A control method for a track traction converter and the track traction converter

Abstract

This disclosure relates to a control method for a track traction converter and a track traction converter. The control method for the track traction converter includes: extracting the steady-state quantity of the intermediate DC voltage of the track traction converter; obtaining the intermediate DC voltage after noise filtering; calculating the given torque compensation amount on the motor side for the current switching cycle based on the steady-state quantity of the intermediate DC voltage, the intermediate DC voltage after noise filtering, and the electrical angular velocity of the motor; and performing torque compensation on the motor side based on the given torque compensation amount to suppress the unbalanced traction current on the intermediate DC side and avoid related vehicle-network operation stability problems caused by the unbalanced traction current of the track.

Description

Technical Field

[0001] This disclosure relates to the field of rail transit converter control technology, and in particular to a control method for a rail traction converter and a rail traction converter. Background Technology

[0002] To ensure reliable vehicle operation and driving safety, strict standards have been established for interference currents. Interference currents generated by rail vehicles mainly originate from two sources: one is the pulse width modulation mode of the traction converter in traditional electric traction systems, and the other is the resonance caused by lumped energy storage components and stray parameters in the vehicle-grid system circuit. The traction converter is a significant source of interference; it is a device that converts DC voltage to AC voltage, and its operating frequency is typically between 2Hz and 2kHz, generating interference currents mainly distributed between 2Hz and 20kHz. Furthermore, the amplitude of interference currents in rail vehicles is also closely related to the operating conditions and control strategies of the traction system.

[0003] During rail vehicle operation, energy interaction between the vehicle and the traction power grid introduces a significant amount of vehicle harmonics into the traction power grid. Certain frequency current harmonics flow back to the grid side with the rails, interfering with the transmission and reception of signals by trackside equipment. The interference current generated by the rail vehicle can be transmitted to other equipment or users through the power supply system, potentially causing instability issues in the operation of the vehicle and the grid in severe cases. Summary of the Invention

[0004] This disclosure provides a control method for a track traction converter and a track traction converter to effectively suppress track unbalanced traction current.

[0005] In a first aspect, this disclosure provides a control method for a track traction converter, including:

[0006] Extract the steady-state quantity of the intermediate DC voltage of the track traction converter;

[0007] Obtain the intermediate DC voltage after noise filtering;

[0008] Based on the steady-state quantity of the intermediate DC voltage, the intermediate DC voltage after noise filtering, and the electrical angular velocity of the motor, calculate the given torque compensation amount on the motor side for the current switching cycle;

[0009] Torque compensation is performed on the motor side based on the given torque compensation amount to suppress the unbalanced traction current on the intermediate DC side.

[0010] In some embodiments, the given torque compensation amount on the motor side for the current switching cycle is calculated based on the steady-state quantity of the intermediate DC voltage, the intermediate DC voltage after noise filtering, and the motor electrical angular velocity, using the following formula:

[0011]

[0012] In the formula, This represents the given torque compensation amount on the motor side, C represents the intermediate support capacitor, and U... dc_st U represents the steady-state quantity of the intermediate DC voltage. dc1 ω represents the intermediate DC voltage after noise filtering. n T represents the electrical angular velocity of the motor. p Indicates the switching cycle.

[0013] In some embodiments, the method further includes:

[0014] In the indirect stator quantity control process, the angle increment of the stator flux in the current switching cycle is calculated. The angle increment includes the steady-state increment angle and the dynamic increment angle. The dynamic increment angle is calculated based on the given torque, the feedback torque, the maximum overturning torque at the previous moment, and the maximum overturning torque at the current moment.

[0015] Based on the conversion relationship of flux linkage voltage, the stator-side voltage component required for SVPWM modulation is obtained based on the angle increment, thereby controlling the magnetic field to run around the circular flux linkage trajectory.

[0016] In some embodiments, the dynamic incremental angle is calculated using the following formula:

[0017]

[0018] In the formula, Δθ dyn δ represents the dynamic increment angle within the current switching cycle. k δ represents the angle between the stator and rotor flux linkages at the current time k. (k-1) T represents the angle between the stator and rotor flux linkages at the previous moment k-1. e * T represents the given torque. e T represents the feedback torque. bk T represents the maximum overturning torque at the current time k. b(k-1) This represents the maximum overturning torque at the current moment k-1.

[0019] In some embodiments, the steady-state quantity of the intermediate DC voltage of the track traction converter is calculated using the following formula:

[0020]

[0021] In the formula, U dc_st τ represents the steady-state quantity of the intermediate DC voltage of the traction converter. L1 denoted by s, the cutoff frequency of the first-order low-pass filter, and s represents the integral.

[0022] In some embodiments, an enhanced phase-locked loop is used to obtain the intermediate DC voltage after noise filtering.

[0023] In some embodiments, the formula for calculating the dynamic incremental angle is obtained as follows:

[0024] The following first formula is established for calculating torque under stator flux linkage and rotor flux linkage:

[0025]

[0026] In the formula, δ represents the angle between the stator and rotor flux linkages; ψ s Indicates stator flux linkage; ψ r Indicates rotor flux linkage; T e P represents torque; n L represents the number of pole pairs of the motor. σ This represents the equivalent leakage inductance of an asynchronous motor in the Γ-type configuration.

[0027] The rotor flux linkage is approximately obtained according to the following second calculation formula:

[0028] |ψ r |=|ψ s |·cosδ

[0029] The second calculation formula is transformed into the following third calculation formula:

[0030]

[0031] When sin2δ=1, the maximum overturning torque of the system is obtained.

[0032]

[0033] Based on the second and third calculation formulas, the included angle between the stator and rotor magnetic flux linkages is calculated as follows:

[0034]

[0035] T within one switching cycle p Within this range, the formula for calculating the dynamic increment angle of torque regulation is obtained as follows:

[0036]

[0037] In the formula, Δθ dyn δ represents the dynamic increment angle within the current switching cycle. k δ represents the angle between the stator and rotor flux linkages at the current time k. (k-1) T represents the angle between the stator and rotor flux linkages at the previous moment k-1. e * T represents the given torque. e T represents the feedback torque. bkT represents the maximum overturning torque at the current time k. b(k-1) This represents the maximum overturning torque at the current moment k-1.

[0038] In a second aspect, this disclosure provides a track traction converter, including a control unit, wherein the control unit controls the track traction converter using the method described in the first aspect.

[0039] Thirdly, this disclosure provides a track induced voltage testing platform for testing the transient induced voltage generated on both sides of the rail by track unbalanced traction current. The track induced voltage testing platform includes:

[0040] Two aluminum tubes are used to simulate the impedance of the rails. Multiple test points are set on the first aluminum tubes to simulate the dynamic process of a train passing over the track circuit under static conditions by continuously moving the test points.

[0041] Two second aluminum tubes simulating axle impedance are respectively connected to two first aluminum tubes to form a closed loop;

[0042] The resistance that simulates the contact impedance between the axle and the rail;

[0043] Test cables, connecting them to the steel rails on both sides respectively;

[0044] The impedance of the resonant unit in the simulated track circuit;

[0045] The traction system is placed above the closed loop. The placement height and the relative layout and wiring of each sub-component of the traction system are simulated in a 1:1 ratio with the layout and wiring of a real vehicle. The traction system includes the track traction converter as described in claim 6.

[0046] In some embodiments, the track induced voltage testing platform is characterized by further including a testing instrument, the testing frequency of which is set according to the operating frequency band of the track circuit.

[0047] Fourthly, this disclosure provides a method for testing track induced voltage, implemented based on the testing platform described in the third aspect. The track induced voltage testing method includes:

[0048] Under different train operation modes, the worst-case conditions of the corresponding track induced voltage were tested and determined.

[0049] Based on the worst operating conditions of track induced voltage under each train operation mode, the worst operating conditions of train track induced voltage are determined.

[0050] Determine whether the track induced voltage corresponding to the worst operating condition of the train track induced voltage meets the preset conditions: if the preset conditions are not met, it indicates that the track imbalance traction current is interfering with the train's track circuit.

[0051] The train operation modes include traction acceleration mode, resistance braking mode and regenerative braking mode, and the worst operating conditions of the track induced voltage include voltage, torque, speed, and open circuit / short circuit.

