Low-cost charging power supply circuit capable of effectively reducing relay current
By employing a high-power DC input power supply and a full-bridge converter in the charging power supply, along with a parallel branch design, large electrolytic capacitors, and microcontroller-controlled relays, the full-bridge converter is optimized, solving the problems of a large number of relays and high heat loss, thus achieving miniaturization and efficient current management of the power supply.
Patent Information
- Application Number
- CN202422838290.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-11-07
- Estimated Expiration
- 2034-11-20
AI Technical Summary
Existing technologies in high-power charging power supplies involve a large number of relays with significant heat loss, which take up space and make it difficult to effectively reduce input inrush current.
It adopts a high-power DC input power supply and a full-bridge converter, combined with a parallel first branch and a second branch design. The first branch includes a large electrolytic capacitor and a resistor to prevent starting inrush current, while the second branch includes a relay controlled by a microcontroller. The current is reduced by controlling the relay's activation, and the full-bridge converter is optimized using MOSFETs and capacitors.
It effectively reduces the number of relays and heat loss, shrinks the power supply size, increases power density, and reduces input current surges.
Smart Images
Figure CN223527815U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a low -cost effectively reduce relay current's charging power supply circuit. BACKGROUND
[0002] With new energy electric car's power battery energy density bigger and bigger, the rate density of the charging power supply equipment matched also must increase, this requires that switching power supply very high efficiency transmits greater power. At the same time, since the power supply equipment occupies the whole closed space and cannot be too large, this makes the power supply output greater power at the same time, the overall volume cannot be too large, and even needs to be reduced. When charging the power battery, the current fed back to the input line is very large, and the current can be dozens of amperes or even hundreds of amperes. In the traditional line transmission of switching power supply, a power resistor and a relay are usually directly connected in series on the input line to slow down the instantaneous start-up current. SUMMARY
[0003] The utility model discloses to the defect that the present high -power density power supply design technology exists, in order to reduce the relay quantity on the line, reduce input line loss, and effectively reduce input impact current, and a low -cost effectively reduce relay current's charging power supply circuit is provided.
[0004] The utility model discloses a low -cost effectively reduce relay current's charging power supply circuit, including high -power direct current input power supply and high -power full -bridge converter, singlechip control circuit, the singlechip control circuit generates control signal and connects the gate of each switch tube in high -power full -bridge converter, and high -power direct current input power supply output passes through high -power full -bridge converter and receives the electric automobile of charging, and includes the first branch and the second branch of parallel connection between high -power direct current input power supply output and high -power full -bridge converter.
[0005] The large electrolytic capacitor device is arranged on the first branch, and the anode of the large electrolytic capacitor device is connected in series with the anti-starting impact current resistor device and then connected to the output end of the high -power direct current input power supply and the input end of the high -power full -bridge converter.
[0006] The relay controlled by the singlechip control circuit is arranged on the second branch, and the two ends of the relay are connected to the output end of the high -power direct current input power supply and the input end of the high -power full -bridge converter.
[0007] Further, in the low -cost effectively reduce relay current's charging power supply circuit, the anti-starting impact current resistor device includes at least two power wire winding resistors in parallel.
[0008] Further, in the low-cost charging power supply circuit for effectively reducing the current of a relay, the circuit for driving the relay to attract further comprises a 12V DC power supply, an output end of the 12V DC power supply being connected to one end of the winding of the relay, and the other end of the winding of the relay being connected to the ground through an electronic switch controlled by the single-chip microcomputer.
[0009] Further, in the low-cost charging power supply circuit for effectively reducing the current of a relay, the electronic switch controlled by the single-chip microcomputer control circuit is a triode Q1, and the low-cost charging power supply circuit further comprises a resistor R4, a resistor R5 and a capacitor C11; the collector and the emitter of the triode Q1 are connected to the other end of the winding of the relay and the ground respectively, the control signal end generated by the single-chip microcomputer control circuit is connected to the base of the triode Q1 through the current-limiting resistor R4, the resistor R5 is arranged between the base and the emitter of the triode Q1, and the capacitor C11 is arranged between the control signal end generated by the single-chip microcomputer control circuit and the ground.
[0010] Further, in the low-cost charging power supply circuit for effectively reducing the current of a relay, the circuit for driving the relay to attract further comprises a diode D2, a resistor R3 and an electrolytic capacitor E11; the diode D2 is arranged at the two ends of the winding of the relay, the anode of the diode D2 being connected to the wire connecting the collector of the triode Q1 and the winding of the relay, the resistor R3 is arranged between the output end of the 12V DC power supply and the cathode of the diode D2, the anode of the electrolytic capacitor E11 being connected to the output end of the 12V DC power supply, and the cathode of the electrolytic capacitor E11 being connected to the winding of the relay.
