Power system of power dragging type excavator

Abstract

The utility model belongs to the technical field of engineering machinery, and particularly relates to a power system of an electric dragging type excavator, which comprises a power grid power supply loop, a generator power supply loop, a rectifier, a motor controller and a driving motor, the power grid power supply loop and the generator power supply loop are connected with the rectifier. The motor controller is connected with the rectifier and the driving motor. The power grid power supply loop and the generator power supply loop are respectively provided with a relay group, and each relay group comprises three relay loops arranged in parallel in a three-phase electric loop; each relay loop comprises a main relay and a pre-charging relay which are connected in parallel, and the pre-charging relay is connected with a pre-charging resistor in series. According to the utility model, the power generator set is additionally arranged on the power-dragging type excavator, so that the power-dragging type excavator can be conveniently transferred; the pre-charging relay loops are respectively arranged in the two power supply loops, so that a capacitor in a rectifier can be prevented from being punctured by large current at the moment that a main loop relay is closed, and the possibility of damage to electrical components is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of engineering machinery, and in particular relates to a power system of a towed electric excavator. Background Art

[0002] The statements in this section merely provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] The towed electric excavator has no power battery pack, which greatly reduces the cost of the whole vehicle. However, the towed electric excavator also has disadvantages. Since the power source of the towed electric excavator comes from the power grid, the moving range of the towed electric excavator is limited by the length of the cable. As a result, when the excavator climbs on the trailer for transfer or moves in harsh environments, its moving range is limited due to the insufficient length of the power grid cable. Utility Model Content

[0004] In order to overcome the above-mentioned deficiencies in the prior art, the utility model provides a power system for a towed electric excavator.

[0005] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0006] The first aspect of the utility model provides a power system for a towed electric excavator, comprising: a power supply circuit of a power grid, a power supply circuit of a generator, a rectifier, a motor controller and a drive motor;

[0007] The grid power supply circuit and the generator power supply circuit are both connected to the rectifier, and the motor controller is connected to the rectifier and the drive motor respectively; the rectifier is used to convert the alternating current provided by the power supply circuit into direct current and provide it to the motor controller;

[0008] The grid power supply circuit and the generator power supply circuit are respectively provided with relay groups, and the relay groups include three relay circuits arranged in parallel in the three-phase power circuit;

[0009] Each relay circuit includes a main relay and a pre-charging relay connected in parallel, and the pre-charging relay is also connected in series with a pre-charging resistor.

[0010] Furthermore, the power grid power supply circuit includes a 380V AC power supply, a current collector and a first relay group; one end of the first relay group is connected to the 380V AC power supply through the current collector, and the other end is connected to the rectifier.

[0011] Furthermore, the generator power supply circuit includes a generator group and a second relay group, one end of the second relay group is connected to the generator power supply circuit, and the other end is connected to the rectifier.

[0012] Furthermore, the first relay group and the second relay group are both connected to a vehicle controller.

[0013] Furthermore, the vehicle controller is connected to an instrument.

[0014] Furthermore, the vehicle controller and the instrument are connected via a CAN bus.

[0015] Furthermore, the generator set includes a diesel engine and a generator, the diesel engine is used to provide kinetic energy for the generator, and the generator is used to generate electric current.

[0016] Furthermore, the output shaft of the driving motor is connected to the main pump via a coupling, and the main pump is connected to a main valve.

[0017] Furthermore, the motor controller is connected to an air conditioning system.

[0018] Furthermore, the motor controller is connected to a water heater.

[0019] One or more of the above technical solutions have the following beneficial effects:

[0020] (1) The utility model adds a generator set to the towed electric excavator, which facilitates the transfer of the towed electric excavator, improves the maneuverability of the towed electric excavator, and solves the defect of limited transfer of the towed electric excavator. Moreover, the excavator is in an unloaded state when transferring, and the load is small, so a large generator set is not required.

[0021] (2) The utility model provides pre-charge relay circuits in the grid power supply circuit and the generator power supply circuit respectively, thereby preventing a large current from breaking down the capacitor in the rectifier at the moment the main circuit relay is closed, so as to reduce the possibility of damage to electrical components and improve the safety of the power system.

