidirectional DC-DC converter of the present invention is not limited to the embodiment.
Drawings
FIG. 1 is a functional block diagram of the present invention;
FIG. 2 is a functional block diagram of the power module of the present invention in a constant voltage mode;
FIG. 3 is a functional block diagram of the power module of the present invention in cross-current mode;
FIG. 4 is a schematic diagram of a circuit structure of the power module and the MCU control module in a connection state according to the present invention;
FIG. 5 is a schematic circuit diagram of a first bidirectional anti-reverse-connection and electrical isolation switch of the present invention;
fig. 6 is a schematic circuit structure diagram of a second bidirectional anti-reverse-connection and electrical isolation switch of the invention.
Detailed Description
In an embodiment, please refer to fig. 1 to 6, a bidirectional DC-DC converter of the present invention is configured to be connected between a first power supply 8 and a second power supply 9 with unequal voltages, and includes an MCU control module 1, a first voltage acquisition circuit 2 configured to acquire a voltage of the first power supply 8 and a voltage of the second power supply 9, and a power unit, where an output of the first voltage acquisition circuit 2 is connected to an input terminal of the MCU control module 1. The power unit comprises at least two power modules 3 connected in parallel, each power module 3 comprises a multiphase bidirectional current controller 33, a power control circuit 31, a current acquisition circuit 32 and a second voltage acquisition circuit 34 used for acquiring the voltage of a first power supply 8 and the voltage of a second power supply 9, the power control circuit 31 is connected with the current acquisition circuit 32, the power control circuit 31 is connected with the first power supply 8, and the current acquisition circuit 32 is connected with the second power supply 9; the output end of the current acquisition circuit 32 and the output end of the second voltage acquisition circuit 34 are respectively connected with the analog quantity acquisition end of the multiphase bidirectional current controller 33, and the driving output end of the multiphase bidirectional current controller 33 is connected with the input end of the power control circuit 31; the enable end and the programmable configuration end of the multiphase bidirectional current controller 33 are respectively connected with the output end of the MCU control module 1. The bi-directional current controller 33 is model LM5170, but is not limited thereto.
In this embodiment, the present invention further includes a first bidirectional anti-reverse-mixing electric isolating switch 4 and a second bidirectional anti-reverse-mixing electric isolating switch 5, where the first bidirectional anti-reverse-mixing electric isolating switch 4 is connected between the power control circuit 31 and the first power supply 8; the second bidirectional anti-reverse and electric isolating switch 5 is connected between the current acquisition circuit 32 and the second power supply 9; the enabling control end of the first bidirectional anti-reverse-connection electric isolating switch 4 and the enabling control end of the second bidirectional anti-reverse-connection electric isolating switch 5 are respectively connected with the MCU control module 1.
In this embodiment, the present invention further includes a first filter circuit 6 and a second filter circuit 7, where the first filter circuit 6 is connected between the first bidirectional anti-reverse-blocking and electrical isolation switch 4 and the first power supply 8; a second filter circuit 7 is connected between the second bidirectional anti-bounce and galvanic isolation switch 5 and the second power supply 9.
In this embodiment, the present invention further includes a first pre-charge circuit 10 for pre-charging the first power supply 8 and a second pre-charge circuit 11 for pre-charging the second power supply 9, wherein an input terminal of the first pre-charge circuit 10 and an input terminal of the second pre-charge circuit 11 are respectively connected to an output terminal of the MCU control module 1. The first pre-charging circuit 10 and the second pre-charging circuit 11 both adopt capacitor charging circuits, and the arrangement of the first pre-charging circuit 10 and the second pre-charging circuit 11 can prevent surge current from occurring when a battery relay is closed in the process of power-on initialization. The MCU control module 1 determines that the first power supply 8 or the second power supply 9 is precharged by detecting the voltages of the first power supply 8 and the second power supply 9 and according to the turn-on direction of the power control circuit 31. During pre-charging, the MCU control module 1 collects the voltages of the first power supply 8 and the second power supply 9 in real time, adjusts the charging current value according to different voltage values, and sends a turn-off instruction to complete a charging period after the MCU control module 1 collects a required charging voltage value.
