Electric power supply system of dump truck with mechatronic transmission

Abstract

FIELD: mining transport machines.SUBSTANCE: power supply system of a dump truck with a mechatronic transmission contains a traction generator and an internal combustion engine. Additionally, a sensor of the effective value of the traction generator current is introduced, connected to the output of the traction generator, a shock-free switching unit, the first input of which is connected through a scaling amplifier to the output of the voltage regulator, the second input is connected to the output of the controlled limiting unit, the control input is connected through a threshold element to the output of the sensor of the effective value of the traction generator current, and the output is connected to the summing input of the second voltage regulator.EFFECT: quality of voltage regulation processes in the mechatronic transmission of a dump truck is improved.1 cl, 1 dwg

Description

[0001] The proposed invention relates to mining transport vehicles and is intended to improve the operating efficiency of dump trucks at mining industry enterprises.

[0002] Known are power supply systems for dump trucks with a mechatronic transmission, comprising a traction generator, the rotor of which is mechanically connected to an internal combustion engine, the rotor winding with an excitation current sensor is connected through a power amplifier to the output of an excitation current regulator, and the stator contains a three-phase winding with an alternating voltage sensor, connected through a series-connected bridge diode rectifier and a module of autonomous three-phase inverters to the stator windings of asynchronous motors of wheel hubs (left and right), a capacitor connected to the output of the bridge diode rectifier and a series-connected braking resistor and a power switch, a DC voltage sensor installed at the output of the bridge diode rectifier and connected by its output to the subtractive input of the voltage regulator, the summing input of which is connected to the output of the voltage setter, and the output is connected to the summing input of the excitation current regulator,the subtractive input of which is connected to the output of the excitation current sensor (USSR Patent No. 861130. IPC B60L 7 / 06. - Published on September 7, 1981; Russian Federation Patent No. 2648652. IPC B60L 11 / 00; B60K 17 / 354. Published on March 27, 2018; Bulletin No. 9; Russian Federation Patent No. 2653945. IPC B60L 11 / 08; H02M 5 / 458; B60W 10 / 105. Published on May 15, 2018, Bulletin No. 14; Kozyaruk A.E. Improving the energy efficiency of the electromechanical transmission of a quarry dump truck / A.E. Kozyaruk, AM Kamyshyan / / Notes of the Mining Institute. 2019. Vol. 239. Pp. 576-582. DOI: 10.31897 / PMI.2019.5.576; Set of traction electrical equipment for BELAZ mining dump trucks. - M., Ruselprom Concern, 2020. - p. 12).

[0003] In known technical solutions, the rotor of a traction generator—a synchronous electric machine—is driven by an internal combustion engine. Three-phase alternating current from the traction generator's stator winding is converted to direct current using a diode rectifier. A capacitor, a braking resistor with a series-connected power switch, and three-phase inverters are connected to the diode rectifier output. Two three-phase inverters supply power to the asynchronous motors of the left and right drive wheel hub motors. The rectifier's output voltage is stabilized by regulating the current in the excitation winding using a DC voltage regulator with a subordinate excitation current control loop. The feedback sensors measure the voltage at the rectifier output and the excitation current.The main disturbances of the DC voltage regulation system are changes in the traction generator rotor speed and the recuperation current during braking of the in-wheel motors. During mechanical-electrical energy conversion during truck braking, the capacitor charges and the rectifier output voltage increases. In this case, the voltage regulation system reduces the traction generator excitation current. As a result, the synchronous generator voltage decreases, but the diode rectifier output voltage remains unregulated during capacitor charging. When the power switch is switched, energy is released from the capacitor and converted into heat in the braking resistor. This results in a decrease in the rectifier output voltage. Feedback increases the traction generator excitation current, causing oscillations in the power supply system.Thus, the known power supply systems of dump trucks do not provide high-quality voltage regulation, and fluctuations lead to additional energy losses.

