Vehicle-mounted power supply pre-charging circuit and device and vehicle

Abstract

The utility model discloses a vehicle-mounted power supply pre-charging circuit and device and a vehicle, the vehicle-mounted power supply pre-charging circuit comprises an MCU control unit, a first voltage detection unit, a second voltage detection unit, a PFC control unit, a first relay and a second relay, the first relay is connected with the first voltage detection unit and the PFC control unit, and the second relay is connected with the PFC control unit. The first relay is connected with the first voltage detection unit, the second relay is connected with the PFC control unit and the second voltage detection unit, the PFC control unit comprises a first connecting end, a second connecting end and a third connecting end, the first connecting end is connected with the first relay, and the second connecting end and the third connecting end are simultaneously connected with the second relay. The circuit is simple in design and low in cost, MCU control is convenient and reliable, the adaptive input interface is an AC / DC interface, the PFC output voltage is 800V, and stable DC voltage can be provided for DC / DC conversion of a post-stage isolation power supply.

Description

A vehicle-mounted power supply pre-charging circuit, device and vehicle Technical Field

[0001] This utility model relates to the field of power supply charging, and in particular to a vehicle power supply pre-charging circuit. Background Technology

[0002] With the rapid development of modern science and technology, the voltage of power batteries for new energy vehicles is getting higher and higher. Currently, the mainstream is the 400V platform, and it is gradually transitioning to the 800V platform. As an important energy conversion part of the new energy vehicle system, the high stability and reliability of the on-board charging power supply directly affect the performance of the entire new energy vehicle system. Especially in the field of electric vehicles, the stability of its system operation directly affects the power system of new energy vehicles.

[0003] To accommodate a shared AC / DC charging interface, the on-board charger must operate at an 800V platform. When the input interface detects DC power, the internal detection circuit disconnects the main power circuit from the DC input, failing to meet the charging requirements. Conversely, when the input interface detects AC power, the internal detection circuit connects the main power circuit to the AC input, thus fulfilling the charging requirement. Because the vehicle current is converted from AC to DC, the power factor must meet power standards. Furthermore, the on-board charger has a high output power, requiring high voltage, high current, and high power during charging. Therefore, a soft start is necessary to achieve operational status during initial startup.

[0004] Commercially available systems typically use single-phase or three-phase power input with a current-limiting resistor connected in series. The pulsating DC voltage, rectified by the internal diodes of the MOSFETs in the full-bridge PFC circuit, is then filtered by electrolytic and film capacitors to obtain a stable DC voltage. This DC voltage is sampled and detected by a voltage detection circuit. When the voltage reaches a certain value, a relay short-circuites the current-limiting resistor, allowing the single-phase or three-phase power to directly connect to the full-bridge PFC circuit, supplying power to the on-board charger and providing startup protection for the on-board charger system. However, when the on-board power input interface is adapted to use a shared AC / DC interface, it adds the input interface and internal main power input circuit switch—a relay. Simultaneously, it must also meet the on-board power supply pre-charging function, requiring two relays and a current-limiting resistor for single-phase input. This not only increases cost and size but also introduces issues such as arcing under load in case of failure. Summary of the Invention

[0005] The main purpose of this utility model is to provide a vehicle power supply pre-charging circuit, which aims to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, this utility model proposes an on-board power supply pre-charging circuit comprising an MCU control unit, a first voltage detection unit, a second voltage detection unit, a PFC control unit, a first relay, and a second relay. The first relay is connected to the first voltage detection unit and the PFC control unit, and the second relay is connected to the PFC control unit and the second voltage detection unit. The PFC control unit includes a first connection terminal, a second connection terminal, and a third connection terminal. The first connection terminal is connected to the first relay, and the second connection terminal and the third connection terminal are simultaneously connected to the second relay.

