Method, device and traction system for damping oscillations of a dc bus voltage of a traction converter

Abstract

The application provides a method and device for inhibiting DC bus voltage oscillation of a traction converter and a traction system, the method comprising: obtaining an oscillation component of bus voltage and inputting the oscillation component into a phase lead link to obtain a current feedforward control compensation quantity; calculating a sum of a torque component of a motor given current vector and the current feedforward control compensation quantity to obtain a torque component of a corrected motor given current vector; calculating a motor voltage vector through a vector control algorithm according to the corrected motor given current vector and an actual motor current vector; and performing pulse width modulation (PWM) according to the motor voltage vector to obtain a driving signal of the traction converter, so that the traction converter provides voltage for the motor under the driving of the driving signal. The application can effectively inhibit DC bus voltage oscillation of the traction converter on the basis of meeting motor control performance, so that the traction converter runs more stably and the reliability of the traction system is improved.

Description

Technical Field

[0001] This invention relates to the field of rail transit, and in particular to a method, apparatus, and traction system for suppressing DC bus voltage oscillations in a traction converter. Background Technology

[0002] The traction system is the core of subway and light rail vehicles. It mainly consists of three parts: an LC filter unit, a traction converter, and a motor, along with other electrical components. The traction converter obtains energy from the external contact network or contact rail, receives a stable DC bus voltage through the LC filter unit, and then outputs corresponding variable frequency and voltage AC power through inversion or rectification, enabling the motor to operate in traction or electric braking mode. When the parameters of the LC resonant filter within the system are mismatched, or when the motor control algorithm parameters change, oscillations in the front-end bus voltage of the traction converter may occur, leading to abnormal fluctuations in the motor's output torque and affecting train comfort. In severe cases, the traction converter may shut down due to overvoltage, undervoltage, or overcurrent protection, potentially causing the power supply station to trip, resulting in power outages in the section and disrupting line operation.

[0003] Currently, asynchronous induction motors still offer advantages over permanent magnet synchronous motors, including lower cost, lower failure rate, and easier maintenance, thus holding a significant share in rail transit. In recent years, asynchronous motor control has evolved from early scalar (V / F) control with poor dynamic performance to direct torque control (DTC) and vector control (FOC). Compared to traditional scalar control, vector control offers higher dynamic response and torque control precision, directly improving overall train performance and comfort. However, in practical applications, bus voltage oscillations are more pronounced when using vector control strategies. Therefore, to better utilize vector control strategies, it is essential to effectively suppress bus voltage oscillations.

[0004] Existing technologies primarily suppress bus voltage oscillations using chopper circuits. This method compares the actual bus voltage with a preset bus voltage limit in the control program. When the actual bus voltage exceeds the limit, the difference is sent to a proportional-integral (PI) regulator to obtain the chopper duty cycle. The chopper circuit is then activated to suppress the divergence of bus voltage oscillations, and some energy is released through the braking resistor. If the actual bus voltage is below the limit, relevant variables are initialized, and the chopper circuit is disabled. Since bus voltage oscillations occur within a specific speed range, if the vehicle operates in traction mode within this range for an extended period, the chopper circuit needs to operate for a considerable time to suppress the divergence of bus voltage oscillations. Simultaneously, a significant amount of energy is consumed through the braking resistor, which converts this energy into heat. This can lead to overheating of the braking resistor, potentially causing the traction converter to shut down or even burning out the braking resistor. Therefore, while chopper methods can suppress the divergence of bus voltage oscillations, they cannot fundamentally eliminate their occurrence; they can only maintain the bus voltage within the limit. Since the motor control performance is greatly affected by the bus voltage, unstable bus voltage can cause fluctuations in motor torque, leading to problems such as vehicle vibration.

[0005] Another existing technology is to correct the motor torque setpoint based on the bus voltage to solve the problem of motor torque fluctuation caused by unstable bus voltage, which in turn causes vehicle vibration. The motor torque setpoint is corrected based on the instantaneous value of the bus voltage, as shown in equation (1).

[0006]

[0007] Where u dc U is the instantaneous value of the bus voltage. d0 Here, ρ is the bus voltage filter value, and T is the adjustment coefficient. ref Assigned motor torque, The actual torque of the motor is used. This method is based on the ability to correct the motor torque setting in real time to solve the vehicle vibration problem caused by motor torque fluctuations. However, if there is a delay between the actual motor torque and the torque setting, it is impossible to correct the motor torque setting in real time, causing the system oscillation to gradually diverge, which in turn affects the smooth output of motor torque and the stability of the traction system. Summary of the Invention

[0008] This invention provides a method, apparatus, and traction system for suppressing DC bus voltage oscillations in traction converters, which solves the problem that existing technologies cannot effectively suppress traction converter bus voltage oscillations.

