JP-7855445-B2 - Electrically driven vehicles

JP7855445B2JP 7855445 B2JP7855445 B2JP 7855445B2JP-7855445-B2

Inventors

北口篤
高田知範
門田充弘
金子悟

Assignees

日立建機株式会社

Dates

Publication Date: 20260508
Application Date: 20220720

Claims (2)

The engine and The engine drives a main generator and an auxiliary generator, A main rectifier that converts the power generated by the main generator into DC power, An auxiliary rectifier that converts the power generated by the auxiliary generator into DC power, The main circuit is supplied with DC power from the aforementioned main rectifier, An auxiliary circuit supplied with DC power from the aforementioned auxiliary rectifier, Storage batteries and A charge/discharge controller that supplies power between the storage battery and the auxiliary circuit, The driving motor and A drive inverter that converts the DC power of the main circuit into AC power and supplies it to the drive motor, Auxiliary motor and An auxiliary inverter that converts the DC power of the auxiliary circuit into AC power and supplies it to the auxiliary motor, A converter that steps down the DC power of the main circuit and supplies it to the auxiliary circuit, An accelerator pedal that instructs the aforementioned drive motor to increase speed, A brake pedal that instructs the aforementioned drive motor to decelerate, The system includes a controller that controls the main generator, the auxiliary generator, the charge/discharge controller, the drive inverter, the auxiliary inverter, and the converter in response to input signals from the accelerator pedal and the brake pedal, In an electric vehicle, the controller controls the drive inverter so that the drive motor generates regenerative power when the brake pedal is operated, Equipped with a vehicle speed sensor that detects vehicle speed, The aforementioned controller, When neither the accelerator pedal nor the brake pedal is operated, and the vehicle speed is above a predetermined threshold, this is detected as a coasting state. In at least a portion of cases where the coasting state is detected, the drive inverter is controlled so that the drive motor generates regenerative power, the converter is activated, and the output power of the converter and the drive power of the auxiliary motor are calculated. If the output power is less than or equal to the drive power, the auxiliary inverter and the charge/discharge controller are controlled so that the output power is supplied only to the auxiliary motor. If the output power is greater than the drive power, the auxiliary inverter and the charge/discharge controller are controlled so that the output power is supplied to the auxiliary motor and the storage battery. The cargo bed and The vehicle further comprises a sensor for detecting the amount of cargo loaded on the cargo bed, The controller detects the coasting state and, if the load amount detected by the sensor is above a predetermined threshold value, it controls the drive inverter to prevent the generation of regenerative power and does not operate the converter. An electric-powered vehicle characterized by the following:
In the electric drive vehicle according to claim 1, Equipped with sensors to detect the downward slope angle of the running surface, The electric vehicle is characterized in that, when the controller detects the coasting state and the downward inclination angle detected by the sensor is less than a predetermined threshold, it controls the drive inverter so that regenerative power is not generated and does not operate the converter.

Description

This invention relates to electric-powered vehicles such as dump trucks. An electric-driven dump truck is based on a four-wheeled vehicle body. The driver's cab and control box are located at the front upper part of the body frame. The power unit, consisting of an engine, generator, and hydraulic pump, is located at the front lower part of the body frame. A rear axle, comprising a drive motor and reduction gear, is located at the rear lower part of the body frame. A cargo bed, adjustable via hydraulic cylinders, extends from the center to the rear of the upper body frame, allowing for the transport of large quantities of materials such as crushed stone or soil. A dump truck is loaded with a large quantity of material using a loading machine (e.g., a hydraulic excavator). After transporting the material to its destination, the dump truck extends its hydraulic cylinders, raising and lowering the loading bed around a hinge pin as the pivot point, releasing the material and completing the transport. It then returns to the loading area and repeats the process. The dump truck described above generates electricity using its engine's main generator. This electricity is then transmitted via an inverter and controller to an electric motor in the rear axle, which drives the motor. The tires rotate via a reduction gear, causing the truck to move. When slowing down or stopping, regenerative braking (electric brakes) is used. The regenerated power is then passed through a heating resistor in a heating brake resistor device, converted into heat, and this heat is dissipated to the outside by a blower. Furthermore, the generator and drive motor generate heat during operation and therefore require cooling; a cooling system is installed. The cooling system is primarily air-cooled, with a cooling blower driven by an electric motor to blow cooling air. The power for this system comes from an auxiliary generator separate from the main generator. The system primarily uses an inverter and controller to drive the auxiliary electric motors, ensuring that the objects being cooled remain below a desired temperature. Prior art documents disclosing electric-driven dump truck technology include, for example, Patent Documents 1 and 2. The hybrid dump truck described in Patent Document 1 stores generated electricity or electricity regenerated during deceleration in a battery, and discharges it during acceleration to drive an electric motor for propulsion. Furthermore, in the hybrid vehicle described in Patent Document 2, when charging the battery with regenerative power during electric braking in the auto-cruise state on a downhill road where driving force is not required, the regenerative power is used to drive an electric pump (auxiliary equipment) and consume the regenerative power before the battery's charge capacity overflows. Japanese Patent Publication No. 2000-299901Japanese Patent Publication No. 2017-30595 Schematic diagram of a dump truck in the first embodiment of the present inventionConfiguration diagram of the electric drive system in the first embodiment of the present inventionControl flow diagram of the electric drive system in the first embodiment of the present inventionConfiguration diagram of the electric drive system in the second embodiment of the present inventionControl flow diagram of the electric drive system in the second embodiment of the present inventionConfiguration diagram of the electric drive system in the third embodiment of the present inventionControl flow diagram of the electric drive system in the third embodiment of the present invention The embodiments of the present invention will be described below with reference to the drawings. In each figure, equivalent elements are denoted by the same reference numerals, and redundant explanations will be omitted as appropriate. Furthermore, while this embodiment applies the electric drive vehicle according to the present invention to a dump truck, the application of the present invention is not limited to this.