CN111835197A - Novel high-power non-isolated double-output DC-DC converter - Google Patents

Novel high-power non-isolated double-output DC-DC converter Download PDF

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Publication number
CN111835197A
CN111835197A CN202010688308.5A CN202010688308A CN111835197A CN 111835197 A CN111835197 A CN 111835197A CN 202010688308 A CN202010688308 A CN 202010688308A CN 111835197 A CN111835197 A CN 111835197A
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resistor
output
pin
voltage
circuit
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马光路
邵洋洋
董静
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Fengxian Hongxiang Electronic Technology Co ltd
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Fengxian Hongxiang Electronic Technology Co ltd
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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L1/00—Supplying electric power to auxiliary equipment of vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L1/00—Supplying electric power to auxiliary equipment of vehicles
    • B60L1/14—Supplying electric power to auxiliary equipment of vehicles to electric lighting circuits
    • 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
    • H02M1/0083—Converters characterised by their input or output configuration
    • H02M1/009—Converters characterised by their input or output configuration having two or more independently controlled outputs
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The invention provides a novel high-power non-isolated double-output DC-DC converter, which comprises a DC/DC main circuit capable of outputting 12V low voltage and a control circuit connected in the main circuit; the control circuit consists of a control chip IC1, an output overcurrent protection circuit, a voltage stabilizing circuit, an oscillation circuit and a pulse output circuit; the invention adopts the relay as the core component of the main circuit output, fundamentally solves various defects of the traditional method of using the MOS tube to make the main circuit output, and greatly improves the technical problems that the double-output converter is easy to damage and has insufficient instantaneous power. The relay driving circuit is simple, stable and reliable, the contact capacity is large, and the impact of large current can be borne. The traditional MOS tube main circuit output mode is complex in driving circuit and high in failure rate, the MOS tube is easily interfered by other circuits, and the impact resistance of large current is poor.

Description

Novel high-power non-isolated double-output DC-DC converter
Technical Field
The invention relates to a converter for converting DC high voltage of an electric vehicle storage battery pack into DC12V low voltage, which is used for providing rated working voltage for a lighting system, a signal indicating system and various auxiliary electrical appliances of a whole vehicle, and belongs to the technical field of circuits. In particular to a novel high-power non-isolated double-output DC-DC converter.
Background
At present, electric vehicles on the market mainly refer to closed type electric three-wheel and four-wheel vehicles, and the types of the electric vehicles are basically provided with electric parts such as a central control lock, an anti-theft alarm, a GPS (global positioning system) and the like which need to be supplied with power for a long time. From the market at present, the high-power non-isolated double-output DC-DC converter used in the vehicle type is easy to damage, has insufficient instantaneous power and other technical problems, causes the failure of the central control lock, and brings hidden dangers to property safety of vehicle owners.
Disclosure of Invention
In order to solve the technical problems, the invention provides a novel high-power non-isolated double-output DC-DC converter which converts the voltage of an electric vehicle storage battery pack, such as 48V, 60V, 72V and the like, into 12V and provides rated working voltage for 12V low-voltage electric appliances on an electric vehicle, such as lighting lamps, instruments, horns, wipers, light indicators, fans, radios, backing images, central control locks, anti-theft alarms, GPS and the like. The functions of input reverse connection protection, input/output overvoltage protection, output overcurrent protection and output short circuit protection can be realized; the invention is mainly applied to the closed type electric three-wheel and four-wheel vehicles.
The invention is realized by the following technical scheme: a novel high-power non-isolated double-output DC-DC converter comprises a DC/DC main circuit capable of outputting 12V low voltage, and a control circuit connected in the main circuit and used for input reverse connection protection, input/output overvoltage protection, output overcurrent protection and output short circuit protection;
the main circuit comprises a DC input, a DC control circuit, a DC auxiliary output and a DC main circuit output, and the DC input and the DC output are both connected with a filter element; one path of the input power supply is connected with a power supply circuit of the control chip, is connected with a resistor R6 in parallel through a resistor R5, is connected with a resistor R3 in parallel and is connected with a resistor R4 in parallel, and is connected with a switching triode V1 to supply power to pins 8, 11 and 12 of the control chip IC 1; the combined action of the resistor R1, the resistor R2, the resistor R78, the capacitor C1 and the voltage stabilizer Q1 provides a stable voltage input signal for the V1, ensures that the V1 stably works in a saturation state, does not influence the working state of the V1 due to the change of the voltage of the storage battery pack, and provides a stable working voltage for the control chip IC1 under the combined action of the filtering of the capacitor C2 and the CD1 and the voltage stabilizing circuit consisting of the resistor R29 and the voltage stabilizing diode Z2; the other path is connected to the drains of NMOS tubes V2 and V3, the cathodes of filter capacitors CD3, CD4, CD5 and CD6 and the cathodes of transient suppression diodes D3 and D4; d3, D4 act as input reverse-connect protection and input overpressure protection. And the anodes of the filter capacitors CD3, CD4, CD5 and CD6 and the drain of the NMOS tube are all connected with the anode of the input power supply.
