An alternating current traction power supply voltage abnormality detection method and system

Abstract

The embodiment of the present application relates to a kind of AC traction power supply network voltage abnormality detection method and system, the method comprises: real-time acquisition instantaneous voltage;Effective voltage value is calculated;Software phase-locked loop calculation is carried out, and network voltage phase-locked loop instantaneous amplitude, network voltage phase angle and frequency, under-voltage, overvoltage, phase-locked loop amplitude anomaly flag bit are set according to the calculation result;When frequency, under-voltage, phase-locked loop amplitude anomaly flag bit are all set to invalid value, phase-locked loop success flag bit is set to valid value;And when frequency, under-voltage, overvoltage or phase-locked loop amplitude anomaly flag bit is set to valid value, the PWM pulse of four-quadrant rectifier is locked processing;Receive pulse state feedback data;Network voltage reconstruction and comparison processing are carried out, and according to comparison result, set distortion / interruption anomaly flag bit;When distortion / interruption anomaly flag bit is set to valid value, the PWM pulse of four-quadrant rectifier is locked processing. Through the present application, the detection response speed is improved, and overcurrent fault can be better avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of rail transit technology, and in particular to a method and system for detecting abnormal network voltage of AC traction power supply. BACKGROUND

[0002] The motor train unit is powered by a single-phase AC 25kV traction power supply network. The power of the 25kV traction power supply network is introduced from the pantograph of the motor train unit to the traction transformer, and then introduced to the traction converter through the secondary side of the traction transformer. The traction control unit of the traction converter collects the supply voltage of the single-phase AC 25kV traction power supply network, and the four-quadrant rectifier of the traction converter rectifies and converts the single-phase AC 25kV power. The abnormal conditions of the network voltage of the AC traction power supply mainly include network voltage undervoltage, network voltage overvoltage, network voltage frequency abnormality, and network voltage distortion / interruption. When the above abnormal conditions occur, if the traction converter of the motor train unit fails to detect the network voltage condition of the traction power supply in time, the control of the four-quadrant rectifier may be unstable, which may cause input overcurrent fault of the four-quadrant rectifier and damage the traction converter device. SUMMARY

[0003] The purpose of the present application is to overcome the defects of the prior art and provide a method and system for detecting abnormal network voltage of AC traction power supply. Through this scheme, the network side current does not need to be collected, the control parameters of the four-quadrant rectifier do not need to be judged, and only the network voltage instantaneous value signal needs to be collected to quickly determine the specific abnormal condition of the network voltage. This avoids the network voltage abnormality mis-detection condition caused by too many analysis factors, improves the detection response speed, and better avoids the overcurrent fault.

[0004] Therefore, the first aspect of the embodiment of the present application provides a method for detecting abnormal network voltage of AC traction power supply, which comprises:

[0005] Real-time collection of the network voltage instantaneous signal of the AC traction power supply network generates the corresponding instantaneous voltage U s ;

[0006] Calculation of the network voltage effective value at the current time generates the corresponding effective voltage value U s_rms ;

[0007] Software phase-locked calculation processing is performed according to the instantaneous voltage U s and the effective voltage value U s_rms , and the network voltage phase-locked instantaneous amplitude PLL_U inp , the network voltage phase angle θ, the frequency abnormality flag, the undervoltage abnormality flag, the overvoltage abnormality flag, and the phase-locked amplitude abnormality flag are set according to the calculation result;

[0008] When the frequency, under-voltage, phase-locked amplitude abnormal flag bit are set to invalid value, set the phase-locked success flag bit to valid value; and when the frequency, under-voltage, over-voltage or phase-locked amplitude abnormal flag bit are set to valid value, generate the first pulse blocking instruction to block the PWM pulse of the four-quadrant rectifier;

[0009] Receive the four-quadrant rectifier pulse state feedback signal, and generate corresponding pulse state feedback data;

[0010] According to the instantaneous voltage U s , the grid voltage phase-locked instantaneous amplitude PLL_U inp , the grid voltage phase angle θ, the phase-locked success flag bit and the pulse state feedback data, perform grid voltage reconstruction and comparison processing, and set the distortion / interruption abnormal flag bit according to the comparison result;

[0011] When the distortion / interruption abnormal flag bit is set to valid value, generate the second pulse blocking instruction to block the PWM pulse of the four-quadrant rectifier.