In this embodiment, the present invention further includes a host ECM12 and a power module 13, the host ECM12 is connected to the MCU control module 1, an input terminal of the power module 13 is connected to the host ECM12, and an output terminal of the power module 13 is connected to an input terminal of the MCU control module 1. The host ECM12 is specifically connected with the MCU control module 1 through a CAN bus, the host ECM12 CAN control the start and stop of the whole converter, the MCU control module 1 receives the requirement of the host ECM12 on a buck-boost circuit, collects the voltage of the first power supply 8/the second power supply 9, sends a charging direction and a charging current instruction to the power module 3, charges the first power supply 8 or the second power supply 9, and sends the working information of the power module 3 to the host ECM 12.
In this embodiment, the programmable configuration end (i.e., the program pin) of the multiphase bidirectional current controller 33 may be designed as an analog quantity receiving port or a digital quantity receiving port, and may also be designed as a communication interface (e.g., I2C, SPI, SCI interface, etc.). The role of the programmable configuration terminal includes the configuration of the following functions:
1) selecting the working direction of the circuit, namely the voltage reduction (BUCK) or voltage Boosting (BOOST) direction;
2) selecting a circuit working mode, namely a constant voltage or constant current mode;
3) configuration of circuit current and voltage: and in the constant voltage mode, the output constant voltage value is configured, and in the constant current mode, the output constant current value is configured.
As shown in fig. 2, the configuration of the constant voltage mode is that the multiphase bidirectional current controller 33 receives a voltage setting instruction of the MCU control module 1, collects a high-voltage side voltage (i.e., a voltage of the first power supply 8) and a low-voltage side voltage (i.e., a voltage of the second power supply 9) through the second voltage collecting circuit 34, configures a duty ratio, and compares the duty ratio with an internal voltage reference, thereby adjusting the PWM duty ratio at any time and maintaining constant voltage output.
The configuration of the constant current mode is as shown in fig. 3, the multiphase bidirectional current controller 33 configures a corresponding constant current duty ratio by receiving a current setting instruction of the MCU control module 1, collects a current through the current collection circuit 32, compares the current with a current setting value, and then adjusts the PWM duty ratio at any time to maintain constant current output.
In this embodiment, as shown in fig. 4, the power control circuit 31 includes a MOS transistor Q1 and a MOS transistor Q2, a drain of the MOS transistor Q1 is connected to the positive electrode of the first power supply 8 after passing through the first bidirectional anti-reverse and electrical isolation switch 4, a source of the MOS transistor Q1 is connected to the drain of the MOS transistor Q2 and is connected to the input end of the current collecting circuit 32, and a source of the MOS transistor Q2 is connected to the negative electrode of the first power supply 8 after passing through the first bidirectional anti-reverse and electrical isolation switch 4; the driving output of the multiphase bidirectional current controller 33 comprises a high side gate driving output 334 and a low side gate driving output 335, the high side gate driving output 334 is connected to the gate of the MOS transistor Q1, and the low side gate driving output 335 is connected to the gate of the MOS transistor Q2.
In this embodiment, as shown in fig. 4, the current collecting circuit 32 includes a resistor R1, one end of the resistor R1 is connected to the source of the MOS transistor Q1 and the drain of the MOS transistor Q2, the other end of the resistor R1 is connected to the anode of the second power supply 9 passing through the second bidirectional anti-reverse and electrically isolated switch 5, and both ends of the resistor R1 are connected to the first analog quantity collecting terminal 331 of the multi-phase bidirectional current controller 33 (the multi-phase bidirectional current controller 33 has a plurality of analog quantity collecting terminals, which are respectively named as the first analog quantity collecting terminal 331, the second analog quantity collecting terminal 332, and the third analog quantity collecting terminal 333).
In this embodiment, the power module 3 further includes a capacitor C1, a capacitor C2, and an inductor L1, the capacitor C1 is connected between the positive electrode and the negative electrode of the first power supply 8 after passing through the first bidirectional anti-reverse-connection electric isolation switch 4, the capacitor C2 is connected between the positive electrode and the negative electrode of the second power supply 9 after passing through the second bidirectional anti-reverse-connection electric isolation switch 5, one end of the inductor L1 is connected to one end of the resistor R1, and the other end of the inductor L1 is connected to the source of the MOS transistor Q1 and the drain of the MOS transistor Q2.