[0052] In some embodiments, before determining the worst-case conditions of the corresponding track induced voltage under different train operation modes, the method further includes:

[0053] After calibrating the testing instrument, set it to maximum value hold mode;

[0054] The background noise test is performed using the aforementioned test instrument, including testing the environmental noise when the traction system is not powered on, and testing the interference of the cable coupling itself by separating the test cable from the aluminum tube and short-circuiting the test cable when the traction system is powered on.

[0055] Once the background noise condition is met, after the traction system is powered on, the steps of testing and determining the worst-case conditions of the corresponding track induced voltage are performed under different train operation modes.

[0056] Fifthly, this disclosure provides a test and evaluation system for the electromagnetic compatibility of trains and axle counters, including:

[0057] The first test antenna is used to receive the magnetic field signals emitted by the train in the X, Y, and Z directions under the first test bandwidth.

[0058] The second test antenna is used to receive the magnetic field signals emitted by the train in the X, Y, and Z directions under the second test bandwidth; the first test bandwidth is lower than the second test bandwidth.

[0059] The acquisition system is used to continuously acquire the magnetic field signals received by the first test antenna and the second test antenna in the form of analog voltage.

[0060] Data analysis system: Based on the analog voltage data collected by the acquisition system each time, evaluate whether the train and the trackside axle counter meet the electromagnetic compatibility. If the train under test and the trackside axle counter do not meet the electromagnetic compatibility, it indicates that the track imbalance traction current interferes with the trackside axle counter signal system. During the actual operation of the train, the control unit of the track traction converter controls the track traction converter using the method described in any one of claims 1 to 5.

[0061] Sixthly, this disclosure provides a method for testing and evaluating the electromagnetic compatibility (EMC) of trains and axle counters, implemented based on the EMC testing and evaluation system for trains and axle counters described in the fifth aspect. The method includes:

[0062] The first test antenna receives the magnetic field signals emitted by the train in the X, Y, and Z directions under the first test bandwidth; the second test antenna receives the magnetic field signals emitted by the train in the X, Y, and Z directions under the second test bandwidth; the first test bandwidth is lower than the second test bandwidth;

[0063] The acquisition system continuously acquires the magnetic field signals received by the first test antenna and the second test antenna in the form of analog voltage.

[0064] The data analysis system evaluates whether the train and the trackside axle counter meet electromagnetic compatibility based on the analog voltage data collected by the acquisition system each time. If the train under test and the trackside axle counter do not meet electromagnetic compatibility, it indicates that the track imbalance traction current interferes with the trackside axle counter signal system. During the actual operation of the train, the control unit of the track traction converter uses the method described in the first aspect to control the track traction converter.

[0065] This disclosure provides a track traction converter control method and a track traction converter. By extracting the steady-state value of the intermediate DC voltage of the track traction converter and obtaining the intermediate DC voltage after noise filtering, and combining this with the motor's electrical angular velocity, the given torque compensation amount on the motor side for the current switching cycle is calculated. Then, based on the given torque compensation amount, torque compensation is performed on the motor side to effectively suppress track unbalanced traction current and avoid related vehicle-to-grid operational stability problems caused by track unbalanced traction current. Furthermore, the transient induced voltage generated by the unbalanced traction current on both sides of the rail is tested using a track induced voltage test platform to evaluate the suppression effect of the track traction converter control method on unbalanced traction current. Furthermore, the electromagnetic compatibility test and evaluation method between the train and the trackside axle counter is used to evaluate whether the train and the trackside axle counter meet electromagnetic compatibility requirements, thereby assessing whether the track unbalanced traction current interferes with the trackside axle counter signal system. Attached Figure Description

[0066] The present disclosure will be described in more detail below based on embodiments and with reference to the accompanying drawings:

[0067] Figure 1 A schematic diagram of a typical subway train main circuit topology provided in this embodiment of the disclosure;

[0068] Figure 2 This is a schematic diagram illustrating the principle of track interference current provided in an embodiment of this disclosure;

[0069] Figure 3 A schematic diagram of the intermediate DC voltage obtained by EPLL as provided in the embodiments of this disclosure;

[0070] Figure 4 ISC principle block diagram provided for embodiments of this disclosure;

[0071] Figure 5 A stator and rotor flux linkage vector operation diagram within a switching cycle is provided for an embodiment of this disclosure;

[0072] Figure 6 A schematic diagram illustrating the response of a conventional PI-type ISC to a step torque, provided in an embodiment of this disclosure.

[0073] Figure 7 A schematic diagram illustrating the response of the feedforward ISC to stage torque provided in an embodiment of this disclosure;

[0074] Figure 8 The conventional ISC control strategy provided in this embodiment of the disclosure has a 50Hz harmonic response.

[0075] Figure 9 The feedforward ISC control strategy provided in this embodiment of the present disclosure is for the 50Hz harmonic case;

[0076] Figure 10 This is a schematic diagram of the track induced voltage test platform provided in the embodiments of this disclosure;

[0077] Figure 11 A top view of the traction system layout provided in an embodiment of this disclosure;

[0078] Figure 12 A side view showing the arrangement of the components of the traction system provided in an embodiment of this disclosure;

[0079] Figure 13 The worst-case induced voltage spectrum under typical operating modes of the traction system provided in this embodiment of the present disclosure is as follows: (a) is the worst-case track induced voltage spectrum under traction acceleration mode, (b) is the worst-case track induced voltage spectrum under resistance braking mode, and (c) is the worst-case track induced voltage spectrum under regenerative braking mode.

[0080] Figure 14 This disclosure provides a requirement for limiting the induced voltage in the audio segment of a track circuit for a certain line.

[0081] Figure 15 A block diagram of a train and axle counter electromagnetic compatibility testing and evaluation system provided in this embodiment of the disclosure;

[0082] Figure 16 This is a schematic diagram of the antenna according to the positional requirements provided in the embodiments of this disclosure;

[0083] Figure 17 A data analysis and processing flowchart provided for embodiments of this disclosure;

[0084] Figure 18 The time-domain waveform extracted from the 28.8kHz out-of-standard frequency point of the Zp30H type shaft counter provided in this embodiment of the disclosure;

[0085] Figure 19 This disclosure provides a data analysis interface for testing and evaluating the electromagnetic compatibility of trains and axle counters in an embodiment of the present disclosure.

[0086] Figure 20 A flowchart of a track traction converter control method provided in an embodiment of this disclosure.

[0087] In the accompanying drawings, the same parts are referred to by the same reference numerals, and the drawings are not drawn to scale. Detailed Implementation

[0088] To enable those skilled in the art to better understand the technical solutions of this disclosure, and to fully understand and implement the process of how this disclosure applies technical means to solve technical problems and achieve corresponding technical effects, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, not all embodiments. The embodiments of this disclosure and the various features within them can be combined with each other without conflict, and the resulting technical solutions are all within the protection scope of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort should fall within the protection scope of this disclosure.

[0089] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this disclosure described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0090] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0091] The principle behind the generation of track interference current is as follows:

[0092] Currently, there are two main power supply systems for subway traction systems: one is a DC 750V power supply system, with an allowable voltage fluctuation range of DC 500-900V, and current is collected by the third rail; the other is a DC 1500V power supply system, with an allowable voltage fluctuation range of DC 1000-1800V, and current is collected by the overhead contact network pantograph, with the rated power of the traction motor generally around 200kW. Figure 1 This is a typical main circuit topology for a subway train. The traction inverter draws power from the pantograph, passes through a DC LC input filter, and drives the induction motor (IM) via IGBTs. The two induction motors are controlled in a rack-mounted control mode, meaning that one inverter module controls both motors.

[0093] DC side current I d Ideally, the traction return current is equal on both rails, flowing back to the track via the overhead contact line. However, in practical applications, due to various factors (mainly the impedance imbalance of the traction circuit itself and the magnetic field coupling of the traction current in adjacent traction circuits), the distribution of the traction return current on the two rails is uneven, resulting in an imbalanced traction current. The difference between the traction return currents on the two rails is called the unbalanced traction current. If an unbalanced traction current exists on the rails, this current may flow through the track circuit (see...). Figure 2 Furthermore, the interference current contains abundant harmonic components within the track signal frequency band. After being demodulated by the track signal receiving equipment, it may affect the identification of low-frequency modulation signals, thereby causing track circuit malfunctions and affecting train operation safety.

