A locomotive power supply control method based on sensorless speed estimation

Abstract

The application provides a locomotive power supply control method and device based on sensorless speed estimation, which comprises the following steps: establishing a first DC bus through battery boosting, forming a second DC bus after boosting, estimating the locomotive motor speed in real time based on a sensorless speed estimation algorithm, enabling battery power supply if the speed does not reach a threshold, exciting and controlling the traction motor at a constant voltage if the speed reaches the standard, generating electricity through SVPWM modulation driving an inverter, reducing the second DC bus to the first DC bus, and inversely converting the first DC bus into single-phase alternating current output. The application solves the technical problem of the risk of main system interference caused by modifying the locomotive traction converter software in the prior art.

Description

Technical Field

[0001] This invention relates to the field of motor drive technology, and more specifically to a locomotive power supply control method based on sensorless speed estimation. Background Technology

[0002] Starting April 1, 2015, China Railway Corporation restructured its Harmony-type locomotives, establishing six maintenance levels: C1, C2, C3, C4, C5, and C6. C1-C4 maintenance is at the section level, while C5 and C6 are higher-level maintenance. Within the section level, some locomotive depots in China lack the capability for C4 maintenance, requiring the assigned locomotives to be transported to depots with C4 maintenance capabilities via a fireless return process. C5 and C6 maintenance are completed at locomotive factories or repair bases, as these cannot be completed within railway bureaus or sections, and also require fireless return transport to locomotive factories or repair bases for repair. As time goes on, more and more locomotives will face high-level maintenance procedures such as C4, C5, and C6. When locomotives are returned to service without power, the pantograph is lowered and there is no electricity, resulting in poor working conditions for the accompanying drivers and crew. As a result, violations of operating procedures and safety accidents have become commonplace. Improving the working conditions for drivers and crew during locomotive return without power is a difficult problem that locomotive users need to solve under the background of safe production.

[0003] Current solutions include utilizing the rotational mechanical energy of the locomotive traction motor during the fireless return process to generate electricity through regenerative braking control of the traction inverter, thereby powering the locomotive's auxiliary equipment. However, the locomotive traction inverter plus traction motor mode requires modification of the locomotive traction converter software, which poses a risk of affecting the main converter. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a locomotive power supply control method based on sensorless speed estimation, in order to solve the technical problem in existing technologies where regenerative braking control of the traction inverter affects the main converter.

[0005] The technical solution adopted in this invention is a locomotive power supply control method based on sensorless speed estimation, comprising: Real-time speed estimation of locomotive motor rotor to generate locomotive motor speed; If the locomotive motor speed does not reach the set threshold, the battery will be used to supply power to civilian loads. If the locomotive motor speed reaches the set threshold, the traction inverter is controlled to excite the locomotive motor. When the excitation time reaches the set time, the traction inverter is controlled to supply power to the outside.

[0006] Furthermore, the rotational speed of the locomotive motor rotor is estimated, including: Based on the input voltage and switching state of the traction inverter, the stator voltage of each camera car motor is reconstructed, and the specific calculation formula is as follows: in, This indicates the stator voltage of the locomotive motor in phase A reconfiguration. This indicates the stator voltage of the B-phase reconfigured locomotive motor. This indicates the stator voltage of the C-phase reconfigured locomotive motor. This indicates the voltage of the second bus. , and These represent the drive signals of the three-phase switching transistors in the three-phase bridge arm of the traction inverter.

[0007] Furthermore, the rotational speed of the locomotive motor rotor is estimated to generate the locomotive motor speed, including: Before the excitation time reaches the set time, the MRAS algorithm is used to estimate the locomotive motor speed of the locomotive motor rotor and generate the locomotive motor speed. After the excitation time reaches the set time, the locomotive motor rotor is estimated using the full-order flux linkage observation algorithm to generate the locomotive motor speed.

[0008] Furthermore, the MRAS algorithm is used to estimate the locomotive motor speed of the locomotive motor rotor, including: The stator current and stator voltage sample values ​​are transformed using Clarke to obtain the voltage and current components of the locomotive motor stator voltage and stator current in the α-β coordinate system. The stator flux linkage is calculated in the voltage model based on the voltage and current components. In the current model, the rotor flux linkage and rotor electric angular velocity are calculated based on the current components. The reference model and the adjustable model are compared according to the following formula to obtain the error signal: in, Indicates the error signal. The stator flux linkage component representing the d-axis. The stator flux linkage component representing the q-axis. Indicates rotor flux linkage. Indicates the rotor's electrical angular velocity; The error signal is PI-regulated according to preset control parameters to output the angular velocity of the locomotive motor rotor and feed it back to the current model.