[0009] The first aspect of the present invention is to provide a method for suppressing bus voltage oscillations in a traction converter, comprising:

[0010] Obtain the oscillation component of the bus voltage;

[0011] The oscillation component of the bus voltage is used as the input of the phase lead circuit to obtain the current feedforward control compensation amount output by the phase lead circuit.

[0012] By calculating the sum of the torque component of the motor's given current vector and the current feedforward control compensation amount, the torque component of the motor's given current vector is corrected to obtain the corrected torque component of the motor's given current vector.

[0013] The motor voltage vector is calculated using a vector control algorithm based on the torque component of the corrected motor current vector, the excitation component of the motor current vector, and the torque and excitation components of the actual motor current vector.

[0014] Based on the motor voltage vector, the drive signal for the traction converter is obtained by performing pulse width modulation (PWM).

[0015] The traction converter is driven by the drive signal so that it provides voltage to the motor under the drive signal.

[0016] A second aspect of the present invention is to provide a device for suppressing oscillations in the bus voltage of a traction converter, comprising:

[0017] The oscillation module is used to acquire the oscillation component of the bus voltage;

[0018] The phase lead circuit is used to take the oscillation component of the bus voltage obtained by the oscillation module as its own input and output the current feedforward control compensation amount.

[0019] The correction module is used to correct the torque component of the motor given current vector by calculating the sum of the torque component of the motor given current vector and the current feedforward control compensation amount output by the phase lead link, so as to obtain the corrected torque component of the motor given current vector.

[0020] The vector control module is used to calculate the motor voltage vector based on the torque component of the corrected motor given current vector, the excitation component of the motor given current vector, and the torque and excitation components of the actual motor current vector obtained by the correction module through the vector control algorithm.

[0021] The modulation module is used to obtain the drive signal of the traction converter by performing PWM modulation based on the motor voltage vector obtained by the vector control module.

[0022] A drive module is used to drive the traction converter according to the drive signal obtained by the modulation module, so that the traction converter provides voltage to the motor under the drive signal.

[0023] A third aspect of the present invention is to provide a traction system comprising: the above-described device for suppressing oscillations in the bus voltage of a traction converter, a traction converter, and a motor;

[0024] The input terminal of the device for suppressing traction converter bus voltage oscillation and the input terminal of the traction converter are connected to the overhead contact line, which provides the bus voltage of the traction converter. The output terminal of the device for suppressing traction converter bus voltage oscillation is connected to the input terminal of the traction converter, the output terminal of the traction converter is connected to the input terminal of the motor, and the output terminal of the motor is connected to the input terminal of the device for suppressing traction converter bus voltage oscillation.

[0025] The present invention provides a method, apparatus, and traction system for suppressing DC bus voltage oscillations in a traction converter. This involves obtaining the oscillation component of the bus voltage and inputting it into a phase-leading element to obtain a current feedforward control compensation amount; calculating the sum of the torque component of the motor's given current vector and the current feedforward control compensation amount to obtain the corrected torque component of the motor's given current vector; calculating the motor voltage vector using a vector control algorithm based on the corrected motor given current vector and the actual motor current vector; and performing PWM modulation on the motor voltage vector to obtain a drive signal for the traction converter, enabling the traction converter to provide voltage to the motor under the drive signal. This invention effectively suppresses traction converter bus voltage oscillations while meeting motor control performance requirements, resulting in more stable traction converter operation and improved traction system reliability. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the method for suppressing oscillations in the bus voltage of a traction converter provided in Embodiment 1 of the present invention.

[0027] Figure 2 This is a schematic diagram of the device for suppressing oscillations of the traction converter bus voltage provided in Embodiment 2 of the present invention;

[0028] Figure 3 This is a control system block diagram of the device for suppressing traction converter bus voltage oscillation provided in Embodiment 2 of the present invention;

[0029] Figure 4 This is a schematic diagram of the traction system provided in Embodiment 3 of the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Figure 1 This is a flowchart illustrating a method for suppressing traction converter bus voltage oscillations according to Embodiment 1 of the present invention. In this embodiment, the executing entity of the method for suppressing traction converter bus voltage oscillations can be an independent device for suppressing traction converter bus voltage oscillations, or it can be a digital signal processor (DSP). The present invention does not limit this to any particular device. Figure 1 As shown, the method includes the following steps:

[0032] 11. Obtain the oscillation component of the bus voltage.