In this embodiment, the second voltage acquisition circuit 34 includes a resistor R2, a resistor R3, a resistor R4, and a resistor R5, one end of the resistor R2 is connected to one end of the resistor R3, the other end of the resistor R2 and the other end of the resistor R3 are respectively connected to the positive electrode and the negative electrode of the first power supply 8 passing through the first bidirectional anti-reverse-reaching electrical isolation switch 4, and the connection end of the resistor R2 and the resistor R3 is connected to the second analog quantity acquisition end 332 of the multiphase bidirectional current controller 33; one end of the resistor R4 is connected with one end of the resistor R5, the other end of the resistor R4 and the other end of the resistor R5 are respectively connected with the anode and the cathode of the second power supply 9 passing through the second bidirectional anti-reverse-connection electric isolating switch 5, and the connecting end of the resistor R4 and the resistor R5 is connected with the third analog quantity acquisition end 333 of the multiphase bidirectional current controller 33.
In this embodiment, the multiphase bidirectional current controller 33 is provided with a temperature sensor therein, and a temperature signal output end thereof is connected to an input end of the MCU control module 1, so that when the internal temperature of the multiphase bidirectional current controller 33 is higher than 125 ℃ or lower than-45 ℃, the whole power module 3 stops working and sends a temperature signal to the MCU module, thereby monitoring the temperature of the power module 3.
In this embodiment, the first power supply 8 is a 48V battery, and the second power supply 9 is a 12V battery, but is not limited thereto.
In this embodiment, the MCU control module 1 adopts a series of chips such as RH850/V850/78K/AURIX/PIC, and has a plurality of output terminals and three analog collecting terminals, each of which is an IO terminal, and the three analog collecting terminals are in one-to-one correspondence with the temperature signal output terminal, the high-side voltage output terminal and the low-side voltage output terminal of the first voltage collecting circuit 2.
In this embodiment, the circuit structure of the first voltage acquisition circuit 2 is the same as that of the second voltage acquisition circuit 34, and the first filter circuit 6 and the second filter circuit 7 are composed of capacitors and inductors, and are used for filtering high-frequency interference noise of the high-frequency switch circuit and protecting the influence of external high-frequency interference on the local power supply.
In this embodiment, the number of the power modules 3 is selected according to the required power, and the higher the required power is, the number of the power modules 3 may be correspondingly increased, whereas the lower the required power is, the number of the power modules 3 may be correspondingly decreased. The number of the power modules 3 is specifically three, but is not limited thereto. The maximum power of each power module 3 is 800W, and the power of 2400W can be achieved after the three power modules 3 are connected in parallel. When the required power is low, the number of the power modules 3 may be one.
In this embodiment, the power module 3 adopts a BUCK-BOOST bidirectional topology circuit structure, and the MCU control module 1 enables the power module 3 through the EN pin of the multiphase bidirectional current controller 33, and sends the circuit direction and the constant voltage or constant current mode to the power module 3 through the programmable configuration end of the multiphase bidirectional current controller 33. When the circuit is in a BUCK mode, the direction of the circuit is from 48V to 12V, the MOS tube Q1 is used as a switching tube, the MOS tube Q2 is used as a rectifying tube, otherwise, when the circuit is in a Boost mode, the direction of the circuit is from 12V to 48V, the MOS tube Q1 is used as a rectifying tube, and the MOS tube Q2 is used as a follow current tube, so that the bidirectional working modes of the circuit BUCK (voltage reduction) and the BOOST (voltage boosting) are realized; the circuit detects the voltage at the side of 48V through a resistor R2 and a resistor R3, detects the voltage at the side of 12V through a resistor R4 and a resistor R5, detects loop current through a resistor R1, and feeds the detected quantity back to the multiphase bidirectional current controller 33, and the multiphase bidirectional current controller 33 realizes the control of the constant voltage or constant current mode of the circuit through the drive adjustment of the drive control circuit. The multiphase bidirectional current controller 33 integrates temperature monitoring, can send a temperature monitoring signal to an AD port (i.e., an analog acquisition port) of the MCU control module 1 for sampling, and when the internal temperature exceeds a set value, the multiphase bidirectional current controller 33 will close the power loop.