[0009] Furthermore, the stator flux linkage is calculated according to the flux linkage estimation formula described below: in, The magnetic flux linkage along the d-axis, The magnetic flux linkage along the q-axis is represented by... and These represent the voltage components of the locomotive motor stator voltage in the α and β coordinate systems, respectively. and These represent the stator current components in the α and β coordinate systems, respectively. express, Indicates the leakage inductance coefficient. Indicates stator inductance, Indicates rotor inductance, This indicates the mutual inductance between the locomotive motor rotor and stator.

[0010] Furthermore, the locomotive motor rotor speed is estimated using a full-order flux linkage observation algorithm, including: based on the stator flux linkage... The stator current and stator voltage sample values ​​are transformed using Clarke to obtain the voltage and current components of the locomotive motor stator voltage and stator current in the α-β coordinate system. Based on the estimated values ​​of stator flux linkage and rotor flux linkage from the feedback, the estimated value of stator current is calculated in the stator current estimation algorithm; Based on the voltage component, current component, stator current estimate, and the feedback stator flux estimate and rotor flux estimate, the stator flux estimate is calculated in the stator flux estimate algorithm and used for feedback output; Based on the stator current estimate, the feedback stator flux estimate, the rotor flux estimate, and the feedback estimated speed, the rotor flux estimate is calculated in the stator flux estimate algorithm and used for feedback output. The error between the sampled stator current value and the estimated stator current value is calculated based on the speed estimation algorithm, and the estimated speed is generated by PI regulation and used for feedback output.

[0011] Furthermore, controlling the traction inverter to excite the locomotive motor includes: Decouple the stator current into torque current and excitation current; The rotor flux linkage and electromagnetic torque are calculated based on the torque current and excitation current, and the rotor electrical angle is calculated by combining the torque current, rotor flux linkage and locomotive motor speed. The rotor electrical angle is converted into rotor speed, and a magnetic flux reference value is set according to the rotor speed. The rotor flux linkage and the flux linkage reference value are adjusted by PI control according to the flux linkage control parameters to generate the excitation current command.

[0012] Furthermore, when the excitation time reaches the set time, the traction inverter is controlled to supply power externally, including: Based on the DC control parameters, the reference voltage and input voltage of the traction inverter are adjusted by a PI controller to generate the desired electromagnetic torque command. Based on the electromagnetic torque control parameters, the desired electromagnetic torque command and the electromagnetic torque are used to generate a torque current command through PI regulation. Based on the torque current control parameters, the torque current command and the torque current are adjusted via PI to generate a voltage component in the direction of the torque current. The rotor electrical angle is converted into rotor speed, and a magnetic flux reference value is set according to the rotor speed. The excitation current command and the excitation current are adjusted by PI control according to the excitation current control parameters to generate a voltage component in the direction of the excitation current. Based on the inverse Pakr transform formula, the stator voltage of the computer motor is: in, The voltage component indicating the direction of the excitation current. The voltage component indicating the direction of the torque current. Indicates the rotor electrical angle, and The voltage component representing the stator voltage of the locomotive motor; The stator voltage of the locomotive motor is input to the SVPWM algorithm to generate a three-phase modulated wave signal, which is used to drive the three-phase bridge arm of the traction inverter.

[0013] Furthermore, before the excitation time reaches the set time, the rotor flux and flux reference value are adjusted by PI to generate an excitation current command according to the standard flux control parameters. After the excitation time reaches the set time, the flux linkage control parameter is set to the maximum flux linkage control parameter; Furthermore, setting a flux linkage reference value based on the rotor speed includes: The rotor speed is fed into the flux linkage command function as described below, and the flux linkage reference value is set according to the speed: in, The value represents the reference value of the magnetic flux, n represents the rotor speed, and N represents the rated speed.

[0014] As can be seen from the above technical solution, the beneficial technical effects of the present invention are as follows: 1. By quickly capturing the rotational speed through a speed estimation algorithm and performing excitation and direct voltage control on the locomotive motor, stable power generation of the locomotive traction motor during the fireless return process can be achieved.