[0012] Preferably, the current grid voltage effective value is calculated to generate corresponding effective voltage value U s_rms , specifically including:

[0013] Take the current time as the starting point, and count the latest n said instantaneous voltage U s within the preset sliding window time t, to generate a sequence U s(k) ; n≥k≥1, n=i*j, i is the total number of power frequency cycles obtained within the latest sliding window time t with the current time as the starting point, and j is the fixed total number of grid voltage instantaneous signal samples in each power frequency cycle;

[0014] According to the sequence U s(k) , calculate the effective voltage value U s_rms ,

[0015] Preferably, the software phase-locked calculation processing is performed according to the instantaneous voltage U s and the effective voltage value U s_rms , and the grid voltage phase-locked instantaneous amplitude PLL_U inp , the grid voltage phase angle θ, the frequency abnormal flag bit, the under-voltage abnormal flag bit, the over-voltage abnormal flag bit and the phase-locked amplitude abnormal flag bit are set according to the calculation result, specifically including:

[0016] Perform stationary coordinate system decomposition operation on the instantaneous voltage U s to generate corresponding α-axis grid voltage component U α and β-axis grid voltage component U β; and performing a rotating coordinate system conversion on the α-axis grid voltage component U α and the β-axis grid voltage component U β to generate a corresponding d-axis grid voltage component U d and a q-axis grid voltage component U q ;

[0017] According to the d-axis grid voltage component U d and the q-axis grid voltage component U q , a grid voltage phase-locked instantaneous amplitude calculation is performed to generate the grid voltage phase-locked instantaneous amplitude PLL_U inp ,

[0018] According to the q-axis grid voltage component U q and a preset q-axis given value , a PI operation is performed to generate a grid-side voltage angular velocity error △ω s ; and the grid-side voltage angular velocity error △ω s is added to a preset power frequency angular velocity to obtain an estimated angular velocity ω s ;

[0019] An integral operation is performed on the estimated angular velocity ω s to obtain the grid voltage phase angle θ;

[0020] According to the estimated angular velocity ω s , a grid voltage frequency f s is calculated, where f s = ω s / 2π;

[0021] When the grid voltage frequency f s is less than a preset minimum frequency threshold f min or greater than a preset maximum frequency threshold f max , the frequency abnormality flag bit is set to a valid value; when the grid voltage frequency f s is greater than or equal to the minimum frequency threshold f min and less than or equal to the maximum frequency threshold f max , the frequency abnormality flag bit is set to an invalid value;

[0022] When the effective voltage value U s_rms is less than a preset minimum grid voltage threshold U s_min , the under-voltage abnormality flag bit is set to a valid value; when the effective voltage value U s_rms is greater than or equal to the minimum grid voltage threshold U s_min , the under-voltage abnormality flag bit is set to an invalid value;

[0023] When the effective voltage value U s_rms is greater than a preset maximum grid voltage threshold U s_max , the overvoltage abnormal flag bit is set as an effective value; when the effective voltage value U s_rms is less than or equal to the maximum grid voltage threshold U s_max , the overvoltage abnormal flag bit is set as an invalid value.

[0024] The first comparison value is calculated as follows: When the first comparison value is greater than a preset maximum phase-locked amplitude threshold U err_max , the phase-locked amplitude abnormal flag bit is set as an effective value; when the first comparison value is less than or equal to the maximum phase-locked amplitude threshold U err_max , the phase-locked amplitude abnormal flag bit is set as an invalid value.

[0025] Preferably, according to the instantaneous voltage U s , the grid voltage phase-locked instantaneous amplitude PLL_U inp , the grid voltage phase angle θ, the phase-locked success flag bit and the pulse state feedback data, grid voltage reconstruction and comparison processing is performed, and a distortion / interruption abnormal flag bit is set according to the comparison result, specifically including:

[0026] According to the grid voltage phase-locked instantaneous amplitude PLL_U inp and the grid voltage phase angle θ, grid voltage target signal reconstruction processing is performed to obtain a corresponding target signal U s_ref , U s_ref = PLL_U inp × sin θ.

[0027] According to the instantaneous voltage U s and the target signal U s_ref , a first signal difference value = |U s_ref -U s | is calculated.

[0028] When a plurality of the first signal difference values continuously obtained in the recent period are all greater than a preset maximum off amplitude U shut_max , a corresponding duration is calculated.

[0029] When the duration is greater than a preset time threshold t shut , and the phase-locked success flag bit and the pulse state feedback data are both effective values, the distortion / interruption abnormal flag bit is set as an effective value; when the duration is less than or equal to the time threshold t shut , or the phase-locked success flag bit is an invalid value, or the pulse state feedback data is an invalid value, the distortion / interruption abnormal flag bit is set as an invalid value.

[0030] Further, the time threshold tshut Less than half of a power frequency cycle.