The DC auxiliary output circuit is formed by connecting the source electrode of an NMOS (N-channel metal oxide semiconductor) tube with an energy storage inductor L1 and the cathodes of Schottky diodes V4 and V5, and is grounded through a capacitor C13 after being connected with a resistor R34 and a resistor R35 in parallel and then being connected with a resistor R36 and a resistor R37 in parallel; the other end of the energy storage inductor L1 is connected with the anodes of the output filter capacitors CD7 and CD8, and is connected with a resistor R38 and a resistor R39 in parallel, and then is connected with a series resistor R40 and a resistor R41 in parallel and then is grounded; the cathodes of the transient suppression diode D5 and the diode D6 are connected; the transient suppression diodes D5, D6 act as output overvoltage protection. The OUT1 terminal is an auxiliary DC output terminal, which has an output as long as the DC input terminal is connected to the battery pack.
The DC main circuit output circuit comprises an optocoupler U1, a resistor R45 and a resistor R46 are connected in series with a first pin of the optocoupler U1, a second pin of the optocoupler U1 is grounded through a resistor R47, and the resistors R45, R46 and R47 are used as voltage-dividing current-limiting resistors of a U1 internal light-emitting diode. The third pin of the optocoupler U1 is connected to the base of a voltage regulator Q5 through a resistor R48, the emitter of the voltage regulator Q5 is grounded, the collector is connected to one end of a coil of the relay K1 and the anode of the diode D8, and the resistor R48 is a base bias resistor of the voltage regulator Q5. The fourth pin of the optocoupler U1 is connected with the cathode of the diode D8 and the other end of the coil of the relay K1, is connected with the fixed contact of the normally open contact of the relay K1 and is connected with the auxiliary output end OUT1, and the movable contact of the normally open contact of the relay K1 is the main circuit output end OUT 2. The diode D8 is used to free-wheel the self-emf generated at the moment of power-off in the coil of relay K1, in order to protect the regulator Q5 from breakdown due to too high self-emf. The DMS end is a main circuit output control interface, the interface needs to be connected with a high-voltage signal of the DC input, and the main circuit output is output.
The control circuit consists of a control chip IC1, an output overcurrent protection circuit, a voltage stabilizing circuit, an oscillation circuit and a pulse output circuit; the voltage stabilizing circuit comprises a voltage stabilizing diode Z2, wherein the anode of the voltage stabilizing diode Z2 is connected to the base electrode of a triode Q3 through a resistor R30, the Q3 supplies power through a resistor R9, the collector electrode of a triode Q3 is connected to the base electrode of a triode Q4, and the resistor R32 and the resistor R33 are upper and lower bias resistors of the base electrode of a triode Q4; one path of an emitter of the triode Q4 is connected with a pin 4 of the control chip IC1, one path of a connecting resistor R31 is connected with a collector of the triode Q4 after being connected in series with the CD2, one path of the emitter is connected with a pin 14 of the control chip IC1, one path of the pin 14 is connected with a pin 4 of the control chip IC1 through a resistor R24, one path of the pin is connected with an anode of the diode D1 through a resistor R12, the other path of the pin is grounded through a filter capacitor C3, and the pin 4 is grounded through a filter capacitor C9. The connection mode of the circuits is mainly used for controlling the dead-zone voltage and the pulse output duty ratio of the chip IC1, and further controlling the NMOS tube to output stable 12V voltage.
The anodes of the Schottky diodes V4 and V5 are grounded through overcurrent detection resistors KT1 and KT2, and the current limiting value of the converter can be adjusted by adjusting the resistance values of the overcurrent detection resistors KT1 and KT 2; after the other path is connected with the resistor R13 and the resistor R44 in parallel, one path is connected to a 15 th pin of the control chip IC1 and used for detecting current, and the 15 th pin is grounded through the filter capacitor C4; the other path is connected to the pin 3 of the control chip IC1 through a resistor R10 and a capacitor C5, and is used for compensating the error of the voltage comparator in the pin 15. When the load of the converter is overlarge, the voltage at two ends of the overcurrent detection resistors KT1 and KT2 is reduced, meanwhile, the potential of the 15 th pin is also reduced, and when the potential of the 15 th pin is lower than the potential of the 16 th pin connected with the ground potential, the duty ratio of output pulses is adjusted through the control chip IC1, so that the output current of the converter is reduced, the output power of the converter is further influenced, the aim of overcurrent protection is fulfilled, and the converter automatically recovers to be normal after the fault is eliminated. The invention is designed to reduce the output power of the converter, and mainly ensures the running safety of the vehicle.