[0015] 2. By simply modifying the wiring to connect the locomotive motor, power generation control can be achieved without modifying the locomotive software or adding sensors, further enhancing the compatibility of this invention. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0017] Figure 1 This is a flowchart illustrating the startup process of Embodiment 1 of the present invention; Figure 2 This is a flowchart illustrating the battery-powered operation in Embodiment 1 of the present invention; Figure 3 This is a flowchart illustrating the shutdown process of Embodiment 1 of the present invention; Figure 4 This is a block diagram of the boost control system in Embodiment 1 of the present invention; Figure 5 This is a block diagram of the MRAS velocity estimation algorithm in Embodiment 1 of the present invention; Figure 6 This is a flowchart of the overall algorithm for the full-order chain observer in Embodiment 1 of the present invention; Figure 7 This is a block diagram of the velocity estimation algorithm in Embodiment 1 of the present invention; Figure 8 This is a flowchart of the full-order chain observation output rotor angle algorithm in Embodiment 1 of the present invention; Figure 9 This is a block diagram of rotor flux linkage calculation in Embodiment 1 of the present invention; Figure 10 This is a block diagram for calculating the rotor electrical angle in Embodiment 1 of the present invention; Figure 11 This is a block diagram of the direct voltage control and flux linkage closed-loop control of the traction inverter in Embodiment 1 of the present invention; Figure 12 This is a block diagram of the buck loop step-down control structure of Embodiment 1 of the present invention; Figure 13 This is a block diagram of the single-phase inverter control according to Embodiment 1 of the present invention; Figure 14 This is a block diagram of the charging current control in Embodiment 1 of the present invention; Figure 15 This is a schematic diagram of the device in Embodiment 2 of the present invention; Figure 16 This is the overall topology diagram of the device in Embodiment 2 of the present invention. Detailed Implementation

[0018] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0019] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0020] This embodiment provides a locomotive power supply control method based on sensorless speed estimation. The working principle of Embodiment 1 is explained in detail below: The startup process in this embodiment is as follows: Figure 1 As shown, it includes: The battery voltage is boosted to establish a first DC bus of 400V.

[0021] The first DC bus is boosted to a second DC bus of 600V.

[0022] The stator voltage of the locomotive motor is digitally reconstructed based on the second DC bus and the switch status.

[0023] Generate an estimated locomotive motor speed for the locomotive motor rotor.

[0024] If the locomotive motor speed does not reach the set threshold, battery power will be activated.

[0025] If the locomotive motor speed reaches the set threshold, the locomotive motor will be energized and subjected to direct voltage control.

[0026] The traction inverter initiates regenerative braking to build up voltage on the second DC bus.

[0027] The voltage of the two DC buses is converted into the voltage of the first DC bus.

[0028] The voltage of the first DC bus is converted into single-phase AC output for power supply to civilian loads. At the same time, the battery is charged when the battery power is below the limit.

[0029] The battery used in this embodiment is a built-in portable storage battery, which provides the energy required for control and traction inverter excitation. In other embodiments, the voltage provided by the locomotive's own battery can be boosted to establish a 400V first DC bus. The storage battery only serves as a starting source; when the rotational speed is insufficient, it automatically switches to battery power to maintain basic lighting and charging, preventing system shutdown.

[0030] In this embodiment, after converting the voltage of the first DC bus into a single-phase AC output, the method further includes charging the battery based on a constant current control strategy.

[0031] The full-order flux linkage observation algorithm is continuously used to estimate the locomotive motor speed of the locomotive motor rotor.

[0032] If the locomotive motor speed does not reach the set threshold, the locomotive motor power generation will be stopped and battery power will be used.

[0033] In this embodiment, the flowchart for enabling battery power is as follows: Figure 2 As shown, it includes: boosting the battery voltage via a bidirectional DC-DC converter to establish a first DC bus.

[0034] The voltage of the first DC bus is converted into single-phase AC output via an isolated single-phase inverter.

[0035] During the above process, if the portable power bank's battery is low, then according to... Figure 3 The shutdown procedure shown executes the shutdown commands sequentially.

[0036] In this embodiment, boosting the battery voltage to establish the first DC bus includes: boosting the battery voltage through a first DC converter to establish the first DC bus. The inverter side of the first DC converter is controlled as a fixed-frequency PWM (first resonant frequency, 50% duty cycle, dead time 300ns), and the rectifier side is uncontrolled rectification, requiring no additional control.

[0037] The first DC bus voltage is boosted to the second DC bus voltage via a second DC converter. The boost control block diagram is as follows: Figure 4 As shown, it includes establishing a PWM control structure based on DC voltage error closed loop, and generating an error signal by comparing the reference voltage (Udc600ref) and the actual voltage (Udc600) of the second DC bus.

[0038] According to the preset control parameters ( Take 1.5, The error signal is PI-regulated by taking 0.1, and the duty cycle command is output to dynamically generate the PWM duty cycle command.

[0039] The PWM signal generated according to the duty cycle command drives the power switch in the boost circuit to maintain the stability of the second DC bus voltage.

