Electric wheel dumper electric braking energy recovery circuit and boost converter

Abstract

The utility model provides an electric wheel dumper electric braking energy recovery circuit and boost converter, comprising four groups of bridge arms, each group of bridge arms comprises an IGBT, an inductor is connected between an upper bridge and a lower bridge of each IGBT, and the other end of the inductor is connected with a low voltage side positive electrode; a chopper and a filter capacitor are arranged on the low-voltage sides of the four groups of bridge arms, and a capacitor bank and a capacitor discharge resistor which are connected in parallel are arranged on the high-voltage sides of the four groups of bridge arms; the chopper is additionally arranged in the electric braking boosting loop, braking energy can be recycled to charge the lithium battery system, peak voltage can be eliminated, the braking energy can be consumed, and meanwhile the safety of the battery system and vehicle running is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of electric wheel dump trucks, and more specifically, to an electric braking energy recovery circuit and a boost converter of an electric wheel dump truck. Background Art

[0002] Electric wheel dump trucks are often used in open-pit mines and are an important tool for mine transportation. Electric wheel dump trucks use electric braking to decelerate during the deceleration process, converting the vehicle's mechanical energy into electrical energy and consuming it through braking resistors. In the current production and application process, there are two main methods for consuming electric braking energy of electric wheel dump trucks: one is to consume the electric braking energy directly through the braking resistor, and the other is to charge the battery system with the electric braking energy through the DC / DC converter, store the braking energy, and then replenish the battery energy to the vehicle during the vehicle traction process. However, the first method will directly consume all the electric braking energy through the resistor, wasting the braking energy; although the other method can store and recover the braking energy, under continuous downhill or special working conditions, the electric braking of the electric wheel dump truck will cause the battery system to be full and unable to absorb the braking energy, or the battery system will fail. At this time, the electric braking will fail, and the vehicle can only rely on mechanical braking for high-speed braking, which is not only easy to cause brake failure, but may even further lead to safety accidents. Utility Model Content

[0003] In order to solve the problem that the electric brake of an electric wheel dump truck may fail when the current battery system is fully charged or fails, the utility model proposes an electric brake energy recovery circuit and a boost converter for an electric wheel dump truck, which combines an electric brake boost circuit and a chopper structure, can recover braking energy to charge the lithium battery system, eliminate peak voltage and consume braking energy, and ensure the safety of the battery system and vehicle driving.

[0004] In order to achieve the above technical effects, the technical solution of the utility model is as follows:

[0005] An electric brake energy recovery circuit for an electric wheel dump truck comprises four groups of bridge arms, each group of bridge arms comprises an IGBT, an inductor is respectively connected between the upper bridge and the lower bridge of each IGBT, and the other end of the inductor is connected to the positive electrode on the low-voltage side; a chopper and a filter capacitor are provided on the low-voltage side of the four groups of bridge arms, and a parallel capacitor group and a capacitor discharge resistor are provided on the high-voltage side.

[0006] This technical solution adds a chopper in the electric brake boost circuit, and the chopper works to make the brake resistor consume energy, thereby ensuring the safety of the electric brake.

[0007] Preferably, the chopper comprises a braking resistor and an IGBT, one end of the braking resistor is connected to the middle node between the upper bridge and the lower bridge of the IGBT, and the other end is connected to the positive electrode of the low-voltage side.

[0008] Here, when the battery system is fully charged, the chopper works and consumes the braking energy on the braking resistor, so that the electric wheel dump truck can continue to maintain electric braking; if the battery system is not fully charged, the chopper can also be put into operation to consume the peak braking energy and ensure the safe operation of the battery system and the bridge arm.

[0009] Preferably, the chopper further comprises a current sensor, and the current sensor is connected in series with the braking resistor.

[0010] Preferably, the high voltage side of the four groups of bridge arms is provided with a pre-charge capacitor, and the pre-charge capacitor is connected in parallel with a capacitor discharge resistor; the positive electrode of the high voltage side is provided with a pre-charge resistor and a pre-charge DC contactor connected in series.