[0033] Specifically, the oscillation component of the traction converter bus voltage can be obtained by bandpass filtering; or, the oscillation component of the traction converter bus voltage can be obtained by low-pass filtering and calculating the difference between the traction converter bus voltage before and after low-pass filtering.

[0034] For example, in a practical application, at the beginning of each control cycle, such as during a 400μs timer interrupt, the DSP controls the external analog-to-digital converter (A / D) to input the mains voltage u. line Bus voltage u dc Bus current i dc Motor three-phase current i a i b i c The sampled data is then transmitted to the DSP via an external data bus through a Field-Programmable Gate Array (FPGA) to obtain the traction converter bus voltage U. d The torque component and excitation component of the actual current vector of the motor.

[0035] When the traction converter bus voltage oscillates, the traction converter bus voltage is low-pass filtered, and the difference between the traction converter bus voltage before and after filtering is calculated to obtain the oscillation component of the traction converter bus voltage.

[0036] 12. Using the oscillation component of the bus voltage as the input of the phase lead circuit, the current feedforward control compensation amount output by the phase lead circuit is obtained.

[0037] The oscillation component of the bus voltage obtained in step 11 is input into the phase lead circuit. After the phase lead circuit calculates and processes the oscillation component, it outputs the current feedforward control compensation amount.

[0038] As one implementation of this embodiment, step 12 may include:

[0039] 121. The oscillation component of the bus voltage is used as the input of the phase lead element and transmitted to the phase lead element;

[0040] 122. Based on the transfer function of the phase-leading element, the oscillation component is calculated and processed to obtain the output current feedforward control compensation amount. The transfer function of the phase-leading element is:

[0041]

[0042] in, in,

[0043] i sqc (s) represents the current feedforward control compensation of the traction converter, s is the complex frequency, K is the bus voltage oscillation suppression coefficient, and T ref To give the motor a given torque, n p Ψ is the number of pole pairs of the motor. Rref To provide the flux linkage for the motor, U d0 ψ is the filtered bus voltage value. m The lead phase required for the current feedforward control compensation, ω m U is the angular frequency of the bus voltage oscillation. err (s) represents the oscillating component of the bus voltage.

[0044] 13. By calculating the sum of the torque component of the motor's given current vector and the current feedforward control compensation amount, the torque component of the motor's given current vector is corrected to obtain the corrected torque component of the motor's given current vector.

[0045] The current feedforward control compensation amount obtained in step 12 and the torque component of the motor given current vector are summed and calculated, and the calculated result is used as the torque component of the corrected motor given current vector.

[0046] This embodiment can realize the real-time correction of the torque component of the motor's given current vector based on the oscillation component of the bus voltage.

[0047] 14. Based on the torque component of the corrected motor current vector, the excitation component of the motor current vector, and the torque and excitation components of the actual motor current vector, the motor voltage vector is calculated using a vector control algorithm.

[0048] The torque component of the corrected motor given current vector, the excitation component of the motor given current vector, and the torque and excitation components of the current actual motor current vector obtained in step 13 are used to calculate the motor voltage vector through a vector control algorithm.

[0049] 15. Based on the motor voltage vector, the drive signal for the traction converter is obtained by pulse width modulation (PWM).

[0050] The motor voltage vector obtained in step 14 is modulated using PWM to obtain the drive signal.

[0051] Specifically, the PWM modulation can be Space Vector Pulse Width Modulation (SVPWM).

[0052] 16. The traction converter is driven by the drive signal so that the traction converter provides voltage to the motor under the drive signal.

[0053] The insulated gate bipolar transistor (IGBT) of the traction converter is driven by the drive signal obtained in step 15, so that the traction converter provides voltage to the motor under the drive signal.