[0040] In this embodiment, the stator voltage of the locomotive motor is digitally reconstructed based on the second DC bus and the switching state. This includes: reconstructing the stator voltage of each phase-shifting car motor based on the second DC bus voltage and the switching state of the inverter for subsequent locomotive motor speed estimation and control. The voltage reconstruction requires the use of three-phase switching transistors PWM23, PWM25, and PWM27 in the traction inverter, as well as 600V direct voltage sampling. The stator voltage of each phase-shifting car motor is reconstructed according to the locomotive motor stator voltage calculation formula described below: in, This indicates the stator voltage of the locomotive motor in phase A reconfiguration. This indicates the stator voltage of the B-phase reconfigured locomotive motor. This indicates the stator voltage of the C-phase reconfigured locomotive motor. This indicates the DC second bus voltage. , and These represent the drive signals for the three-phase switching transistors in the three-phase bridge arm.

[0041] In this embodiment, velocity estimation is performed by two separate velocity estimation algorithms: the MRAS velocity estimation algorithm and the full-order flux linkage observation velocity estimation algorithm. The advantages and disadvantages of the two algorithms are as follows: The advantage of the MRAS speed estimation algorithm is that it tracks the speed quickly and can be used for speed testing before the device is connected to generate electricity (to determine whether the speed has reached the range of the generating speed) and during the excitation stage. The disadvantage is that after the 600V direct voltage generates active power under load, the speed estimation will cause a steady-state error. The larger the active power, the larger the steady-state error. If the steady-state error of the speed estimation is too large, the rotor flux will be uncontrollable.

[0042] The advantage of full-order flux observation speed estimation is that the steady-state error generated by speed estimation is much smaller when under load, and it can be used for direct voltage control in the load generation stage after excitation is completed; the disadvantage is that the initial tracking speed is slow, so it cannot be used for speed testing and excitation stage.

[0043] Therefore, before excitation, the MRAS algorithm is used to estimate the locomotive motor rotor speed, generating the locomotive motor speed. After excitation, the full-order flux linkage observation speed estimation algorithm is used to generate the estimated locomotive motor rotor speed. Accurate speed estimation via algorithms eliminates the need for hardware sensors, reducing maintenance costs and improving the applicability of this method.

[0044] In this embodiment, the MRAS velocity estimation algorithm block diagram is further shown as follows: Figure 5 As shown, the locomotive motor speed estimation using the MRAS algorithm includes: Using three-phase quantities directly for modeling and calculation is quite complex. The Clarke transform converts the quantities in the three-phase stationary coordinate system into a two-phase orthogonal stationary coordinate system. This achieves two-phase equivalence, reducing the amount of computation while preserving energy equivalence. Therefore, the stator current sampling values ​​are transformed using the Clarke transform to obtain the voltage and current components of the locomotive motor stator voltage and stator current in the α-β coordinate system. in, , and These represent the sampled values ​​of the three-phase stator current. , and These represent the sampled values ​​of the stator voltage of the three-camera motor.

[0045] A reference model is an idealized output signal introduced into a control system that describes the desired dynamic response of the system; in this embodiment, a voltage model is selected. An adjustable model is one whose parameters can be adjusted. The model used to match the reference model is typically a low-order dynamic system; in this embodiment, a current model is chosen. In the reference model, the stator flux linkage is calculated using the flux linkage estimation formula described below: in, The magnetic flux linkage along the d-axis, The magnetic flux linkage along the q-axis is represented by... and These represent the voltage components of the locomotive motor stator voltage in the α and β coordinate systems, respectively. and These represent the stator current components in the α and β coordinate systems, respectively. express, Indicates the leakage inductance coefficient. Indicates stator inductance, Indicates rotor inductance, This indicates the mutual inductance between the locomotive motor rotor and stator.

[0046] Wherein, the leakage inductance coefficient is: In the adjustable model, the rotor flux linkage and rotor electric angular velocity are calculated based on the stator current: The reference model and the adjustable model are compared to obtain the error signal: in, Indicates the error signal. The magnetic flux linkage along the d-axis, The magnetic flux linkage along the q-axis is represented by... Indicates rotor flux linkage. This indicates the rotor's electrical angular velocity.

[0047] According to the preset control parameters ( Take 6500, The error signal is PI-regulated (taking 1000) to output the estimated angular velocity of the locomotive motor rotor. Used for estimating locomotive motor speed: In this embodiment, the overall algorithm flowchart of the full-order chain observer is as follows: Figure 6 As shown, the velocity estimation algorithm flowchart in the overall algorithm of the full-order chain observer is as follows: Figure 7 As shown, its control parameters are shown in Table 1: Table 1. Velocity estimation parameters for the full-order flux linkage observer In the overall algorithm of the full-order chain observer, the stator current and stator voltage are calculated using the Clark transform with a 3 / 2 equal amplitude as shown below: Estimated value of stator current , The calculation is as follows: The estimated value of stator flux linkage is calculated as follows: The rotor flux linkage is estimated as follows: In the formulas for estimating stator flux linkage and rotor flux linkage, the coefficient k is the speed adaptive rate coefficient, which is set to 0.7.