[0031] The second aspect of the embodiment of the present application provides a system for implementing the network voltage abnormality detection method of the first aspect, the system comprising: a network voltage signal acquisition module, a software phase-locked operation and judgment module, a network voltage reconstruction and comparison detection module, and a four-quadrant PWM pulse control module;

[0032] The network voltage signal acquisition module is connected with the software phase-locked operation and judgment module and the network voltage reconstruction and comparison detection module respectively; the network voltage signal acquisition module is used to acquire the network voltage instantaneous signal of the AC traction power supply network in real time, generate the corresponding instantaneous voltage U s , calculate the network voltage effective value at the current time to generate the corresponding effective voltage value U s_rms , and send the instantaneous voltage U s and the effective voltage value U s_rms to the software phase-locked operation and judgment module, and send the instantaneous voltage U s to the network voltage reconstruction and comparison detection module;

[0033] The software phase-locked operation and judgment module is connected with the network voltage reconstruction and comparison detection module and the four-quadrant PWM pulse control module respectively; the software phase-locked operation and judgment module is used to perform software phase-locked calculation processing according to the instantaneous voltage U s and the effective voltage value U s_rms , set the network voltage phase-locked instantaneous amplitude PLL_U inp , the network voltage phase angle θ, the frequency abnormality flag, the under-voltage abnormality flag, the over-voltage abnormality flag, and the phase-locked amplitude abnormality flag according to the calculation result, set the phase-locked success flag to an effective value when the frequency, under-voltage, and phase-locked amplitude abnormality flags are all invalid values, generate a first pulse blocking instruction when the frequency, under-voltage, over-voltage, or phase-locked amplitude abnormality flag is set to an effective value, send the network voltage phase-locked instantaneous amplitude PLL_U inp , the network voltage phase angle θ, and the phase-locked success flag to the network voltage reconstruction and comparison detection module, and send the first pulse blocking instruction to the four-quadrant PWM pulse control module;

[0034] The network voltage reconstruction and comparison detection module is connected with the four-quadrant PWM pulse control module; the network voltage reconstruction and comparison detection module is used to receive the four-quadrant rectifier pulse state feedback signal sent by the four-quadrant PWM pulse control module, generate the corresponding pulse state feedback data, and generate the corresponding pulse state feedback data according to the instantaneous voltage U s , the network voltage phase-locked instantaneous amplitude PLL_U inp, the grid voltage phase angle θ, the phase-locked success flag and the pulse state feedback data, performs grid voltage reconstruction and comparison processing, and sets a distortion / interruption abnormality flag according to a comparison result; and when the distortion / interruption abnormality flag is set to a valid value, generates a second pulse blocking instruction; and sends the second pulse blocking instruction to the four-quadrant PWM pulse control module;

[0035] The four-quadrant PWM pulse control module is configured to collect a pulse state feedback signal of the four-quadrant rectifier in real time, and send the four-quadrant rectifier pulse state feedback signal to the grid voltage reconstruction and comparison detection module; and the four-quadrant PWM pulse control module is further configured to block PWM pulses of the four-quadrant rectifier when receiving the first or second pulse blocking instruction.

[0036] The present application provides an AC traction power supply grid voltage abnormality detection method and system, a software phase-locked loop determination processing flow is given, the values of frequency, under-voltage, over-voltage and phase-locked amplitude abnormality flags are determined according to grid voltage frequency and effective voltage value, so that the real-time abnormal working condition of the motor train unit is quickly obtained; and the phase-locked success is determined when the frequency, under-voltage and phase-locked amplitude abnormality flags are all invalid values. A processing flow of reconstructing a grid voltage target signal according to the software phase-locked result is given, and the absolute difference between the reconstructed target signal and the grid voltage instantaneous value signal is determined, and if the difference is too large, it indicates that the grid voltage is seriously distorted or interrupted. The present application fully utilizes the filtering delay effect of the software phase-locked loop, so that the grid voltage reconstruction is feasible, and the reconstruction result is used as a comparison reference for the real-time grid voltage signal. The present application only collects the grid voltage instantaneous value signal for determination, avoids the grid voltage abnormality false detection condition caused by too many analysis factors, improves the detection response speed, and can better avoid over-current faults. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 A schematic diagram of an AC traction power supply grid voltage abnormality detection method provided for the first embodiment of the present application;

[0038] Figure 2 A phase-locked operation process schematic diagram provided for the first embodiment of the present application;

[0039] Figure 3 A structure schematic diagram of an AC traction power supply grid voltage abnormality detection system provided for the second embodiment of the present application. DETAILED DESCRIPTION

[0040] Embodiments of the present application are described below in detail, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0041] When the motor train unit is in working state, the network voltage abnormality detection method for AC traction power supply provided by the embodiment of the present application protects the traction converter on the train unit in real time, and the embodiment of the present application judges the network voltage abnormality working condition by collecting network voltage instantaneous value signals, and if an abnormality is found, a pulse blocking instruction is generated to block the PWM pulse of the four-quadrant rectifier of the traction converter, thereby avoiding the damage of the four-quadrant rectifier input overcurrent fault to the traction converter caused by abnormal network voltage working condition; Figure 1 The network voltage abnormality detection method for AC traction power supply provided by the embodiment of the present application is shown in the schematic diagram as shown in Figure 1 The method comprises the following steps:

[0042] Step 1, real-time collection of network voltage instantaneous signals of the AC traction power supply network to generate corresponding instantaneous voltage U s .