[0054] Taking a practical application as an example, when the traction system is working, the DSP obtains the torque component and excitation component of the traction converter bus voltage and the actual motor current vector. When the traction converter bus voltage oscillates, a low-pass filter is applied to the traction converter bus voltage to obtain the filtered traction converter bus voltage. The difference between the traction converter bus voltage before and after the low-pass filter is calculated to obtain the oscillation component of the traction converter bus voltage. The oscillation component of the traction converter bus voltage is input into the phase lead circuit to obtain the current feedforward control compensation amount. The sum of the torque component of the motor's given current vector and the current feedforward control compensation amount is calculated to obtain the corrected torque component of the motor's given current vector. Based on the corrected torque component of the motor's given current vector and the excitation component of the motor's given current vector... The torque component and excitation component of the actual motor current vector are used to calculate the motor voltage vector through a vector control algorithm. Based on the motor voltage vector, the drive signal of the traction converter is obtained through PWM modulation. The traction converter is driven by the drive signal so that it provides voltage to the motor. The motor obtains the corrected actual current under the voltage provided by the traction converter. According to the working principle of the motor, the actual motor torque is directly proportional to the actual motor current vector. That is, the actual motor torque is finally corrected in real time based on the oscillation component of the traction converter bus voltage, thereby suppressing the divergence of the oscillation of the traction converter bus voltage, improving the stability of the traction system, and thus suppressing the oscillation of the traction converter bus voltage.

[0055] Furthermore, since oscillations in the traction converter bus voltage can cause abnormal fluctuations in the actual motor torque, the oscillations in the traction converter bus voltage can be determined by real-time detection of whether the fluctuations in the actual motor torque are within a preset allowable range. Based on this, as one implementation of this embodiment, the method may further include: real-time detection of whether the fluctuations in the actual motor torque are within a preset allowable range; if not, adjusting K and ψ. m and ω m The value of any one or more parameters.

[0056] Specifically, the bus voltage oscillation angular frequency ω in the transfer function m And / or the required lead phase ψ for the current feedforward control compensation of the traction converter m The bus voltage oscillation suppression coefficient K can be a fixed value preset in the phase lead stage, or it can be adjustable. For example, assuming the fluctuation of the actual torque of the motor exceeds a certain fluctuation range, the current feedforward control compensation amount can be adjusted by adjusting the values ​​of the above parameters, thereby ultimately reducing the fluctuation of the actual torque of the motor. Specifically, by adjusting the bus voltage oscillation angular frequency ω... mThe maximum lead angular frequency of the current feedforward control compensation output of the phase lead circuit can be adjusted, and the required lead phase ψ of the traction converter's current feedforward control compensation can be adjusted accordingly. m The maximum leading phase of the current feedforward control compensation output by the phase lead circuit can be adjusted. The magnitude of the current feedforward control compensation output by the phase lead circuit can be adjusted by adjusting the bus voltage oscillation suppression coefficient K.

[0057] The method for suppressing traction converter bus voltage oscillation provided in this embodiment involves inputting the oscillation component of the bus voltage into a phase-leading stage to obtain a current feedforward control compensation amount. This compensation amount is then used to correct the torque component of the motor's given current vector. Based on the corrected given current vector and the actual current vector, a vector control algorithm is used to calculate the motor voltage vector. PWM modulation is then applied to the motor voltage vector to obtain the drive signal for the traction converter, enabling the traction converter to provide voltage to the motor under the drive signal. This embodiment effectively suppresses traction converter bus voltage oscillation while meeting motor control performance requirements, resulting in more stable traction converter operation and improved traction system reliability.

[0058] Figure 2 This is a schematic diagram of the device for suppressing traction converter bus voltage oscillation provided in Embodiment 2 of the present invention. In this embodiment, the device for suppressing traction converter bus voltage oscillation can be a standalone device or part of a DSP processor; the present invention does not limit this to such a device. Figure 2 As shown, the device includes:

[0059] The oscillation module 21 is used to acquire the oscillation component of the bus voltage.

[0060] As one implementation of this embodiment, the oscillation module may include: a bandpass filter unit, used to obtain the oscillation component of the bus voltage by bandpass filtering the traction converter bus voltage.

[0061] In another embodiment of this invention, the oscillation module may include:

[0062] The low-pass filter unit is used to filter the bus voltage of the traction converter.

[0063] The calculation unit is used to calculate the difference between the traction converter bus voltage before and after low-pass filtering, and to obtain the oscillation component of the bus voltage.

