Electric shovel high-voltage power supply system self-voltage-stabilizing device and method based on DVR energy compensation strategy

Abstract

An electric shovel high-voltage power supply system self-voltage-stabilizing device and method based on a DVR energy compensation strategy comprises a voltage monitoring module, a DVR energy compensation module and a control module, a change-over switch is arranged between the DVR energy compensation module and an electric shovel high-voltage power supply system, all the modules cooperate with one another, the voltage monitoring module completes real-time sensing of voltage signals, and the control module is connected with the DVR energy compensation module. The control module completes strategy operation and instruction issuing based on a sensing signal, the DVR energy compensation module completes energy storage and conversion and compensation voltage injection according to a control instruction, the change-over switch completes intervention and quit of the compensation module according to a power supply state, and a sensing-operation-execution-feedback closed-loop control system is formed. Stable voltage control of the high-voltage power supply system of the electric shovel is realized. The system is high in energy storage utilization rate and high in environmental adaptability, can effectively inhibit power grid harmonic waves and reactive power loss, prolongs the service life of electric shovel equipment, reduces the production energy consumption and maintenance cost of mining areas, and is suitable for various mining electric shovel high-voltage power supply scenes.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, specifically to a self-stabilizing device and method for a high-voltage power supply system for electric shovels based on a DVR energy compensation strategy. Background Technology

[0002] Electric shovels are large-tonnage, purely electric mining equipment. The high-voltage electricity required for their power is supplied by the mine's power grid. However, mines are often located in special areas such as plateaus and mountains, with complex power supply environments. The mine's power grid is powered by a combination of thermal power, wind power, and photovoltaic power. There are many electrical devices in the same area, and the transmission lines are complex and prone to short circuits. The starting impact of large motors and the power fluctuations of new energy sources can cause many harmonic spikes in the power grid and voltage fluctuations of ≥20%. However, the maximum instantaneous fluctuation range of the power grid allowed by electric shovel equipment is only ≤15%.

[0003] Excessive power grid fluctuations can cause electric shovels to shut down abnormally, or even damage electrical components such as IGBT modules, rectifier-inverter modules, and transformers, increasing the frequency of equipment maintenance, severely reducing the service life of electric shovels and mining efficiency, and causing huge economic losses.

[0004] Mining production equipment has extremely high requirements for power supply voltage stability. The existing high-voltage power supply system in mining areas still has the following problems: First, the load fluctuates greatly. The start-up and shutdown of large equipment causes voltage dips / surges. When an electric shovel starts digging, the current increases by 3-5 times the rated value, resulting in a voltage dip of 15%-30% for 50-200ms. Second, the power supply lines are long, and line losses and external interference cause voltage deviations. Third, the three-phase asynchronous motor load of the electric shovel generates 7%-12% reactive power loss. The rectifier circuit introduces the 3rd, 5th, and 7th harmonics, with a total harmonic distortion rate of 8%-15%. Moreover, the three-phase imbalance on the grid side often exceeds 3%, further aggravating power supply instability. Fourth, traditional voltage stabilization devices (voltage regulators, reactors) have slow response speeds, cannot cope with transient voltage changes, and have no energy compensation capabilities, thus failing to fundamentally solve the voltage stability problem.

[0005] DVRs are effective devices for addressing voltage sags and fluctuations in power systems, but their traditional technologies have significant drawbacks: traditional DVRs use capacitors or batteries as energy storage units. Capacitors have small energy storage capacity, which cannot meet long-term compensation requirements, while batteries have short charge and discharge lifespans, slow response speeds, and high maintenance costs. Furthermore, traditional DVR voltage compensation strategies are mostly based on PID control of voltage deviations, without considering the state of charge (SOC) of the energy storage unit, which can easily lead to over-discharge or under-charging of the energy storage, affecting the compensation effect and the lifespan of the energy storage unit.

[0006] There is currently research on compensation strategies for abnormal voltage fluctuations in power supply systems, but the electric shovel industry has not yet disclosed technical patents related to voltage stabilization of high-voltage power supply systems. There is an urgent need for an improved DVR compensation technology that is adapted to the characteristics of high-voltage power supply in electric shovels, so as to achieve high-precision, fast and stable control, while improving energy storage utilization and device reliability.

[0007] DVR: (Dynamic Voltage Restorer)

[0008] SOC: (State of charge) state of charge.

[0009] VSC: (Voltage Source Converter) Voltage source converter. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a self-stabilizing device and method for electric shovel high-voltage power supply system based on DVR energy compensation strategy. This solves the problems of large voltage fluctuation, poor voltage stabilization effect, low energy storage utilization, slow response speed and poor environmental adaptability of the existing electric shovel high-voltage power supply system, and realizes high precision, fast and stable output of electric shovel high-voltage power supply system.