One path of the other end of the energy storage inductor L1 is connected in series with a resistor R16 through a resistor R15 and then is connected to a1 st pin of a control chip IC1, and the energy storage inductor L1 is used for detecting voltage and stabilizing the output voltage of the converter; the resistor R5 and the resistor R6 are output voltage sampling resistors. The capacitor C6 and the resistor R14 form a filter circuit of the voltage comparator in the 1 st pin, so that the anti-interference performance of the voltage comparator is improved, and the stability of the output voltage of the converter is further improved; the other path is connected to the 14 th pin of the control chip IC1 through a resistor R17, a diode D1 and a resistor R12, and is connected to the 4 th pin of the control chip IC1 through a resistor R18, a diode D2 and a diode Z3; the potential of the No. 2 pin of the control chip IC1 is divided by the +5V reference voltage output by the No. 14 pin of the control chip through a resistor R23 and then connected to the No. 2 pin; the coupling capacitor C11 and the coupling capacitor C10 are respectively connected between pins 1 and 2 and pins 2 and 3 of the control chip IC 1; when the output voltage of the converter is higher for some reason but does not exceed the output overvoltage protection voltage, the voltage detected by the 1 st pin is compared with the potential of the 2 nd pin, the voltage of the 1 st pin is higher than the potential of the 2 nd pin, and the duty ratio of output pulses is adjusted and reduced through the inside of the control chip IC1, so that the output voltage of the converter is reduced; conversely, the duty ratio of the output pulse is increased, so that the output voltage of the converter is increased; thereby achieving the purpose of stabilizing the output voltage of the converter.
The oscillating circuit consists of a resistor C8 and a capacitor R20 and is connected with pins 5 and 6 of a control chip IC 1;
the 9 th pin and the 10 th pin of the control chip IC1 output pulses in a parallel output mode, the 13 th pin pulse output mode of the control chip IC1 is set at the end and grounded, and the output pulses are connected with the gates of NMOS tubes V2 and V3 to drive the NMOS tubes to work through a triode Q2, a diode D7, a resistor R19, a capacitor C7 and a coupling transformer T1 through a capacitor C12 and a resistor R25 and a resistor R26 in one path; when the NMOS tubes V2 and V3 are conducted, the output current is filtered by the filter capacitors CD7 and CD8 to supply power to a load; when the NMOS transistors V2 and V3 are turned off, the energy storage inductor L1 forms an energy storage circuit to convert magnetic energy into electric energy, the polarity of the electric energy is negative on the left and positive on the right, and the schottky diodes V4 and V5 are turned on to form a freewheeling circuit to continue to supply power to the load, so that the load obtains smooth direct current; when the output voltage is higher than the set maximum allowable output voltage, the transient suppression diodes D5 and D6 break down reversely to form an output overvoltage protection circuit; the output voltage of the converter is almost zero, so that the load is protected from being damaged. The other path of connecting resistor R27 is connected with the diode Z1 in parallel and then is connected with the resistor R28, and the main function of the resistor R28 is to protect the grid electrode of the NMOS tube, so that the NMOS tube is protected from being damaged. The pulse supplies power to a transistor Q2 through rectification of a diode D7, and a resistor R19 is a base bias resistor of Q2.
The NMOS tube, the input power supply filter capacitor, the output power supply filter capacitor and the Schottky diode are connected into the circuit in at least two parallel connection modes.
The relay K1 is a 4120 type 40A14VDC relay, the coil voltage is 12VDC, American standard, and a group of normally open contacts. The specific models are as follows: 4120-1A-12 DU.
The energy storage inductor L1 is a ring inductor.
The coupling transformer T1 is a toroidal transformer.
The model of the control chip IC1 is TL494I industrial grade chip.
The control chip IC1 is provided with sixteen pins including a1 st pin V1 (+), a 2 nd pin V1 (-), a 3 rd pin VOUTC, a 4 th pin CONT, a 5 th pin CT, a 6 th pin RT, a 7 th pin GND, an 8 th pin CA, a 9 th pin EA, a 10 th pin EB, an 11 th pin CB, a 12 th pin VCC, a 13 th pin OUT CON, a14 th pin +5V, a 15 th pin V2 (1), and a 16 th pin V2 (+).