[0011] Here, during the power-on process of the battery system, the pre-charge DC contactor is closed to pre-charge the pre-charge capacitor.

[0012] Preferably, a current sensor is provided on each group of bridge arms, and the current sensor is connected in series with the inductor to facilitate positioning during maintenance and troubleshooting.

[0013] Preferably, the low-voltage side positive poles of the four groups of bridge arms are provided with a first main circuit switch, and the high-voltage side positive poles of the four groups of bridge arms are provided with a second main circuit switch, and the second main circuit switch is connected in parallel with the pre-charging resistor and the pre-charging DC contactor.

[0014] Here, when the pre-charge capacitor needs to be pre-charged, the first main circuit switch and the second main circuit switch are disconnected, and the pre-charge DC contactor is closed, so that the pre-charge capacitor is pre-charged; after the pre-charging is completed, the first main circuit switch and the second main circuit switch are closed, so that the boost circuit is connected.

[0015] Preferably, the low-voltage side positive poles and high-voltage side positive poles of the four groups of bridge arms are respectively provided with current sensors.

[0016] Preferably, voltage sensors are respectively provided on the low-voltage side and the high-voltage side of the four groups of bridge arms.

[0017] Here, by setting up current sensors and voltage sensors, when abnormal voltage or abnormal current is collected, fault response is carried out in a timely manner to facilitate maintenance and safety inspection.

[0018] Preferably, the low-voltage side positive poles of the four groups of bridge arms are also provided with fuses, and the fuses are connected in series with the first main circuit switch to further ensure circuit safety.

[0019] The utility model also provides an electric brake boost converter for an electric wheel dump truck. The boost converter is provided with the electric brake energy recovery circuit for the electric wheel dump truck.

[0020] Compared with the prior art, the beneficial effects of the technical solution of the utility model are:

[0021] The utility model proposes an electric brake energy recovery circuit and a boost converter for an electric wheel dump truck, comprising four groups of bridge arms, each group of bridge arms comprising an IGBT, an inductor connected between the upper bridge and the lower bridge of each IGBT, and the other end of the inductor connected to the positive electrode on the low-voltage side; a chopper and a filter capacitor are provided on the low-voltage side of the four groups of bridge arms, and a parallel capacitor group and a capacitor discharge resistor are provided on the high-voltage side; a chopper is added to the electric brake boost circuit, which can not only recover the braking energy to charge the lithium battery system, but also eliminate the peak voltage and consume the braking energy, while ensuring the safety of the battery system and the vehicle driving. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of the electric braking energy recovery circuit of the electric wheel dump truck proposed in an embodiment of the utility model. DETAILED DESCRIPTION

[0023] The following will describe the implementation of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention.

[0024] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0025] Example 1

[0026] like Figure 1 As shown, this embodiment proposes an electric brake energy recovery circuit for an electric wheel dump truck, wherein the low voltage side of the circuit is connected to the vehicle electric brake DC bus, and the high voltage side, i.e., the battery side, is connected to a lithium battery system.

[0027] The electric braking energy recovery circuit of the electric wheel dump truck includes four groups of bridge arms, wherein the first bridge arm includes IGBT VT1, inductor L1 and current sensor SC1, wherein the inductor L1 and current sensor SC1 are connected in series, one end of which is connected to the middle node between the upper bridge and the lower bridge of VT1, and the other end is connected to the positive electrode on the low voltage side; the second bridge arm includes IGBT VT2, inductor L2 and current sensor SC2, wherein the inductor L2 and current sensor SC2 are connected in series, one end of which is connected to the middle node between the upper bridge and the lower bridge of VT2, and the other end is connected to the positive electrode on the low voltage side; the third bridge arm includes IGBT VT3, inductor L3 and current sensor SC3, wherein the inductor L3 and current sensor SC3 are connected in series, one end of which is connected to the middle node between the upper bridge and the lower bridge of VT3, and the other end is connected to the positive electrode on the low voltage side; the fourth bridge arm includes IGBT VT4, inductor L4 and current sensor SC4, wherein the inductor L4 and current sensor SC4 are connected in series, one end of which is connected to the middle node between the upper bridge and the lower bridge of VT4, and the other end is connected to the positive electrode on the low voltage side.