[0094] Example 1

[0095] Figure 20 This is a flowchart illustrating a control method for a track traction converter provided in an embodiment of this disclosure. Figure 20 As shown, a control method for a track traction converter can be applied to the control unit of the traction converter. The method includes:

[0096] Step S11: Extract the steady-state quantity of the intermediate DC voltage of the track traction converter.

[0097] The energy on the intermediate DC side across the intermediate supporting capacitor C can be expressed by the following formula:

[0098]

[0099] In the formula, W C U represents the energy on the intermediate supporting capacitor, C represents the intermediate supporting capacitor, and U represents the energy on the intermediate supporting capacitor. dc U represents the intermediate DC voltage. dc_stThis represents the stable quantity obtained through a first-order low-pass filter.

[0100] The steady-state value of the intermediate DC voltage of the traction converter is extracted using a first-order low-pass filter LPF1.

[0101]

[0102] In the formula, U dc_st τ represents the steady-state quantity of the intermediate DC voltage of the traction converter. L1 s represents the cutoff frequency of the first-order low-pass filter LPF1, and s represents the integral.

[0103] Step S12: Obtain the intermediate DC voltage after noise filtering.

[0104] Currently, a common method for extracting harmonic components of intermediate voltage is using bandpass filters. However, the European testing scope for the characteristic frequency band of track interference currents is quite broad, and setting the cutoff frequency of the bandpass filter cannot fully cover the test frequency band. In some embodiments of this example, by means of... Figure 3 The enhanced phased-locked loop (EPLL) shown obtains the intermediate DC voltage after noise filtering. This voltage contains harmonic components across various frequency bands. When the harmonic components in a certain frequency band are prominent, U... dc1 It can reflect the data more realistically. Utilizing its higher frequency range, faster lock-in time, and better noise performance, it can capture significant harmonic quantities in the intermediate voltage components. It can capture significant harmonic quantities in the intermediate voltage components with wide bandwidth, speed, and interference resistance.

[0105] Step S13: Based on the steady-state quantity of the intermediate DC voltage, the intermediate DC voltage after noise filtering, and the motor electrical angular velocity, calculate the given torque compensation amount on the motor side in the current switching cycle.

[0106] Traditional methods for suppressing and compensating for interference current typically use only the first deviation of the intermediate voltage to adjust the torque. This embodiment, based on the energy flow relationship between the DC and AC sides, adopts a compensation method using the square difference of the intermediate voltage to accurately compensate for torque regulation. It can more accurately feed back the effect on the torque based on fluctuations in the intermediate voltage.

[0107] The energy fluctuation on the intermediate supporting capacitor can be obtained according to equation (1).

[0108]

[0109] When ΔW CA value greater than 0 indicates an increase in intermediate-side energy, while a value greater than 0 indicates a decrease in intermediate-side energy. When intermediate-side energy fluctuates, adjustments need to be made on the motor side to maintain stable energy. The expression for motor-side energy is as follows:

[0110]

[0111] In the formula, P m Indicates the motor-side power, ω n Indicates the electrical angular velocity of the motor. This indicates the motor's commanded torque, also known as the motor's torque command.

[0112] In a switching cycle T p The energy on the motor side can be expressed as

[0113]

[0114] On the DC and AC sides, based on the energy transfer process, the following equivalent relationships exist.

[0115]

[0116] Furthermore, stable control of the intermediate DC side can be achieved by compensating for the torque at the motor end.

[0117] From equation (6), we can obtain

[0118]

[0119] In the formula, This represents the given torque compensation amount on the motor side, C represents the intermediate support capacitor, and U... dc_st U represents the steady-state quantity of the intermediate DC voltage. dc1 ω represents the intermediate DC voltage after noise filtering. n T represents the electrical angular velocity of the motor. p Indicates the switching cycle.

[0120] When the DC-side intermediate voltage fluctuates upward, energy consumption is increased by increasing the given torque on the motor side; when the DC-side intermediate voltage fluctuates downward, energy consumption is reduced by decreasing the given torque on the motor side, thereby suppressing the fluctuation of the DC-side intermediate voltage. Based on the steady-state value of the intermediate DC voltage, the intermediate DC voltage after noise filtering, and the motor's electrical angular velocity, the given torque compensation amount on the motor side for the current switching cycle is calculated using equation (7), which is more accurate than the original method of adjusting torque using only the difference in intermediate voltage.

[0121] Step S14: Perform torque compensation on the motor side based on the given torque compensation amount to suppress the unbalanced traction current on the intermediate DC side.

[0122] By extracting the steady-state value of the intermediate DC voltage of the track traction converter and obtaining the intermediate DC voltage after noise filtering, and combining it with the electric angular velocity of the motor, the given torque compensation amount on the motor side in the current switching cycle is calculated. Then, based on the given torque compensation amount, torque compensation is performed on the motor side. This allows the fluctuation of the intermediate DC voltage to be accurately fed back to the torque, so as to effectively suppress the interference current of track unbalanced traction current and avoid related vehicle-network operation stability problems caused by track unbalanced traction current.

[0123] Traditional PI-type indirect stator quantity control principle, such as Figure 4 As shown. By sampling the motor current i a and i b Considering the inverter model error and combining it with high-precision voltage reconstruction technology, the reconstructed voltage u is obtained. a u b and u c i is obtained through a 3 / 2 transformation. sα i sβ u sα u sβ Then, using the full-order flux linkage observer motor model, we obtain |ψ s |、|ψ r |、T e Steady-state incremental angle Δθ stat It is obtained from the following formula

[0124]

[0125] In the formula, ψ s Indicates stator flux linkage; ψ r Indicates rotor flux linkage; T * e R represents the given torque; r ω represents the rotor resistance in the Γ-type equivalent circuit of an asynchronous motor; n This indicates the motor feedback speed; ω1 represents the stator angular frequency, ω s Slip angular velocity; T p Indicates the switching period; P n This indicates the number of pole pairs of the motor.

[0126] Given torque T * e With feedback torque T e The dynamic incremental angle Δθ is output through the PI controller. dyn

[0127]

[0128] Δθ is the angular increment of the stator flux linkage during one switching cycle.

[0129] Δθ=Δθ stat +Δθdyn (10)

[0130] Then, based on the conversion relationship of flux linkage voltage, as shown in equation (11), the required U after SVMW modulation is obtained. sα Components and U sβ The components, in turn, control the magnetic field to move around the circular magnetic flux trajectory.

[0131]

[0132] In the formula, R s i represents the rotor resistance in the Γ-type equivalent circuit of an asynchronous motor. s U represents the stator current. s Indicates the stator side voltage. This indicates the change in magnetic flux linkage.

[0133] From the above-mentioned traditional ISC (Indirect Stator-flux-oriented Control) control, it can be seen that torque regulation adopts PI control, as shown in equation (9), which has an integral inertia element, which will affect the response speed of torque regulation. In this embodiment, the ISC control removes the integral element in the traditional PI control. Based on the relationship between the stator and rotor flux linkage angle and the torque in one switching cycle, the theoretical formula of the dynamic phase angle increment (dynamic increment angle) of the stator flux linkage is derived, eliminating the integral element and greatly improving the torque response speed.

[0134] In some embodiments, the method of this embodiment further includes:

[0135] In the indirect stator quantity control process, the angle increment of the stator flux linkage in the current switching cycle is calculated. The angle increment includes the steady-state increment angle and the dynamic increment angle. The dynamic increment angle is calculated based on the given torque, feedback torque, the maximum overturning torque at the previous moment, and the maximum overturning torque at the current moment.

[0136] Based on the conversion relationship of flux linkage voltage, the stator-side voltage component required for SVPWM modulation is obtained based on the angle increment, thereby controlling the magnetic field to run around the circular flux linkage trajectory.

[0137] Figure 5 This is a vector diagram of the stator and rotor flux linkage within one switching cycle. The subscript k represents the current time, and the subscript k-1 represents the previous time. The current time and the previous time differ by one switching cycle T. p The first formula for calculating torque under stator flux linkage and rotor flux linkage can be expressed as follows:

[0138]

[0139] In the formula, δ represents the angle between the stator and rotor flux linkages; ψs Indicates stator flux linkage; ψ r Indicates rotor flux linkage; T e P represents torque; n L represents the number of pole pairs of the motor. σ This represents the equivalent leakage inductance of an asynchronous motor (Γ-type).

[0140] Since the angle between the stator and rotor flux linkages is small, the rotor flux linkage can be approximated by the following second calculation formula.