[0007] In one embodiment, the first relay includes a first normally open contact and a second normally open contact, the second relay includes a third normally open contact and a fourth normally open contact, the first normally open contact is connected to the live wire, the second normally open contact is connected to a first connection terminal of the PFC control unit, the second connection terminal of the PFC control unit is connected to the fourth normally open contact, and the third normally open contact is connected to a third connection terminal of the PFC control unit.

[0008] In one embodiment, the on-board power supply pre-charging circuit further includes a charging inductor, the two ends of which are respectively connected to the second normally open contact and the first connection terminal of the PFC control unit.

[0009] In one embodiment, the on-board power supply pre-charging circuit further includes a first electrolytic capacitor and a second electrolytic capacitor, wherein a first end of the first electrolytic capacitor is connected to a second connection end, a second end of the first electrolytic capacitor is connected to a first end of the second electrolytic capacitor, and a second end of the second electrolytic capacitor is connected to the fourth normally open contact.

[0010] In one embodiment, the on-board power supply pre-charging circuit further includes a current-limiting inductor, the first end of which is connected to the second end of the second electrolytic capacitor, and the second end of which is connected to the fourth normally open contact.

[0011] In one embodiment, the on-board power supply pre-charging circuit further includes a diode, the second terminal of the current-limiting inductor is connected to the cathode of the diode, and the anode of the diode is connected to the second voltage detection unit.

[0012] In one embodiment, a current-limiting resistor is connected in parallel across the two ends of the second relay.

[0013] In one embodiment, the PFC control unit includes a first MOS switch, a second MOS switch, a third MOS switch, and a fourth MOS switch. The first MOS switch and the third MOS switch are connected in series to form a first circuit, and the second MOS switch and the fourth MOS switch are connected in series to form a second circuit. The first circuit and the second circuit are connected in parallel. The connection point between the first MOS switch and the third MOS switch is the first connection terminal, the connection point between the first MOS switch and the second MOS switch is the second connection terminal, and the connection point between the third MOS switch and the fourth MOS switch is the third connection terminal.

[0014] In addition, this utility model also provides an on-board power pre-charging device, which includes the on-board power pre-charging circuit described above.

[0015] In addition, this utility model also provides a vehicle, which includes the on-board power pre-charging device described above.

[0016] In the technical solution of this utility model, the on-board power supply pre-charging circuit includes an MCU control unit, a first voltage detection unit, a second voltage detection unit, a PFC control unit, a first relay, and a second relay. The first relay is connected to the first voltage detection unit and the PFC control unit, and the second relay is connected to the PFC control unit and the second voltage detection unit. The PFC control unit includes a first connection terminal, a second connection terminal, and a third connection terminal. The first connection terminal is connected to the first relay, and the second connection terminal and the third connection terminal are simultaneously connected to the second relay.

[0017] In this application, the first voltage detection unit detects the input voltage and reports it to the MCU control unit. The MCU control unit controls whether the first relay is activated, and activates the second relay by connecting the second voltage detection unit and the PFC control unit. This application features a simple design, low cost, convenient and reliable MCU control, and supports both AC and DC input interfaces. The 800V PFC output voltage provides a stable DC voltage for subsequent isolated power supply DC / DC conversion. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 is a circuit diagram of the vehicle power supply pre-charging circuit according to an embodiment of the present invention.

[0020] Explanation of reference numerals: 10, MCU control unit; 20, first voltage detection unit; 30, second voltage detection unit; 40, PFC control unit; K1, first relay; K2, second relay; L1, charging inductor; L2, current limiting inductor; C1, first electrolytic capacitor; C2, second electrolytic capacitor; Q1, first MOS switch; Q2, second MOS switch; Q3, third MOS switch; Q4, fourth MOS switch; D1, diode; L, live wire; N, neutral wire.

[0021] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0024] Furthermore, in this utility model, the use of terms such as "first," "second," etc., is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0026] This utility model provides a vehicle power supply pre-charging circuit.