[0064] For example, in a practical application, at the beginning of each control cycle, such as during a 400μs timer interrupt, the Digital Signal Processor (DSP) controls an external analog-to-digital converter (A / D) to process the mains voltage u. line Bus voltage u dc Bus current i dc Motor three-phase current i a i b i c The sampled data is then transmitted to the DSP via an external data bus through a Field-Programmable Gate Array (FPGA) to obtain the traction converter bus voltage U. d The torque component and excitation component of the actual current vector of the motor.

[0065] When the traction converter bus voltage oscillates, the low-pass filter unit in the oscillation module 21 performs low-pass filtering on the traction converter bus voltage to obtain the filtered traction converter bus voltage. The calculation unit calculates the difference between the traction converter bus voltage before and after low-pass filtering to obtain the oscillation component of the traction converter bus voltage. The phase lead element 22 uses the oscillation component of the bus voltage obtained by the oscillation module 21 as its input and outputs a current feedforward control compensation amount.

[0066] The oscillation module 21 inputs the oscillation component of the obtained bus voltage into the phase lead circuit 22. After the phase lead circuit 22 calculates and processes the oscillation component, it outputs the current feedforward control compensation amount.

[0067] As one implementation of this embodiment, the phase lead element 22 may include:

[0068] The signal transmission unit 221 is used to transmit the oscillation component of the bus voltage as the input of the phase lead element 22 to the phase lead element 22.

[0069] The phase lead element 22 is specifically used to calculate and process the oscillation component according to the transfer function of the phase lead element, and output a current feedforward control compensation amount. The transfer function of the phase lead element is:

[0070]

[0071] in, in,

[0072] i sqc(s) represents the current feedforward control compensation of the traction converter, s is the complex frequency, K is the bus voltage oscillation suppression coefficient, and T ref To give the motor a given torque, n p Ψ is the number of pole pairs of the motor. Rref To provide the flux linkage for the motor, U d0 ψ is the filtered bus voltage value. m The lead phase required for the current feedforward control compensation, ω m U is the angular frequency of the bus voltage oscillation. err (s) represents the oscillating component of the bus voltage.

[0073] The correction module 23 is used to correct the torque component of the motor given current vector by calculating the sum of the torque component of the motor given current vector and the current feedforward control compensation amount output by the phase lead link 22, so as to obtain the corrected torque component of the motor given current vector.

[0074] The correction module 23 sums the current feedforward control compensation amount obtained by the phase lead link 22 and the torque component of the motor given current vector, and uses the calculated result as the torque component of the corrected motor given current vector.

[0075] This embodiment can realize the real-time correction of the torque component of the motor's given current vector based on the oscillation component of the bus voltage.

[0076] The vector control module 24 is used to calculate the motor voltage vector based on the torque component of the corrected motor given current vector, the excitation component of the motor given current vector, and the torque and excitation components of the actual motor current vector obtained by the correction module 23 through a vector control algorithm.

[0077] The vector control module 24 uses the torque component of the corrected motor given current vector, the excitation component of the motor given current vector, and the torque and excitation components of the current actual motor current vector obtained by the correction module 23 to calculate the motor voltage vector through the vector control algorithm.

[0078] The modulation module 25 is used to obtain the drive signal of the traction converter by performing PWM modulation based on the motor voltage vector obtained by the vector control module 24.

[0079] The modulation module 25 performs PWM modulation on the motor voltage vector obtained by the vector control module 24 to obtain the drive signal.

[0080] Specifically, the PWM modulation can be Space Vector Pulse Width Modulation (SVPWM).

[0081] The drive module 26 is used to drive the traction converter according to the drive signal obtained by the modulation module 25, so that the traction converter provides voltage to the motor under the drive signal.

[0082] The drive module 26 uses the drive signal obtained by the modulation module 25 to drive the insulated gate bipolar transistor (IGBT) of the traction converter, so that the traction converter provides voltage to the motor under the drive signal.