[0011] Further, in the low-cost charging power supply circuit for effectively reducing the current of a relay, the large electrolytic capacitor element comprises at least two parallel-connected aluminum electrolytic capacitors.
[0012] Further, in the low-cost charging power supply circuit for effectively reducing the current of a relay, each arm of the large power full-bridge converter comprises at least two parallel-connected electronic switches controlled by the single-chip microcomputer control circuit.
[0013] Further, in the low-cost charging power supply circuit for effectively reducing the current of a relay, each arm of the large power full-bridge converter comprises a first MOS tube and a second MOS tube; the source of the first MOS tube is connected to the source of the second MOS tube, the drain of the first MOS tube is connected to the drain of the second MOS tube, the gate of the first MOS tube is connected to the output end of the single-chip microcomputer control circuit for generating a control signal of the arm, and the gate of the second MOS tube is connected to the drain of the first MOS tube through a current-limiting resistor; a capacitor is arranged between the source and the drain of the second MOS tube.
[0014] In this invention, a resistor element for preventing starting surge current is provided between the large electrolytic capacitor and the power output terminal. When charging the electric car wash, the resistor element for preventing starting surge current is bypassed due to the relay closing, thus reducing heat generation.
[0015] In this invention, a power wire-wound resistor and a relay are connected in parallel to the input main line and the positive terminal of the electrolytic capacitor. The current borne by the relay is only the effective ripple current of the electrolytic capacitor, and its current value is generally only half that of the main line. In high-power line transmission, the number of relays is effectively reduced, and the heat loss on the line is reduced, further reducing the overall size and achieving the purpose of increasing power density.
[0016] The present invention will be described in more detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0017] Appendix Figure 1 This is a schematic diagram of the charging power supply circuit of Embodiment 1 of this utility model;
[0018] Appendix Figure 2 This is a schematic diagram of the relay drive circuit of Embodiment 1 of this utility model;
[0019] Appendix Figure 3 This is a schematic diagram of the charging power supply circuit of Embodiment 2 of this utility model;
[0020] Appendix Figure 4 This is a block diagram of the overall circuit of the charging device. Detailed Implementation
[0021] Example 1 illustrates a low-cost charging circuit that effectively reduces relay current. This charging power supply circuit is used for charging electric vehicles. Typically, electric vehicle charging stations have numerous charging devices, also known as charging piles. Each charging pile has a large, high-power switching power supply that converts 220VAC to DC, referred to as a high-power DC input power supply. In this example, the switching power supply converts 220VAC to 100VDC, also referred to as 100VDC power. Inside the charging pile, to ensure power supply for its electronic components, there is an auxiliary VCC power supply component. This auxiliary VCC power supply component converts the 100VDC to various power supplies such as +5V, +12V, and -12V required by electronic components like microcontrollers and relays. In practice, a single switching power supply can also be used to directly convert 220VAC to these various DC power supplies for microcontrollers, relays, etc.
[0022] like Figure 1 and Figure 4As shown, the low-cost charging power supply circuit of the embodiment effectively reduces the relay current, comprising a 100VDC high-power DC input power supply and a high-power full-bridge converter, a single-chip microcomputer control circuit; the single-chip microcomputer control circuit generates a control signal to the gate of each switch tube in the high-power full-bridge converter, and the output of the high-power DC input power supply is connected to the electric vehicle to be charged through the high-power full-bridge converter; a first branch and a second branch are connected in parallel between the output end of the high-power DC input power supply and the high-power full-bridge converter.
[0023] The first branch is between the output end of the 100VDC high-power DC input power supply and the input end (input bus) of the high-power full-bridge converter, and a large electrolytic capacitor device is arranged on the branch, the anode of the large electrolytic capacitor device is connected in series with a starting impact current resistance device, and then connected to the output end of the high-power DC input power supply and the input end of the high-power full-bridge converter; the starting impact current resistance device comprises at least two power wire-wound resistors connected in parallel, and the starting impact current resistance device comprises one or more power wire-wound resistors connected in parallel. The power wire-wound resistor must be a high-pulse resistor, which is connected between the input main circuit and the positive electrode of the large electrolytic capacitor, and its main purpose is to charge the electrolytic capacitor and provide sufficient energy for the power transmission in the later stage. The resistance value can be selected according to the size of the input impact current to adjust the specific charging time, so that the current rises slowly and linearly, reduces the instantaneous current impact on the input port, and prolongs the service life of the input device. In addition, in other embodiments, the starting impact current resistance device is also arranged between the positive electrode of the large electrolytic capacitor and the input end (input bus) of the high-power full-bridge converter in the first branch, as shown in Figure 3 .