[0011] This invention is achieved through the following technical solution: a self-stabilizing device for a high-voltage power supply system of an electric shovel based on a DVR energy compensation strategy, comprising a voltage monitoring module, a DVR energy compensation module, and a control module. The voltage monitoring module includes an input voltage monitoring module and an output voltage monitoring module installed on the high-voltage power supply system of the electric shovel. The DVR energy compensation module includes a bidirectional DC / DC converter, an LC filter module, a SOC monitoring module, and a supercapacitor bank. The control module includes a DSP controller. A switching switch is provided between the DVR energy compensation module and the high-voltage power supply system of the electric shovel. The DSP controller is connected to the voltage monitoring module, the output voltage monitoring module, the switching switch, and the SOC monitoring module.

[0012] Furthermore, the bidirectional DC / DC converter includes a three-phase bridge inverter topology composed of multiple IGBT power switches.

[0013] The LC filter module consists of a filter inductor and a filter capacitor, forming an LC low-pass filter used to filter out high-order harmonics from the output of the three-phase inverter.

[0014] The supercapacitor bank adopts a combination of series and parallel connections, and the voltage of each supercapacitor unit is balanced through a voltage equalization circuit.

[0015] The control module includes sub-modules for voltage deviation calculation, compensation voltage command generation, energy storage state judgment, and charge / discharge control. It introduces energy storage state of charge (SOC) feedback to achieve coordinated control of compensation voltage and energy storage state.

[0016] A self-stabilizing method for a high-voltage power supply system for electric shovels based on a DVR energy compensation strategy, applied to the self-stabilizing device of any of the above claims, includes the following steps:

[0017] S1, the input voltage monitoring module and the output voltage monitoring module respectively collect the input voltage U of the electric shovel's high-voltage power supply system in real time. in and output voltage U out The collected voltage signal is then transmitted to the control module.

[0018] S2. The control module preprocesses the acquired voltage signal, including filtering, synchronization, and RMS value calculation, to obtain the RMS value U of the input voltage. in（rms） and the effective value of the output voltage U out（rms） ;

[0019] S3. Calculate the voltage deviation ΔU and determine whether the voltage deviation ΔU meets the power supply requirements of the equipment.

[0020] S4. If the requirements are met, the switch remains closed; if not, based on the improved energy storage DVR compensation strategy, the required compensation voltage U is calculated according to the state of charge (SOC) of the energy storage module. comp Disconnect the switch;

[0021] S5. Based on the calculated compensation voltage U comp Generate drive signals for the DVR compensation module and generate charge / discharge control signals for the bidirectional DC / DC converter based on the state of charge (SOC).

[0022] S6, DVR energy compensation module will compensate voltage U comp The electric shovel is equipped with a high-voltage power supply system, and a bidirectional DC / DC converter and supercapacitor bank perform charging and discharging operations according to the charging and discharging control signal.

[0023] S7. Repeat steps S1-S6 to achieve real-time stable control of the output voltage of the electric shovel's high-voltage power supply system.

[0024] In steps S3 and S4, the voltage deviation ΔU and the compensation voltage U comp The calculation formula is:

[0025] ΔU=U ref -U out（rms）

[0026] U comp =K p •ΔU+Ki •ʃΔUdt+K d •(dΔU / dt)+K soc •(SOC ref -SOC)

[0027] Among them, K p K i K d These are the proportional coefficient, integral coefficient, and derivative coefficient of the PID controller, respectively, K. soc The feedback coefficient of SOC, SOC ref and SOC are the rated state of charge and actual state of charge of the energy storage module, respectively; U ref This refers to the rated effective output value of the high-voltage power supply system for electric shovels.

[0028] The formula for calculating the State of Charge (SOC) of the energy storage module is as follows:

[0029]

[0030] Where SOC0 is the initial state of charge of the energy storage module, and C sc i represents the capacitance value of the supercapacitor. sc (t) represents the charging and discharging current of the supercapacitor.

[0031] In step S5, the instantaneous value of the compensation voltage u output by the three-phase inverter is... comp (t) is generated using Space Vector Pulse Width Modulation (SVPWM) technology, and the calculation formula is as follows:

[0032]

[0033] Among them, U dc M represents the DC voltage output by the energy storage module, and M is the modulation ratio. The angular frequency of the power grid. To compensate for the phase difference between the voltage and the grid voltage, n is the harmonic order;

[0034] The output voltage U of the bidirectional DC / DC converter dc The control formula is:

[0035] U dc =U sc ×(N1 / N2)×D

[0036] Among them, U sc N is the terminal voltage of the supercapacitor, N1 / N2 is the transformation ratio, and D is the duty cycle of the converter.