The invention has the beneficial effects that: the invention adopts the relay as the core component of the main circuit output, fundamentally solves various defects of the traditional method of using the MOS tube to make the main circuit output, and greatly improves the technical problems that the double-output converter is easy to damage and has insufficient instantaneous power. The relay driving circuit is simple, stable and reliable, the contact capacity is large, and the impact of large current can be borne. The traditional MOS tube main circuit output mode is complex in driving circuit and high in failure rate, the MOS tube is easily interfered by other circuits, and the impact resistance of large current is poor.
Drawings
Fig. 1 is a schematic circuit diagram of the present invention.
Detailed Description
A novel high-power non-isolated double-output DC-DC converter comprises a DC/DC main circuit capable of outputting 12V low voltage, and a control circuit connected in the main circuit and used for input reverse connection protection, input/output overvoltage protection, output overcurrent protection and output short circuit protection;
the main circuit comprises a DC input, a DC control circuit, a DC auxiliary output and a DC main circuit output, and the DC input and the DC output are both connected with a filter element; one path of the input power supply is connected with a power supply circuit of the control chip, is connected with a resistor R6 in parallel through a resistor R5, is connected with a resistor R3 in parallel and is connected with a resistor R4 in parallel, and is connected with a switching triode V1 to supply power to pins 8, 11 and 12 of the control chip IC 1; the combined action of the resistor R1, the resistor R2, the resistor R78, the capacitor C1 and the voltage stabilizer Q1 provides a stable voltage input signal for the V1, ensures that the V1 stably works in a saturation state, does not influence the working state of the V1 due to the change of the voltage of the storage battery pack, and provides a stable working voltage for the control chip IC1 under the combined action of the filtering of the capacitor C2 and the CD1 and the voltage stabilizing circuit consisting of the resistor R29 and the voltage stabilizing diode Z2; the other path is connected to the drains of NMOS tubes V2 and V3, the cathodes of filter capacitors CD3, CD4, CD5 and CD6 and the cathodes of transient suppression diodes D3 and D4; d3, D4 act as input reverse-connect protection and input overpressure protection. And the anodes of the filter capacitors CD3, CD4, CD5 and CD6 and the drain of the NMOS tube are all connected with the anode of the input power supply.
The DC auxiliary output circuit is formed by connecting the source electrode of an NMOS (N-channel metal oxide semiconductor) tube with an energy storage inductor L1 and the cathodes of Schottky diodes V4 and V5, and is grounded through a capacitor C13 after being connected with a resistor R34 and a resistor R35 in parallel and then being connected with a resistor R36 and a resistor R37 in parallel; the other end of the energy storage inductor L1 is connected with the anodes of the output filter capacitors CD7 and CD8, and is connected with a resistor R38 and a resistor R39 in parallel, and then is connected with a series resistor R40 and a resistor R41 in parallel and then is grounded; the cathodes of the transient suppression diode D5 and the diode D6 are connected; the transient suppression diodes D5, D6 act as output overvoltage protection. The OUT1 terminal is an auxiliary DC output terminal, which has an output as long as the DC input terminal is connected to the battery pack.
The DC main circuit output circuit comprises an optocoupler U1, a resistor R45 and a resistor R46 are connected in series with a first pin of the optocoupler U1, a second pin of the optocoupler U1 is grounded through a resistor R47, and the resistors R45, R46 and R47 are used as voltage-dividing current-limiting resistors of a U1 internal light-emitting diode. The third pin of the optocoupler U1 is connected to the base of a voltage regulator Q5 through a resistor R48, the emitter of the voltage regulator Q5 is grounded, the collector is connected to one end of a coil of the relay K1 and the anode of the diode D8, and the resistor R48 is a base bias resistor of the voltage regulator Q5. The fourth pin of the optocoupler U1 is connected with the cathode of the diode D8 and the other end of the coil of the relay K1, is connected with the fixed contact of the normally open contact of the relay K1 and is connected with the auxiliary output end OUT1, and the movable contact of the normally open contact of the relay K1 is the main circuit output end OUT 2. The diode D8 is used to free-wheel the self-emf generated at the moment of power-off in the coil of relay K1, in order to protect the regulator Q5 from breakdown due to too high self-emf. The DMS end is a main circuit output control interface, the interface needs to be connected with a high-voltage signal of the DC input, and the main circuit output is output.
