Electric slow-moving control system and heavy-loaded mining car

Abstract

The present invention discloses an electric retarding control system and a heavy-duty mining vehicle, comprising a controller, a power system, an electric drive system, a braking resistor, a frequency converter, a heat dissipation fan and a drive motor; the electric drive system is respectively connected to the controller, the power system, the braking resistor and the drive motor, the drive motor is connected to the controller, the braking resistor is connected to the frequency converter, and the frequency converter is connected to the heat dissipation fan. The present invention utilizes the electrical characteristics of the electric motor to apply reverse torque to it, converting the vehicle's kinetic energy into electrical energy, thereby realizing the function of reducing the speed of the heavy-duty mining vehicle, and the converted energy is consumed by the braking resistor. The heat dissipation fan of the braking resistor adopts an AC motor, and the AC motor controller is integrated into the braking resistor. During braking, energy is provided by the voltage at the resistor terminal to ensure the normal operation of the heat dissipation fan. At the same time, the fan speed and the fan angle can be adjusted according to the working conditions, thereby realizing the control of the heat dissipation air volume.

Description

Technical Field

[0001] The invention relates to an electric retarding control system and a heavy-loaded mining car, belonging to the technical field of heavy-loaded mining car control. Background Art

[0002] In large-scale open-pit mine transportation, heavy-duty mine carts are the primary means of transport. These carts are primarily divided into mechanical and electric drive vehicles. Electric drive vehicles dominate the market, with their key features: an engine as the power source, driving a generator to generate electricity and power subsequent equipment. They lack complex gear trains and offer low maintenance costs. In the early days of electric drive vehicles, DC transmission systems were predominant. With the advancement of electronic switching devices and their control technology, AC drive vehicles have gradually gained a significant market share. However, DC motors are still used to drive fans to dissipate heat for brake resistors.

[0003] Due to the characteristics of mine transportation routes, half of a working cycle is spent in a braking state. Therefore, the importance of the brake resistor as a key component of electric mine cars is particularly prominent. However, the DC motors currently used are complex in structure, require regular maintenance, and have a high failure rate, which is a major shortcoming of electric mine cars. The current solution is to replace the DC motor with an AC motor and add a circuit to the DC bus to control the AC motor. Its main components are: frequency converter-transformer-rectifier-inverter. The disadvantages of this circuit are complex structure, inflexible motor control, high cost, and a significant increase in vehicle cost. If the motor and its controller can be integrated into the brake resistor based on its operating characteristics, the structure will be greatly simplified and the cost will be reduced. Summary of the Invention

[0004] In view of the above problems existing in the prior art, the present invention provides an electric retarding control system and a heavy-loaded mining car.

[0005] In order to achieve the above-mentioned object, the present invention adopts an electric retarding control system, which includes a controller, a power system, an electric drive system, a braking resistor, a frequency converter, a cooling fan and a drive motor;

[0006] The electric drive system is connected to the controller, the power system, the braking resistor and the drive motor respectively. The drive motor is connected to the controller, the braking resistor is connected to the frequency converter, and the frequency converter is connected to the heat dissipation fan.

[0007] As an improvement, the electric drive system includes a rectifier, a DC bus, an inverter and a chopper circuit, and the braking resistor is connected to the electric drive system through the chopper circuit.

[0008] As an improvement, the braking resistor is connected to the electric drive system via a DC chopper circuit.

[0009] As an improvement, the power supply of the frequency converter is connected in parallel to a braking resistor branch, and the parallel position is adjusted as needed to change the frequency converter terminal voltage and its output voltage.

[0010] As an improvement, the frequency converter is a two-level or three-level converter.

[0011] As an improvement, the frequency converter calculates the heat dissipation demand according to the voltage value and the existence time of the voltage at the resistor terminal, and controls the speed of the heat dissipation fan.

[0012] As an improvement, the braking resistor measures the ventilation volume during operation, and adjusts the angle of the cooling fan according to the calculated heat dissipation demand and the measured ventilation volume of the braking resistor.

[0013] As an improvement, the motor of the heat dissipation fan is an AC motor.

[0014] As an improvement, the drive motor includes a first drive motor and a second drive motor connected in parallel.

[0015] Finally, the present invention also provides a heavy-loaded mining car, on which the electric retarding control system is installed.