[0027] As shown in Figure 1, the vehicle power supply pre-charging circuit provided in this embodiment of the present invention includes an MCU control unit 10, a first voltage detection unit 20, a second voltage detection unit 30, a PFC control unit 40, a first relay K1, and a second relay K2. The first relay K1 is connected to the first voltage detection unit 20 and the PFC control unit 40, and the second relay K2 is connected to the PFC control unit 40 and the second voltage detection unit 30. The PFC control unit 40 includes a first connection terminal, a second connection terminal, and a third connection terminal. The first connection terminal is connected to the first relay K1, and the second connection terminal and the third connection terminal are simultaneously connected to the second relay K2.

[0028] In this embodiment, the first voltage detection unit 20 detects the input voltage and reports it to the MCU control unit 10. The MCU control unit 10 controls whether the first relay K1 is activated, and the MCU control unit 10 activates the second relay K2 by turning on the second voltage detection unit 30 and the PFC control unit 40. This application has a simple design, low cost, convenient and reliable MCU control, and meets the requirements of AC / DC interface for the adaptable input interface. The PFC output voltage of 800V can provide a stable DC voltage for the subsequent isolated power supply DC / DC conversion.

[0029] The first relay K1 includes a first normally open contact and a second normally open contact, and the second relay K2 includes a third normally open contact and a fourth normally open contact. The first normally open contact is connected to the live wire L, the second normally open contact is connected to the first connection terminal of the PFC control unit 40, the second connection terminal of the PFC control unit 40 is connected to the fourth normally open contact, and the third normally open contact is connected to the third connection terminal of the PFC control unit 40. The on-board power supply pre-charging circuit also includes a charging inductor L1, the two ends of which are connected to the second normally open contact and the first connection terminal of the PFC control unit 40, respectively.

[0030] The on-board power supply pre-charging circuit also includes a first electrolytic capacitor C1 and a second electrolytic capacitor C2. The first end of the first electrolytic capacitor C1 is connected to the second connection end, the second end of the first electrolytic capacitor C1 is connected to the first end of the second electrolytic capacitor C2, and the second end of the second electrolytic capacitor C2 is connected to the fourth normally open contact.

[0031] The on-board power supply pre-charging circuit also includes a current-limiting inductor L2. The first terminal of the current-limiting inductor L2 is connected to the second terminal of the second electrolytic capacitor C2, and the second terminal of the current-limiting inductor L2 is connected to the fourth normally open contact. The on-board power supply pre-charging circuit also includes a diode D1. The second terminal of the current-limiting inductor L2 is connected to the cathode of the diode D1, and the anode of the diode D1 is connected to the second voltage detection unit 30. A current-limiting resistor is connected in parallel across the two ends of the second relay K2.

[0032] The PFC control unit 40 includes a first MOS switch Q1, a second MOS switch Q2, a third MOS switch Q3, and a fourth MOS switch Q4. The first MOS switch Q1 and the third MOS switch Q3 are connected in series to form a first circuit, and the second MOS switch Q2 and the fourth MOS switch Q4 are connected in series to form a second circuit. The first circuit and the second circuit are connected in parallel. The connection point of the first MOS switch Q1 and the third MOS switch Q3 is the first connection terminal, the connection point of the first MOS switch Q1 and the second MOS switch Q2 is the second connection terminal, and the connection point of the third MOS switch Q3 and the fourth MOS switch Q4 is the third connection terminal.