The control circuit consists of a control chip IC1, an output overcurrent protection circuit, a voltage stabilizing circuit, an oscillation circuit and a pulse output circuit; the voltage stabilizing circuit comprises a voltage stabilizing diode Z2, wherein the anode of the voltage stabilizing diode Z2 is connected to the base electrode of a triode Q3 through a resistor R30, the Q3 supplies power through a resistor R9, the collector electrode of a triode Q3 is connected to the base electrode of a triode Q4, and the resistor R32 and the resistor R33 are upper and lower bias resistors of the base electrode of a triode Q4; one path of an emitter of the triode Q4 is connected with a pin 4 of the control chip IC1, one path of a connecting resistor R31 is connected with a collector of the triode Q4 after being connected in series with the CD2, one path of the emitter is connected with a pin 14 of the control chip IC1, one path of the pin 14 is connected with a pin 4 of the control chip IC1 through a resistor R24, one path of the pin is connected with an anode of the diode D1 through a resistor R12, the other path of the pin is grounded through a filter capacitor C3, and the pin 4 is grounded through a filter capacitor C9. The connection mode of the circuits is mainly used for controlling the dead-zone voltage and the pulse output duty ratio of the chip IC1, and further controlling the NMOS tube to output stable 12V voltage.
The anodes of the Schottky diodes V4 and V5 are grounded through overcurrent detection resistors KT1 and KT2, and the current limiting value of the converter can be adjusted by adjusting the resistance values of the overcurrent detection resistors KT1 and KT 2; after the other path is connected with the resistor R13 and the resistor R44 in parallel, one path is connected to a 15 th pin of the control chip IC1 and used for detecting current, and the 15 th pin is grounded through the filter capacitor C4; the other path is connected to the pin 3 of the control chip IC1 through a resistor R10 and a capacitor C5, and is used for compensating the error of the voltage comparator in the pin 15. When the load of the converter is overlarge, the voltage at two ends of the overcurrent detection resistors KT1 and KT2 is reduced, meanwhile, the potential of the 15 th pin is also reduced, and when the potential of the 15 th pin is lower than the potential of the 16 th pin connected with the ground potential, the duty ratio of output pulses is adjusted through the control chip IC1, so that the output current of the converter is reduced, the output power of the converter is further influenced, the aim of overcurrent protection is fulfilled, and the converter automatically recovers to be normal after the fault is eliminated. The invention is designed to reduce the output power of the converter, and mainly ensures the running safety of the vehicle.
One path of the other end of the energy storage inductor L1 is connected in series with a resistor R16 through a resistor R15 and then is connected to a1 st pin of a control chip IC1, and the energy storage inductor L1 is used for detecting voltage and stabilizing the output voltage of the converter; the resistor R5 and the resistor R6 are output voltage sampling resistors. The capacitor C6 and the resistor R14 form a filter circuit of the voltage comparator in the 1 st pin, so that the anti-interference performance of the voltage comparator is improved, and the stability of the output voltage of the converter is further improved; the other path is connected to the 14 th pin of the control chip IC1 through a resistor R17, a diode D1 and a resistor R12, and is connected to the 4 th pin of the control chip IC1 through a resistor R18, a diode D2 and a diode Z3; the potential of the No. 2 pin of the control chip IC1 is divided by the +5V reference voltage output by the No. 14 pin of the control chip through a resistor R23 and then connected to the No. 2 pin; the coupling capacitor C11 and the coupling capacitor C10 are respectively connected between pins 1 and 2 and pins 2 and 3 of the control chip IC 1; when the output voltage of the converter is higher for some reason but does not exceed the output overvoltage protection voltage, the voltage detected by the 1 st pin is compared with the potential of the 2 nd pin, the voltage of the 1 st pin is higher than the potential of the 2 nd pin, and the duty ratio of output pulses is adjusted and reduced through the inside of the control chip IC1, so that the output voltage of the converter is reduced; conversely, the duty ratio of the output pulse is increased, so that the output voltage of the converter is increased; thereby achieving the purpose of stabilizing the output voltage of the converter.
The oscillating circuit consists of a resistor C8 and a capacitor R20 and is connected with pins 5 and 6 of a control chip IC 1;
the 9 th pin and the 10 th pin of the control chip IC1 output pulses in a parallel output mode, the 13 th pin pulse output mode of the control chip IC1 is set at the end and grounded, and the output pulses are connected with the gates of NMOS tubes V2 and V3 to drive the NMOS tubes to work through a triode Q2, a diode D7, a resistor R19, a capacitor C7 and a coupling transformer T1 through a capacitor C12 and a resistor R25 and a resistor R26 in one path; when the NMOS tubes V2 and V3 are conducted, the output current is filtered by the filter capacitors CD7 and CD8 to supply power to a load; when the NMOS transistors V2 and V3 are turned off, the energy storage inductor L1 forms an energy storage circuit to convert magnetic energy into electric energy, the polarity of the electric energy is negative on the left and positive on the right, and the schottky diodes V4 and V5 are turned on to form a freewheeling circuit to continue to supply power to the load, so that the load obtains smooth direct current; when the output voltage is higher than the set maximum allowable output voltage, the transient suppression diodes D5 and D6 break down reversely to form an output overvoltage protection circuit; the output voltage of the converter is almost zero, so that the load is protected from being damaged. The other path of connecting resistor R27 is connected with the diode Z1 in parallel and then is connected with the resistor R28, and the main function of the resistor R28 is to protect the grid electrode of the NMOS tube, so that the NMOS tube is protected from being damaged. The pulse supplies power to a transistor Q2 through rectification of a diode D7, and a resistor R19 is a base bias resistor of Q2.