[0037] The output voltage U of the electric shovel's high-voltage power supply system out With input voltage U in Compensation voltage U compThe relationship formula is:

[0038]

[0039] Among them, U comp（rms） To compensate for the effective value of the voltage, This represents the phase difference between the input voltage and the compensation voltage.

[0040] The present invention has the following advantages:

[0041] 1. High voltage stabilization accuracy, meeting the stringent working requirements of electric shovels: The DVR compensation strategy of this invention introduces SOC feedback, which greatly improves the voltage stabilization accuracy, far exceeding the working requirements of electric shovels. It effectively avoids faults such as electric shovel motor stalling and contactor tripping caused by voltage fluctuations, and significantly improves the operating efficiency of electric shovels in mining areas.

[0042] 2. Fast response speed and effective suppression of dynamic voltage fluctuations: The use of supercapacitor energy storage (response speed in milliseconds) and high-performance DSP control greatly reduces the response time of the compensation strategy. It can quickly suppress dynamic voltage fluctuations of 10-50ms caused by electric shovel startup, load switching, etc., and greatly shorten the voltage recovery time, adapting to the power supply characteristics of electric shovel transient load changes.

[0043] 3. High energy storage utilization and extended energy storage unit lifespan: Through real-time SOC calculation and feedback control, the SOC of the energy storage module is stabilized in the optimal range, avoiding ineffective charging and discharging, and the compensation time is significantly extended under the same energy storage capacity; moreover, the cycle life of the supercapacitor can reach more than 100,000 times, solving the problems of low utilization and short lifespan of traditional energy storage units.

[0044] 4. High reliability and adaptability to harsh working environments in mines: The energy storage element uses supercapacitors with an operating temperature range of -40℃ to 70℃, making it highly adaptable to various environments; each module of the device adopts a high-sealing design with ≥IP65, and the drive module has built-in overcurrent, overvoltage, and overheat protection. The device has a mean time between failures (MTBF) of ≥5000 hours, which is twice that of traditional DVRs.

[0045] 5. High energy efficiency, reducing energy consumption and operating costs: SVPWM technology improves DC voltage utilization, which is significantly higher than traditional SPWM technology, and the power factor compensation is ≈1, avoiding reactive power loss; the overall efficiency of the device is ≥90%, saving 10% energy compared to traditional DVR. Based on the annual power consumption of 1 million kWh for electric shovels, it can save more than 100,000 yuan in electricity costs per year.

[0046] 6. Comprehensive solution to multiple problems in electric shovel power supply system: This invention not only achieves voltage stabilization, but also effectively suppresses grid harmonics, compensates for reactive power loss, and alleviates the impact of three-phase imbalance on the electric shovel power supply system. It improves the power quality of the electric shovel high-voltage power supply system from multiple dimensions, reduces the probability of electrical component damage, lowers equipment maintenance costs, and extends the overall service life of electric shovel equipment. Attached Figure Description

[0047] The accompanying drawings, as part of this invention, are provided to further illustrate the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation thereof. Clearly, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0048] In the attached diagram:

[0049] Figure 1 This is a topology diagram of the self-regulating voltage system of the present invention;

[0050] Figure 2 This is a flowchart of the monitoring and DVR compensation control of the present invention.

[0051] In the diagram: 1. DVR module, 2. Input voltage monitoring module, 3. Switch, 4. DSP controller, 5. Output voltage monitoring module, 6. Bidirectional DC / DC converter, 7. LC filter module, 8. SOC monitoring module, 9. Supercapacitor bank.

[0052] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0054] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0055] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0056] like Figure 1 The self-stabilizing device for a high-voltage power supply system of an electric shovel based on a DVR energy compensation strategy is shown. It consists of three core modules: a voltage monitoring module, a DVR energy compensation module, and a control module. A switching switch 3 is provided between the DVR energy compensation module 1 and the high-voltage power supply system of the electric shovel. The modules are connected by electrical circuits to achieve signal transmission and energy interaction. A switching switch 3 is also provided between the DVR energy compensation module 1 and the main circuit of the high-voltage power supply system of the electric shovel, which serves as a control node for the compensation module to enter and exit the power supply system, so as to realize the flexible switching of the device between voltage stabilization compensation mode and conventional power supply mode.

[0057] The voltage monitoring module includes an input voltage monitoring module 2 and an output voltage monitoring module 5 installed on the high-voltage power supply system of the electric shovel. The input voltage monitoring module 2 is connected in series between the mine power grid and the input terminal of the high-voltage power supply system of the electric shovel, and the output voltage monitoring module 5 is connected in series between the output terminal of the high-voltage power supply system of the electric shovel and the load of the electric shovel. Both monitoring modules communicate bidirectionally with the DSP controller 4 of the control module through shielded signal lines. The core function is to collect the input and output voltage analog signals of the power supply system in real time, convert them into digital signals and transmit them to the DSP controller 4, and at the same time receive the sampling instructions from the controller to realize the dynamic adjustment of the sampling frequency and sampling accuracy.