[0028] The low-voltage side of the four groups of bridge arms is provided with a chopper and parallel filter capacitors C6 and C7; in this embodiment, the model of the filter capacitor C6 is 0.47uF / 1700V, and the model of C7 is 3300uF / 1500V;

[0029] The high voltage side of the four bridge arms is provided with capacitor groups C1-C4 and capacitor discharge resistor R1 connected in parallel; in this embodiment, the model of the capacitor groups C1-C4 is 0.47uF / 1700V.

[0030] In this embodiment, the chopper includes a braking resistor R3, an IGBT VT5 and a current sensor SC7, wherein the braking resistor R3 is connected in series with the current sensor SC7, one end of which is connected to the middle node between the upper bridge and the lower bridge of VT5, and the other end is connected to the positive electrode of the low voltage side. Adding a chopper to the electric braking boost circuit can not only recover braking energy to charge the lithium battery system, but also eliminate peak voltage and consume braking energy, while ensuring the safety of the battery system and vehicle driving.

[0031] Furthermore, the positive poles on the low-voltage sides of the four groups of bridge arms are provided with a first main circuit switch K1, and the positive poles on the high-voltage sides of the four groups of bridge arms are provided with a second main circuit switch K2.

[0032] A pre-charge capacitor C5 is provided on the high voltage side of the four groups of bridge arms, and the pre-charge capacitor C5 is connected in parallel with the capacitor discharge resistor R1; in this embodiment, the model of the pre-charge capacitor C5 is 2200uF / 1500V;

[0033] The positive electrodes of the high-voltage sides of the four groups of bridge arms are provided with a pre-charging resistor R2 and a pre-charging DC contactor K3 connected in series, and the pre-charging resistor R2 and the pre-charging DC contactor K3 are connected in parallel with the second main circuit switch K2. The pre-charging DC contactor K3 is closed, the pre-charging capacitor C5 is in a pre-charging state, and then the first main circuit switch K1 and the second main circuit switch K2 are closed, so that the boost circuit is turned on.

[0034] As a preferred embodiment, the low-voltage side positive poles and high-voltage side positive poles of the four groups of bridge arms are respectively provided with current sensors SC5 and SC6; further, the low-voltage side and high-voltage side of the four groups of bridge arms are also respectively provided with voltage sensors TV1 and TV2.

[0035] The positive electrodes on the low-voltage sides of the four groups of bridge arms are also provided with a fuse Fu1, and the fuse Fu1 is connected in series with the first main circuit switch K1 to further ensure circuit safety.

[0036] Example 2

[0037] In this embodiment, based on the electric brake energy recovery circuit of the electric wheel dump truck described in Embodiment 1, as shown in FIG. Figure 1 As shown, when the battery system is powered on, the pre-charging DC contactor K3 is closed, the pre-charging capacitor C5 is in the pre-charging state, and then the first main circuit switch K1 and the second main circuit switch K2 are closed, so that the boost circuit is turned on.

[0038] When the electric wheel dump truck is electrically braked, the lower bridges of the IGBT VT1 to VT4 work, so that the braking energy is used to charge the lithium battery system by boosting the voltage; when the energy of the lithium battery system is charged to more than 80%, the IGBT VT1 to VT4 stop working and no longer charge the lithium battery system. At this time, the IGBT VT5 in the chopper starts working and consumes the braking energy on the braking resistor R3, so that the electric wheel dump truck can continue to maintain electric braking.