[0033] In this application, the live wire L is connected to the first normally open contact of the first relay K1, the second normally open contact of the first relay K1 is connected to pin 1 of the charging inductor L1, pin 2 of the charging inductor L1 is connected to the D terminal (first connection terminal) of the PFC control unit 40, the H terminal (second connection terminal) of the PFC control unit 40 is connected to pin 1 of the first electrolytic capacitor C1, pin 2 of the first electrolytic capacitor C1 is connected to pin 1 of the second electrolytic capacitor C2, pin 2 of the second electrolytic capacitor C2 is connected to pin 1 of the current-limiting inductor L2, pin 2 of the current-limiting inductor L2 is connected to the fourth normally open contact of the second relay K2, the third normally open contact 1 of the second relay K2 is connected to the G terminal (third connection terminal) of the PFC control unit 40, a current-limiting resistor is connected in parallel across the two normally open contacts of the second relay K2, pin 2 of the current-limiting inductor L2 is connected to the cathode of the diode D1, and the anode of the diode D1 is connected to the second voltage detection unit 30.

[0034] Control switches S1 and S2 are controlled by the MCU control unit 10, thereby controlling the activation of K1 and K2. The first voltage detection unit 20 detects the voltage between the first normally open contact and the second normally open contact of the first relay K1 and the neutral line N, and reports it to the MCU control unit 10. The MCU control unit 10 determines whether the input is DC voltage or AC voltage. When it is determined to be DC voltage, the MCU control unit 10 enables the control switch S1 to be at a low level, and the first relay K1 is not activated.

[0035] When the voltage is determined to be AC, the MCU control unit 10 enables the control switch S1 to go high, and the first relay K1 is energized. The second voltage detection unit 30 detects the output voltage at point H of the PFC control unit 40 and reports it to the MCU control unit 10. The MCU control unit 10 determines when to enable the control switch S2 to go high, thereby controlling the energization of the second relay K2. By detecting the voltage change at the anode of diode D1, the MCU determines whether the second relay K2 is fully energized, thus realizing the vehicle power supply pre-charging function.

[0036] In the above embodiment, the first relay K1 and the second relay K2 can be of model HF115KF-T / 12-HS3T.

[0037] Please refer to Figure 1. After the vehicle power input interface is connected to the system power supply, the voltage between point A and point C is detected by the first voltage detection unit 20 and reported to the MCU control unit 10. The MCU control unit 10 determines whether the system power supply is DC voltage or AC voltage. When it detects and determines that it is DC voltage, it executes the instruction to keep the first relay K1 inactive. That is, when it is determined to be DC voltage, the MCU control unit 10 enables the control switch S1 to be low level, and the first relay K1 is not energized. When it detects and determines that it is AC voltage, it executes the instruction to activate the second relay K2. When it is determined to be AC ​​voltage, the MCU control unit 10 enables the control switch S1 to be high level, and the first relay K1 is energized.

[0038] After the first relay K1 is energized, the AC voltage passes through the charging inductor L1, the internal diode D1 of the PFC control unit 40, and the rectified voltage passes through the electrolytic capacitor, the current-limiting inductor L2, and the current-limiting resistor to complete the primary pre-charge voltage of the bus PFC, which is 1.414 times the input AC voltage. The second voltage detection unit 30 detects the output voltage at point H of the PFC control unit 40 and reports it to the MCU control unit 10. The MCU control unit 10 determines when to enable the control switch S2 to be high, thereby controlling the energization of the second relay K2. When the second relay K2 is energized, the MCU control unit 10 turns on the internal MOS transistor of the PFC control unit 40 and charges the bus electrolytic capacitor with constant current. When the bus PFC voltage approaches 800V, the MCU changes the internal logic control mechanism to charge the bus electrolytic capacitor with constant voltage.

[0039] The MCU determines whether the second relay K2 is fully engaged by detecting the change in the anode level of diode D1. The first voltage detection unit 20 detects that the voltage difference between AC and BC is less than a certain value within a certain time, which determines whether the first relay K1 is fully engaged. The MCU control unit 10 realizes the vehicle power supply pre-charging function by controlling the timing of the first relay K1, PFC control unit 40, and the first relay K1.