[0058] The DVR energy compensation module 1 includes a bidirectional DC / DC converter 6, an LC filter module 7, a SOC monitoring module 8, and a supercapacitor bank 9. The input of this module is connected to the energy storage output of the supercapacitor bank 9, and its output is connected in parallel with the main circuit of the electric shovel's high-voltage power supply system via a switch 3. The SOC monitoring module 8 is connected to the supercapacitor bank 9 through current and voltage acquisition terminals and communicates with the DSP controller 4 via a signal line. The control terminal of the bidirectional DC / DC converter 6 receives charging and discharging control signals from the DSP controller 4, realizing bidirectional energy conversion and transmission. Additionally, the DVR energy compensation module also includes an energy storage module and a drive module. The energy storage module includes a supercapacitor and a bidirectional DC / DC converter, used to store and release electrical energy, providing stable DC voltage support for the DVR energy compensation module. The drive module receives drive signals output from the control module, amplifies them, and drives the bidirectional DC / DC converter in the energy storage module and the three-phase inverter in the DVR compensation module. The DVR energy compensation module receives compensation control signals output from the control module, converts the DC voltage provided by the energy storage module into the required AC compensation voltage, and injects the compensation voltage into the electric shovel's high-voltage power supply system.

[0059] The control module, with the DSP controller 4 as its core, has built-in sub-modules for voltage deviation calculation, compensation voltage command generation, energy storage status judgment, and charge / discharge control. It is electrically connected to the two acquisition units of the voltage monitoring module, the control terminal of the switch 3, and the SOC monitoring module 8 through signal lines. Its core function is to process the acquired voltage signals, calculate the compensation strategy, and generate and output various control signals. It is the "control center" of the entire device.

[0060] The modules work together to achieve real-time sensing of voltage signals. The control module performs strategy calculations and issues commands based on the sensed signals. The DVR energy compensation module stores, converts, and injects compensation voltage according to the control commands. Switch 3 intervenes and withdraws the compensation module according to the power supply status, forming a closed-loop control system of "sensing-calculation-execution-feedback" to achieve stable voltage control of the electric shovel's high-voltage power supply system.

[0061] like Figure 1The diagram illustrates a self-regulating voltage regulator for a high-voltage power supply system for electric shovels based on a DVR energy compensation strategy. The bidirectional DC / DC converter 6 includes a three-phase bridge inverter topology composed of multiple IGBT power switches. The IGBT power switches are selected from high-voltage, high-current industrial-grade devices, and each IGBT is connected in parallel with an anti-parallel diode and an absorption capacitor to achieve overvoltage and overcurrent protection. The three-phase bridge inverter topology adopts a phase-shifted full-bridge structure design. The PWM pulse signal output by the DSP controller 4 controls the on / off timing of the IGBTs. It can convert the DC voltage output by the supercapacitor bank 9 into an AC voltage that meets the grid requirements, providing compensation voltage for the power supply system. It can also rectify the AC voltage of the grid into a DC voltage when the grid voltage is stable and the supercapacitor bank 9 is undercharged, charging the supercapacitor bank 9. This achieves bidirectional energy flow and stable transmission, with a conversion efficiency of over 95%, meeting the energy transmission requirements of the high-voltage power supply system for electric shovels.

[0062] like Figure 1 The diagram illustrates a self-stabilizing device for a high-voltage power supply system of an electric shovel based on a DVR energy compensation strategy. The LC filter module 7 consists of a filter inductor and a filter capacitor forming an LC low-pass filter, used to filter out high-order harmonics from the output of the three-phase inverter, suppress harmonic interference to the power supply system, ensure the waveform quality of the compensation voltage, and keep the compensation voltage injected into the power supply system consistent with the grid voltage waveform, thus avoiding damage to the electric shovel's electrical components caused by harmonic distortion.

[0063] like Figure 1 The diagram illustrates a self-stabilizing device for a high-voltage power supply system of an electric shovel based on a DVR energy compensation strategy. The supercapacitor bank 9 is constructed using a series and parallel combination. A voltage equalization circuit is used to achieve voltage balance among the supercapacitor units, enabling real-time adjustment of the terminal voltage of each supercapacitor unit. This avoids voltage imbalance caused by manufacturing errors or wear and tear of the capacitor units, prevents overvoltage damage to individual capacitor units, and extends the overall service life of the supercapacitor bank. In addition, the drive module has built-in overcurrent, overvoltage, and overheat protection. The sealing design of each module of the device has a protection level of ≥IP65. The supercapacitors operate in a temperature range of -40℃ to 70℃, making them suitable for harsh environments such as mines, plateaus, and mountains, and providing stable DC voltage support for the compensation module.