[0022] Advantages of additional aspects of the present invention will be partially given in the following description, and partially become apparent from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0024] Figure 1 This is a schematic diagram of a towed electric excavator power system according to Example 1. DETAILED DESCRIPTION

[0025] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0026] Embodiment 1

[0027] like Figure 1 As shown, the utility model proposes a power system for a towed electric excavator, comprising: a power supply circuit of a power grid, a power supply circuit of a generator, a rectifier, a motor controller and a drive motor; the power supply circuit of the power grid and the power supply circuit of the generator are both connected to the rectifier, and the motor controller is respectively connected to the rectifier and the drive motor;

[0028] The rectifier is used to convert the AC power provided by the power supply circuit into DC power and provide it to the motor controller. The motor controller includes an inverter module. The motor controller controls the inverter module to invert the DC power to generate suitable AC power to supply the drive motor and other modules.

[0029] Relay groups are respectively provided in the grid power supply circuit and the generator power supply circuit, and the relay group includes three relay circuits arranged in parallel in the three-phase power circuit; each relay circuit includes a main relay and a pre-charging relay connected in parallel, and the pre-charging relay is also connected in series with a pre-charging resistor.

[0030] The utility model arranges relay groups on the collector on the power line and the three-phase circuit at the output end of the generator set, which are respectively a first relay group (collector relay group) and a second relay group (generator set relay group). Each phase circuit in the relay group has a main relay and a pre-charging circuit, and the pre-charging circuit includes a pre-charging relay and a pre-charging resistor.

[0031] When three-phase electricity is input to the rectifier, the pre-charging relays of the three pre-charging circuits are closed at the same time first. Due to the large resistance of the pre-charging resistor, the rectifier and internal capacitors and other electrical components are pre-charged with a small current. After the pre-charging is completed (after it is fully charged), the main relay of the three-phase circuit is closed to supply a large current to the rectifier.

[0032] The utility model sets a pre-charging circuit, which can realize a small current to supply power to the rectifier, thereby preventing a large instantaneous current from breaking down the internal components of the rectifier, such as a capacitor; moreover, the pre-charging circuit uses a small current to detect whether the circuit is fault-free, and the system will alarm if there is a circuit break or other faults. By setting a pre-charging circuit, the possibility of damage to electrical components is reduced, and a circuit break fault is detected by using a small current, thereby improving the safety of the power system.

[0033] As a further technical solution, the grid power supply circuit includes a 380V AC power supply, a collector and a first relay group; one end of the first relay group is connected to the 380V AC power supply through the collector, and the other end is connected to the rectifier.

[0034] The generator power supply circuit comprises a generator group and a second relay group, one end of the second relay group is connected to the generator power supply circuit, and the other end is connected to the rectifier.

[0035] The first relay group and the second relay group are both connected to the vehicle controller, and the vehicle controller is connected to the instrument.

[0036] The instrument communicates with the vehicle controller VCU through the CAN bus, controls the vehicle controller VCU to power each relay port on the line, and thus controls the closure state of the relay.

[0037] The operator selects the excavator working mode on the instrument panel, including working state or transfer state; when selecting the working state, firstly, the VCU will not control any relay in the generator set relay group, and secondly, the VCU will close the pre-charge relay in the collector relay group to pre-charge the circuit, and then after pre-charging, the VCU will disconnect each pre-charge relay at the same time, thereby controlling the three main relays to be closed at the same time, thereby providing power for the entire system, which ensures the uniqueness of the power source and the current will not flow into other circuits to cause damage to electrical components.

[0038] When the transition state is selected, the VCU controls the pre-charging relay in the generator set relay group to close. After pre-charging, the VCU disconnects each pre-charging relay at the same time and controls the main relay to close, thereby using the generator set to provide power for the system.

[0039] When the field is to be transferred, the relay closing process is the same as the relay closing process during operation. The pre-charge relay in the generator relay group is controlled to be energized, and then the main relays are closed at the same time, and the pre-charge relays are disconnected at the same time. During this period, the relays in the collector relay group remain disconnected. The operator removes the cable from the grid on the collector and uses the generator set to generate electricity.