[0004] Consequently, the disadvantages of known technical solutions are the low quality of regulation processes and increased energy losses during voltage fluctuations.

[0005] Among the known technical solutions, the closest in terms of the achieved result is the power supply system of a dump truck with a mechatronic transmission, containing a traction generator, the rotor of which is mechanically connected to an internal combustion engine, the rotor winding with an excitation current sensor is connected through a power amplifier to the output of the excitation current regulator, and the stator contains a three-phase winding with an alternating voltage sensor connected through a series-connected bridge diode rectifier and a module of autonomous three-phase inverters to the stator windings of the asynchronous motors of the motor-wheels (left and right), a capacitor connected to the output of the bridge diode rectifier and a series-connected braking resistor and a power switch, a DC voltage sensor installed at the output of the bridge diode rectifier and connected by the output to the subtractive input of the first voltage regulator,the summing input of which is connected to the output of the voltage regulator, and the output is connected to the controlled limiting unit, the control input of which is connected to the output of the voltage regulator, a second voltage regulator, the subtracting input of which is connected to the output of the alternating voltage sensor, and the output is connected to the summing input of the excitation current regulator, the subtracting input of which is connected to the excitation current sensor (Patent of the Russian Federation No. 2757093. IPC B60K6 / 20; B60K6 / 24; B60K6 / 26; B60L7 / 00; B60D33 / 067. Published 11.10.2021. Bulletin No. 29).,

[0006] In a well-known technical solution, the rotor of a traction generator—a synchronous electric machine—is driven by an internal combustion engine. Three-phase alternating voltage from the traction generator's stator winding is converted to direct voltage using a diode rectifier. A capacitor, a braking resistor with a series-connected power switch, and three-phase inverters are connected to the diode rectifier output. Two three-phase inverters supply power to the asynchronous motors of the left and right drive wheel hub motors. The DC voltage stabilization system at the diode rectifier output is a three-loop automatic control system. The main circuit is closed based on the voltage at the diode rectifier output and maintains this voltage proportional to the reference signal coming from the reference signal output to the summing input of the first voltage regulator. The internal slave circuit is closed based on the output current of the diode rectifier.The second slave circuit is closed based on the output voltage of the traction generator. The reference signal for this circuit is the output signal of the first voltage regulator, converted by the limiting unit. The signal's lower limit is proportional to the output voltage of the control unit, i.e., the setpoint voltage at the output of the diode rectifier. This means that when the reference signal at the control unit's output changes, a corresponding change occurs at the output of the limiting unit, causing a change in the output voltage of the traction generator. As a result, the DC voltage is stabilized by changing the excitation current of the traction generator.If the DC voltage at the diode rectifier output increases with a constant reference signal, for example, during braking of a dump truck and energy recovery, the output voltage of the first voltage regulator decreases, but the output signal of the limiting unit remains at a level proportional to the reference signal from the reference output. As a result, the output voltage of the traction generator stabilizes at the set level, and the DC voltage at the diode rectifier output is corrected by discharging the capacitor into the braking resistors accordingly.

[0007] During mechanical-electrical energy conversion during braking, the capacitor charges and the rectifier output voltage increases. In this case, the voltage regulation system reduces the traction generator excitation current. When the power switch is switched, the capacitor's energy is released and converted into heat in the braking resistor. As a result, the rectifier output voltage decreases. This leads to an increase in the traction generator excitation current. This results in voltage fluctuations at the rectifier output. Fluctuations in the inverter supply voltage cause fluctuations in the voltage amplitude at their outputs. This leads to increased energy losses in the components of the hub motor's electric drive system.

[0008] Therefore, the disadvantage of the known technical solution is the low quality of regulation processes and an increase in energy losses during voltage fluctuations.

[0009] The purpose of the proposed invention is to improve the quality of voltage regulation processes in the mechatronic transmission of a dump truck.