[0039] As another implementation mode, when the lower bridge of IGBT VT1-VT4 is still in operation, the chopper is also put into operation to consume the peak braking energy and ensure the safety of the lithium battery system and IGBT VT1-VT4.

[0040] In general, the electric braking energy recovery circuit of the electric wheel dump truck described in this embodiment is suitable for vehicles whose electric braking voltage is lower than the voltage of the lithium battery system. When electric braking is performed, the DC / DC boosts the lithium battery system to charge, or consumes energy through the chopper working brake resistor; when the lithium battery system is charged more or the DC / DC fails, the braking energy can be consumed by the chopper. During the traction process, the energy of the lithium battery system is discharged to the DC bus through the DC / DC step-down, and the DC bus side is connected to the inverter, and the inverter is connected to the drive motor to achieve the recovery and utilization of braking energy. This solution ensures that the electric wheel dump truck does not consume too much electric braking energy during the electric braking process and saves most of the electric braking energy. At the same time, by designing a chopper on the low-voltage side of the bridge arm, the safety of electric braking is ensured.

[0041] Example 3

[0042] This embodiment provides an electric brake boost converter for an electric wheel dump truck, wherein the boost converter is provided with the electric brake energy recovery circuit for the electric wheel dump truck, such as Figure 1 As shown, it includes: four groups of bridge arms, wherein the first bridge arm includes IGBT VT1, inductor L1 and current sensor SC1, the inductor L1 and current sensor SC1 are connected in series, one end is connected to the middle node between the upper bridge and the lower bridge of VT1, and the other end is connected to the positive electrode on the low voltage side; the second bridge arm includes IGBT VT2, inductor L2 and current sensor SC2, the inductor L2 and current sensor SC2 are connected in series, one end is connected to the middle node between the upper bridge and the lower bridge of VT2, and the other end is connected to the positive electrode on the low voltage side; the third bridge arm includes IGBT VT3, inductor L3 and current sensor SC3, the inductor L3 and current sensor SC3 are connected in series, one end is connected to the middle node between the upper bridge and the lower bridge of VT3, and the other end is connected to the positive electrode on the low voltage side; the fourth bridge arm includes IGBT VT4, inductor L4 and current sensor SC4, the inductor L4 and current sensor SC4 are connected in series, one end is connected to the middle node between the upper bridge and the lower bridge of VT4, and the other end is connected to the positive pole on the low-voltage side; by setting the chopper, it is ensured that the electric wheel dump truck will not consume too much electric braking energy during the electric braking process and most of the electric braking energy is saved. At the same time, by designing the chopper on the low-voltage side of the bridge arm, the safety of electric braking is guaranteed.

[0043] The low-voltage side of the four bridge arms is provided with a chopper and parallel filter capacitors C6 and C7; the high-voltage side of the four bridge arms is provided with parallel capacitor groups C1-C4 and capacitor discharge resistors R1; the chopper includes a brake resistor R3, IGBTVT5 and a current sensor SC7, the brake resistor R3 is connected in series with the current sensor SC7, one end of which is connected to the middle node between the upper bridge and the lower bridge of VT5, and the other end is connected to the positive electrode of the low-voltage side. Adding a chopper to the electric brake boost circuit can not only recover the braking energy to charge the lithium battery system, but also eliminate the peak voltage and consume the braking energy, while ensuring the safety of the battery system and the vehicle driving.

[0044] The positive poles on the low-voltage side of the four bridge arms are provided with a first main circuit switch K1, and the positive poles on the high-voltage side of the four bridge arms are provided with a second main circuit switch K2. The high-voltage side of the four bridge arms is provided with a pre-charge capacitor C5, and the pre-charge capacitor C5 is connected in parallel with the capacitor discharge resistor R1; the positive poles on the high-voltage side of the four bridge arms are also provided with a pre-charge resistor R2 and a pre-charge DC contactor K3 connected in series, and the pre-charge resistor R2 and the pre-charge DC contactor K3 are connected in parallel with the second main circuit switch K2.