[0043] Step 2, calculation of the network voltage effective value at the current time to generate corresponding effective voltage value U s_rms ;

[0044] Specifically, step 21, taking the current time as the starting point, the latest n instantaneous voltages U s are counted according to the preset sliding window time t to generate sequence U s(k) ;

[0045] Wherein, n≥k≥1, n=i*j, i is the total number of power frequency cycles obtained within the latest sliding window time t from the current time as the starting point, and j is the fixed total number of network voltage instantaneous signal samples in each power frequency cycle;

[0046] Step 22, calculation of the effective voltage value U s(k) from the sequence U s_rms ,

[0047]

[0048] Here, in order to enhance the anti-interference ability of the effective value calculation, the sliding window method is used for data counting, and the statistical data is calculated by root mean square; the sliding window time is fixed as the sliding window time t.

[0049] For example, t is 0.1 second, the power frequency period T is 20 milliseconds, the total number of samples j in a single power frequency period T is 100 times, then i=t / T=100 / 20=5 power frequency periods, n=i*j=5*100=500 total number of samples, then the current time of the net voltage effective value is the most recent 500 times of instantaneous voltage U s The root mean square calculation result of the amplitude.

[0050] Step 3, according to the instantaneous voltage U s and the effective voltage value U s_rms , the software phase-locked calculation processing is carried out, and the net voltage phase-locked instantaneous amplitude PLL_U inp , the net voltage phase angle θ, the frequency abnormal flag, the under-voltage abnormal flag, the over-voltage abnormal flag and the phase-locked amplitude abnormal flag are set according to the calculation result;

[0051] Specifically includes: step 31, the instantaneous voltage U s is carried out stationary coordinate system decomposition operation, and the corresponding α-axis net voltage component U α and the β-axis net voltage component U β are generated; and according to the corresponding relationship between the stationary coordinate system and the rotating coordinate system, the α-axis net voltage component U α and the β-axis net voltage component U β are carried out rotating coordinate system conversion, and the corresponding d-axis net voltage component U d and q-axis net voltage component U q are generated;

[0052] Step 32, according to the d-axis net voltage component U d and the q-axis net voltage component U q , the net voltage phase-locked instantaneous amplitude calculation is carried out, and the net voltage phase-locked instantaneous amplitude PLL_U inp is generated,

[0053]

[0054] Step 33, according to the q-axis net voltage component U q and the preset q-axis given value , PI operation is carried out to generate the net side voltage angular velocity error △ω s ; and the net side voltage angular velocity error △ω s is added to the preset power frequency angular velocity to obtain the estimated angular velocity ω s ;

[0055] Step 34, the integral operation is carried out on the estimated angular velocity ω s to obtain the net voltage phase angle θ;

[0056] Step 35, the net voltage frequency f is calculated according to the estimated angular velocity ω s ​s , f s = ω s / 2π;

[0057] Here, the above steps 31-35 are the data calculation process of software phase-locked calculation, as shown in the schematic diagram of phase-locked operation process provided by Embodiment One of the present application; the following steps 36-39 are the judgment of the states of the four flag bits of frequency abnormal flag bit, under-voltage abnormal flag bit, over-voltage abnormal flag bit and phase-locked amplitude abnormal flag bit according to the results of software phase-locked calculation, i.e. the grid voltage frequency f s , effective voltage value U s_rms , grid voltage phase-locked instantaneous amplitude PLL_U inp and corresponding comparison threshold value; Figure 2

[0058] Step 36, when the grid voltage frequency f s is less than the preset minimum frequency threshold value f min or greater than the preset maximum frequency threshold value f max , the frequency abnormal flag bit is set as effective value; when the grid voltage frequency f s is greater than or equal to the minimum frequency threshold value f min and less than or equal to the maximum frequency threshold value f max , the frequency abnormal flag bit is set as invalid value;

[0059] Here, the effective value is usually 1 and the invalid value is usually 0; the current step is to judge the state of the frequency abnormal flag bit, if the frequency abnormal flag bit is 1, it means that the current detection finds that the grid voltage frequency is abnormal, and the corresponding abnormal working condition is the grid voltage frequency abnormal working condition;

[0060] Step 37, when the effective voltage value U s_rms is less than the preset minimum grid voltage threshold value U s_min , the under-voltage abnormal flag bit is set as effective value; when the effective voltage value U s_rms is greater than or equal to the minimum grid voltage threshold value U s_min , the under-voltage abnormal flag bit is set as invalid value;