[0048] Full-order chain observation velocity estimation output rotational speed The corresponding rotor angle Calculation as Figure 8 As shown, by converting the two flux linkage estimates into amplitude and angle as real and imaginary parts respectively, we can obtain... The conversion calculation is as follows: In this embodiment, furthermore, if the locomotive motor speed reaches a set threshold, the locomotive motor is subjected to excitation and direct voltage control. Excitation control means that when the locomotive motor speed reaches the set threshold, a magnetic field needs to be established for the locomotive motor, i.e., excitation; otherwise, the locomotive motor cannot generate electricity normally. The excitation process is achieved by applying appropriate voltage and current to the stator of the locomotive motor through the traction inverter to gradually establish the rotor flux linkage.

[0049] After the locomotive motor under direct voltage control starts generating electricity, the voltage at the locomotive motor terminal is regulated by the traction inverter to ensure that the output voltage can be stably maintained at the target bus voltage, which in this embodiment is to maintain the second bus voltage of 600V.

[0050] In this embodiment, the three-phase stator current of the locomotive motor is first collected, and the stator current is subjected to an equal power dq coordinate transformation to decouple the stator current into torque current and excitation current: in, Indicates the excitation current. Represents torque current. , , These represent the three-phase stator currents.

[0051] The rotor flux linkage calculation flowchart is as follows: Figure 9 As shown, the rotor flux linkage is calculated based on the torque current and excitation current according to the rotor flux linkage calculation formula described below: in, Indicates rotor flux linkage. This indicates the mutual inductance between the locomotive motor rotor and stator. Indicates the excitation current. The electromagnetic time constant of the rotor is represented by... To address the flux attenuation caused by rotor resistance, a closed-loop observer is designed, and a negative feedback term is introduced to dynamically compensate for the flux attenuation caused by the resistor.

[0052] The flowchart for calculating the rotor electrical angle is as follows: Figure 10 As shown, the rotor electrical angle is calculated based on the torque current and excitation current according to the rotor electrical angle calculation formula described below: in, Indicates the rotor electrical angle, This represents the estimated angular velocity. Represents the extreme logarithm (4). This indicates the mutual inductance between the locomotive motor rotor and stator. Represents torque current. The electromagnetic time constant of the rotor is represented by... This indicates rotor flux linkage.

[0053] The electromagnetic torque is calculated based on the torque current component and the excitation current component according to the magnetic torque calculation formula described below. in, Indicates electromagnetic torque. This indicates the mutual inductance between the locomotive motor rotor and stator. Represents torque current. Represents the extreme logarithm. This indicates rotor flux linkage.

[0054] In this embodiment, the block diagram of the traction inverter direct voltage control and flux linkage closed-loop control is as follows: Figure 11 As shown, it includes: Based on the DC control parameters, the reference voltage Udc600ref and the actual voltage Udc600 of the second DC bus are used to generate the desired electromagnetic torque command through PI regulation. DC control parameters include DC voltage control proportional parameters and DC voltage control integral parameters.

[0055] The desired electromagnetic torque command is generated according to the electromagnetic torque control parameters. With electromagnetic torque Torque current command is generated through PI control. The electromagnetic torque control parameters include electromagnetic torque proportional parameters and electromagnetic torque integral parameters.

[0056] The torque current command is based on the torque current control parameters. With torque current The voltage component in the direction of the generated torque current is adjusted by PI control. It is used to compensate for torque current tracking error. The torque current control parameters include torque current proportional parameters and torque current integral parameters.

[0057] The rotor electrical angle is converted into rotor speed, and a flux linkage reference value is set according to the rotor speed.

[0058] The rotor flux is adjusted according to the flux control parameters. With magnetic flux reference value Excitation current command is generated through PI regulation. The flux linkage control parameters include the proportional parameters and integral parameters of flux linkage control.

[0059] Magnetic flux reference value It depends on the engine speed; when the engine speed is low (below 1050 rpm)... The instruction is 0.5. When the rotor speed is high, field weakening control is required. The faster the motor speed, the smaller the required flux linkage, because at the same flux linkage, a higher speed generates a larger back electromotive force, which makes it difficult to stably control the 600V DC voltage. It is a linear function related to the rotational speed with upper and lower limits: ARM program 100-fold dimension conversion: in, represents the reference value of magnetic flux, and n represents the rotor speed.

[0060] The excitation current command is based on the excitation current control parameters. With excitation current The voltage component in the direction of the excitation current is generated by PI regulation. It is used to compensate for the tracking error of the excitation current. The excitation current control parameters include the proportional parameter of the excitation current and the integral parameter of the excitation current.