In this embodiment, as shown in fig. 5, the first bidirectional anti-reverse-blocking and electrical isolating switch 4 includes a MOS driver U1, a diode D1, a diode D2, a capacitor C3, a capacitor C4, a resistor R6, a resistor R7, and a first MOS unit 14, where the first MOS unit 14 includes a MOS component or at least two MOS components connected in parallel, and the MOS component includes two MOS transistors, where sources of the two MOS transistors are connected together and connected to an input pin of an under-voltage locking comparator of the MOS driver U1; the anode of the diode D1, the drain of one of the MOS transistors of the MOS component and one end of the capacitor C3 are connected together to form a V1 end, the V1 end is connected to the anode of the first power supply 8 filtered by the first filter circuit 6, the cathode of the diode D1 is connected to the power input pin of the MOS driver U1, and the gate of one of the MOS transistors of the MOS component is connected to the input pin of the overvoltage protection comparator of the MOS driver U1; the anode of the diode D2, the drain of the other MOS transistor of the MOS device, and one end of the capacitor C4 are connected together to form a V2 terminal, the V2 terminal is connected to the power control circuit 31 (specifically, the V2 terminal is connected to the drain of the MOS transistor Q1), and the cathode of the diode D2 is connected to the output voltage detection pin of the MOS driver U1; the resistor R6 is connected between the undervoltage locking comparator input pin and the overvoltage protection comparator input pin of the MOS driver U1, and the resistor R7 is connected between the grounding pin and the undervoltage locking comparator input pin of the MOS driver U1; the other end of the capacitor C3, the other end of the capacitor C4 and a grounding pin of the MOS driver U1 are connected together and connected with the cathode of the first power supply 8 filtered by the first filter circuit 6; an enabling input pin of the MOS driver U1 is connected with the output end of the MCU control module 1.
In this embodiment, as shown in fig. 6, the second bidirectional anti-reverse-connection-preventing electrical isolation switch 5 includes a MOS driver U2, a diode D3, a diode D4, a capacitor C5, a capacitor C6, a resistor R8, a resistor R9, and a second MOS unit 15, where the second MOS unit 15 includes a MOS component or at least two MOS components connected in parallel, where the MOS component includes two MOS transistors, and sources of the two MOS transistors are connected together and connected to an input pin of an under-voltage-locked comparator of the MOS driver U2; the anode of the diode D3, the drain of one of the MOS transistors of the MOS component and one end of the capacitor C5 are connected together to form a V3 end, the V3 end is connected to the current acquisition circuit 32 (specifically, the V4 end is connected to the other end of the resistor R2), the cathode of the diode D3 is connected to the power input pin of the MOS driver U2, and the gate of one of the MOS transistors of the MOS component is connected to the input pin of the overvoltage protection comparator of the MOS driver U2; the anode of the diode D4, the drain of the other MOS transistor of the MOS component, and one end of the capacitor C6 are connected together to form a V4 terminal, the V4 terminal is connected to the anode of the second power supply 9 filtered by the second filter circuit 7, and the cathode of the diode D4 is connected to the output voltage detection pin of the MOS driver U2; the resistor R8 is connected between the undervoltage locking comparator input pin and the overvoltage protection comparator input pin of the MOS driver U2, and the resistor R9 is connected between the grounding pin and the undervoltage locking comparator input pin of the MOS driver U2; the other end of the capacitor C5, the other end of the capacitor C6 and a ground pin of the MOS driver U2 are connected together, and connected to the negative electrode of the second power supply 9 filtered by the second filter circuit 7; an enabling input pin of the MOS driver U2 is connected with the output end of the MCU control module 1.