[0064] like Figure 1 The diagram shows a self-stabilizing device for a high-voltage power supply system for electric shovels based on a DVR energy compensation strategy. The SOC monitoring module 8 integrates a voltage acquisition unit, a current acquisition unit, and a state of charge calculation chip. It calculates the actual state of charge of the supercapacitor bank 9 in real time and transmits the calculation results to the DSP controller 4 through a signal line. This provides energy storage status feedback for the compensation strategy calculation of the control module, enabling real-time monitoring and early warning of abnormalities in the energy storage status.

[0065] like Figure 1The diagram illustrates a self-stabilizing device for a high-voltage power supply system of an electric shovel based on a DVR energy compensation strategy. The control module includes submodules for voltage deviation calculation, compensation voltage command generation, energy storage state judgment, and charge / discharge control. It introduces state of charge (SOC) feedback for the energy storage to achieve coordinated control of the compensation voltage and the energy storage state. Specifically:

[0066] Voltage Deviation Calculation Submodule: Receives the input and output voltage RMS values ​​transmitted by the voltage monitoring module, combines them with the rated output RMS value of the electric shovel's high-voltage power supply system, and calculates the actual voltage deviation ΔU, providing a basis for calculating the compensation voltage;

[0067] The compensation voltage command generation submodule calculates the required compensation voltage U based on the PID control algorithm and the voltage deviation ΔU and SOC feedback signal. comp It generates corresponding PWM drive instructions to provide control signals for the three-phase bridge inverter topology;

[0068] Energy storage status determination submodule: Receives the actual state of charge transmitted from the SOC monitoring module 8 and compares it with the rated state of charge (SOC). ref By comparison, the charging and discharging requirements of supercapacitor group 9 are determined. When SOC < 0.4, it is determined to be undercharging; when SOC > 0.8, it is determined to be overcharging; when 0.4 ≤ SOC ≤ 0.8, it is determined to be within the normal operating range.

[0069] Charge and discharge control submodule: Based on the energy storage status judgment result, it generates charge and discharge control signals for bidirectional DC / DC converter 6 to control the charging, discharging or standby state of supercapacitor group 9, thereby maximizing the energy storage utilization rate.

[0070] A self-stabilizing method for a high-voltage power supply system of an electric shovel based on a DVR energy compensation strategy is applied to any of the self-stabilizing devices mentioned above. This method employs a closed-loop real-time control strategy to achieve dynamic and stable control of the output voltage of the high-voltage power supply system of the electric shovel, and includes the following steps:

[0071] S1. Real-time acquisition and transmission of voltage signals

[0072] Input voltage monitoring module 2 and output voltage monitoring module 5 respectively collect the input voltage U of the electric shovel's high-voltage power supply system in real time. in and output voltage U out The collected voltage signal is then transmitted to the control module.

[0073] S2, Voltage Signal Preprocessing

[0074] The control module preprocesses the acquired voltage signal, including filtering, synchronization, and RMS calculation, to obtain the RMS value U of the input voltage. in（rms） and the effective value of the output voltage U out（rms） ;

[0075] S3. Voltage Deviation Calculation and Compensation Requirement Judgment

[0076] Based on the pre-processed effective voltage value, the voltage deviation ΔU is first calculated to determine whether the voltage deviation ΔU meets the power supply requirements of the equipment.

[0077] The voltage deviation ΔU and the compensation voltage U comp The calculation formula is:

[0078] ΔU=U ref -U out（rms）

[0079] Among them, U ref This is the rated effective value of the high-voltage power supply system for the electric shovel; it is a fixed value preset in the DSP controller 4 according to the technical parameters of the electric shovel equipment.

[0080] After completing the voltage deviation calculation, compare |ΔU| with the maximum allowable voltage deviation value of the electric shovel equipment (preset as U). ref Compare |ΔU| to 15% of the original value to determine if the voltage deviation meets the equipment power supply requirements: if |ΔU| ≤ 15%U ref If the voltage deviation is deemed to meet the requirements, the power supply system does not require compensation; if |ΔU|>15%U ref The voltage deviation is determined to be non-compliant, and the power supply system needs voltage compensation.

[0081] S4. Compensation Voltage Calculation and Switch Control

[0082] If the voltage deviation meets the equipment power supply requirements, switch 3 remains closed, DVR energy compensation module 1 is in standby mode, and the electric shovel high-voltage power supply system is directly powered by the mine power grid.