[0024] Here, the large electrolytic capacitor device is composed of 10 aluminum electrolytic capacitors E1, E2…E10 connected in parallel, the electrolytic capacitors are fully charged through the power wire-wound resistor, and after the relay is attracted, the single-chip microcomputer controls the power transmission of the later-stage full-bridge power conversion circuit to transfer energy to the load end.
[0025] A relay controlled by the single-chip microcomputer control circuit is arranged on the second branch, as shown in Figure 1 , 3 The branch starts from the output end of the 100VDC power supply, passes through the two ends of the relay, and is connected to the bus of the charger at K of Figure 1 , and the two ends of the relay are connected to the output end of the high-power DC input power supply and the input end of the high-power full-bridge converter, respectively. The circuit for driving the relay to be attracted is as follows Figure 2As shown, including 12VDC power supply, 12VDC power output end of the relay winding one end, the other end of the relay winding through the electronic switch controlled by a single-chip microcomputer ground. Single-chip microcomputer control circuit controlled electronic switch for triode Q1, also includes resistance R4 and resistance R5, capacitor C11; triode Q1 collector and emitter are connected to the other end of the relay winding and ground, the single-chip microcomputer control circuit generates control signal end through the current limiting resistor R4 triode Q1 base; resistance R5 is set between the base and emitter of triode Q1, capacitor C11 is set between the single-chip microcomputer control circuit generates control signal end and ground. Drive relay circuit also includes diode D2, resistor R3 and electrolytic capacitor E11; diode D2 is set in the two ends of the relay winding, anode connected to the collector of triode Q1 and the wire connected to the relay winding, resistance R3 is set between the 12VDC power output end and the cathode of diode D2, the anode of electrolytic power E11 is connected to the 12VDC power output end, the cathode is connected to the relay winding. In this embodiment, the resistance, capacitance, triode together constitute the drive circuit of the relay, provide the required operating current of the relay, so that it can be reliably attracted; diode is connected in parallel with the relay, so that its internal coil demagnetization, inhibit the electric spark on the contact, improve the service life of the relay.
[0026] The relay part of the embodiment includes one or more relays. The relay is connected in parallel with the input main line and the positive electrode of the large electrolytic capacitor. When the electrolytic capacitor at the input end is fully charged through the power winding resistor, the single-chip microcomputer controls the drive circuit to attract the relay. At this time, the power winding resistor has been short-circuited, connecting the main line and the positive electrode of the electrolytic capacitor. The main line, the positive electrode of the electrolytic capacitor, and the positive terminal of the full-bridge converter at the back end are connected together, providing the required low-noise, stable energy for the output load. During this period, the effective current of the relay is very small relative to the current on the main line, only about half of the current on the main line. The loss is reduced by half compared to the conventional relay circuit connection method, and the required number can also be reduced.
[0027] As shown in Figure 1 and Figure 3 Each arm of the high-power full-bridge converter includes at least two parallel electronic switches controlled by a single-chip microcomputer control circuit.
[0028] In this embodiment, each arm of the high-power full-bridge converter includes a first MOS tube and a second MOS tube. The source of the first MOS tube is connected to the source of the second MOS tube, and the drain of the first MOS tube is connected to the drain of the second MOS tube. The gate of the first MOS tube is connected to the output terminal of the single-chip microcomputer control circuit that generates the control signal for the arm. The gate of the second MOS tube is connected to the drain of the first MOS tube through a current limiting resistor. A capacitor is set between the source and drain of the second MOS tube.
[0029] In this embodiment, the high-power full-bridge converter section includes eight transistors (or more) and two transformers. Once the input electrolytic capacitor is fully charged, the microcontroller controls the appropriate activation of the subsequent high-power full-bridge circuit to achieve stable operation with minimal input current surges. The secondary windings of the two transformers are connected to the charging circuit of the electric vehicle.
[0030] In this embodiment, a relay is placed in series on the branch of the electrolytic capacitor. This ensures that the current passing through the relay is only half of the effective current on the electrolytic capacitor, which is about half the size of the current in the main circuit. This greatly reduces the current flowing through the relay. In the use of high-power power supply products, this has great advantages in reducing heat loss and increasing power density. For the entire power supply product, its size and weight are also greatly reduced.