[0141] |ψ r |=|ψ s |·cosδ (13)

[0142] The second calculation formula in equation (13) is transformed into the following third calculation formula.

[0143]

[0144] When sin2δ=1, the maximum overturning torque of the system can be obtained.

[0145]

[0146] According to equations (13) and (14), the included angle between the stator and rotor flux linkages can be calculated as follows:

[0147]

[0148] T within one switching cycle p Within this range, the dynamic increment angle of torque regulation can be rewritten as the following formula:

[0149]

[0150] In the formula, Δθ dyn δ represents the dynamic increment angle within the current switching cycle. k δ represents the angle between the stator and rotor flux linkages at the current time k. (k-1) T represents the angle between the stator and rotor flux linkages at the previous moment k-1. e * T represents the given torque. e T represents the feedback torque. bk T represents the maximum overturning torque at the current time k. b(k-1) This represents the maximum overturning torque at the current moment k-1. The dynamic increment angle is calculated using formula (17) to achieve feedforward ISC control, eliminating the need for the integral element used in traditional ISC to ensure unbiased tracking control between the feedback torque and the given torque.

[0151] Traditional ISC control uses PI control for torque regulation, which includes an integral inertia element, affecting the torque regulation response speed. When harmonic disturbances exist in the intermediate DC-side current, the torque response speed of the traditional method cannot be effectively adjusted. This embodiment, however, employs feedforward indirect stator quantity control, eliminating the integral delay element in the traditional control loop, resulting in a faster torque response speed. It can effectively suppress interference currents generated by the rail vehicle, achieving a step torque response time of approximately 2ms with virtually no overshoot. It also effectively suppresses interference currents and maintains good stability of the intermediate DC-side DC current.

[0152] Figure 6 and Figure 7 The figure shows a comparison of the two methods for step torque response. It can be seen from the figure that the torque response of the traditional PI-type ISC has hysteresis and overshoot, while the torque response of the feedforward ISC in this embodiment is fast and the tracking is stable, which effectively verifies the fast torque response characteristics of this embodiment.

[0153] During the test, the system was simulated to accelerate under load to a stable speed and then decelerate. Specifically, the test system was driven by the auxiliary system to first stabilize at 200 r / min, then the test system was loaded to its rated speed, and then driven by the auxiliary motor to 800 r / min, before decelerating back to 200 r / min. The intermediate DC current was collected, and the harmonics of the intermediate DC current in the 50Hz frequency band were compared and analyzed. The analysis was based on the 0.72A limit standard at 50Hz for a certain subway system. Figure 8 and Figure 9 As shown in the analysis, the traditional method results in a large amplitude at 800 r / min, exceeding the limit standard; while the feedforward ISC control strategy has a good suppression effect on the DC current stability of the intermediate DC side, and the amplitude of the intermediate DC current at 50 Hz is basically below the limit.

[0154] Example 2

[0155] This disclosure provides a track traction converter, including a control unit, which controls the track traction converter using the method provided in Embodiment 1.

[0156] It should be understood that this embodiment has all the beneficial effects of Embodiment 1.

[0157] Example 3

[0158] The aforementioned track imbalance traction current (interference current) cannot be directly measured. Before or after suppression using the method in Example 1, it is impossible to assess whether the track imbalance traction current interferes with the train's track circuits or verify the suppression effect of Example 1 on the track imbalance current through measured values. Instead, analysis is performed using the amplitude of the intermediate DC current in the characteristic frequency band. Furthermore, the above-mentioned test is a ground-based combined test, which may differ from the situation of the entire vehicle on the track surface. To better assess the magnitude of the track interference current, this disclosure provides a track induced voltage test platform for testing the transient induced voltage generated on both sides of the rail by the track imbalance traction current. This track induced voltage test platform includes:

[0159] Two aluminum tubes are used to simulate the impedance of the rails. Multiple test points are set on the first aluminum tubes to simulate the dynamic process of a train passing over the track circuit under static conditions by continuously moving the test points.

[0160] Two second aluminum tubes simulating axle impedance are respectively connected to two first aluminum tubes to form a closed loop;

[0161] The resistance that simulates the contact impedance between the axle and the rail;

[0162] Test cables, connecting them to the steel rails on both sides respectively;

[0163] The impedance of the resonant unit in the simulated track circuit;

[0164] The traction system is placed above the closed loop. The placement height and the relative layout and wiring of each sub-component of the traction system are simulated in a 1:1 ratio with the layout and wiring of a real vehicle. The traction system includes the track traction converter as described in claim 6.

[0165] In this embodiment, a joint test platform for the train traction system, rails, and track circuits, built according to a 1:1 scale to simulate the actual layout and wiring of the entire vehicle, is used to realistically reproduce the process by which track interference current generates transient induced voltage on both sides of the rails during the dynamic operation of the train, thereby interfering with the track circuit. This provides a solution for the actual dynamic track induced voltage test and suppression of the entire vehicle.

[0166] Figure 10 A specific example of a track induced voltage testing platform setup, where: 01: aluminum tube simulating rail impedance; 02: aluminum tube simulating axle impedance; 03: aluminum tube simulating rail impedance; 04: resistance simulating the impedance of the axle-rail connection; 05: aluminum tube simulating axle impedance; 06: twisted-pair test cable, properly connected to both sides of the rail; 07: audio FFT analyzer; 08: test point; 09: impedance of the resonant unit in the track circuit; 10: traction system.

[0167] The track induced voltage testing platform uses two long aluminum tubes and two short aluminum tubes to form a closed loop. The long aluminum tubes are used to simulate actual steel rails, and the two short aluminum tubes are used to simulate vehicle wheel axles. There are certain requirements for the aluminum tube model, outer diameter, and wall thickness.

[0168] The traction system is placed above a closed loop made of aluminum tubing. Its placement height, as well as the relative layout and wiring of each sub-component of the traction system, are completely simulated in a 1:1 scale to the layout and wiring of a real vehicle. Figure 10 A top view showing the arrangement of the various sub-components of the traction system is displayed. Figure 11 A side view showing the arrangement of the various sub-components of the traction system is displayed. (The motor is actually present, but not shown in the drawing.) Figure 12 A side view showing the arrangement of the components of the traction system is displayed.

[0169] R A Used to simulate the lap resistance between vehicle axles and rails, with a value of 0.1 to 0.2 Ω (R can be omitted here). A (Direct short circuit). The entire test is divided into short circuit test (R... A Connection) and open circuit test (R) A (Disconnection), where the short-circuit test is used to simulate a train passing over the track circuit, and the track circuit is located in a closed loop formed by the rails and axles. The open-circuit test is used to simulate a train axle crossing an insulated section of the rails, and the track circuit is located in a loop formed by the rails and axles.

[0170] R B The impedance used to simulate the tuning unit of the track circuit has a value of 0 to 2 Ω. The track induced voltage is the voltage measured across its terminals. R can be omitted here. B You can directly measure the open-circuit voltage, or you can connect a real track circuit tuning unit.

[0171] 0, 1, 2...n refers to the test points that need to be continuously moved. The test values ​​are taken from the maximum values ​​measured at these points, used to simulate the dynamic process of a train passing over the track circuit under static conditions. The spacing between adjacent test points is 0.1 to 0.5 meters.

[0172] The test cables are twisted-pair to minimize the spatial magnetic field coupled to the cable loops. Each cable should be securely connected to the aluminum tube using rail clamps.

[0173] In some cases, the track induced voltage test platform also includes test instruments, the test frequency of which is set according to the operating frequency band of the track circuit. In one example, the test instrument uses an audio FFT analyzer, and the test frequency should be set according to the operating frequency band of the track circuit, for example, between tens of Hz and tens of kHz, and the instrument's test accuracy should reach the μV level.

[0174] Example 4

[0175] This disclosure provides a method for testing track induced voltage, implemented based on the test platform of Embodiment 3. The track induced voltage testing method includes:

[0176] Under different train operation modes, the worst-case conditions of the corresponding track induced voltage were tested and determined.

[0177] Based on the worst operating conditions of track induced voltage under each train operation mode, the worst operating conditions of train track induced voltage are determined.

[0178] Determine whether the track induced voltage corresponding to the worst operating condition of the train track induced voltage meets the preset conditions: if the preset conditions are not met, it indicates that the track imbalance traction current interferes with the train's track circuit; if the preset conditions are met, it indicates that the track imbalance traction current does not interfere with the train's track circuit.