[0083] If the voltage deviation does not meet the requirements, the required compensation voltage U is calculated based on the improved energy storage DVR compensation strategy and the state of charge (SOC) of the energy storage module. comp At the same time, a disconnect command is sent to the switching switch 3 to enable the DVR energy compensation module 1 to engage in the electric shovel high-voltage power supply system and prepare to inject compensation voltage.

[0084] The compensation voltage U comp The calculation formula is:

[0085] U comp =K p •ΔU+K i •ʃΔUdt+K d •(dΔU / dt)+K soc •(SOC ref -SOC)

[0086] Among them, Kp K i K d These are the proportional coefficient, integral coefficient, and derivative coefficient of the PID controller, respectively, K. soc The feedback coefficient of SOC, SOC ref and SOC are the rated state of charge and actual state of charge of the energy storage module, respectively;

[0087] The formula for calculating the State of Charge (SOC) of the energy storage module is as follows:

[0088]

[0089] Where SOC0 is the initial state of charge of the energy storage module, and C sc i represents the capacitance value of the supercapacitor. sc (t) represents the charging and discharging current of the supercapacitor; it is collected in real time by the current sensor of the SOC monitoring module 8, and the change in the amount of supercapacitor charge is obtained through integration calculation, thereby calculating the actual state of charge (SOC).

[0090] S5, Generation of drive signal and charge / discharge control signal

[0091] DSP controller 4 calculates the compensation voltage U comp Combining the phase information of the grid voltage, the space vector pulse width modulation (SVPWM) technique is used to generate the PWM drive signal for the DVR compensation module. The duty cycle is based on the compensation voltage U. comp The size of the dynamic adjustment is used to control the on / off timing of the IGBT power switches in the bidirectional DC / DC converter 6;

[0092] The instantaneous value of the compensation voltage u output by the three-phase inverter comp (t) is generated using Space Vector Pulse Width Modulation (SVPWM) technology, and the calculation formula is as follows:

[0093]

[0094] Among them, U dc M represents the DC voltage output by the energy storage module, and M is the modulation ratio. The angular frequency of the power grid. To compensate for the phase difference between the voltage and the grid voltage, n is the harmonic order;

[0095] The output voltage U of the bidirectional DC / DC converter dc The control formula is:

[0096] U dc =U sc ×(N1 / N2)×D

[0097] Among them, U scN1 is the terminal voltage of the supercapacitor, N1 / N2 is the transformation ratio, and D is the duty cycle of the converter.

[0098] S6, Compensation voltage injection and charge / discharge operation execution

[0099] After receiving the drive signal and charge / discharge control signal output by the DSP controller 4, the DVR energy compensation module 1 first amplifies the drive signal to drive the three-phase bridge inverter topology of the bidirectional DC / DC converter 6 to work, converting the DC voltage output by the supercapacitor bank 9 into an AC compensation voltage. After the LC filter module 7 filters out high-order harmonics, the compensation voltage U... comp Precise injection into the main circuit of the electric shovel's high-voltage power supply system achieves voltage compensation, enabling the power supply system's output voltage to quickly recover to its rated effective value U. ref ;

[0100] Specifically, the bidirectional DC / DC converter 6 includes a three-phase bridge inverter topology composed of multiple IGBT power switches, which can perform charging and discharging operations.

[0101] When the voltage supplied by the power grid in the mining area is higher than the forward threshold required by the equipment, the bridge circuit in the bidirectional DC / DC converter 6 is forward-biased, and the supercapacitor group 9 is charged. The supercapacitor group 9 absorbs the "surplus" power in the power grid.

[0102] When the voltage supplied by the power grid in the mining area is lower than the negative threshold required by the equipment, the bridge circuit in the bidirectional DC / DC converter 6 conducts in reverse, and the supercapacitor bank 9 discharges, releasing the stored electricity to replenish the system's power.

[0103] Meanwhile, the bidirectional DC / DC converter 6 and the supercapacitor bank 9 perform precise charging and discharging operations according to the charging and discharging control signal: during charging, the grid energy is rectified and then charged to the supercapacitor bank 9 through the charging circuit. The charging current is limited by the current limiting resistor to avoid overcurrent charging; during discharging, the supercapacitor bank 9 releases energy to the bidirectional DC / DC converter 6 through the discharging circuit. The discharging current is dynamically adjusted according to the magnitude of the compensation voltage to ensure a stable output of the compensation voltage.

[0104] The output voltage U of the electric shovel's high-voltage power supply system out With input voltage U in Compensation voltage U comp The relationship formula is:

[0105]

[0106] Among them, U comp（rms） To compensate for the effective value of the voltage, This represents the phase difference between the input voltage and the compensation voltage.

[0107]

[0108] Where T is the sampling period;

[0109] S7, cyclic control achieves real-time voltage regulation.