[0045] The pre-charging DC contactor K3 is closed, the pre-charging capacitor C5 is in the pre-charging state, and then the first main circuit switch K1 and the second main circuit switch K2 are closed, so that the boost circuit is connected.

[0046] As a preferred embodiment, the positive electrodes on the low voltage side and the positive electrodes on the high voltage side of the four bridge arms are respectively provided with current sensors SC5 and SC6; further, the low voltage side and the high voltage side of the four bridge arms are respectively provided with voltage sensors TV1 and TV2. The positive electrodes on the low voltage side of the four bridge arms are also provided with a fuse Fu1, which is connected in series with the first main circuit switch K1 to further ensure circuit safety.

[0047] Furthermore, this embodiment also provides an electric wheel dump truck, in which the above-mentioned electric brake boost converter for the electric wheel dump truck is provided.

[0048] Obviously, the above embodiments of the utility model are only examples for clearly explaining the utility model, and are not intended to limit the implementation methods of the utility model. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the utility model should be included in the protection scope of the claims of the utility model.

Claims

1. An electric braking energy recovery circuit for an electric wheel dump truck, characterized in that: It comprises four groups of bridge arms, each group of bridge arms comprises an IGBT, an inductor is respectively connected between the upper bridge and the lower bridge of each IGBT, and the other end of the inductor is connected to the positive electrode on the low-voltage side; a filter capacitor and a chopper are arranged on the low-voltage side of the four groups of bridge arms, and a parallel capacitor group and a capacitor discharge resistor are arranged on the high-voltage side.

2. The electric braking energy recovery circuit of the electric wheel dump truck according to claim 1 is characterized in that: The chopper comprises a braking resistor and an IGBT, one end of the braking resistor is connected to the middle node between the upper bridge and the lower bridge of the IGBT, and the other end is connected to the positive electrode of the low-voltage side.

3. The electric braking energy recovery circuit of the electric wheel dump truck according to claim 2 is characterized in that: The chopper further comprises a current sensor which is connected in series with the braking resistor.

4. The electric braking energy recovery circuit of the electric wheel dump truck according to claim 1, characterized in that: The high voltage side of the four groups of bridge arms is provided with a pre-charge capacitor, which is connected in parallel with a capacitor discharge resistor; the positive electrode of the high voltage side is provided with a pre-charge resistor and a pre-charge DC contactor connected in series.

5. The electric braking energy recovery circuit of the electric wheel dump truck according to claim 1, characterized in that: A current sensor is respectively provided on each group of bridge arms, and the current sensor is connected in series with the inductor.

6. The electric braking energy recovery circuit of the electric wheel dump truck according to claim 4, characterized in that: The positive poles on the low voltage sides of the four groups of bridge arms are provided with a first main circuit switch, and the positive poles on the high voltage sides of the four groups of bridge arms are provided with a second main circuit switch, and the second main circuit switch is connected in parallel with the pre-charging resistor and the pre-charging DC contactor.

7. The electric braking energy recovery circuit of an electric wheel dump truck according to claim 1, characterized in that: The low-voltage side positive poles and high-voltage side positive poles of the four groups of bridge arms are respectively provided with current sensors.

8. The electric braking energy recovery circuit of an electric wheel dump truck according to claim 1, characterized in that: Voltage sensors are respectively provided on the low-voltage side and the high-voltage side of the four groups of bridge arms.

9. The electric braking energy recovery circuit of an electric wheel dump truck according to claim 1, characterized in that: The positive poles on the low-voltage sides of the four groups of bridge arms are also provided with fuses, and the fuses are connected in series with the first main circuit switch.

10. An electric brake boost converter for an electric wheel dump truck, characterized in that: The boost converter is provided with an electric braking energy recovery circuit for an electric wheel dump truck as claimed in any one of claims 1 to 9.

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