[0179] The train operation modes include traction acceleration mode, resistance braking mode and regenerative braking mode. The worst operating conditions for track induced voltage include voltage, torque, speed, and open circuit / short circuit.

[0180] In some cases, before determining the worst-case operating condition of the corresponding track induced voltage under different train operation modes, the test method in this embodiment further includes:

[0181] After calibrating the testing instrument, set it to maximum value hold mode;

[0182] Background noise testing was conducted using testing instruments, including testing the ambient noise when the traction system was not powered on, and testing the interference of the cable coupling itself by separating the test cable from the aluminum tube and short-circuiting the test cable when the traction system was powered on.

[0183] Once the background noise condition is met, after the traction system is powered on, the steps of testing and determining the worst-case conditions of the corresponding track induced voltage are performed under different train operation modes.

[0184] In a specific example, the procedure for testing track induced voltage is as follows:

[0185] Step 1, according to Figure 10 A track-induced voltage testing platform was built, and the various components of the traction system were tested according to... Figure 11 and Figure 12 Make arrangements.

[0186] Step 2: After calibrating the audio FFT analyzer, set it to maximum hold mode, with the analysis frequency band set based on the track circuit operating frequency band, and the frequency resolution in Hz.

[0187] Step 3: Conduct a background noise test.

[0188] ① Test the environmental noise when the traction system is not powered on. Two to three test points can be selected.

[0189] ② With the traction system powered on, disconnect the test cable from the aluminum tube, and then short-circuit the test cable to test the interference of the cable's own coupling. Two to three test points can be selected.

[0190] Step 4: After confirming that the background noise is sufficiently low and meets the requirements, conduct the formal test after powering on the traction system:

[0191] Traction acceleration mode – Open circuit operation is performed at rated voltage, full torque, and maximum speed respectively (R) A Disconnection) and short circuit (R) A Connection test, including all test points. Determine the worst-case scenario for track induced voltage in this mode (including specific test points, open circuit or short circuit);

[0192] Resistive braking mode – Open circuit operation is performed at rated voltage, full torque, and maximum speed respectively (R) A Disconnection) and short circuit (R) A Connection test, including all test points. Determine the worst-case scenario for track induced voltage in this mode (including specific test points, open circuit or short circuit);

[0193] Regenerative braking mode – open circuit operation is performed at rated voltage, full torque, and maximum speed respectively (R A Disconnection) and short circuit (R) A Connection test, including all test points. Determine the worst-case scenario for track induced voltage in this mode (including specific test points, open circuit or short circuit);

[0194] In some cases, after determining the worst operating conditions of the track induced voltage in the above three modes (including specific test points, open circuit or short circuit), the rated voltage is reduced to 80% and 60%, and the test is carried out again under the worst operating conditions.

[0195] In a specific example, the worst-case induced voltage spectrum under typical operating conditions of a traction system is as follows: Figure 13 As shown, Figure 13 In the diagram, (a) is the worst track induced voltage spectrum under traction acceleration mode, (b) is the worst track induced voltage spectrum under resistance braking mode, and (c) is the worst track induced voltage spectrum under regenerative braking mode.

[0196] Step 5: After completing all the worst-case operating conditions described above, identify the corresponding mode, induced voltage, torque, speed, and open / short circuit parameters for each worst-case track induced voltage condition. If the track induced voltage corresponding to this worst-case condition does not meet the relevant requirements, measures to suppress the induced voltage should be implemented under this condition to provide a solution for subsequent dynamic track induced voltage tests of the entire vehicle.

[0197] In one example, the induced voltage limitation requirement for the audio segment of a certain track circuit is as follows: Figure 14 As shown.

[0198] It should be noted that the track induced voltage testing method of this embodiment can be implemented either before or after the method of Embodiment 1. When implemented before implementation, the method of Embodiment 1 is determined by judging whether the track induced voltage corresponding to the worst-case operating condition of the train track induced voltage meets preset conditions, and then by judging whether the track imbalance traction current interferes with the train's track circuit, thus determining whether to implement the method of Embodiment 1. When implemented after implementation, the method of Embodiment 1 is determined by judging whether the track induced voltage corresponding to the worst-case operating condition of the train track induced voltage meets preset conditions, and then by judging whether the track imbalance traction current interferes with the train's track circuit, thus determining the effectiveness of the method of Embodiment 1 in suppressing the track imbalance traction current (track interference current).

[0199] Example 5

[0200] Axle counters are safety devices used to detect whether train axles occupy track sections. Compared with track circuits, they have a series of advantages, such as being unaffected by track conditions, not requiring track cutting or track insulation, and being suitable for long track sections, thus gaining popularity in railway transportation. However, with the widespread adoption of axle counters in track surface signaling systems and the trend towards high voltage, high power, and high switching frequency in electrified vehicles, the electromagnetic compatibility issue between the two is becoming increasingly serious. The magnitude of track interference current can also affect the axle counter's signaling system. Standards such as EN 50238-3 and EN 50617 specify relevant test methods and specific limit requirements for magnetic field interference from vehicles to axle counters. The GB / T 28807.3 standard is used to manage the electromagnetic compatibility between vehicles and axle counters. Currently, domestically produced trains (metro, EMU, diesel locomotives, etc.) must undergo electromagnetic compatibility assessment and certification with axle counters before being exported overseas or put into operation on lines equipped with axle counters in coastal areas of China.

[0201] However, due to the large number of axle counter types, different working signal standards, and overlapping working frequency bands in the railway industry, the electromagnetic compatibility assessment methods for different types of axle counters and their vehicles also differ. Currently, the domestic rail transit field lacks a complete electromagnetic compatibility assessment and testing system that can cover the entire frequency band and all axle counter types. The system provided in this embodiment fills this technological gap in this context.

[0202] This disclosure provides a train and axle counter electromagnetic compatibility testing and evaluation system for testing and evaluating the electromagnetic compatibility of trains and trackside trains with axle counters. The system includes:

[0203] The first test antenna is used to receive the magnetic field signals emitted by the train in the X, Y, and Z directions under the first test bandwidth.

[0204] The second test antenna is used to receive the magnetic field signals emitted by the train in the X, Y, and Z directions under the second test bandwidth; the first test bandwidth is lower than the second test bandwidth.

[0205] The acquisition system is used to continuously acquire the magnetic field signals received by the first test antenna and the second test antenna in the form of analog voltage.

[0206] Data analysis system: Based on the analog voltage data collected by the acquisition system each time, evaluate whether the train and the trackside axle counter meet the electromagnetic compatibility. If the train under test and the trackside axle counter do not meet the electromagnetic compatibility, it indicates that the track imbalance traction current interferes with the trackside axle counter signal system. During the actual operation of the train, the control unit of the track traction converter controls the track traction converter using the method of Example 1.

[0207] The first test antenna is a low-frequency test antenna, the second test antenna is a high-frequency test antenna, and the magnetic field signal can refer to the electromagnetic wave signal.

[0208] The system in this embodiment uses electromagnetic wave signals received by high- and low-frequency test antennas to determine whether the train and the trackside axle counter meet electromagnetic compatibility requirements, in order to assess whether the track unbalanced current interferes with the trackside axle counter signal system, and to evaluate the effectiveness of the method in Embodiment 1. Alternatively, before executing the method in Embodiment 1, it can first determine whether the track unbalanced current interferes with the trackside axle counter signal system. If the track unbalanced current interferes with the trackside axle counter signal system, then the method in Embodiment 1 can be executed to suppress the interference of the track unbalanced current.

[0209] In a specific example, a train and axle counter electromagnetic compatibility testing and evaluation system, such as... Figure 15 As shown:

[0210] 01——Test Train: In normal mode and degraded mode, the train accelerates from speed v1 to speed v3 or brakes from speed v3 to speed v1 through the antenna with 1 / 3 of the maximum traction force.

[0211] 02 - Low-frequency test antenna: Contains three independent orthogonal coils to receive magnetic field signals (electromagnetic wave signals) emitted by the train in the X, Y, and Z directions. The test bandwidth is 10kHz to 100kHz.

[0212] 03—High-Frequency Test Antenna: Contains three independent orthogonal coils to receive magnetic field signals (electromagnetic wave signals) emitted by the train in the X, Y, and Z directions. The test bandwidth is 100kHz to 1.3MHz. The antenna installation position conforms to the PD CLC-TS50238-3 standard. Figure 16 As shown.