[0083] Taking a practical application as an example, when the traction system is working, the DSP obtains the torque component and excitation component of the traction converter bus voltage and the actual motor current vector. When the traction converter bus voltage oscillates, the low-pass filter unit in the oscillation module 21 performs low-pass filtering on the traction converter bus voltage to obtain the filtered traction converter bus voltage. The calculation unit in the oscillation module 21 calculates the difference between the traction converter bus voltage before and after low-pass filtering to obtain the oscillation component of the traction converter bus voltage. The signal transmission unit 221 inputs the oscillation component of the traction converter bus voltage into the phase lead element 22 to obtain the current feedforward control compensation amount. The correction module 23 calculates the sum of the torque component of the motor given current vector and the current feedforward control compensation amount to obtain the corrected torque component of the motor given current vector. The vector control module 24 controls the motor given current vector according to the corrected torque component. The torque component of the current vector, the excitation component of the motor's given current vector, and the torque and excitation components of the actual current vector of the motor are used to calculate the motor voltage vector through a vector control algorithm. The modulation module 25 obtains the drive signal of the traction converter through PWM modulation based on the motor voltage vector. The drive module 26 uses the drive signal to drive the traction converter so that the traction converter provides voltage to the motor under the drive signal. The motor obtains the corrected actual current under the action of the voltage provided by the traction converter. According to the working principle of the motor, the actual torque of the motor is directly proportional to the actual current vector of the motor. That is, the actual torque of the motor is finally corrected in real time based on the oscillation component of the traction converter bus voltage, thereby suppressing the divergence of the oscillation of the traction converter bus voltage, improving the stability of the traction system, and thus suppressing the oscillation of the traction converter bus voltage.

[0084] Furthermore, since oscillations in the traction converter bus voltage can cause abnormal fluctuations in the actual motor torque, the oscillations in the traction converter bus voltage can be determined by real-time detection of whether the fluctuations in the actual motor torque are within a preset allowable range. Based on this, as one embodiment of this invention, the device may further include: a detection module, used to detect in real-time whether the fluctuations in the actual motor torque are within a preset allowable range; if not within the allowable range, then adjusting K and ψ.m and ω m The value of any one or more parameters.

[0085] Specifically, the bus voltage oscillation angular frequency ω in the transfer function m And / or the required lead phase ψ for the current feedforward control compensation of the traction converter m And / or the bus voltage oscillation suppression coefficient K can be a fixed value preset in the phase lead element 22, or it can be adjustable. For example, assuming that the fluctuation of the actual torque of the current motor exceeds a certain fluctuation range, the current feedforward control compensation amount can be adjusted by adjusting the value of the above parameters, thereby ultimately reducing the fluctuation of the actual torque of the motor. Specifically, by adjusting the bus voltage oscillation angular frequency ω m The maximum lead angular frequency of the current feedforward control compensation output of the phase lead circuit 22 can be adjusted, thereby adjusting the required lead phase ψ of the traction converter's current feedforward control compensation. m The maximum leading phase of the current feedforward control compensation output by the phase lead circuit 22 can be adjusted. By adjusting the bus voltage oscillation suppression coefficient K, the magnitude of the current feedforward control compensation output by the phase lead circuit 22 can be adjusted.

[0086] Figure 3 This is a block diagram of the control system for the device used to suppress traction converter bus voltage oscillations according to Embodiment 2 of the present invention. Figure 3 As shown, the low-pass filter unit in the oscillation module 21 affects the traction converter bus voltage U. d A low-pass filter is performed to obtain the filtered traction converter bus voltage. The calculation unit in the oscillation module 21 calculates the difference between the traction converter bus voltage before and after filtering to obtain the oscillation component u of the bus voltage. err and the oscillation component u of the bus voltage err The output is processed by phase lead circuit 22; the current feedforward control compensation amount i obtained after processing by phase lead circuit 22 is... sqc The output is given to the correction module 23, which then adjusts the current feedforward control compensation amount i. sqc The torque component i of the given current vector of the motor sqref Summation is performed to obtain the torque component i of the corrected motor given current vector. sq * And the torque component i of the corrected motor current vector. sq * The output is given to the vector control module 24; the vector control module 24 calculates the torque component i of the corrected motor current vector. sq * and the excitation component i of the given current vector of the motorsdref The torque component i of the current actual motor current vector sq and excitation component i sd The motor voltage vector Us is calculated using a vector control algorithm and output to the modulation module 25. The modulation module 25 obtains a drive signal based on the motor voltage vector Us through PWM modulation and transmits the drive signal to the drive module 26. The drive module 26 drives the traction converter according to the drive signal, so that the traction converter provides voltage to the motor under the drive signal. The device for suppressing traction converter bus voltage oscillation provided in this embodiment obtains a current feedforward control compensation amount by inputting the oscillation component of the bus voltage into a phase lead element. The torque component of the motor's given current vector is corrected based on the current feedforward control compensation amount. The motor voltage vector is calculated using a vector control algorithm based on the corrected motor given current vector and the actual motor current vector. PWM modulation is performed on the motor voltage vector to obtain the drive signal for the traction converter, so that the traction converter provides voltage to the motor under the drive signal. This embodiment can effectively suppress traction converter bus voltage oscillation while meeting motor control performance requirements, making the traction converter operate more stably and improving the reliability of the traction system.