The NMOS tube, the input power supply filter capacitor, the output power supply filter capacitor and the Schottky diode are connected into the circuit in at least two parallel connection modes.
The relay K1 is a 4120 type 40A14VDC relay, the coil voltage is 12VDC, American standard, and a group of normally open contacts. The specific models are as follows: 4120-1A-12 DU.
The energy storage inductor L1 is a ring inductor.
The coupling transformer T1 is a toroidal transformer.
The model of the control chip IC1 is TL494I industrial grade chip.
The control chip IC1 is provided with sixteen pins including a1 st pin V1 (+), a 2 nd pin V1 (-), a 3 rd pin VOUTC, a 4 th pin CONT, a 5 th pin CT, a 6 th pin RT, a 7 th pin GND, an 8 th pin CA, a 9 th pin EA, a 10 th pin EB, an 11 th pin CB, a 12 th pin VCC, a 13 th pin OUT CON, a14 th pin +5V, a 15 th pin V2 (1), and a 16 th pin V2 (+).

Claims (7)

1. A novel high-power non-isolated double-output DC-DC converter is characterized by comprising a DC/DC main circuit capable of outputting 12V low voltage and a control circuit connected in the main circuit and used for input reverse connection protection, input/output overvoltage protection, output overcurrent protection and output short circuit protection;
the main circuit comprises a DC input, a DC control circuit, a DC auxiliary output and a DC main circuit output, and the DC input and the DC output are both connected with a filter element; one path of the input power supply is connected with a power supply circuit of the control chip, is connected with a resistor R6 in parallel through a resistor R5, is connected with a resistor R3 in parallel and is connected with a resistor R4 in parallel, and is connected with a switching triode V1 to supply power to pins 8, 11 and 12 of the control chip IC 1; the combined action of the resistor R1, the resistor R2, the resistor R78, the capacitor C1 and the voltage stabilizer Q1 provides a stable voltage input signal for the V1, ensures that the V1 stably works in a saturation state, does not influence the working state of the V1 due to the change of the voltage of the storage battery pack, and provides a stable working voltage for the control chip IC1 under the combined action of the filtering of the capacitor C2 and the CD1 and the voltage stabilizing circuit consisting of the resistor R29 and the voltage stabilizing diode Z2; the other path is connected to the drains of NMOS tubes V2 and V3, the cathodes of filter capacitors CD3, CD4, CD5 and CD6 and the cathodes of transient suppression diodes D3 and D4; d3 and D4 play roles of input reverse connection protection and input overpressure protection; the anodes of the filter capacitors CD3, CD4, CD5 and CD6 and the drain of the NMOS tube are all connected with the anode of the input power supply;
the DC auxiliary output circuit is formed by connecting the source electrode of an NMOS (N-channel metal oxide semiconductor) tube with an energy storage inductor L1 and the cathodes of Schottky diodes V4 and V5, and is grounded through a capacitor C13 after being connected with a resistor R34 and a resistor R35 in parallel and then being connected with a resistor R36 and a resistor R37 in parallel; the other end of the energy storage inductor L1 is connected with the anodes of the output filter capacitors CD7 and CD8, and is connected with a resistor R38 and a resistor R39 in parallel, and then is connected with a series resistor R40 and a resistor R41 in parallel and then is grounded; the cathodes of the transient suppression diode D5 and the diode D6 are connected; the transient suppression diodes D5 and D6 play a role in output overvoltage protection; the OUT1 end is an auxiliary DC output end, and the port can output as long as the DC input end is connected with a storage battery pack;
the DC main circuit output circuit comprises an optocoupler U1, a resistor R45 and a resistor R46 are connected in series with a first pin of the optocoupler U1, a second pin of the optocoupler U1 is grounded through a resistor R47, and the optocouplers of the resistor R45, the resistor R46 and the resistor R47 are used as voltage-dividing and current-limiting resistors of a light-emitting diode in the U1; a third pin of the optocoupler U1 is connected with a base electrode of a voltage stabilizer Q5 through a resistor R48, an emitter electrode of the voltage stabilizer Q5 is grounded, a collector electrode is connected with one end of a coil of the relay K1 and is connected with an anode of a diode D8, and a resistor R48 is a base electrode bias resistor of the voltage stabilizer Q5; a fourth pin of the optocoupler U1 is connected with a cathode of the diode D8 and the other end of the coil of the relay K1, is connected with a fixed contact of a normally open contact of the relay K1 and is also connected with an auxiliary output end OUT1, and a movable contact of the normally open contact of the relay K1 is a main circuit output end OUT 2; the diode D8 is used for freewheeling by the self-induced electromotive force generated at the moment of power failure of the coil of the relay K1, so as to protect the voltage regulator Q5 from being broken down by the excessively high self-induced electromotive force; the DMS end is a main circuit output control interface which needs to be accessed with a high-voltage signal of DC input, and the main circuit output is output;