[0213] 04, 05 – High-Speed ​​Acquisition System: This system continuously acquires magnetic field interference received by the high- and low-frequency test antennas in the X, Y, and Z directions in the form of simulated voltages across at least six channels. The single-channel sampling frequency meets a requirement of 3MHz / s, and the continuous acquisition time is sufficient to allow a train to pass completely through the test antenna. The entire acquisition system uses NI acquisition boards as hardware and employs a LabVIEW-based human-machine interface for interaction. Test engineers can configure the sampling rate, signal range, source impedance, etc., within the interface.

[0214] 06—Data Analysis System: Analyzes and processes up to 6 channels of voltage data collected by the high-speed acquisition system each time, thereby assessing whether the train and axle counter meet electromagnetic compatibility requirements.

[0215] The data analysis system is developed based on the Matlab GUI platform, and the entire data analysis and processing workflow is as follows: Figure 17 As shown:

[0216] ① Data Input Module: This module is responsible for storing at least 6 channels of large-capacity signal data continuously acquired by the high-speed acquisition system (acquisition board) into Matlab memory. In this module, the signal data is compressed into binary format. This function can reduce the subsequent signal processing time by at least 90% and enable real-time online result determination for on-site testing.

[0217] ②Analysis Mode Selection Module: Defines two analysis modes, including: TSI CCS-based analysis mode and specific axle counter-based analysis mode. The former requires analysis of the operating frequency band of 10kHz-1.3MHz, which includes all axle counter types, while the latter only requires analysis of the operating frequency band of a specific type of axle counter (such as 27kHz-32kHz for ZP30H). The two modes have different analysis algorithms and evaluation criteria.

[0218] When the TSI CCS analysis mode is selected, the system will automatically assign short-time Fourier analysis parameters, including Hanning window length and overlap rate, to the initial calculations of the three Out-band and three In-band frequency bands.

[0219] In one example, when the TSI CCS analysis mode is selected, the system automatically divides the analysis frequency band into six intervals, including three in-band and three out-band. Different short-time Fourier analysis parameters are initially assigned to each interval, as shown below:

[0220] Out-band1

[0221] Analysis frequency band: 10kHz-27kHz;

[0222] Short-time Fourier parameters: Hanning window, window time 1ms, overlap rate 50%.

[0223] In-band1

[0224] Analysis frequency band: 27kHz-52kHz;

[0225] Short-time Fourier parameters: Hanning window, window time 1ms, overlap rate 75%.

[0226] Out-band2

[0227] Analysis frequency band: 52kHz-234kHz;

[0228] Short-time Fourier parameters: Hanning window, window time 1ms, overlap rate 50%.

[0229] In-band2

[0230] Analysis frequency band: 234kHz-363kHz;

[0231] Short-time Fourier parameters: Hanning window, window time 0.5ms, overlap rate 75%.

[0232] Out-band3

[0233] Analysis frequency band: 363kHz-740kHz;

[0234] Short-time Fourier parameters: Hanning window, window time 1ms, overlap rate 50%.

[0235] In-band3

[0236] Analysis frequency band: 740kHz-1250kHz;

[0237] Short-time Fourier parameters: Hanning window, window time 0.5ms, overlap rate 75%.

[0238] When a specific axle counter analysis mode is selected, the system will assign digital filtering and integration parameters to each axle counter type, including filter type, filter order, filter bandwidth, center frequency shift step, integration time, and integration window overlap rate.

[0239] In one example, after selecting a specific axle counter analysis mode, the system automatically identifies seventeen selectable axle counter types, each with preset digital filter analysis parameters. Taking Thales' Zp30H axle counter as an example, its digital filter analysis parameters are as follows:

[0240] Zp30H type shaft counter

[0241] Analysis frequency band: 27kHz-32kHz; Filter type: Butterworth fourth-order bandpass filter; 3dB bandwidth: 240Hz; Filter center frequency shift step: 80% of the 3dB bandwidth; Integration time: 4ms; Overlap rate: 75%.

[0242] ③ Analysis Direction Selection Module: The user defines the data direction for each analysis. Combined with the analysis frequency band in ②, the system automatically assigns the antenna compensation coefficient and standard limit for that direction and frequency band.

[0243] In one example, the user defines the direction of data analysis, combined with the analysis frequency band. The system will automatically assign antenna calibration compensation factors and standard limits for evaluation based on the technical manual provided by the antenna manufacturer and the European axle counter standard documents. For example:

[0244] a. Analysis mode: TSI CCS mode; Analysis frequency band: In-band1 (27kHz-52kHz); Analysis direction: X direction.

[0245] Standard limit: 93 dBuA / m; Antenna coefficient: 36 dB@27 kHz, 31 dB@52 kHz (the antenna coefficient at the intermediate frequency is obtained by interpolation algorithm).

[0246] b. Analysis mode: Specific axle counter mode; Axle counter type: Zp30H type; Analysis frequency band: 27kHz-32kHz; Analysis direction: Z direction.

[0247] Standard limit: 101 dBuA / m; Antenna coefficient: 36 dB@27 kHz, 35.5 dB@32 kHz (the antenna coefficient at the intermediate frequency is obtained by interpolation algorithm).

[0248] ④ TSI CCS initial calculation module: It uses the short-time Fourier algorithm to calculate and compares the calculated voltage result with the standard magnetic field limit after compensating the antenna coefficient. This module has a fast calculation speed and can be used for the initial scanning and judgment of the results.

[0249] The mathematical formula for the short-time Fourier transform is:

[0250]

[0251] s(t) represents the time-domain data of the input voltage;

[0252] h(t) is a window function.

[0253] The mathematical formula for converting the voltage superposition antenna compensation coefficient into a magnetic field value is as follows:

[0254] s(f) dBuA / m =s(f) dBvV +AF(f) dB

[0255] s(f) dBuA / m The converted frequency domain magnetic field value;

[0256] s(f) dBuV The voltage value in the frequency domain is obtained from the short-time Fourier transform.

[0257] AF(f) dB This is the antenna compensation coefficient.

[0258] ⑤ Calculation module for specific axle counters: Perform digital filtering analysis on the frequency band corresponding to the selected axle counter, and compare the calculated voltage result with the standard magnetic field limit after superimposing the antenna compensation coefficient.

[0259] In one example, the data is processed by digital bandpass filtering and sliding integration within the frequency band corresponding to the selected axle counter type. The calculated voltage result is then superimposed with the antenna compensation coefficient and compared with the standard magnetic field value (standard limit) for a decision.

[0260] The calculation process is as follows:

[0261] Step 1: Calculate the coefficients of the first Butterworth bandpass filter, with the filter center frequency being the starting frequency f of the analysis band. start .

[0262] [b,a]=butter(n,[W1,W2],'bandpass')

[0263] n is the order of the bandpass filter designed by butter();

[0264] butter(n,[W1,W2]) will return the 2*n order filter coefficients;

[0265] W1 and W2 are the 3dB cutoff frequencies of the bandpass filter;

[0266] b represents the coefficients of the numerator polynomial of the system transfer function;

[0267] a represents the coefficients of the denominator polynomial of the system transfer function.

[0268] Step 2: Perform bandpass filtering on the data.

[0269] s(t) withfilter =filter(b,a,s(t)) withoutfilter )

[0270] s(t) withfilter This is the filtered data;

[0271] s(t) withoutfilter This is the data before filtering.

[0272] Step 3: Perform sliding integral processing on the data.

[0273] s(t) withfilter+rms =rms[s(t)] withfilter ,T int [overlap]

[0274] s(t) withfilter This refers to data that only undergoes filtering.

[0275] T int The integration time;

[0276] overlap is the integral overlap rate;

[0277] s(t) withfilter+rms This is the data after processing with the sliding integral.

[0278] Step 4: Take s(t) withfilter+rms The maximum value in the data is used as the center frequency f of the first Butterworth bandpass filter. start The corresponding calculation result is represented as s(f1).

[0279] Step 5: Calculate the coefficients of the second Butterworth bandpass filter, with the filter center frequency being f. start +Δf, where Δf is the step size for shifting the filter's center frequency.

[0280] Step 6: Perform bandpass filtering on the data.

[0281] Step 7: Perform sliding integral processing on the data.

[0282] Step 8: Take the maximum value of the data after bandpass filtering and sliding integral processing as the center frequency f of the second Butterworth bandpass filter. start The calculation result corresponding to +Δf is represented as s(f2). ......