[0087] Figure 4 This is a schematic diagram of the traction system provided in Embodiment 3 of the present invention. Figure 4 As shown, the traction system includes: a device 1 for suppressing oscillation of the traction converter bus voltage as described in any embodiment of the second embodiment of the present invention, a traction converter 2, and a motor 3;

[0088] The input terminals of the device 1 for suppressing traction converter bus voltage oscillation and the input terminal of the traction converter 2 are connected to a contact network (not shown), which provides the bus voltage of the traction converter 2. The output terminal of the device 1 for suppressing traction converter bus voltage oscillation is connected to the input terminal of the traction converter 2, the output terminal of the traction converter 2 is connected to the input terminal of the motor 3, and the output terminal of the motor 3 is connected to the input terminal of the device 1 for suppressing traction converter bus voltage oscillation.

[0089] As one embodiment of this invention, the traction system may further include: an LC resonant filter disposed between the overhead contact line and the traction converter 2;

[0090] The input terminal of the LC resonant filter is connected to the contact network, and the output terminal of the LC resonant filter is connected to the input terminal of the traction converter 2 and the input terminal of the device 1 for suppressing the oscillation of the traction converter bus voltage.

[0091] Furthermore, the traction system may also include: a current collection circuit disposed between the contact wire and the LC resonant filter, wherein the input end of the current collection circuit is connected to the contact wire, and the output end of the current collection circuit is connected to the input end of the LC resonant filter and the input end of the device 1 for suppressing the oscillation of the traction converter bus voltage.

[0092] Taking a practical application as an example, when the traction system is working, the LC resonant filter filters the energy obtained from the external contact network or contact rail to obtain the DC bus voltage. The LC resonant filter transmits the obtained DC bus voltage to the traction converter 2. The device 1 for suppressing the oscillation of the traction converter bus voltage obtains data such as the DC bus voltage from the contact network and the LC resonant filter, and obtains data such as the current actual current of the motor from the motor 3. After processing the data, the device 1 for suppressing the oscillation of the traction converter bus voltage obtains the drive signal of the traction converter 2, and drives the traction converter 2 through the drive signal. Under the drive of the drive signal, the traction converter 2 inverts or rectifies the DC bus voltage and outputs the corresponding variable frequency and variable voltage AC power to the motor 3. The motor 3 operates in traction mode or electric braking mode under the drive of the variable frequency and variable voltage AC power.

[0093] The traction system provided in this embodiment obtains energy from the external contact network through a traction converter. Driven by a drive signal provided by a device that suppresses oscillations in the traction converter bus voltage, the traction converter outputs corresponding variable frequency and variable voltage AC power through inversion or rectification, enabling the motor to operate in traction or electric braking mode. This traction system effectively suppresses oscillations in the traction converter bus voltage while meeting motor control performance requirements, resulting in more stable traction converter operation and improved traction system reliability.

[0094] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the above-described apparatus and system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0095] 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.

Claims

1. A method for suppressing bus voltage oscillation in a traction converter, characterized in that, include: Obtain the oscillation component of the bus voltage; The oscillation component of the bus voltage is used as the input of the phase lead circuit to obtain the current feedforward control compensation amount output by the phase lead circuit. By calculating the sum of the torque component of the motor's given current vector and the current feedforward control compensation amount, the torque component of the motor's given current vector is corrected to obtain the corrected torque component of the motor's given current vector. The motor voltage vector is calculated using a vector control algorithm based on the torque component of the corrected motor current vector, the excitation component of the motor current vector, and the torque and excitation components of the actual motor current vector. Based on the motor voltage vector, the drive signal for the traction converter is obtained by pulse width modulation (PWM). The traction converter is driven by the drive signal so that the traction converter provides voltage to the motor under the drive signal. The step of using the oscillation component of the bus voltage as the input to the phase lead circuit to obtain the current feedforward control compensation amount output by the phase lead circuit includes: The oscillation component of the bus voltage is used as the input to the phase lead circuit and transmitted to the phase lead circuit. Based on the transfer function of the phase lead element, the oscillation component is calculated and processed to obtain the output current feedforward control compensation amount. The transfer function of the phase lead element is: in, , ,in, i sqc (s) represents the current feedforward control compensation of the traction converter, s is the complex frequency, K is the bus voltage oscillation suppression coefficient, and T ref To give the motor a given torque, n p Ψ is the number of pole pairs of the motor. Rref To provide the flux linkage for the motor, U d0 This is the filtered bus voltage value. The lead phase required for current feedforward control compensation. U is the angular frequency of the bus voltage oscillation. err (s) represents the oscillating component of the bus voltage.