[0061] In this embodiment, further, after the traction inverter is started to excite the locomotive motor for 2 seconds, the full-order flux linkage observation algorithm is used to generate an estimated value of the locomotive motor speed for the locomotive motor rotor, and the flux linkage control parameter is increased to a set threshold.

[0062] Meanwhile, the flux linkage control parameters need to be changed during the excitation and generation phases. After motor excitation is completed and 400V voltage stabilization is achieved (approximately 2 seconds after excitation begins), the flux linkage control parameters need to be increased. During the excitation phase, smaller control parameters are needed to prevent the reactive power from rising too quickly and causing overcurrent in the traction inverter. During the generation phase after excitation, even larger control parameters are needed to ensure that the flux linkage remains stable at the commanded value, because changes in load power and motor speed during generation will cause flux linkage fluctuations.

[0063] The specific values ​​of the above-mentioned direct pressure control and flux linkage control algorithm parameters in this embodiment are shown in the table below: Table 2. Parameters of Direct Pressure Control and Flux Control Algorithms Based on the inverse Pakr transform formula, the stator voltage of the computer motor is: in, and The voltage component representing the stator voltage of the locomotive motor. The voltage component indicating the direction of the excitation current. The voltage component indicating the direction of the torque current. This represents the rotor electrical angle, which is taken here during the excitation phase. The corresponding speed output by MRAS during the excitation phase, after 2 seconds of excitation start, has sufficient time to track the motor speed based on the speed observed across the entire flux linkage. Therefore, the speed at this point should be adjusted 2 seconds after the start of excitation. Input, switch to Figure 8 The rotor angle described in .

[0064] The locomotive motor stator voltage input SVPWM algorithm generates a three-phase modulated wave signal, and the voltage vector command generated by the control algorithm is converted into actual switching action to drive the three-phase bridge arm of the traction inverter.

[0065] The SVPWM calculation is as follows: Let the calculated sector value be N. The sector value N is calculated as follows: If we set intermediate variables A, B, and C, then: Set intermediate variables X, Y, and Z, and calculate the values ​​of X, Y, and Z: Set intermediate variables Since the triangular carrier wave is set to 5000Hz with an amplitude of 0-1200-0, and the modulation wave amplitude range is set to 500±500, therefore let =2000; The input value for this part is calculated as follows. , , 600V direct voltage target value The output values ​​are X, Y, and Z, calculated as follows: Set intermediate variables , ,calculate , This part calculates the value based on the input values ​​X, Y, Z and the sector value N, and outputs the value. , The calculation is as follows: Set intermediate variables , ,calculate , The value is the input value for this part of the calculation. , , The output value is , The calculation is as follows: Calculation of intermediate variables , , The input value for this part of the calculation is , , The output value is , , The calculation is as follows: Let the modulated wave be , , This part calculates the input value. , , And the sector value N, the output value is the modulated wave. , , The calculation is as follows: In this embodiment, after the traction inverter initiates regenerative braking and builds up voltage on the 600V second DC bus, The voltage of the two DC buses is converted into the first DC bus. The 600V bus is stepped down through a buck circuit to establish the first 400V DC bus. The control structure block diagram is as follows. Figure 12 As shown in the table below, its control parameters are as follows: Table 3 Control Parameters The step of converting the voltage of the first DC bus into a single-phase AC output for power supply to residential loads, and converting the voltage of the first DC bus into a single-phase AC output via an isolated single-phase inverter, involves an isolated DC-DC converter circuit and an H-bridge. The isolated DC-DC converter circuit is controlled on the inverter side using a fixed-frequency duty cycle PWM (first resonant frequency, 50% duty cycle, 300ns dead time), while the rectifier side is uncontrolled rectification, requiring no additional control. The H-bridge function is for single-phase inversion. The single-phase inverter control block diagram is shown below. Figure 13 As shown in the table below, its control parameters are as follows: Table 4 Control Parameters In this embodiment, during the battery charging step, phase shift control achieves charging current control by changing the phase difference between the two bridge arms on the inverter side of the isolated DC-DC circuit. The control block diagram is as follows: Figure 14 As shown in the table below, its control parameters are as follows: Table 5 Control Parameters Example 2 This embodiment implements the method in Embodiment 1, and provides a locomotive power supply control device, as shown in the schematic diagram below. Figure 15 As shown, the corresponding overall device topology diagram is as follows: Figure 16 As shown, it includes: a first bidirectional DC-DC converter for boosting the battery voltage to establish a first DC bus.

[0066] A two-stage traction inverter, comprising a second bidirectional DC-DC converter and a traction inverter; The second bidirectional DC-DC converter connects the first bidirectional DC-DC converter and the traction converter, and is used to bidirectionally convert the first DC bus at one end of the first bidirectional DC-DC converter to the second DC bus at one end of the traction converter.