[0284] When designing the Nth Butterworth bandpass filter with center frequency f start +N*Δf is greater than the termination frequency f of the analysis band. stop This concludes the bandpass filtering + sliding integral processing flow.

[0285] The final step: converting the voltage superposition antenna compensation coefficient into a magnetic field value.

[0286] s(f) dBuA / m =s(f) dBvV +AF(f) dB

[0287] s(f) dBuA / m The converted frequency domain magnetic field value;

[0288] s(f) dBuV The voltage value in the frequency domain is obtained from the short-time Fourier transform.

[0289] AF(f) dB This is the antenna compensation coefficient.

[0290] ⑥ Initial calculation decision of TSI CCS: If the calculation results of the three Out-band and three In-band frequency bands do not exceed the limits in the X, Y, and Z directions, then the train and axle counter are deemed to meet electromagnetic compatibility in this test. If the calculation results of some frequency bands exceed the limits, then proceed to decision ⑧.

[0291] ⑦ Calculation decision for specific axle counter analysis: If the calculation results for the frequency band corresponding to the selected axle counter do not exceed the limits in the X, Y, and Z directions, then the train and axle counter are deemed to meet electromagnetic compatibility in this test. If the calculation results exceed the limits, then the train and axle counter are deemed to not meet electromagnetic compatibility in this test, and the user may choose to perform vehicle interference location analysis.

[0292] ⑧ TSI CCS In-band frequency band exceedance judgment: If the calculation result output by ⑥ exceeds the limit in the In-band frequency band, then proceed to ⑨ for secondary calculation; if the calculation result output by ⑥ exceeds the limit in the Out-band frequency band instead of the In-band frequency band, then in this test, it is determined that the train and the axle counter do not meet the electromagnetic compatibility, and the user can choose to perform vehicle interference location analysis.

[0293] ⑨ The secondary calculation module of TSI CCS: performs secondary calculations on the In-band exceeding the standard frequency band of decision ⑧, and analyzes it using a series of digital filters, such as... Figure 6 As shown, taking the In-band 1 (27kHz-52kHz) analysis as an example, the first 4th-order Butterworth bandpass filter has a center frequency of 27kHz and a bandwidth of 300Hz. The time-domain data is filtered and then integrated with at least 75% overlap, and the maximum value is taken, which represents the voltage at 27kHz. The second filter has a center frequency of 27.24kHz, and the same processing is performed, taking the maximum value to represent the voltage at 27.24kHz. This process is repeated to complete the data processing within the 27kHz-52kHz frequency band. Finally, the antenna coefficient is compensated to convert the voltage value into a magnetic field value and compare it with the limit. Generally, the result of the digital filtering analysis in the secondary calculation is smaller than the result of the initial short-time Fourier analysis, but the calculation time is longer.

[0294] The TSI CCS secondary calculation module performs secondary calculations on the In-band exceeding the standard frequency band in decision ⑧. It uses digital bandpass filtering and sliding integral to process the data, compensates the antenna coefficient for the calculated voltage result, and compares it with the standard magnetic field value for decision. The processing flow is similar to that in the specific axis counter calculation module in Part ⑤, the difference being the analysis frequency band and analysis parameter settings.

[0295] Taking In-band 3 data processing as an example, the analysis band and analysis parameters are as follows:

[0296] Analysis frequency band: 740kHz-1250kHz; Filter type: Butterworth fourth-order bandpass filter; 3dB bandwidth: 1000Hz; Filter center frequency shift step: 80% of the 3dB bandwidth; Integration time: 1.5ms; Overlap rate: 75%.

[0297] ⑩ TSI CCS secondary calculation judgment: If the result of the secondary calculation for all In-band out-of-standard frequency band data is less than the standard limit, then the train and axle counter are deemed to meet electromagnetic compatibility standards in this test. If the result is greater than the standard limit, then the train and axle counter are deemed to not meet electromagnetic compatibility standards. Users can choose to perform vehicle interference location analysis.

[0298] Taking the Zp30H type shaft counter as an example, Figure 18The time-domain waveform of the 28.8kHz out-of-standard frequency point of this type of axle counter is presented. It can be observed that during the process of the vehicle passing the test antenna from the front to the rear, the magnetic field emitted by the vehicle itself exceeds the standard limit shown by the red line at approximately 5s and 10s. Combined with the vehicle's operating speed in this test, the vehicle's position corresponding to the out-of-standard time point can be calculated, thus locating the vehicle interference source and providing a solution for subsequent vehicle rectification. The data analysis interface for the electromagnetic compatibility test and evaluation of the train and axle counter provided in this embodiment is as follows. Figure 19 As shown, the initial calculation results of the TSI CCS analysis mode in a certain test are presented.

[0299] Example 6

[0300] This disclosure provides a method for testing and evaluating the electromagnetic compatibility (EMC) of trains and axle counters, based on the EMC testing and evaluation system for trains and axle counters described in Embodiment 5. The method includes:

[0301] The first test antenna receives the magnetic field signals emitted by the train in the X, Y, and Z directions under the first test bandwidth; the second test antenna receives the magnetic field signals emitted by the train in the X, Y, and Z directions under the second test bandwidth; the first test bandwidth is lower than the second test bandwidth.

[0302] The acquisition system continuously acquires the magnetic field signals received by the first test antenna and the second test antenna in the form of analog voltage.

[0303] The data analysis system evaluates whether the train and the trackside axle counter meet electromagnetic compatibility based on the analog voltage data collected by the acquisition system each time. If the train under test and the trackside axle counter do not meet electromagnetic compatibility, it indicates that the track imbalance traction current interferes with the trackside axle counter signal system. During the actual operation of the train, the control unit of the track traction converter uses the method described in the first aspect to control the track traction converter.

[0304] For specific implementation details of this method, please refer to Example 5.

[0305] It should be noted that the electromagnetic compatibility (EMC) testing and evaluation method for the train and axle counter in this embodiment can be implemented either before or after the method in Embodiment 1. When implemented before implementation, the analog voltage data collected by the acquisition system each time is used to evaluate whether the train and the trackside axle counter meet EMC requirements. This determines whether the track imbalance traction current interferes with the trackside axle counter signal system, and thus whether the method in Embodiment 1 should be implemented. When implemented after implementation, the analog voltage data collected by the acquisition system each time is used to evaluate whether the train and the trackside axle counter meet EMC requirements. This determines whether the track imbalance traction current interferes with the trackside axle counter signal system, and thus determines the effectiveness of the method in Embodiment 1 in suppressing the track imbalance traction current (track interference current).

[0306] Example 7

[0307] Based on the above embodiments, this embodiment provides a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method described in Embodiment 1 above.

[0308] In some embodiments of this example, a computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the steps of the method described in Embodiment 1 above.

[0309] In some embodiments of this example, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps of the method described in Embodiment 1 above.

[0310] The processor may include, but is not limited to, one or more processors or microprocessors. Each processor may be implemented as an Application Specific Integrated Circuit (ASIC), Digital Signal Processor (DSP), Digital Signal Processing Device (DSPD), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), controller, microcontroller, microprocessor, or other electronic component, for executing the methods in the above embodiments.

[0311] Computer-readable storage media can be implemented by any type of volatile or non-volatile storage device or a combination thereof. Computer-readable storage media may include, but are not limited to, random access memory (RAM), read-only memory (ROM), flash memory, EPROM memory, EEPROM memory, registers, and computer storage media (e.g., hard disks, floppy disks, solid-state drives, removable disks, CD-ROMs, DVD-ROMs, Blu-ray discs, etc.).

[0312] Computer-readable storage media may also store at least one computer-executable program / instruction, such as computer-readable instructions. Computer-readable storage media include, but are not limited to, volatile memory and / or non-volatile memory. Volatile memory may include, for example, random access memory (RAM) and / or cache memory. Computer-readable storage media may include, for example, read-only memory (ROM), hard disk, flash memory, etc. For example, a non-transitory computer-readable storage medium may be connected to a computing device such as a computer, and then, when the computing device executes the computer-readable instructions stored on the computer-readable storage medium, the various methods described above can be performed.

[0313] In addition, the computer device may include (but is not limited to) a data bus, an input / output (I / O) bus, a display, and input / output devices (e.g., keyboard, mouse, speakers, etc.).