In this embodiment, the first MOS unit 14 and the second MOS unit 15 are implemented by connecting three groups of MOS devices in parallel, which is only designed according to the main loop current and the current value of the matching MOSFET, and may also be implemented by connecting 1 group, 2 groups, or more groups of MOS devices in parallel according to the magnitude of the main loop current. The model of each MOS tube is FDWS86380, and MOS driver U1 and MOS driver U2 select a high-side drive IC with the model of LM5060 respectively. The first bidirectional anti-reverse and electric isolating switch 4 works according to the following principle: no matter the terminal V1 is used as the input side or the terminal V2 is used as the input side, when the circuit is connected reversely, the diode D1 and the diode D2 both play a role of preventing reverse, the MOS driver U1 cannot be powered and cannot operate, the first MOS unit 14 cannot be driven, and the circuit cannot operate. In fig. 5, each MOS component of the first MOS unit 14 adopts a back-to-back connection manner of two MOS transistors, that is, the S-pole of the previous stage MOSFET (MOS transistor Q24, MOS transistor Q26, and MOS transistor Q28) is connected in series with the S-pole of the next stage MOSFET (MOS transistor Q25, MOS transistor Q27, and MOS transistor Q29), so that the body diodes of the MOSFETs are connected in series in the reverse direction, and thus the current on the V1 side and the current on the V2 side cannot flow in through the body diodes of the MOSFETs, thereby realizing the function of preventing reverse rotation in two directions. When the circuits are paired, if the side of V1 is the input terminal, the side of V1 supplies power to the MOS driver U1 through the diode D1, the MOS driver U1 operates normally, whereas if the side of V2 is the input terminal, the V2 supplies power to the MOS driver U1 through the diode D2, the MOS driver U1 can also work normally, the MCU control module 1 can enable and control the MOS driver U1 through the enable input pin of the MOS driver U1, when the enable input pin of MOS driver U1 is high, MOS driver U1 is enabled, then the two sets of MOSFETs in fig. 5 (MOS transistor Q24, MOS transistor Q26, MOS transistor Q28 and MOS transistor Q25, MOS transistor Q27, MOS transistor Q29) are all conducting, the circuit is switched on, when the enable input pin of MOS driver U1 is low, the MOS driver U1 is turned off, the first MOS unit 14 is turned off, and the load side and the input side are disconnected, so that the electrical isolation between the power supply side and the internal load power circuit side is achieved.
In fig. 6, each MOS component of the second OS unit 15 adopts a back-to-back connection of two MOS transistors, that is, the S-pole of the previous stage MOSFET (the MOS transistor Q34, the MOS transistor Q36, and the MOS transistor Q38) and the S-pole of the next stage MOSFET (the MOS transistor Q35, the MOS transistor Q37, and the MOS transistor Q39) are connected in series, so that the body diodes of the MOSFETs are connected in series in reverse. The working principle of the second bidirectional anti-reverse-connection electric isolating switch 5 is the same as that of the first bidirectional anti-reverse-connection electric isolating switch 4, and the description thereof is omitted.
The bidirectional reverse-prevention electric isolating switch has the advantages that the bidirectional reverse-prevention function of the circuit and the function of on-off control of the load circuit and the power input end are realized by arranging the first bidirectional reverse-prevention electric isolating switch 4 and the second bidirectional reverse-prevention electric isolating switch 5. Meanwhile, when the circuit is switched on, the conduction voltage drop of the MOSFET is almost zero, and the power consumption is greatly different from that of a rectifier diode, so that the circuit has great advantages when applied to the input end protection of a high-power supply.
The power module 3 of the bidirectional DC-DC converter adopts the multiphase bidirectional current controller 33 as a control core, so that the circuit design is very simple, the principle is clear, the number of discrete components is small, the reliability is high, the power unit adopts a modular design, the power configuration is flexible, the power module can be directly used in parallel, a current loop and a switch loop are minimized, a zero-voltage current cross point switch is used as a zero-loss switch, the efficiency is improved, the generation of high-frequency noise is obviously reduced, the EMI performance is good, the switching frequency of the circuit can be improved, the volume of a power inductor is reduced, higher power density and efficiency are achieved, and the overall solution is optimized.
The above embodiments are only used to further illustrate a bidirectional DC-DC converter of the present invention, but the present invention is not limited to the embodiments, and any simple modification, equivalent change and modification made to the above embodiments according to the technical spirit of the present invention fall within the protection scope of the technical solution of the present invention.

Claims (10)

1. A bidirectional DC-DC converter is used for being connected between a first power supply and a second power supply with unequal voltages and comprises an MCU control module, a first voltage acquisition circuit and a power unit, wherein the first voltage acquisition circuit is used for acquiring a first power supply voltage and a second power supply voltage; the method is characterized in that: the power unit comprises a power module or at least two power modules connected in parallel, the power module comprises a multiphase bidirectional current controller, a power control circuit, a current acquisition circuit and a second voltage acquisition circuit for acquiring a first power supply voltage and a second power supply voltage, the power control circuit is connected with the current acquisition circuit, the power control circuit is connected with a first power supply, and the current acquisition circuit is connected with a second power supply; the output end of the current acquisition circuit and the output end of the second voltage acquisition circuit are respectively connected with the analog quantity acquisition end of the multiphase bidirectional current controller, and the driving output end of the multiphase bidirectional current controller is connected with the input end of the power control circuit; the multi-phase bidirectional current controller enabling end and the programmable configuration end are respectively connected with the MCU control module.