[0040] During the entire on-board power supply pre-charging process, the first voltage detection unit 20 needs to detect the input voltage AC voltage and report it to the MCU control unit 10. The MCU control unit 10 controls whether the first relay K1 is energized. The MCU control unit 10 completes the energization of the second relay K2 by turning on the MOSFETs of the second voltage detection unit 30 and the PFC control unit 40.

[0041] Furthermore, the present invention also provides an on-board power pre-charging device, which includes the aforementioned on-board power pre-charging circuit.

[0042] In addition, this utility model also provides a vehicle that includes the above-mentioned vehicle power pre-charging device.

[0043] Since the vehicle-mounted power pre-charging device and the vehicle both adopt all the technical solutions of the above embodiments, they at least have all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0044] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the concept of the present utility model and using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present utility model.

Claims

1. A vehicle-mounted power supply pre-charging circuit, characterized in that, The on-board power supply pre-charging circuit includes an MCU control unit, a first voltage detection unit, a second voltage detection unit, a PFC control unit, a first relay, and a second relay. The first relay is connected to the first voltage detection unit and the PFC control unit, and the second relay is connected to the PFC control unit and the second voltage detection unit. The PFC control unit includes a first connection terminal, a second connection terminal, and a third connection terminal. The first connection terminal is connected to the first relay, and the second connection terminal and the third connection terminal are simultaneously connected to the second relay.

2. The on-board power supply pre-charging circuit according to claim 1, characterized in that, The first relay includes a first normally open contact and a second normally open contact, the second relay includes a third normally open contact and a fourth normally open contact, the first normally open contact is connected to the live wire, the second normally open contact is connected to the first connection terminal of the PFC control unit, the second connection terminal of the PFC control unit is connected to the fourth normally open contact, and the third normally open contact is connected to the third connection terminal of the PFC control unit.

3. The on-board power supply pre-charging circuit according to claim 2, characterized in that, The on-board power supply pre-charging circuit also includes a charging inductor, the two ends of which are respectively connected to the second normally open contact and the first connection terminal of the PFC control unit.

4. The on-board power supply pre-charging circuit according to claim 3, characterized in that, The on-board power supply pre-charging circuit also includes a first electrolytic capacitor and a second electrolytic capacitor. The first end of the first electrolytic capacitor is connected to the second connection end, the second end of the first electrolytic capacitor is connected to the first end of the second electrolytic capacitor, and the second end of the second electrolytic capacitor is connected to the fourth normally open contact.

5. The on-board power supply pre-charging circuit according to claim 4, characterized in that, The on-board power supply pre-charging circuit also includes a current-limiting inductor, the first end of which is connected to the second end of the second electrolytic capacitor, and the second end of which is connected to the fourth normally open contact.

6. The on-board power supply pre-charging circuit according to claim 5, characterized in that, The on-board power supply pre-charging circuit also includes a diode, the second terminal of the current-limiting inductor is connected to the cathode of the diode, and the anode of the diode is connected to the second voltage detection unit.

7. The on-board power supply pre-charging circuit according to claim 1, characterized in that, A current-limiting resistor is connected in parallel across the two ends of the second relay.

8. The on-board power supply pre-charging circuit according to claim 1, characterized in that, The PFC control unit includes a first MOS switch, a second MOS switch, a third MOS switch, and a fourth MOS switch. The first MOS switch and the third MOS switch are connected in series to form a first circuit, and the second MOS switch and the fourth MOS switch are connected in series to form a second circuit. The first circuit and the second circuit are connected in parallel. The connection point between the first MOS switch and the third MOS switch is the first connection terminal, the connection point between the first MOS switch and the second MOS switch is the second connection terminal, and the connection point between the third MOS switch and the fourth MOS switch is the third connection terminal.

9. A vehicle-mounted power supply pre-charging device, characterized in that, The vehicle power pre-charging device includes a vehicle power pre-charging circuit as described in any one of claims 1-8.

10. A vehicle, characterized in that, The vehicle includes the on-board power pre-charging device as described in claim 9.

Images