[0314] The processor can communicate with external devices via the I / O bus through wired or wireless networks.

[0315] In one embodiment, the at least one computer-executable instruction may also be compiled into or comprise a software product / computer program product, wherein one or more computer-executable instructions are executed by a processor to perform the steps of the various functions and / or methods in the embodiments described herein.

[0316] In the embodiments provided in this disclosure, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0317] It should be noted that, in this disclosure, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element limited by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0318] While the embodiments disclosed herein are as described above, the foregoing content is merely for the purpose of facilitating understanding of this disclosure and is not intended to limit this disclosure. Any person skilled in the art to which this disclosure pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope of this disclosure; however, the scope of patent protection of this disclosure shall still be determined by the scope defined in the appended claims.

Claims

1. A control method for a track traction converter, characterized in that, include: The steady-state quantity of the intermediate DC voltage of the track traction converter is extracted using the following calculation formula. In the formula, This represents the steady-state quantity of the intermediate DC voltage of the traction converter. This represents the cutoff frequency of a first-order low-pass filter. Represents the integral. Indicates the intermediate DC voltage; The intermediate DC voltage after noise filtering is obtained through an enhanced phase-locked loop; The following calculation formula is used to calculate the given torque compensation amount on the motor side during the current switching cycle, based on the steady-state quantity of the intermediate DC voltage, the intermediate DC voltage after noise filtering, and the motor's electrical angular velocity. ， In the formula, This indicates the amount of torque compensation given on the motor side. This indicates the intermediate support capacitor. This represents the steady-state quantity of the intermediate DC voltage. This represents the intermediate DC voltage after noise filtering. Indicates the electrical angular velocity of the motor. Indicates the switching cycle; Torque compensation is performed on the motor side based on the given torque compensation amount to suppress the unbalanced traction current on the intermediate DC side.

2. The method according to claim 1, characterized in that, Also includes: In the indirect stator quantity control process, the angle increment of the stator flux in the current switching cycle is calculated, and the angle increment includes the steady-state increment angle and the dynamic increment angle. The dynamic incremental angle is calculated based on the given torque, feedback torque, the maximum overturning torque at the previous moment, and the maximum overturning torque at the current moment. Based on the conversion relationship of flux linkage voltage, the stator-side voltage component required for SVPWM modulation is obtained based on the angle increment, thereby controlling the magnetic field to run around the circular flux linkage trajectory.

3. The method according to claim 2, characterized in that, The dynamic incremental angle is calculated using the following formula: ， In the formula, This represents the dynamic increment angle within the current switching cycle. Indicates the current time k The angle between the stator and rotor flux linkages, Indicates the previous moment k -1 is the stator-rotor flux linkage angle. Indicates a given torque, Indicates feedback torque. Indicates the current time k The maximum overturning torque, Indicates the current time k -1 is the maximum overturning torque.

4. The method according to claim 3, characterized in that, The formula for calculating the dynamic increment angle is obtained as follows: The following first formula is established for calculating torque under stator flux linkage and rotor flux linkage: In the formula, Indicates the angle between the stator and rotor magnetic flux linkages; Indicates stator flux linkage; Indicates rotor flux linkage; T e Indicates feedback torque; Indicates the number of pole pairs of the motor; Indicates asynchronous motor Type equivalent leakage inductance; The rotor flux linkage is approximately obtained according to the following second calculation formula: The second calculation formula is transformed into the following third calculation formula: when At that time, the maximum disruptive torque of the system is obtained. Based on the second and third calculation formulas, the included angle between the stator and rotor magnetic flux linkages is calculated as follows: T within one switching cycle p Within this range, the formula for calculating the dynamic increment angle of torque regulation is obtained as follows: In the formula, This represents the dynamic increment angle within the current switching cycle. Indicates the current time k The angle between the stator and rotor flux linkages, Indicates the previous moment k -1 is the stator-rotor flux linkage angle. Indicates a given torque, Indicates feedback torque. Indicates the current time k The maximum overturning torque, Indicates the current time k -1 is the maximum overturning torque.

5. A track traction converter, comprising a control unit, characterized in that, The control unit controls the track traction converter using the method described in any one of claims 1 to 4.

6. A track induced voltage testing platform, characterized in that, The track induced voltage test platform, used to test the transient induced voltage generated on both sides of the rail by track imbalance traction current, includes: Two aluminum tubes are used to simulate the impedance of the rails. Multiple test points are set on the first aluminum tubes to simulate the dynamic process of a train passing over the track circuit under static conditions by continuously moving the test points. Two second aluminum tubes simulating axle impedance are respectively connected to two first aluminum tubes to form a closed loop; The resistance simulating the contact impedance between the axle and the rail; Test cables, connecting them to the steel rails on both sides respectively; The impedance of the resonant unit in the simulated track circuit; The traction system is placed above the closed loop. The placement height and the relative layout and wiring of each sub-component of the traction system are simulated in a 1:1 manner to the layout and wiring of a real vehicle. The traction system includes the track traction converter as described in claim 5.

7. The track induced voltage testing platform according to claim 6, characterized in that, It also includes testing instruments, the testing frequency of which is set according to the operating frequency band of the track circuit.

8. A method for testing track induced voltage, characterized in that, Based on the test platform described in claim 6 or 7, the track induced voltage test method includes: Under different train operation modes, the worst-case conditions of the corresponding track induced voltage were tested and determined. Based on the worst operating conditions of track induced voltage under each train operation mode, the worst operating conditions of train track induced voltage are determined. Determine whether the track induced voltage corresponding to the worst operating condition of the train track induced voltage meets the preset conditions: if the preset conditions are not met, it indicates that the track imbalance traction current is interfering with the train's track circuit. The train operation modes include traction acceleration mode, resistance braking mode and regenerative braking mode, and the worst operating conditions of the track induced voltage include voltage, torque, speed, and open circuit / short circuit.

9. The method for testing track induced voltage according to claim 8, characterized in that, Before determining the worst-case conditions for track induced voltage under different train operation modes, the following steps are also included: After calibrating the testing instrument, set it to maximum value hold mode; The background noise test is performed using the aforementioned test instrument, including testing the environmental noise when the traction system is not powered on, and testing the interference of the cable coupling itself by separating the test cable from the aluminum tube and short-circuiting the test cable when the traction system is powered on. Once the background noise condition is met, after the traction system is powered on, the steps of testing and determining the worst-case conditions of the corresponding track induced voltage are performed under different train operation modes.

10. A test and evaluation system for electromagnetic compatibility between trains and axle counters, characterized in that, include: The first test antenna is used to receive the magnetic field signals emitted by the train in the X, Y, and Z directions under the first test bandwidth. The second test antenna is used to receive the magnetic field signals emitted by the train in the X, Y, and Z directions under the second test bandwidth; The first test bandwidth is lower than the second test bandwidth; The acquisition system is used to continuously acquire the magnetic field signals received by the first test antenna and the second test antenna in the form of analog voltage. Data analysis system: Based on the analog voltage data collected by the acquisition system each time, evaluate whether the train and the trackside axle counter meet the electromagnetic compatibility. If the train and the trackside axle counter do not meet the electromagnetic compatibility, it indicates that the track imbalance traction current interferes with the trackside axle counter signal system. During the actual operation of the train, the control unit of the track traction converter controls the track traction converter using the method described in any one of claims 1 to 4.

11. A method for testing and evaluating the electromagnetic compatibility of trains and axle counters, characterized in that, Based on the electromagnetic compatibility testing and evaluation system for trains and axle counters as described in claim 10, the electromagnetic compatibility testing and evaluation method for trains and axle counters includes: The first test antenna receives the magnetic field signals emitted by the train in the X, Y, and Z directions under the first test bandwidth; the second test antenna receives the magnetic field signals emitted by the train in the X, Y, and Z directions under the second test bandwidth; the first test bandwidth is lower than the second test bandwidth; The acquisition system continuously acquires the magnetic field signals received by the first test antenna and the second test antenna in the form of analog voltage. The data analysis system evaluates whether the train and the trackside axle counter meet electromagnetic compatibility based on the analog voltage data collected by the acquisition system each time. If the train under test and the trackside axle counter do not meet electromagnetic compatibility, it indicates that the track imbalance traction current interferes with the trackside axle counter signal system. During the actual operation of the train, the control unit of the track traction converter controls the track traction converter using the method described in any one of claims 1 to 4.

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