2. The bi-directional DC-DC converter of claim 1, wherein: the power control circuit also comprises a first bidirectional anti-reverse-connection electric isolating switch and a second bidirectional anti-reverse-connection electric isolating switch, wherein the first bidirectional anti-reverse-connection electric isolating switch is connected between the power control circuit and the first power supply; the second bidirectional anti-reverse and electric isolation switch is connected between the current acquisition module and the second power supply; the enabling control end of the first bidirectional anti-reverse-connection electric isolating switch and the enabling control end of the second bidirectional anti-reverse-connection electric isolating switch are respectively connected with the output end of the MCU control module.
3. The bi-directional DC-DC converter of claim 2, wherein: the first filter circuit is connected between the first bidirectional anti-reverse-connection-prevention and electric isolation switch and the first power supply; a second filter circuit is connected between the second bidirectional anti-reverse-blocking electrical isolation switch and the second power supply.
4. A bidirectional DC-DC converter according to claim 2 or 3, characterized in that: the power control circuit comprises an MOS tube Q1 and an MOS tube Q2, the drain electrode of the MOS tube Q1 is connected with the anode of the first power supply after passing through the first bidirectional anti-reverse and electric isolating switch, the source electrode of the MOS tube Q1 is connected with the drain electrode of the MOS tube Q2 and is connected with the input end of the current acquisition circuit, and the source electrode of the MOS tube Q2 is connected with the cathode of the first power supply after passing through the first bidirectional anti-reverse and electric isolating switch; the drive output end of the multiphase bidirectional current controller comprises a high-side gate drive output end and a low-side gate drive output end, the high-side gate drive output end is connected with the grid electrode of the MOS transistor Q1, and the low-side gate drive output end is connected with the grid electrode of the MOS transistor Q2.
5. The bi-directional DC-DC converter of claim 4, wherein: the current acquisition circuit comprises a resistor R1, one end of the resistor R1 is connected with the source electrode of the MOS transistor Q1 and the drain electrode of the MOS transistor Q2, the other end of the resistor R1 is connected with the anode of a second power supply which passes through the second bidirectional anti-reverse and electric isolating switch, and two ends of the resistor R1 are connected with a first analog quantity acquisition end of the multiphase bidirectional current controller.
6. The bi-directional DC-DC converter of claim 4, wherein: the power module further comprises a capacitor C1, a capacitor C2 and an inductor L1, wherein the capacitor C1 is connected between the positive electrode and the negative electrode of the first power supply after passing through the first bidirectional anti-reverse and electric isolating switch, the capacitor C2 is connected between the positive electrode and the negative electrode of the second power supply after passing through the second bidirectional anti-reverse and electric isolating switch, one end of the inductor L1 is connected with one end of the resistor R1, and the other end of the inductor L1 is connected with the source electrode of the MOS transistor Q1 and the drain electrode of the MOS transistor Q2.
7. A bidirectional DC-DC converter according to claim 2 or 3, characterized in that: the second voltage acquisition circuit comprises a resistor R2, a resistor R3, a resistor R4 and a resistor R5, one end of the resistor R2 is connected with one end of a resistor R3, the other end of the resistor R2 and the other end of the resistor R3 are respectively connected with the anode and the cathode of the first power supply which passes through the first bidirectional anti-reverse and electric isolating switch, and the connecting end of the resistor R2 and the resistor R3 is connected with the second analog quantity acquisition end of the multiphase bidirectional current controller; one end of the resistor R4 is connected with one end of the resistor R5, the other end of the resistor R4 and the other end of the resistor R5 are respectively connected with the anode and the cathode of a second power supply passing through the second bidirectional anti-reverse-connection electric isolating switch, and the connecting end of the resistor R4 and the resistor R5 is connected with a third analog quantity acquisition end of the multi-phase bidirectional current controller.