2. The method according to claim 1, characterized in that, The acquisition of the oscillation component of the bus voltage includes: The oscillation component of the traction converter bus voltage is obtained by bandpass filtering; or, The traction converter bus voltage is low-pass filtered, and the difference between the traction converter bus voltage before and after the low-pass filtering is calculated to obtain the oscillation component of the bus voltage.

3. The method according to claim 1, characterized in that, The method further includes: The system monitors in real time whether the fluctuation of the motor's actual torque is within the preset allowable range. If it is not within the allowable range, K is adjusted. and The value of any one or more parameters.

4. A device for suppressing voltage oscillation at the bus of a traction converter, characterized in that, include: The oscillation module is used to acquire the oscillation component of the bus voltage; The phase lead circuit is used to take the oscillation component of the bus voltage obtained by the oscillation module as its own input and output the current feedforward control compensation amount. The correction module is used to correct the torque component of the motor given current vector by calculating the sum of the torque component of the motor given current vector and the current feedforward control compensation amount output by the phase lead link, so as to obtain the corrected torque component of the motor given current vector. The vector control module is used to calculate the motor voltage vector based on the torque component of the corrected motor given current vector, the excitation component of the motor given current vector, and the torque and excitation components of the actual motor current vector obtained by the correction module through the vector control algorithm. The modulation module is used to obtain the drive signal of the traction converter by performing PWM modulation based on the motor voltage vector obtained by the vector control module. A drive module is used to drive the traction converter according to the drive signal obtained by the modulation module, so that the traction converter provides voltage to the motor under the drive signal; The phase lead element includes: A signal transmission unit is used to transmit the oscillation component of the bus voltage as the input of the phase lead element to the phase lead element. The phase lead element is specifically used to calculate and process the oscillation component based on its transfer function, and output a current feedforward control compensation amount. The transfer function of the phase lead element is: in, , , i sqc (s) represents the current feedforward control compensation of the traction converter, s is the complex frequency, K is the bus voltage oscillation suppression coefficient, and T ref To give the motor a given torque, n p Ψ is the number of pole pairs of the motor. Rref To provide the flux linkage for the motor, U d0 This is the bus voltage filtering value. The lead phase required for current feedforward control compensation. U is the angular frequency of the bus voltage oscillation. err (s) represents the oscillation component of the bus voltage; The oscillation module includes a bandpass filter unit, used to obtain the oscillation component of the bus voltage by bandpass filtering the traction converter bus voltage.

5. The apparatus according to claim 4, characterized in that, The oscillation module includes: The low-pass filter unit is used to filter the bus voltage of the traction converter. The calculation unit is used to calculate the difference between the traction converter bus voltage before and after low-pass filtering, and to obtain the oscillation component of the bus voltage.

6. The apparatus according to claim 4, characterized in that, The device further includes: The detection module is used to detect in real time whether the fluctuation of the actual torque of the motor is within a preset allowable range. If it is not within the allowable range, K is adjusted. and The value of any one or more parameters.

7. A traction system, characterized in that, include: The device for suppressing bus voltage oscillation of the traction converter, the traction converter, and the motor as described in any one of claims 4-6; The input terminal of the device for suppressing traction converter bus voltage oscillation and the input terminal of the traction converter are connected to the overhead contact line, which provides the bus voltage of the traction converter. The output terminal of the device for suppressing traction converter bus voltage oscillation is connected to the input terminal of the traction converter, the output terminal of the traction converter is connected to the input terminal of the motor, and the output terminal of the motor is connected to the input terminal of the device for suppressing traction converter bus voltage oscillation.

8. The traction system according to claim 7, characterized in that, The system further includes: an LC resonant filter disposed between the overhead contact line and the traction converter; The input terminal of the LC resonant filter is connected to the overhead contact line, and the output terminal of the LC resonant filter is connected to the input terminal of the traction converter and the input terminal of the device for suppressing the oscillation of the traction converter bus voltage.

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