[0061] Here, the current step is to judge the state of the under-voltage abnormal flag bit, if the under-voltage abnormal flag bit is 1, it means that the current detection finds that the grid voltage has continuous under-voltage abnormality, and the corresponding abnormal working condition is the grid voltage under-voltage abnormal working condition;

[0062] Step 38, when the effective voltage value U s_rms is greater than the preset maximum grid voltage threshold value U s_max , the over-voltage abnormal flag bit is set as effective value; when the effective voltage value U s_rms is less than or equal to the maximum grid voltage threshold value U s_max , the over-voltage abnormal flag bit is set as invalid value;​

[0063] Here, the current step is to judge the state of the over-voltage abnormal flag, and if the over-voltage abnormal flag is 1, it means that the current detection finds that the network voltage appears a persistent over-voltage abnormality, and the corresponding abnormal working condition is the network over-voltage abnormal working condition.

[0064] Step 39, calculating When the first comparison value is greater than the preset maximum phase-locked amplitude threshold U err_max , the phase-locked amplitude abnormal flag is set to a valid value; when the first comparison value is less than or equal to the maximum phase-locked amplitude threshold U err_max , the phase-locked amplitude abnormal flag is set to an invalid value.

[0065] Here, the current step is to judge the state of the phase-locked amplitude abnormal flag, and if the phase-locked amplitude abnormal flag is 1, it means that the current detection finds that the network voltage phase-locked instantaneous amplitude PLL_U inp is too high, and the corresponding abnormal working condition is the phase-locked amplitude abnormal working condition.

[0066] Step 4, when the frequency, under-voltage, and phase-locked amplitude abnormal flags are all set to invalid values, the phase-locked success flag is set to a valid value; and when the frequency, under-voltage, over-voltage, or phase-locked amplitude abnormal flag is set to a valid value, a first pulse blocking instruction is generated to block the PWM pulse of the four-quadrant rectifier.

[0067] Here, if any one of the frequency abnormal flag, under-voltage abnormal flag, over-voltage abnormal flag, and phase-locked amplitude abnormal flag is 1, it means that the working condition of the traction converter is abnormal, and in this case, a pulse blocking instruction needs to be generated immediately to block the PWM pulse of the four-quadrant rectifier.

[0068] Step 5, receiving a four-quadrant rectifier pulse state feedback signal to generate corresponding pulse state feedback data.

[0069] Here, the four-quadrant rectifier pulse state feedback signal is used to represent the fault state of the four-quadrant rectifier, and if it is a valid value 1, it means that the four-quadrant rectifier is faulty, and if it is an invalid value 0, it means that the four-quadrant rectifier is working normally.

[0070] Step 6, according to the instantaneous voltage U s , the network voltage phase-locked instantaneous amplitude PLL_U inp , the network voltage phase angle θ, the phase-locked success flag, and the pulse state feedback data, performing network voltage reconstruction and comparison processing, and setting the distortion / interruption abnormal flag according to the comparison result;

[0071] Here, it is actually to identify whether the difference between the reconstructed grid voltage target signal and the instantaneous voltage signal is abnormal continuously in a period of time, and if so, further combined with the phase-locked success flag and the pulse state feedback data to judge whether the grid voltage condition is in distortion or interruption state;

[0072] Specifically includes: step 61, according to the grid voltage phase-locked instantaneous amplitude PLL_U inp and grid voltage phase angle θ, the grid voltage target signal reconstruction processing is carried out, and the corresponding target signal U s_ref , s_ref = PLL_U inp × sin θ is obtained.

[0073] Step 62, according to the instantaneous voltage U s and the target signal U s_ref , the first signal difference = |U s_ref -U s | is calculated.

[0074] Step 63, when the plurality of first signal difference continuously obtained recently are all greater than the preset maximum off amplitude U shut_max , the corresponding duration is calculated.

[0075] Step 64, when the duration is greater than the preset time threshold t shut , and the phase-locked success flag and the pulse state feedback data are all valid values, set the distortion / interruption abnormal flag to a valid value; when the duration is less than or equal to the time threshold t shut , or the phase-locked success flag is invalid, or the pulse state feedback data is invalid, set the distortion / interruption abnormal flag to an invalid value; wherein the time threshold t shut is less than half a power frequency period.

[0076] Here, when the duration is greater than the preset time threshold t shut , it means that the difference between the reconstructed grid voltage target signal and the instantaneous voltage signal is abnormal continuously in a period of time, and if the phase-locked success flag is 1 and the pulse state feedback data is 1, the distortion / interruption abnormal flag is set to 1, and the distortion / interruption abnormal flag is 1, which means that the grid voltage condition is in distortion or interruption state; here, the time threshold t shut is less than half a power frequency period, so as to ensure that the serious distortion or interruption of the traction power supply grid voltage can be detected within half a power frequency period.