[0010] The stated objective is achieved in that in a known power supply system of a dump truck with a mechatronic transmission, containing a traction generator, the rotor of which is mechanically connected to an internal combustion engine, the rotor winding with an excitation current sensor is connected through a power amplifier to the output of the excitation current regulator, and the stator contains a three-phase winding with an alternating voltage sensor, connected through a series-connected bridge diode rectifier and a module of autonomous three-phase inverters to the stator windings of the asynchronous motors of the motor-wheels (left and right), a capacitor connected to the output of the bridge diode rectifier and an electric braking unit containing a series-connected braking resistor and a power switch, a DC voltage sensor installed at the output of the bridge diode rectifier and connected by the output to the subtractive input of the first voltage regulator,the summing input of which is connected to the output of the voltage regulator, and the output is connected to a controlled limiting unit, the control input of which is connected to the output of the voltage regulator, a second voltage regulator, the subtracting input of which is connected to the output of the alternating voltage sensor, and the output is connected to the summing input of the excitation current regulator, the subtracting input of which is connected to the excitation current sensor, additionally introduced is a sensor of the effective value of the traction generator current, connected to the output of the traction generator, a shockless switching unit, the first input of which is connected via a scaling amplifier to the output of the voltage regulator, the second input is connected to the output of the controlled limiting unit, the control input is connected via a threshold element to the output of the sensor of the effective value of the traction generator current, and the output is connected to the summing input of the second voltage regulator.

[0011] Compared to the closest similar solution, the proposed technical solution has the following new features (elements):

[0012] - traction generator current value sensor;

[0013] - shockless switching unit;

[0014] - scaling amplifier.

[0015] Therefore, the claimed technical solution meets the requirement of “novelty”.

[0016] The proposed invention improves the quality of control processes in the hub motor electric drive system. This is achieved by using a switchable slave voltage control loop of the traction generator in the DC voltage regulation system at the rectifier output. In traction mode, the dump truck's power supply system is a three-loop system for automatically regulating the DC voltage at the diode rectifier output. The main loop is closed to the voltage at the diode rectifier 18 output and maintains this voltage proportional to the setpoint voltage. The internal slave loop is closed to the excitation current of the traction generator. The second slave loop is closed to the output voltage of the traction generator. As a result, the DC voltage is stabilized by changing the excitation current of the traction generator.

[0017] When the dump truck is braking, the power supply system is a dual-loop system for automatically regulating the AC voltage at the traction generator output. The main loop is closed to the traction generator voltage and maintains this voltage proportional to the setpoint voltage. The internal slave loop is closed to the traction generator excitation current. As a result, the traction generator output voltage stabilizes at a set level, which corresponds to the required DC voltage at the output of the diode rectifier without recuperation. The DC voltage at the diode rectifier output is corrected by discharging the capacitor into the braking resistor. This eliminates oscillations in the traction generator voltage regulation subsystem.

[0018] Switching of the second voltage regulation circuit from slave to main occurs when the traction generator current decreases below the threshold level and the threshold element controlling the shock-free switching unit switches.

[0019] Therefore, the claimed technical solution meets the requirement of “positive effect”.

[0020] For each distinguishing feature, a search was conducted for known technical solutions in the field of mining equipment, hybrid transport and mechatronics.

[0021] The traction generator current sensor, shock-free switching units and scaling amplifiers used to match signals in two control circuits have not been found in known technical solutions for similar purposes.

[0022] Thus, the specified features ensure that the claimed technical solution meets the requirement of “significant differences”.

[0023] The essence of the proposed invention is explained by the drawing. Fig. 1 shows a diagram of the power supply system of a dump truck with a mechatronic transmission, where the following is indicated: 1 - DC link voltage regulator; 2 and 3 - asynchronous motors of the motor-wheels (left and right); 4 - the first voltage regulator; 5 - a scaling amplifier; 6 - a module of autonomous three-phase inverters; 7 - a controlled limiting unit; 8 - a DC voltage sensor; 9 - a shockless switching unit; 10 - a threshold element; 11 - a braking resistor; 12 - a power switch; 13 - the second voltage regulator; 14 - an excitation current regulator; 15 - a capacitor; 16 - a power amplifier; 17 - an AC voltage sensor; 18 - a bridge diode rectifier; 19 - an excitation current sensor; 20 - a diesel engine; 21 - a traction generator; 22 - sensor of the effective value of the traction generator current.