[0110] Repeat steps S1-S6 to achieve real-time stable control of the output voltage of the electric shovel's high-voltage power supply system.

[0111] To further improve the voltage regulation and control effect of the device, this invention also includes charging and discharging power, compensation power, voltage stability accuracy, and compensation strategy response time as supplementary control factors to achieve multi-parameter coordinated control, as detailed below:

[0112] The charging and discharging power P of the energy storage module sc The calculation formula is:

[0113] P sc =U sc ×i sc (t)

[0114] Among them, by calculating the charging and discharging power in real time, the maximum charging and discharging power is limited to avoid over-power charging and discharging of the supercapacitor bank 9;

[0115] The compensation power P of the DVR module comp The calculation formula is:

[0116]

[0117] Among them, I out（rms） This refers to the effective value of the output current of the electric shovel's high-voltage power supply system. To compensate for the power factor, the compensation power is calculated and matched to the output power of supercapacitor group 9 to ensure the compensation effect.

[0118] The formula for calculating the voltage stability accuracy δ of the high-voltage power supply system of the electric shovel is:

[0119] δ=|ΔU| / U ref ×100%

[0120] The present invention has a provisional accuracy of 1%. By calculating the voltage stability accuracy in real time and dynamically adjusting the parameters of the PID controller, the voltage stability accuracy is always maintained within 1%.

[0121] The response time t of the DVR module compensation strategy res The calculation formula is:

[0122]

[0123] Where, ω n Let ω be the system's natural angular frequency, γ be the damping coefficient, and ΔU be the frequency. maxFor the maximum voltage deviation, ΔU tol To determine the allowable voltage deviation value for the system, the operation logic of the control program is optimized by calculating the response time, thereby controlling the response time of the compensation strategy to within 5ms and achieving rapid suppression of dynamic voltage fluctuations.

[0124] This invention relates to a self-stabilizing device and method for a high-voltage power supply system for electric shovels based on a DVR energy compensation strategy. The device includes a voltage monitoring module, a DVR energy compensation module, and a control module. The voltage monitoring module acquires input and output voltage signals in real time. The DVR energy compensation module integrates a bidirectional DC / DC converter, an LC filter module, a SOC monitoring module, and a supercapacitor bank. The control module uses a DSP controller as its core and incorporates SOC feedback from energy storage to achieve coordinated control. The method involves steps such as voltage acquisition, preprocessing, deviation calculation, compensation strategy generation, drive signal output, compensation voltage injection, and cyclic control. It combines an improved energy storage-based DVR compensation strategy with SVPWM technology to quickly and accurately adjust the power supply voltage. This invention addresses the problems of large voltage fluctuations, poor voltage stabilization, and low energy storage utilization in existing electric shovel high-voltage power supply systems. It boasts advantages such as high voltage stabilization accuracy, fast response speed, high energy storage efficiency, and strong reliability. It can be directly applied to high-voltage power supply systems for various mining electric shovels and is also adaptable to voltage stabilization scenarios for other heavy-duty electrical equipment in mines. The device has a compact structure and is easy to install; the method and algorithm are simple and easy to implement. It can significantly improve the voltage stability and power quality of electric shovel high-voltage power supply systems, reduce equipment failure probability and maintenance costs, and increase the efficiency of mining operations. It has significant industrial application value and economic benefits and is suitable for large-scale promotion and application.

[0125] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0126] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features found in other embodiments but not others, combinations of features from different embodiments are also within the scope of protection of this invention and form different embodiments. For example, in the embodiments described above, those skilled in the art can use them in combination based on known technical solutions and the technical problems to be solved by this application.

[0127] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A self-stabilizing device for a high-voltage power supply system of an electric shovel based on a DVR energy compensation strategy, characterized in that: The system includes a voltage monitoring module, a DVR energy compensation module, and a control module. The voltage monitoring module includes an input voltage monitoring module (2) and an output voltage monitoring module (5) installed on the electric shovel's high-voltage power supply system. The DVR energy compensation module (1) includes a bidirectional DC / DC converter (6), an LC filter module (7), a SOC monitoring module (8), and a supercapacitor group (9). The control module includes a DSP controller (4). A switching switch (3) is provided between the DVR energy compensation module (1) and the electric shovel's high-voltage power supply system. The DSP controller (4) is connected to the voltage monitoring module (2), the output voltage monitoring module (5), the switching switch (3), and the SOC monitoring module (8).

2. The self-stabilizing device for a high-voltage power supply system for an electric shovel based on a DVR energy compensation strategy as described in claim 1, characterized in that: The bidirectional DC / DC converter (6) includes a three-phase bridge inverter topology consisting of multiple IGBT power switches.