[0067] The traction inverter is connected to the locomotive motor via a modified traction wiring connection. It is used to excite and control the locomotive motor with direct voltage, and to build up voltage on the second DC bus when regenerative braking is started. A single-phase inverter, connected to the second bidirectional DC-DC converter and the first bidirectional DC-DC converter, is used to convert the voltage of the first DC bus into single-phase AC power and output it to civilian loads through a single-phase power supply port.

[0068] The central controller is used to coordinate the control of the first bidirectional DC-DC converter, the two-stage traction inverter and the single-phase inverter based on bus direct voltage control, locomotive motor stator voltage reconstruction, speed estimation and excitation control strategies.

[0069] The device is directly connected to the stator winding of the traction motor of the Harmony electric locomotive. When the Harmony electric locomotive is running without power, the entire locomotive does not draw power from the overhead contact line, but is pulled by other locomotives, and the locomotive's motor does not work.

[0070] The device uses DC power carried by the battery, which is boosted to DC400V by the first bidirectional DC converter, then boosted to DC600V by the second bidirectional DC converter, and then inverted into AC power with adjustable voltage and frequency by the traction inverter to establish an excitation magnetic field for the traction motor.

[0071] While establishing the excitation magnetic field, the rotational speed of the traction motor under the current state is predicted based on the sensorless speed measurement principle. Induced current and alternating magnetic fields are generated within the rotor of the squirrel-cage traction motor. At this time, the excitation frequency of the stator windings is changed, causing the traction motor to enter a braking and generating state.

[0072] The three-phase AC power generated by the traction motor is rectified into DC 600V DC power by the traction inverter, then the voltage is reduced to DC 400V by the second bidirectional DC-DC converter, and finally output as AC 220V by the isolated single-phase inverter for use by electrical equipment. The output single-phase 220V AC power has the same voltage and frequency as the mains electricity and can be used for household electrical appliances such as kettles, air conditioners, and lighting equipment, providing convenience for the passengers.

[0073] When the battery power is insufficient, the battery module can be charged through the first bidirectional DC-DC converter. The equipment can be put into use when the speed of the traction Harmony electric locomotive is greater than 30 km / h, and the equipment can automatically shut down and limit the output power of the inverter when the speed is less than 30 km / h.

[0074] In this embodiment, the above-mentioned external device is used to achieve a three-stage energy conversion of battery boosting, traction inverter power generation, and single-phase inverter output, which completely avoids the risk of modifying locomotive software and hardware, improves the compatibility of the device, shortens the deployment time, indirectly improves the driver and passenger environment, and thus reduces accidents caused by violations of operating procedures.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A locomotive power supply control method based on sensorless speed estimation, characterized in that, include: Real-time speed estimation of locomotive motor rotor to generate locomotive motor speed; If the locomotive motor speed does not reach the set threshold, the battery will be used to supply power to civilian loads. If the locomotive motor speed reaches the set threshold, the traction inverter is controlled to excite the locomotive motor. When the excitation time reaches the set time, the traction inverter is controlled to supply power to the outside.

2. The locomotive power supply control method based on sensorless speed estimation according to claim 1, characterized in that, Estimating the rotational speed of the locomotive motor rotor includes: Based on the input voltage and switching state of the traction inverter, the stator voltage of each camera car motor is reconstructed, and the specific calculation formula is as follows: in, This indicates the stator voltage of the locomotive motor in phase A reconfiguration. This indicates the stator voltage of the B-phase reconfigured locomotive motor. This indicates the stator voltage of the C-phase reconfigured locomotive motor. This indicates the voltage of the second bus. , and These represent the drive signals of the three-phase switching transistors in the three-phase bridge arm of the traction inverter.

3. The locomotive power supply control method based on sensorless speed estimation according to claim 1, characterized in that, The rotational speed of the locomotive motor rotor is estimated to generate the locomotive motor speed, including: Before the excitation time reaches the set time, the MRAS algorithm is used to estimate the locomotive motor speed of the locomotive motor rotor and generate the locomotive motor speed. After the excitation time reaches the set time, the locomotive motor rotor is estimated using the full-order flux linkage observation algorithm to generate the locomotive motor speed.