[0024] The power supply system of a dump truck with a mechatronic transmission contains a traction generator 21, the rotor of which is mechanically connected to an internal combustion engine 20, the rotor winding with an excitation current sensor 19 is connected through a power amplifier 16 to the output of an excitation current regulator 14, and the stator contains a three-phase winding with an alternating voltage sensor 17, connected through a series-connected bridge diode rectifier 18 and a module of autonomous three-phase inverters 6 to the stator windings of asynchronous motors of wheel motors 2 and 3 (left and right); a capacitor 15 connected to the output of the bridge diode rectifier 18 and a braking resistor 11 and a power switch 12 connected in series, a DC voltage sensor 8 installed at the output of the bridge diode rectifier 18 and connected by its output to the subtracting input of the first voltage regulator 4, the summing input of which is connected to the output of the voltage regulator 1,and the output is connected to the controlled limiting unit 7, the control input of which is connected to the output of the voltage setter 1, the second voltage regulator 13, the subtracting input of which is connected to the output of the alternating voltage sensor 17, and the output is connected to the summing input of the excitation current regulator 14, the subtracting input of which is connected to the excitation current sensor 19, the effective current value sensor 22, connected to the output of the traction generator 21, the shockless switching unit 9, the first input of which is connected through the scaling amplifier 5 to the output of the voltage setter 1, the second input is connected to the output of the controlled limiting unit 7, the control input of which is connected through the threshold element 10 to the output of the effective current value sensor 22 of the traction generator 21, and the output is connected to the summing input of the second voltage regulator 13.

[0025] The power supply system of the dump truck with a mechatronic transmission operates as follows. The rotor of the traction generator 21 - a synchronous electric machine, is driven by the internal combustion engine 20. The three-phase alternating voltage from the stator winding of the traction generator 21 is converted into direct voltage using a bridge diode rectifier 18. A capacitor 15, a braking resistor 11 with a series-connected power switch 12 and a module of three-phase autonomous inverters 6 are connected to the output of the bridge diode rectifier 18. Three-phase inverters 6 provide power supply to asynchronous motors 2 and 3 of the left and right drive motor-wheels of the dump truck. The stabilization of the output voltage of the bridge diode rectifier 18 is carried out by regulating the current in the excitation winding of the traction generator 21 using the amplifier 16, the input of which is connected to the output of the excitation current regulator 14.The alternating voltage sensor 17 is intended for generating a signal proportional to the effective value of the voltage of the traction generator 21. The output signal of the effective value current sensor 22 of the traction generator 21 acts on the input of the threshold element 10, which generates an output signal with a logical zero level if the effective current of the traction generator does not exceed the threshold value I0, or a signal with a logical one level if the effective current exceeds the threshold value I0.

[0026] The setpoint signal for the power supply system is formed at the output of voltage setpoint regulator 1. This signal acts simultaneously on the summing input of the first voltage regulator 4, the control input of the controlled limiting unit 7 and, through the scaling amplifier 5, on the first input of the bumpless switching unit 9. The signal from the output of the voltage sensor 8 acts on the subtracting input of the first voltage regulator 4. The first voltage regulator 4 calculates the DC voltage regulation error at the output of the diode rectifier 18 and converts it in accordance with the selected control law, for example, the proportional-integral law. The main function of the first voltage regulator 4 is to stabilize the DC voltage at the output of the diode rectifier 18. The output signal of the first voltage regulator 4, through the controlled limiting unit 7, acts on the second input of the bumpless switching unit 9.At the output of the controlled limiting unit 9, a reference signal is generated for the second voltage regulator 13, which regulates the output voltage of the traction generator 21. The upper and lower limiting levels of the signal at the output of the controlled limiting unit 9 are set proportional to the output signal of the voltage regulator 1 and are regulated in accordance with the reference signal for the first voltage regulator 4. The difference between the upper and lower limiting levels determines the maximum permissible range of change in the voltage of the traction generator 21.