[0040] The generator set includes a diesel engine and a generator. The diesel engine is used to provide kinetic energy for the generator. The rotation of the engine drives the generator to generate electricity. The generator generates alternating current, which is modulated by a rectifier and a motor controller to control the drive motor.

[0041] As a further technical solution, the output shaft of the driving motor is connected to the main pump through a coupling, and the main pump is connected to the main valve; a solenoid valve is provided in the main valve, and the solenoid valve is controlled by a motor controller; the main pump rotates to press the hydraulic oil into the main valve, and by controlling the switch of the solenoid valve on the main valve, the hydraulic oil flows through different pipelines, thereby controlling different actions of the excavator.

[0042] The driving motor drives the main pump to transport the hydraulic oil to the excavator's travel hydraulic pipeline through the main valve, thereby driving the excavator to move. Because the excavator's working device does not work during the transfer, only the travel mechanism needs to be driven, so a smaller power generator set can be selected to save costs.

[0043] The power source of the towed electric excavator is 380V electricity from the power grid. The current is transmitted to the rectifier of the vehicle through a collector. The rectifier rectifies the AC power of the power grid into DC power, which is inverted through the motor controller to control the motor to drive the main pump to rotate. The hydraulic oil transmitted by the main pump is delivered to each hydraulic pipeline through the main valve.

[0044] As a further technical solution, the motor controller is connected to the air conditioning system and the water heater.

[0045] The motor controller also includes a DC-DC converter, which is used to convert a DC power supply into a DC (or approximate DC) power supply of different voltages to output a suitable DC power supply to certain high-voltage devices, such as the air conditioning system and the PCT water heater, to achieve heating or cooling of the cab air conditioning.

[0046] Although the above describes the specific implementation methods of the utility model in combination with the accompanying drawings, it is not intended to limit the scope of protection of the utility model. Technical personnel in the relevant field should understand that on the basis of the technical solution of the utility model, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the scope of protection of the utility model.

Claims

1. A towed electric excavator power system, characterized in that: include: Grid power supply circuit, generator power supply circuit, rectifier, motor controller and drive motor; The grid power supply circuit and the generator power supply circuit are both connected to the rectifier, and the motor controller is connected to the rectifier and the drive motor respectively; the rectifier is used to convert the alternating current provided by the power supply circuit into direct current and provide it to the motor controller; The grid power supply circuit and the generator power supply circuit are respectively provided with relay groups, and the relay groups include three relay circuits arranged in parallel in the three-phase power circuit; Each relay circuit includes a main relay and a pre-charging relay connected in parallel, and the pre-charging relay is also connected in series with a pre-charging resistor.

2. A towed electric excavator power system according to claim 1, characterized in that: The power grid power supply circuit includes a 380V AC power supply, a current collector and a first relay group; one end of the first relay group is connected to the 380V AC power supply through the current collector, and the other end is connected to the rectifier.

3. A towed electric excavator power system according to claim 2, characterized in that: The generator power supply circuit includes a generator group and a second relay group, one end of the second relay group is connected to the generator power supply circuit, and the other end is connected to the rectifier.

4. A towed electric excavator power system according to claim 3, characterized in that: The first relay group and the second relay group are both connected to the vehicle controller.

5. A towed electric excavator power system according to claim 4, characterized in that: The vehicle controller is connected to the instrument.

6. A towed electric excavator power system according to claim 5, characterized in that: The vehicle controller and the instrument are connected via a CAN bus.

7. A towed electric excavator power system according to claim 3, characterized in that: The generator set comprises a diesel engine and a generator, wherein the diesel engine is used to provide kinetic energy for the generator, and the generator is used to generate electric current.

8. The power system of a towed electric excavator according to claim 1, characterized in that: The output shaft of the driving motor is connected to the main pump through a coupling, and the main pump is connected to a main valve.

9. A towed electric excavator power system according to claim 1, characterized in that: The motor controller is connected to the air conditioning system.

10. A towed electric excavator power system according to claim 1, characterized in that: The motor controller is connected to the water heater.

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