the control circuit consists of a control chip IC1, an output overcurrent protection circuit, a voltage stabilizing circuit, an oscillation circuit and a pulse output circuit; the voltage stabilizing circuit comprises a voltage stabilizing diode Z2, wherein the anode of the voltage stabilizing diode Z2 is connected to the base electrode of a triode Q3 through a resistor R30, the Q3 supplies power through a resistor R9, the collector electrode of a triode Q3 is connected to the base electrode of a triode Q4, and the resistor R32 and the resistor R33 are upper and lower bias resistors of the base electrode of a triode Q4; one path of an emitter of the triode Q4 is connected with a pin 4 of the control chip IC1, one path of a connecting resistor R31 is connected with a collector of the triode Q4 after being connected in series with the CD2, one path of the emitter is connected with a pin 14 of the control chip IC1, one path of the pin 14 is connected with a pin 4 of the control chip IC1 through a resistor R24, one path of the pin is connected with an anode of a diode D1 through a resistor R12, the other path of the pin is grounded through a filter capacitor C3, and the pin 4 is grounded through a filter capacitor C9; the connection mode of the circuits is mainly used for controlling the dead-zone voltage and the pulse output duty ratio of the chip IC1 and further controlling the NMOS tube to output stable 12V voltage;
the anodes of the Schottky diodes V4 and V5 are grounded through overcurrent detection resistors KT1 and KT2, and the current limiting value of the converter can be adjusted by adjusting the resistance values of the overcurrent detection resistors KT1 and KT 2; after the other path is connected with the resistor R13 and the resistor R44 in parallel, one path is connected to a 15 th pin of the control chip IC1 and used for detecting current, and the 15 th pin is grounded through the filter capacitor C4; the other path is connected to a pin 3 of the control chip IC1 through a resistor R10 and a capacitor C5 and is used for compensating the error of a voltage comparator in the pin 15; when the load of the converter is overlarge, the voltage at two ends of the overcurrent detection resistors KT1 and KT2 is reduced, meanwhile, the potential of the 15 th pin is also reduced, and when the potential of the 15 th pin is lower than the potential of the 16 th pin connected with the ground potential, the duty ratio of output pulses is adjusted through the control chip IC1, so that the output current of the converter is reduced, the output power of the converter is further influenced, the aim of overcurrent protection is fulfilled, and the converter automatically recovers to be normal after the fault is eliminated;
one path of the other end of the energy storage inductor L1 is connected in series with a resistor R16 through a resistor R15 and then is connected to a1 st pin of a control chip IC1, and the energy storage inductor L1 is used for detecting voltage and stabilizing the output voltage of the converter; the resistor R5 and the resistor R6 are output voltage sampling resistors; the capacitor C6 and the resistor R14 form a filter circuit of the voltage comparator in the 1 st pin, so that the anti-interference performance of the voltage comparator is improved, and the stability of the output voltage of the converter is further improved; the other path is connected to the 14 th pin of the control chip IC1 through a resistor R17, a diode D1 and a resistor R12, and is connected to the 4 th pin of the control chip IC1 through a resistor R18, a diode D2 and a diode Z3; the potential of the No. 2 pin of the control chip IC1 is divided by the +5V reference voltage output by the No. 14 pin of the control chip through a resistor R23 and then connected to the No. 2 pin; the coupling capacitor C11 and the coupling capacitor C10 are respectively connected between pins 1 and 2 and pins 2 and 3 of the control chip IC 1; when the output voltage of the converter is higher for some reason but does not exceed the output overvoltage protection voltage, the voltage detected by the 1 st pin is compared with the potential of the 2 nd pin, the voltage of the 1 st pin is higher than the potential of the 2 nd pin, and the duty ratio of output pulses is adjusted and reduced through the inside of the control chip IC1, so that the output voltage of the converter is reduced; conversely, the duty ratio of the output pulse is increased, so that the output voltage of the converter is increased; thereby achieving the purpose of stabilizing the output voltage of the converter;