[0077] Step 7, when the distortion / interruption abnormal flag is set to a valid value, a second pulse blocking instruction is generated to block the PWM pulse of the four-quadrant rectifier.

[0078] Here, the distortion / disruption abnormal flag is 1, indicating that the current working condition of the traction converter is an abnormal working condition, and in this case, the pulse blocking instruction is generated immediately to perform PWM pulse blocking operation on the four-quadrant rectifier.

[0079] The system for implementing the network voltage abnormality detection method for the AC traction power supply provided in the first embodiment has the structure as shown in Figure 3 The system for implementing the network voltage abnormality detection method for the AC traction power supply provided in the second embodiment has the structure as shown in the structural schematic diagram, and the system comprises a network voltage signal acquisition module 201, a software phase-locked operation and judgment module 202, a network voltage reconstruction and comparison detection module 203, and a four-quadrant PWM pulse control module 204.

[0080] The network voltage signal acquisition module 201 is connected with the software phase-locked operation and judgment module 202 and the network voltage reconstruction and comparison detection module 203 respectively; the network voltage signal acquisition module 201 is used to acquire the network voltage instantaneous signal of the AC traction power supply network in real time, generate the corresponding instantaneous voltage U s , calculate the effective value of the network voltage at the current time to generate the corresponding effective voltage value U s_rms , and send the instantaneous voltage U s and the effective voltage value U s_rms to the software phase-locked operation and judgment module 202, and send the instantaneous voltage U s to the network voltage reconstruction and comparison detection module 203.

[0081] The software phase-locked operation and judgment module 202 is connected with the network voltage reconstruction and comparison detection module 203 and the four-quadrant PWM pulse control module 204 respectively; the software phase-locked operation and judgment module 202 is used to perform software phase-locked calculation processing according to the instantaneous voltage U s and the effective voltage value U s_rms , set the network voltage phase-locked instantaneous amplitude PLL_U inp , the network voltage phase angle θ, the frequency abnormal flag, the under-voltage abnormal flag, the over-voltage abnormal flag, and the phase-locked amplitude abnormal flag according to the calculation result, set the phase-locked success flag to an effective value when the frequency, under-voltage, and phase-locked amplitude abnormal flags are all invalid values, generate a first pulse blocking instruction when the frequency, under-voltage, over-voltage, or phase-locked amplitude abnormal flag is set to an effective value, send the network voltage phase-locked instantaneous amplitude PLL_U inp , the network voltage phase angle θ, and the phase-locked success flag to the network voltage reconstruction and comparison detection module 203, and send the first pulse blocking instruction to the four-quadrant PWM pulse control module 204.

[0082] The grid voltage reconstruction and comparison detection module 203 is connected with the four-quadrant PWM pulse control module 204; the grid voltage reconstruction and comparison detection module 203 is used for receiving the four-quadrant rectifier pulse state feedback signal sent by the four-quadrant PWM pulse control module 204, generating corresponding pulse state feedback data; and according to the instantaneous voltage U s , the grid voltage phase-locked instantaneous amplitude PLL_U inp , the grid voltage phase angle θ, the phase-locked success flag bit and the pulse state feedback data, performing grid voltage reconstruction and comparison processing, and setting the distortion / interruption abnormal flag bit according to the comparison result; and when the distortion / interruption abnormal flag bit is set to a valid value, generating a second pulse blocking instruction; and sending the second pulse blocking instruction to the four-quadrant PWM pulse control module 204.

[0083] The four-quadrant PWM pulse control module 204 is used for collecting the pulse state feedback signal of the four-quadrant rectifier in real time, generating the four-quadrant rectifier pulse state feedback signal to the grid voltage reconstruction and comparison detection module 203; the four-quadrant PWM pulse control module 204 is also used for blocking the PWM pulse of the four-quadrant rectifier when receiving the first or second pulse blocking instruction.

[0084] The grid voltage abnormality detection system for AC traction power supply provided in the second embodiment of the present application can execute the method steps in the method embodiments, and has similar implementation principles and technical effects, which will not be described here.

[0085] In summary, the grid voltage abnormality detection method and system for AC traction power supply provided in the embodiments of the present application have at least the following technical effects or advantages: 1) the filter delay effect of the software phase-locked loop is fully utilized to make the grid voltage reconstruction feasible and the reconstruction result is used as the comparison reference of the real-time grid voltage signal; 2) the grid voltage instantaneous value signal is collected for judgment, which avoids the grid voltage abnormality false detection condition caused by too many analysis factors, improves the detection response speed, and can better avoid the overcurrent fault.