[0016] Compared to existing technologies, this invention utilizes the electrical characteristics of the motor to apply reverse torque, converting the vehicle's kinetic energy into electrical energy. This allows heavy-duty mining vehicles to slow down, with the converted energy dissipated by the braking resistor. The braking resistor's cooling fan uses an AC motor, with the AC motor controller integrated into the braking resistor. During braking, the voltage across the resistor terminals provides energy, ensuring the fan's proper operation. The fan's speed and angle can be adjusted according to operating conditions, thereby controlling the cooling airflow. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the principle of the present invention;

[0018] Figure 2 This is a schematic diagram of fan speed control according to the present invention;

[0019] In the figure: 1. Controller, 2. Power system, 3. Electric drive system, 4. Braking resistor, 5. Inverter, 6. Cooling fan, 7. Drive motor 1, 8. Drive motor 2. DETAILED DESCRIPTION

[0020] To make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below. However, it should be understood that the specific embodiments described herein are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention pertains. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0022] like Figure 1 、 Figure 2 As shown, an electric retarding control system includes a controller 1, a power system 2, an electric drive system 3, a braking resistor 4, a frequency converter 5, a cooling fan 6 and a drive motor;

[0023] The electric drive system 3 is connected to the controller 1 via a CAN bus. The electric drive system 3 is connected to the power system 2, drive motor 1 7, and drive motor 2 8 via three-phase AC power. Drive motors 1 7 and 2 8 are each connected to the controller 1, and drive motors 1 7 and 2 8 transmit speed and current signals to the controller. The electric drive system 3 is connected to a brake resistor 4, which is connected to a frequency converter 5, which is connected to a cooling fan 6. During traction, the power system 2 and the electric drive system 3 provide energy, which drives drive motors 1 7 and 2 8. During braking, drive motors 1 7 and 2 8 input energy into the electric drive system 3, which in turn supplies energy to the brake resistor 4 and the frequency converter 5 to control the operation of the cooling fan 6, which provides cooling air to the brake resistor 4. Furthermore, during braking, the heat dissipation capacity of the brake resistor 4 is adjusted by a combination of fan speed and fan angle, maximizing the cooling air volume and improving heat dissipation capacity. This same set of equipment ensures system hot backup, enhancing the braking capacity and reliability of heavy-load mining vehicles.

[0024] As an improvement of the embodiment, the electric drive system 3 includes a rectifier, a DC bus, an inverter and a chopper circuit. The braking resistor 4 is connected to the electric drive system 3 through the DC chopper circuit. The braking resistor 4 can be divided into several branches according to the braking requirements of the mine car. Different branches can be closed according to the requirements to achieve different braking power requirements.

[0025] As an improvement to the embodiment, the inverter power supply is connected in parallel to a braking resistor branch. The parallel connection position can be adjusted as needed to change the inverter terminal voltage and its output voltage to meet the needs of cooling fans with different power. Inverter 5 can be two-level or three-level, depending on the voltage of the parallel resistor. If connected in parallel at both ends of the braking resistor branch, a three-level inverter is selected to reduce the voltage level of the inverter's IGBT. If connected in parallel in the middle of the braking resistor branch, a two-level inverter is selected.

[0026] As an improvement to the embodiment, the inverter 5 can calculate the heat dissipation demand based on the voltage value and the existence time of the resistor terminal voltage, control the speed of the heat dissipation fan, and ensure the effectiveness and efficiency of the brake resistor heat dissipation under different working conditions.

[0027] As an improvement to the embodiment, the braking resistor 4 measures the ventilation volume during operation, and adjusts the angle of the cooling fan according to the calculated heat dissipation demand and the measured ventilation volume of the braking resistor to achieve closed-loop control of the system, and the angle controller of the cooling fan 6 is integrated in the inverter 5.

[0028] As an improvement to the embodiment, the motor of the heat dissipation fan 6 adopts an AC motor, which reduces the use cost and has higher reliability than that of a DC motor.

[0029] Finally, the present invention also provides a heavy-loaded mining car, on which the electric retarding control system is installed.

[0030] Specific working process:

[0031] During electric braking, the motor switches from a motoring state to a feeding state, where power is rectified by diodes and flows into the DC bus. When the DC bus voltage exceeds a set value, it is discharged to brake resistor 4 via a DC chopper circuit. When the DC bus voltage drops to a set lower value, the chopper circuit is shut off. While the chopper circuit is operating, the cooling fan inverter adjusts the motor speed and fan angle based on the resistor branch voltage and operating time, achieving precise heat dissipation from brake resistor 4 and ensuring the effectiveness and efficiency of the braking system.