8. A bi-directional DC-DC converter according to claim 3, characterized in that: the first bidirectional anti-reverse-connection and electric isolation switch comprises an MOS driver U1, a diode D1, a diode D2, a capacitor C3, a capacitor C4, a resistor R6, a resistor R7 and a first MOS unit, wherein the first MOS unit comprises an MOS component or at least two MOS components connected in parallel, the MOS component comprises two MOS tubes, and the sources of the two MOS tubes are connected together and are connected with an input pin of an under-voltage locking comparator of the MOS driver U1; the anode of the diode D1, the drain of one of the MOS tubes of the MOS component and one end of the capacitor C3 are connected together and connected with the anode of the first power supply filtered by the first filter circuit, the cathode of the diode D1 is connected with the power supply input pin of the MOS driver U1, and the gate of one of the MOS tubes of the MOS component is connected with the overvoltage protection comparator input pin of the MOS driver U1; the anode of the diode D2, the drain of the other MOS tube of the MOS component and one end of the capacitor C4 are connected together and connected with the power control circuit, and the cathode of the diode D2 is connected with the output voltage detection pin of the MOS driver U1; the resistor R6 is connected between the undervoltage locking comparator input pin and the overvoltage protection comparator input pin of the MOS driver U1, and the resistor R7 is connected between the grounding pin and the undervoltage locking comparator input pin of the MOS driver U1; the other end of the capacitor C3, the other end of the capacitor C4 and a grounding pin of the MOS driver U1 are connected together and connected with the cathode of the first power supply filtered by the first filter circuit; an enabling input pin of the MOS driver U1 is connected with the output end of the MCU control module;
the second bidirectional anti-reverse-connection and electric isolation switch comprises a MOS driver U2, a diode D3, a diode D4, a capacitor C5, a capacitor C6, a resistor R8, a resistor R9 and a second MOS unit, wherein the second MOS unit comprises a MOS component or at least two MOS components connected in parallel, the MOS component comprises two MOS tubes, and the sources of the two MOS tubes are connected together and are connected with an input pin of an under-voltage locking comparator of the MOS driver U2; (ii) a The anode of the diode D3, the drain of one of the MOS tubes of the MOS component and one end of the capacitor C5 are connected together and are connected with the current acquisition circuit, the cathode of the diode D3 is connected with the power supply input pin of the MOS driver U2, and the gate of one of the MOS tubes of the MOS component is connected with the overvoltage protection comparator input pin of the MOS driver U2; the anode of the diode D4, the drain of the other MOS transistor of the MOS component and one end of the capacitor C6 are connected together and connected with the anode of the second power supply filtered by the second filter circuit, and the cathode of the diode D4 is connected with the output voltage detection pin of the MOS driver U2; the resistor R8 is connected between the undervoltage locking comparator input pin and the overvoltage protection comparator input pin of the MOS driver U2, and the resistor R9 is connected between the grounding pin and the undervoltage locking comparator input pin of the MOS driver U2; the other end of the capacitor C5, the other end of the capacitor C6 and a grounding pin of the MOS driver U2 are connected together and connected with the cathode of the second power supply filtered by the second filter circuit; an enabling input pin of the MOS driver U2 is connected with the output end of the MCU control module.
9. The bi-directional DC-DC converter of claim 1, wherein: the MCU control module is used for controlling the MCU control module to control the power supply to be charged, and comprises a first pre-charging circuit used for pre-charging the first power supply and a second pre-charging circuit used for pre-charging the second power supply, wherein the input end of the first pre-charging circuit and the input end of the second pre-charging circuit are respectively connected with the output end of the MCU control module; the MCU power supply device further comprises a host machine ECM and a power supply module, wherein the host machine ECM is connected with the MCU control module, the input end of the power supply module is connected with the host machine ECM, and the output end of the power supply module is connected with the input end of the MCU control module.
10. The bi-directional DC-DC converter of claim 1, wherein: the temperature signal output end of the multiphase bidirectional current controller is connected with the input end of the MCU control module; the first power supply is a 48V battery and the second power supply is a 12V battery.
CN202010555318.1A 2020-06-17 2020-06-17 Bidirectional DC-DC converter Pending CN113809918A (en)

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CN202010555318.1A CN113809918A (en) 2020-06-17 2020-06-17 Bidirectional DC-DC converter

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CN202010555318.1A CN113809918A (en) 2020-06-17 2020-06-17 Bidirectional DC-DC converter

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