[0086] The skilled person should further realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed herein can be realized in electronic hardware, computer software or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the components and steps of the examples have been described in the above description in general terms. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0087] The steps of a method or algorithm described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in random access memory (RAM), flash memory, read-only memory (ROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and

[0088] The above detailed description describes the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for detecting abnormal grid voltage in AC traction power supply, characterized in that, The method includes: The instantaneous voltage signal of the AC traction power supply network is acquired in real time, and the corresponding instantaneous voltage U is generated. s ; Calculate the corresponding effective voltage value U based on the current grid voltage RMS value. s_rms ; According to the instantaneous voltage U s and the effective voltage value U s_rms Perform software phase-locked loop (PLL) calculations and set the instantaneous amplitude PLL_U of the mains voltage based on the calculation results. inp The following flags are set: mains voltage phase angle θ, frequency abnormality flag, undervoltage abnormality flag, overvoltage abnormality flag, and phase-locked loop amplitude abnormality flag. When the frequency, undervoltage, and phase-locked loop amplitude abnormal flags are all set to invalid values, the phase-locked loop success flag is set to an effective value; and when the frequency, undervoltage, overvoltage, or phase-locked loop amplitude abnormal flags are set to an effective value, a first pulse blocking command is generated to block the PWM pulse of the four-quadrant rectifier. Receive the pulse status feedback signal from the four-quadrant rectifier and generate the corresponding pulse status feedback data; According to the instantaneous voltage U s The instantaneous amplitude of the mains voltage phase-locked loop (PLL_U) inp The mains voltage phase angle θ, the phase-locked loop success flag, and the pulse status feedback data are used for mains voltage reconstruction and comparison processing, and distortion / interruption abnormality flags are set according to the comparison results. When the distortion / interruption exception flag is set to a valid value, a second pulse blocking command is generated to block the PWM pulse of the four-quadrant rectifier. Wherein, according to the instantaneous voltage U s and the effective voltage value U s_rms Perform software phase-locked loop (PLL) calculations and set the instantaneous amplitude PLL_U of the mains voltage based on the calculation results. inp The mains voltage phase angle θ, frequency abnormality flag, undervoltage abnormality flag, overvoltage abnormality flag, and phase-locked loop amplitude abnormality flag include: For the instantaneous voltage U s Perform a static coordinate system decomposition operation to generate the corresponding α-axis net pressure component U. α and β-axis network pressure component U β And according to the correspondence between the stationary coordinate system and the rotating coordinate system, the α-axis network compression component U is... α and the β-axis network pressure component U β Perform a coordinate system transformation to generate the corresponding d-axis net pressure component U. d and q-axis network pressure component U q ; According to the d-axis network pressure component U d and the q-axis network pressure component U q Perform instantaneous amplitude calculation of the mains voltage phase-locked loop (PLL_U) to generate the instantaneous amplitude of the mains voltage phase-locked loop. inp , According to the q-axis network pressure component U q and the preset q-axis value Perform PI calculation to generate the grid-side voltage angular velocity error Δω s ; and the side voltage angular velocity error Δω s With the preset power frequency angular velocity Add them together to obtain the estimated angular velocity ω. s ; For the estimated angular velocity ω s The phase angle θ of the grid voltage is obtained by performing an integral operation; Based on the estimated angular velocity ω s The calculated grid voltage frequency f s f s =ω s / 2π; When the grid voltage frequency f s Less than the preset minimum frequency threshold f min Or greater than the preset maximum frequency threshold f max When the frequency anomaly flag is set to a valid value, the frequency anomaly flag is set to a valid value; when the mains voltage frequency f s Greater than or equal to the minimum frequency threshold f min And less than or equal to the maximum frequency threshold f max When this occurs, the frequency anomaly flag is set to an invalid value; When the effective voltage value U s_rms Less than the preset minimum network voltage threshold U s_min When the undervoltage abnormality flag is set to a valid value, the valid voltage value U... s_rms Greater than or equal to the minimum network voltage threshold U s_min When this occurs, the undervoltage abnormality flag is set to an invalid value; When the effective voltage value U s_rms Greater than the preset maximum network voltage threshold U s_max When the overvoltage abnormality flag is set to an effective value, the effective voltage value U... s_rms Less than or equal to the maximum network voltage threshold U s_max At this time, the overvoltage abnormality flag bit is set to an invalid value; calculate When the first comparison value is greater than the preset maximum phase-locked loop amplitude threshold U err_max When the phase-locked loop amplitude abnormality flag is set to a valid value; when the first comparison value is less than or equal to the maximum phase-locked loop amplitude threshold U err_max When this occurs, the phase-locked loop amplitude abnormality flag is set to an invalid value; The instantaneous voltage U s The instantaneous amplitude of the mains voltage phase-locked loop (PLL_U) inp The mains voltage phase angle θ, the phase-locked loop success flag, and the pulse status feedback data are used for mains voltage reconstruction and comparison processing. Based on the comparison results, distortion / interruption anomaly flags are set, specifically including: According to the instantaneous amplitude of the mains voltage phase-locked loop (PLL_U) inp The target signal U is reconstructed using the grid voltage phase angle θ. s_ref U s_ref =PLL_U inp ×sinθ; According to the instantaneous voltage U s and the target signal U s_ref Calculate the first signal difference = |U s_ref -U s |; When multiple recently obtained differences of the first signal are all greater than the preset maximum cutoff amplitude U shut_max Calculate the corresponding duration. When the duration is greater than the preset duration threshold t shut When both the phase-locked success flag and the pulse status feedback data are valid values, the distortion / interruption exception flag is set to a valid value; when the duration is less than or equal to the duration threshold t shut If the phase-locked success flag is invalid, or the pulse status feedback data is invalid, the distortion / interruption exception flag is set to invalid. The duration threshold t shut Less than half a power frequency cycle.