[0027] The shockless switching unit 9 connects the output of the voltage setter 1 to the summing input of the second voltage regulator 13 via the scaling amplifier 5 or the output of the controlled limiting unit 7, depending on the state of the threshold element 10. In this case, the shockless switching unit 9 ensures a smooth change in the output signal when switching signals at the inputs.

[0028] In the traction mode, the effective current of the traction generator exceeds the threshold level I0, a logical one signal is acting at the output of the threshold element 10. The shockless switching unit 9 commutates the output of the controlled limiting unit 7 with the summing input of the second voltage regulator 13. The signal from the output of the voltage sensor 17 of the traction generator 21 is acting at the subtractive input of the second voltage regulator 13. The second voltage regulator 13 calculates the regulation error of the voltages of the stator windings of the traction generator 21 and converts it in accordance with the selected control law, for example, the proportional-integral law. The main function of the second voltage regulator 17 is to stabilize the voltage of the traction generator 21. The output signal of the second voltage regulator 13 acts on the summing input of the excitation current regulator 14, at the subtractive input of which the output signal of the excitation current sensor 19 is acting.The excitation current regulator 14 calculates the excitation current regulation error and converts it in accordance with the selected regulation law, for example, the proportional-integral law. The output signal of the excitation current regulator 14 is fed to the input of the power amplifier 16, which is connected to the excitation winding of the traction generator 21. Thus, in the traction mode, the electric power supply system of the dump truck is a three-circuit system for automatically regulating the direct voltage at the output of the diode rectifier 18. The main circuit is closed according to the voltage at the output of the diode rectifier 18 and maintains this voltage proportional to the reference voltage coming from the output of the voltage setter 1 to the summing input of the first voltage regulator 4. The internal slave circuit is closed according to the excitation current of the traction generator 21. The second slave circuit is closed according to the output voltage of the traction generator 21.The reference signal for this circuit is the output signal of the first voltage regulator 4, converted by the controlled limiting unit 7. The upper and lower levels of the signal limiting are proportional to the output voltage of the regulator 1, i.e., the set value of the voltage at the output of the diode rectifier 18. This means that when the reference signal changes, a corresponding change in the signal at the output of the controlled limiting unit 7 occurs, causing a change in the output voltage of the traction generator 21. As a result, the DC voltage is stabilized due to a change in the excitation current of the traction generator 21.

[0029] In the braking mode of the dump truck, energy recovery occurs and the voltage on the capacitor 15 increases. At the same time, the current of the traction generator 21 decreases and the threshold element 10 switches. The shockless switching unit 9 connects the summing input of the second voltage regulator through the scaling amplifier 5 to the input of the voltage setter 1. Thus, in the braking mode, the power supply system of the dump truck is a two-circuit system for automatically regulating the alternating voltage at the output of the traction generator 21. The main circuit is closed according to the voltage of the traction generator 21 and maintains this voltage proportional to the reference voltage coming from the output of the voltage setter 1 through the scaling amplifier 5 to the summing input of the second voltage regulator 13. The internal slave circuit is closed according to the excitation current of the traction generator 21.As a result, the output voltage of traction generator 21 stabilizes at a predetermined level, which corresponds to the required DC voltage at the output of diode rectifier 18 without recuperation. The DC voltage at the output of diode rectifier 18 is corrected by discharging capacitor 15 into braking resistor 11. This eliminates oscillations in the voltage regulation subsystem of traction generator 21.

[0030] Scaling amplifier 5 is designed to match the reference signal with the output voltage of the traction generator 21 and the voltage at the output of the diode rectifier 18, taking into account the transmission coefficients of the voltage sensors 8 and the alternating voltage 17.