[0032] Based on the vehicle's electric slowdown requirements, the inverter power supply can be connected in parallel across the resistor branch or in the middle of the resistor to meet the control requirements of motors with different power levels. The inverter can also be selected as a two-level or three-level drive based on the voltage level, reducing costs. The cooling fan angle controller is integrated into the inverter. Adjusting the fan angle can adjust the air flow and flow rate, allowing a wide range of cooling capabilities to be achieved using the same system.

[0033] Example 1

[0034] An electric drive mining car, comprising a controller 1, a power system 2, an electric drive system 3, a braking resistor 4, a frequency converter 5, a cooling fan 6 and a drive motor;

[0035] During the braking and deceleration phase, the traction motor's characteristics are utilized to operate in a feeding state. After rectification, the energy is consumed by the braking resistor grid. Heat from the braking resistor is dissipated through forced air cooling by a cooling fan 6. The cooling fan 6 is driven by an AC motor, and the AC motor speed is controlled by a frequency converter 5 integrated with the braking resistor 4. The braking resistor 4 is connected to the electric drive system 3 via a cable. The frequency converter 5 is connected in parallel to a branch of the braking resistor 4 via a cable. The controller 1 is connected to the AC motor via a cable, and the AC motor is connected to the cooling fan 6.

[0036] During braking, the electric drive system 3 discharges to the braking resistor 4 through the chopper circuit. The inverter 5 connected in parallel to a resistance branch accurately calculates the heat dissipation demand based on the voltage at the resistor terminal and the voltage action time, and adjusts the AC fan speed and the cooling fan angle to achieve heat dissipation of the resistor.

[0037] During the entire working process, the energy fed back from the motor during braking is used to drive the fan for heat dissipation, thereby realizing the recovery and utilization of braking energy and achieving energy saving. At the same time, the AC motor has a simple structure and is more reliable than the DC pulsating motor, which improves the reliability of the braking system.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A heavy-load mining vehicle, comprising an electric retarding control system, wherein the electric retarding control system comprises a controller (1), characterized in that: It also includes a power system (2), an electric drive system (3), a brake resistor (4), a frequency converter (5), a cooling fan (6) and a drive motor; The electric drive system (3) is respectively connected to the controller (1), the power system (2), the braking resistor (4) and the drive motor; the drive motor is connected to the controller (1); the braking resistor (4) is connected to the frequency converter (5); and the frequency converter (5) is connected to the cooling fan (6); The frequency converter (5) is connected in parallel to a braking resistor branch, and the parallel position is adjusted as needed to change the frequency converter terminal voltage and its output voltage. The frequency converter (5) calculates the heat dissipation demand based on the voltage value and the existence time of the resistor terminal voltage, and controls the speed of the heat dissipation fan (6); the ventilation volume of the braking resistor (4) during operation is measured, and the angle of the heat dissipation fan (6) is adjusted according to the calculated heat dissipation demand and the measured ventilation volume of the braking resistor; During braking, the electric drive system (3) discharges to the braking resistor (4) through the chopper circuit, and the frequency converter (5) connected in parallel to a braking resistor branch accurately calculates the heat dissipation demand based on the resistor terminal voltage and the voltage action time, and adjusts the cooling fan speed and the cooling fan angle to achieve heat dissipation of the resistor.

2. A heavy-load mining vehicle according to claim 1, characterized in that: The electric drive system (3) comprises a rectifier, a DC bus, an inverter and a chopper circuit, and the braking resistor (4) is connected to the electric drive system (3) via the chopper circuit.

3. A heavy-load mining vehicle according to claim 2, characterized in that: The braking resistor (4) is connected to the electric drive system (3) via a DC chopper circuit.

4. A heavy-load mining vehicle according to claim 1, characterized in that: The frequency converter (5) is a two-level or three-level converter.

5. A heavy-load mining vehicle according to claim 1, characterized in that: The motor of the heat dissipation fan (6) is an AC motor.

6. A heavy-load mining vehicle according to claim 1, characterized in that: The drive motor comprises a drive motor 1 (7) and a drive motor 2 (8) connected in parallel.

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