2. The method for detecting abnormal grid voltage in AC traction power supply according to claim 1, characterized in that, The effective voltage value U is generated by calculating the effective value of the grid voltage at the current moment. s_rms Specifically, it includes: Starting from the current time, the most recent n instantaneous voltages U are counted according to a preset sliding window duration t. s Generate sequence U s(k) ; n≥k≥1, n=i*j, i is the total number of power frequency cycles obtained within the most recent sliding window duration t with the current time as the starting point, and j is the fixed total number of samples of the instantaneous grid voltage signal within each power frequency cycle; According to the sequence U s(k) The effective voltage value U is calculated and generated. s_rms , 3. A system for implementing the AC traction power supply grid voltage anomaly detection method according to any one of claims 1-2, characterized in that, The system includes: a mains voltage signal acquisition module, a software phase-locked loop operation and judgment module, a mains voltage reconstruction and comparison detection module, and a four-quadrant PWM pulse control module; The mains voltage signal acquisition module is connected to the software phase-locked loop operation and judgment module and the mains voltage reconstruction and comparison detection module, respectively; the mains voltage signal acquisition module is used to acquire the instantaneous mains voltage signal of the AC traction power supply network in real time and generate the corresponding instantaneous voltage U. s It also calculates the corresponding effective voltage value U based on the current grid voltage RMS value. s_rms ; and the instantaneous voltage U s and the effective voltage value U s_rms Send to the software phase-locked loop (PLL) calculation and judgment module; and send the instantaneous voltage U s Send to the network voltage reconstruction and comparison detection module; The software phase-locked loop (PLL) calculation and judgment module is connected to the mains voltage reconstruction and comparison detection module and the four-quadrant PWM pulse control module, respectively; the software PLL calculation and judgment module is used to calculate the instantaneous voltage U. s and the effective voltage value U s_rms Perform software phase-locked loop (PLL) calculations and set the instantaneous amplitude PLL_U of the mains voltage based on the calculation results. inp The system sets the following flags: mains voltage phase angle θ, frequency anomaly flag, undervoltage anomaly flag, overvoltage anomaly flag, and phase-locked loop amplitude anomaly flag. When the frequency, undervoltage, and phase-locked loop amplitude anomaly flags are all set to invalid values, the phase-locked loop success flag is set to an effective value. When the frequency, undervoltage, overvoltage, or phase-locked loop amplitude anomaly flag is set to an effective value, a first pulse blocking command is generated. The instantaneous amplitude of the mains voltage phase-locked loop, PLL_U, is then set. inp The mains voltage phase angle θ and the phase-locked loop success flag are sent to the mains voltage reconstruction and comparison detection module; and the first pulse blocking command is sent to the four-quadrant PWM pulse control module. The mains voltage reconstruction and comparison detection module is connected to the four-quadrant PWM pulse control module; the mains voltage reconstruction and comparison detection module is used to receive the four-quadrant rectifier pulse status feedback signal sent by the four-quadrant PWM pulse control module, generate corresponding pulse status feedback data, and based on the instantaneous voltage U... s The instantaneous amplitude of the mains voltage phase-locked loop (PLL_U) inp The mains voltage phase angle θ, the phase-locked loop success flag, and the pulse status feedback data are used for mains voltage reconstruction and comparison processing, and a distortion / interruption abnormality flag is set according to the comparison result; when the distortion / interruption abnormality flag is set to a valid value, a second pulse blocking command is generated; and the second pulse blocking command is sent to the four-quadrant PWM pulse control module. The four-quadrant PWM pulse control module is used to acquire the pulse state feedback signal of the four-quadrant rectifier in real time, generate the pulse state feedback signal of the four-quadrant rectifier and send it to the grid voltage reconstruction and comparison detection module; the four-quadrant PWM pulse control module is also used to block the PWM pulse of the four-quadrant rectifier when it receives the first or second pulse blocking command.

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