[0031] The main disturbances of the DC voltage regulation system are changes in the rotor speed of traction generator 21 and the regenerative current during braking of the in-wheel motors. During the mechanical-electrical energy conversion, capacitor 15 is charged and the voltage at the rectifier output increases. When the voltage at capacitor 15 rises above a predetermined threshold, power switch 12 opens, discharging capacitor 15 into braking resistor 11. The voltage at the output of traction generator 21 is maintained constant.

[0032] Thus, the use of an additional subordinate voltage regulation circuit for traction generator 21 in the dump truck's power supply system ensures traction generator voltage stabilization when the DC link voltage increases during energy recovery. As a result, an increase in DC link voltage during regenerative braking does not cause a change in the output voltage of generator 21. The recovered energy is converted into heat in the braking resistors. This improves the quality of regulation processes in the dump truck's power supply system with a mechatronic transmission.

[0033] Therefore, the use in the proposed power supply system of a dump truck with a mechatronic transmission containing a traction generator, the rotor of which is mechanically connected to an internal combustion engine, the rotor winding with an excitation current sensor is connected through a power amplifier to the output of the excitation current regulator, and the stator contains a three-phase winding with an alternating voltage sensor, connected through a series-connected bridge diode rectifier and a module of autonomous three-phase inverters to the stator windings of the asynchronous motors of the motor-wheels (left and right), a capacitor connected to the output of the bridge diode rectifier and a series-connected braking resistor and a power switch, a DC voltage sensor installed at the output of the bridge diode rectifier and connected by the output to the subtracting input of the first voltage regulator, the summing input of which is connected to the output of the voltage regulator,and the output is connected to a controlled limiting unit, the control input of which is connected to the output of the voltage regulator, a second voltage regulator, the subtracting input of which is connected to the output of the alternating voltage sensor, and the output is connected to the summing input of the excitation current regulator, the subtracting input of which is connected to the excitation current sensor, additionally a sensor of the effective value of the traction generator current, connected to the output of the traction generator, a shockless switching unit, the first input of which is connected via a scaling amplifier to the output of the voltage regulator, the second input is connected to the output of the controlled limiting unit, the control input is connected via a threshold element to the output of the sensor of the effective value of the traction generator current, and the output is connected to the summing input of the second voltage regulator, improves the quality of the control processes in the mechatronic transmission of a dump truck.

[0034] The use of the proposed technical solution on quarry dump trucks will improve the quality of control processes for the dump truck's mechatronic system.

Claims

An electric power supply system of a dump truck with a mechatronic transmission, comprising a traction generator, the rotor of which is mechanically connected to an internal combustion engine, the rotor winding with an excitation current sensor is connected through a power amplifier to the output of an excitation current regulator, and the stator contains a three-phase winding with an alternating voltage sensor, connected through a series-connected bridge diode rectifier and a module of autonomous three-phase inverters to the stator windings of the asynchronous motor-wheels (left and right), a capacitor connected to the output of the bridge diode rectifier and a series-connected braking resistor and a power switch, a DC voltage sensor installed at the output of the bridge diode rectifier and connected by its output to the subtracting input of the first voltage regulator, the summing input of which is connected to the output of the voltage regulator, and the output is connected to the controlled limiting unit,the control input of which is connected to the output of the voltage regulator, the second voltage regulator, the subtracting input of which is connected to the output of the alternating voltage sensor, and the output is connected to the summing input of the excitation current regulator, the subtracting input of which is connected to the excitation current sensor, characterized in that a sensor of the effective value of the traction generator current is additionally introduced, connected to the output of the traction generator, a shockless switching unit, the first input of which is connected through a scaling amplifier to the output of the voltage regulator, the second input is connected to the output of the controlled limiting unit, the control input is connected through a threshold element to the output of the sensor of the effective value of the traction generator current, and the output is connected to the summing input of the second voltage regulator.

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