[0031] The charging circuit operation process in this embodiment is as follows:
[0032] The charging pile is connected to 220VAC mains power, and the switching power supply (high-power DC input power supply) works to generate 100VDC power; the electrolytic capacitors E1, E2...E10 are charged through resistors R1 and R2;
[0033] The auxiliary power supply operates to generate the DC power required by the microcontroller, relays, and other components inside the charging pile.
[0034] When the microcontroller control circuit is powered on, it detects whether an electric vehicle charging interface is inserted into the charging pile. Once an electric car wash charging interface is detected, it controls the relay to close and simultaneously generates control signals to control the opening or closing of the electronic switches of the high-power full-bridge converter to charge the electric car wash.
Claims
1. A low-cost charging power supply circuit effectively reducing the relay current, comprising a high-power DC input power supply and a high-power full-bridge converter, a single-chip microcomputer control circuit; the single-chip microcomputer control circuit generates a control signal connected to the gate of each switch tube in the high-power full-bridge converter, and the high-power DC input power supply output passes through the high-power full-bridge converter to charge an electric vehicle; characterized in that: The first branch and the second branch are connected in parallel between the output end of the high-power DC input power supply and the high-power full-bridge converter. A large electrolytic capacitor is arranged on the first branch, and the anode of the large electrolytic capacitor is connected in series with a starting current protection resistor and then connected to the output end of the high-power DC input power supply and the input end of the high-power full-bridge converter. A relay controlled by the single-chip microcomputer control circuit is arranged on the second branch, and the relay is connected to the output end of the high-power DC input power supply and the input end of the high-power full-bridge converter.
2. The low cost charge power supply circuit for effectively reducing the relay current according to claim 1, characterized by: The starting current protection resistor comprises at least two power wire-wound resistors connected in parallel.
3. The low cost charge source circuit for effectively reducing the relay current of claim 1, wherein: The circuit for driving the relay to be attracted comprises a 12VDC power supply, one end of the winding of the relay is connected to the output end of the 12VDC power supply, and the other end of the winding of the relay is connected to the ground through an electronic switch controlled by the single-chip microcomputer control circuit.
4. The low cost charge source circuit for effectively reducing the relay current of claim 3, wherein: The electronic switch controlled by the single-chip microcomputer control circuit is a transistor Q1, and the circuit further comprises a resistor R4, a resistor R5 and a capacitor C11; the collector and the emitter of the transistor Q1 are connected to the other end of the winding of the relay and the ground, respectively; the control signal end of the single-chip microcomputer control circuit is connected to the base of the transistor Q1 through the current-limiting resistor R4; the resistor R5 is arranged between the base and the emitter of the transistor Q1, and the capacitor C11 is arranged between the control signal end of the single-chip microcomputer control circuit and the ground.
5. The low cost charge source circuit for effectively reducing the relay current of claim 4, wherein: The circuit for driving the relay to be attracted further comprises a diode D2, a resistor R3 and an electrolytic capacitor E11; the diode D2 is arranged at the two ends of the winding of the relay, the anode of the diode D2 is connected to the wire connecting the collector of the transistor Q1 and the winding of the relay, the resistor R3 is arranged between the output end of the 12VDC power supply and the cathode of the diode D2, the anode of the electrolytic capacitor E11 is connected to the output end of the 12VDC power supply, and the cathode of the electrolytic capacitor E11 is connected to the winding of the relay.
6. The low cost charge source circuit for effectively reducing the relay current of claim 1, wherein: The large electrolytic capacitor comprises at least two aluminum electrolytic capacitors connected in parallel.
7. A low cost charge power supply circuit for effectively reducing the relay current according to any one of claims 1 to 6, characterized by: Each arm of the high-power full-bridge converter comprises at least two electronic switches controlled by the single-chip microcomputer control circuit connected in parallel.
8. The low cost charge source circuit for effectively reducing the relay current of claim 7, wherein: Each arm of the high-power full-bridge converter comprises a first MOS transistor and a second MOS transistor; the source of the first MOS transistor is connected to the source of the second MOS transistor, the drain of the first MOS transistor is connected to the drain of the second MOS transistor, the gate of the first MOS transistor is connected to the output end of the single-chip microcomputer control circuit for generating a signal for controlling the arm, the gate of the second MOS transistor is connected to the drain of the first MOS transistor through a current-limiting resistor, and a capacitor is arranged between the source and the drain of the second MOS transistor.