4. The locomotive power supply control method based on sensorless speed estimation according to claim 3, characterized in that, The locomotive motor rotor speed is estimated using the MRAS algorithm, including: The stator current and stator voltage sample values ​​are transformed using Clarke to obtain the voltage and current components of the locomotive motor stator voltage and stator current in the α-β coordinate system. The stator flux linkage is calculated in the voltage model based on the voltage and current components. In the current model, the rotor flux linkage and rotor electric angular velocity are calculated based on the current components. The reference model and the adjustable model are compared according to the following formula to obtain the error signal: in, Indicates the error signal. The stator flux linkage component representing the d-axis. The stator flux linkage component representing the q-axis. Indicates rotor flux linkage. Indicates the rotor's electrical angular velocity; The error signal is PI-regulated according to preset control parameters to output the angular velocity of the locomotive motor rotor and feed it back to the current model.

5. The locomotive power supply control method based on sensorless speed estimation according to claim 4, characterized in that, Calculate the stator flux linkage using the following formula for estimating flux linkage: in, The magnetic flux linkage along the d-axis, The magnetic flux linkage along the q-axis is represented by... and These represent the voltage components of the locomotive motor stator voltage in the α and β coordinate systems, respectively. and These represent the stator current components in the α and β coordinate systems, respectively. express, Indicates the leakage inductance coefficient. Indicates stator inductance, Indicates rotor inductance, This indicates the mutual inductance between the locomotive motor rotor and stator.

6. The locomotive power supply control method based on sensorless speed estimation according to claim 3, characterized in that, The locomotive motor rotor speed is estimated using a full-order flux linkage observation algorithm, including: based on the stator flux linkage. The stator current and stator voltage sample values ​​are transformed using Clarke to obtain the voltage and current components of the locomotive motor stator voltage and stator current in the α-β coordinate system. Based on the estimated values ​​of stator flux linkage and rotor flux linkage from the feedback, the estimated value of stator current is calculated in the stator current estimation algorithm; Based on the voltage component, current component, stator current estimate, and the feedback stator flux estimate and rotor flux estimate, the stator flux estimate is calculated in the stator flux estimate algorithm and used for feedback output; Based on the stator current estimate, the feedback stator flux estimate, the rotor flux estimate, and the feedback estimated speed, the rotor flux estimate is calculated in the stator flux estimate algorithm and used for feedback output. The error between the sampled stator current value and the estimated stator current value is calculated based on the speed estimation algorithm, and the estimated speed is generated by PI regulation and used for feedback output.

7. The locomotive power supply control method based on sensorless speed estimation according to claim 3, characterized in that, Controlling the traction inverter to excite the locomotive motor includes: Decouple the stator current into torque current and excitation current; The rotor flux linkage and electromagnetic torque are calculated based on the torque current and excitation current, and the rotor electrical angle is calculated by combining the torque current, rotor flux linkage and locomotive motor speed. The rotor electrical angle is converted into rotor speed, and a magnetic flux reference value is set according to the rotor speed. The rotor flux linkage and the flux linkage reference value are adjusted by PI control according to the flux linkage control parameters to generate the excitation current command.

8. The locomotive power supply control method based on sensorless speed estimation according to claim 3, characterized in that, When the excitation time reaches the set time, the traction inverter is controlled to supply power to the outside, including: Based on the DC control parameters, the reference voltage and input voltage of the traction inverter are adjusted by a PI controller to generate the desired electromagnetic torque command. Based on the electromagnetic torque control parameters, the desired electromagnetic torque command and the electromagnetic torque are used to generate a torque current command through PI regulation. Based on the torque current control parameters, the torque current command and the torque current are adjusted via PI to generate a voltage component in the direction of the torque current. The rotor electrical angle is converted into rotor speed, and a magnetic flux reference value is set according to the rotor speed. The excitation current command and the excitation current are adjusted by PI control according to the excitation current control parameters to generate a voltage component in the direction of the excitation current. Based on the inverse Pakr transform formula, the stator voltage of the computer motor is: in, The voltage component indicating the direction of the excitation current. The voltage component indicating the direction of the torque current. Indicates the rotor electrical angle, and The voltage component representing the stator voltage of the locomotive motor; The stator voltage of the locomotive motor is input to the SVPWM algorithm to generate a three-phase modulated wave signal, which is used to drive the three-phase bridge arm of the traction inverter.

9. A locomotive power supply control method based on sensorless speed estimation according to any one of claims 7 or 8, characterized in that, Before the excitation time reaches the set time, the rotor flux and flux reference value are adjusted by PI to generate an excitation current command according to the standard flux control parameters. After the excitation time reaches the set time, the flux linkage control parameter is set to the maximum flux linkage control parameter.

10. A locomotive power supply control method based on sensorless speed estimation according to claim 8, characterized in that, Setting the flux linkage reference value based on the rotor speed includes: The rotor speed is fed into the flux linkage command function as described below, and the flux linkage reference value is set according to the speed: in, The value represents the reference value of the magnetic flux, n represents the rotor speed, and N represents the rated speed.

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