3. The self-stabilizing device for a high-voltage power supply system for an electric shovel based on a DVR energy compensation strategy as described in claim 1, characterized in that: The LC filter module (7) consists of a filter inductor and a filter capacitor forming an LC low-pass filter, used to filter out high-order harmonics from the output of the three-phase inverter.

4. The self-stabilizing device for a high-voltage power supply system for an electric shovel based on a DVR energy compensation strategy as described in claim 1, characterized in that: The supercapacitor bank (9) adopts a combination of series and parallel connections, and the voltage of each supercapacitor unit is balanced through a voltage equalization circuit.

5. The self-stabilizing device for a high-voltage power supply system for an electric shovel based on a DVR energy compensation strategy as described in claim 1, characterized in that: The control module includes sub-modules for voltage deviation calculation, compensation voltage command generation, energy storage state judgment, and charge / discharge control. It introduces energy storage state of charge (SOC) feedback to achieve coordinated control of compensation voltage and energy storage state.

6. A self-stabilizing method for a high-voltage power supply system for electric shovels based on a DVR energy compensation strategy, applied to the self-stabilizing device described in any one of claims 1-5, characterized in that, Includes the following steps: S1, the input voltage monitoring module (2) and the output voltage monitoring module (5) respectively collect the input voltage of the electric shovel high voltage power supply system in real time. U in and output voltage U out The collected voltage signal is then transmitted to the control module. S2. The control module preprocesses the acquired voltage signal, including filtering, synchronization, and RMS calculation, to obtain the RMS value of the input voltage. U in（rms） and the effective value of the output voltage U out（rms） ; S3, Calculate voltage deviation ΔU Determine voltage deviation ΔU Does it meet the equipment power supply requirements? S4. If the requirements are met, switch (3) remains closed; if the requirements are not met, the required compensation voltage is calculated based on the state of charge (SOC) of the energy storage module according to the improved energy storage DVR compensation strategy. U comp Disconnect the switch (3); S5. Based on the calculated compensation voltage U comp Generate the drive signal for the DVR compensation module and generate the charge / discharge control signal for the bidirectional DC / DC converter (6) based on the state of charge (SOC). S6, DVR energy compensation module (1) will compensate voltage U comp The high-voltage power supply system of the electric shovel, the bidirectional DC / DC converter (6) and the supercapacitor group (9) perform charging and discharging operations according to the charging and discharging control signal; S7. Repeat steps S1-S6 to achieve real-time stable control of the output voltage of the electric shovel's high-voltage power supply system.

7. The self-stabilizing method for a high-voltage power supply system for electric shovels based on a DVR energy compensation strategy as described in claim 6, characterized in that: In steps S3 and S4, the voltage deviation ΔU and the compensation voltage U comp The calculation formula is: ΔU=U ref －U out（rms） U comp =K p •ΔU+K i •ʃΔUdt+K d •(dΔU / dt)+K soc •(SOC ref -SOC) in, K p 、K i 、K d These are the proportional coefficient, integral coefficient, and derivative coefficient of the PID controller. K soc The feedback coefficient of SOC. SOC ref and SOC These are the rated state of charge and the actual state of charge of the energy storage module, respectively. U ref This refers to the rated effective output value of the high-voltage power supply system for electric shovels.

8. The self-stabilizing method for a high-voltage power supply system for electric shovels based on a DVR energy compensation strategy as described in claim 7, characterized in that: The formula for calculating the State of Charge (SOC) of the energy storage module is as follows: ； in, SOC 0 This represents the initial state of charge of the energy storage module. C sc This refers to the capacitance value of the supercapacitor. i sc (t) This refers to the charging and discharging current of the supercapacitor.

9. The self-stabilizing method for a high-voltage power supply system for an electric shovel based on a DVR energy compensation strategy as described in claim 6, characterized in that: In step S5, the instantaneous value of the compensation voltage output by the three-phase inverter u comp (t) It is generated using Space Vector Pulse Width Modulation (SVPWM) technology, and the calculation formula is as follows: ； in, U dc M represents the DC voltage output by the energy storage module, and M is the modulation ratio. The angular frequency of the power grid. To compensate for the phase difference between the voltage and the grid voltage, n For harmonic order; The output voltage of the bidirectional DC / DC converter U dc The control formula is: U dc =U sc ×(N 1 / N 2 )×D in, U sc This is the terminal voltage of the supercapacitor. N1 / N2 The transformation ratio is... D This represents the duty cycle of the converter.

10. The self-stabilizing method for a high-voltage power supply system for an electric shovel based on a DVR energy compensation strategy as described in claim 6, characterized in that: Output voltage of electric shovel high-voltage power supply system U out With input voltage U in Compensation voltage U comp The relationship formula is: ； in, U comp（rms） To compensate for the effective value of the voltage, This represents the phase difference between the input voltage and the compensation voltage.

Images