the oscillating circuit consists of a resistor C8 and a capacitor R20 and is connected with pins 5 and 6 of a control chip IC 1;
the 9 th pin and the 10 th pin of the control chip IC1 output pulses in a parallel output mode, the 13 th pin pulse output mode of the control chip IC1 is set at the end, grounded and passes through a triode Q2, a diode D7, a resistor R19, a capacitor C7 and a coupling transformer T1; after passing through the capacitor C12, one path of the voltage is connected with the grid electrodes of the NMOS tubes V2 and V3 through the resistor R25 and the resistor R26 to drive the NMOS tubes to work; when the NMOS tubes V2 and V3 are conducted, the output current is filtered by the filter capacitors CD7 and CD8 to supply power to a load; when the NMOS transistors V2 and V3 are turned off, the energy storage inductor L1 forms an energy storage circuit to convert magnetic energy into electric energy, the polarity of the electric energy is negative on the left and positive on the right, and the schottky diodes V4 and V5 are turned on to form a freewheeling circuit to continue to supply power to the load, so that the load obtains smooth direct current; when the output voltage is higher than the set maximum allowable output voltage, the transient suppression diodes D5 and D6 break down reversely to form an output overvoltage protection circuit; the output voltage of the converter is almost zero, so that the load is protected from being damaged; the other path of connecting resistor R27 is connected with a diode Z1 in parallel and then is connected with a resistor R28, and the main function of the resistor R28 is to protect the grid electrode of the NMOS tube so as to protect the NMOS tube from being damaged; the pulse supplies power to a transistor Q2 through rectification of a diode D7, and a resistor R19 is a base bias resistor of Q2.
2. The novel high-power non-isolated dual-output DC-DC converter according to claim 1, wherein the NMOS transistor, the input power filter capacitor, the output power filter capacitor, and the Schottky diode are connected to the circuit in at least two parallel ways.
3. The novel high-power non-isolated two-way output DC-DC converter as claimed in claim 1, wherein the relay K1 is a 4120 type 40A14VDC relay with a 12VDC coil voltage, American standard, having a set of normally open contacts; the specific models are as follows: 4120-1A-12 DU.
4. The novel high-power non-isolated two-way output DC-DC converter according to claim 1, wherein the energy storage inductor L1 is a ring inductor.
5. The novel high-power non-isolated two-way output DC-DC converter according to claim 1, wherein the coupling transformer T1 is a toroidal transformer.
6. The novel high-power non-isolated two-way output DC-DC converter as claimed in claim 1, wherein the type of the control chip IC1 is TL494I technical grade chip.
7. The novel high-power non-isolated dual-output DC-DC converter according to claim 1, wherein the control chip IC1 has sixteen pins including a1 st pin V1 (+), a 2 nd pin V1 (-), a 3 rd pin VOUTC, a 4 th pin CONT, a 5 th pin CT, a 6 th pin RT, a 7 th pin GND, an 8 th pin CA, a 9 th pin EA, a 10 th pin EB, a 11 th pin CB, a 12 th pin VCC, a 13 th pin OUTCON, a14 th pin +5V, a 15 th pin V2 (1), a 16 th pin V2 (+).
CN202010688308.5A 2020-07-16 2020-07-16 Novel high-power non-isolated double-output DC-DC converter Pending CN111835197A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010688308.5A CN111835197A (en) 2020-07-16 2020-07-16 Novel high-power non-isolated double-output DC-DC converter

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Application Number Priority Date Filing Date Title
CN202010688308.5A CN111835197A (en) 2020-07-16 2020-07-16 Novel high-power non-isolated double-output DC-DC converter

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112224049A (en) * 2020-12-11 2021-01-15 北京理工大学深圳汽车研究院(电动车辆国家工程实验室深圳研究院) DC/DC conversion device and filtering method for hydrogen fuel cell power system
CN112542035A (en) * 2020-12-18 2021-03-23 无锡蓝天电子股份有限公司 Fire alarm device capable of automatically finishing bus voltage

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112224049A (en) * 2020-12-11 2021-01-15 北京理工大学深圳汽车研究院(电动车辆国家工程实验室深圳研究院) DC/DC conversion device and filtering method for hydrogen fuel cell power system
CN112224049B (en) * 2020-12-11 2021-03-09 北京理工大学深圳汽车研究院(电动车辆国家工程实验室深圳研究院) DC/DC conversion device and filtering method for hydrogen fuel cell power system
CN112542035A (en) * 2020-12-18 2021-03-23 无锡蓝天电子股份有限公司 Fire alarm device capable of automatically finishing bus voltage

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Application publication date: 20201027