JP7526021B2 - Station building power supply device, regeneration determination method, and regeneration determination program - Google Patents

Description

This disclosure relates to a station power supply device that supplies regenerative power from an electric vehicle to a station, a regeneration determination method, and a regeneration determination program.

Conventionally, there is known a station power supply device that converts regenerative power generated by an electric vehicle connected to an overhead line from high-voltage DC power to low-voltage AC power and supplies the converted low-voltage AC power to station facilities. Regenerative power is generated, for example, when an electric vehicle decelerates, and when regenerative power is generated by an electric vehicle, the voltage of the overhead line rises. The station power supply device compares the voltage of the overhead line with a regeneration determination value, and when the voltage of the overhead line is equal to or greater than the regeneration determination value, performs a regenerative recovery operation to convert the regenerative power from high-voltage DC power to low-voltage AC power.

In order for the station building power supply device to efficiently recover regenerative power, it is desirable to set the regeneration judgment value slightly higher than the no-load voltage, which is the voltage of the overhead line in an unloaded state in which neither the overhead line nor the electric car is supplying power from the overhead line. Therefore, Patent Document 1 discloses a technology that estimates the no-load voltage from the overhead line voltage when it is determined that the overhead line voltage does not contain a ripple component, and adds an additional value to the estimated no-load voltage to set the regeneration judgment value.

International Publication No. WO 2016/132508

However, in the technology described in Patent Document 1, the estimated no-load voltage is added with an additional value to set the regeneration judgment value, taking into account the accuracy of the no-load voltage estimation. Therefore, in the technology described in Patent Document 1, the greater the difference between the estimated no-load voltage and the actual no-load voltage, the greater the discrepancy between the timing at which the station power supply device judges that the electric car has started regenerative operation and the timing at which the electric car actually starts regenerative operation. This timing discrepancy reduces the accuracy of the judgment as to whether the electric car is performing regenerative operation.

The present disclosure has been made in consideration of the above, and aims to provide a station power supply device that can improve the accuracy of determining whether an electric car is performing regenerative operation.

In order to solve the above-mentioned problems and achieve the objective, the station building power supply device disclosed herein includes an overhead line voltage detection unit, a ripple voltage detection unit, and a regenerative operation determination unit. The overhead line voltage detection unit detects the voltage of the overhead line connected to the electric car. The ripple voltage detection unit detects the ripple voltage, which is the voltage of the ripple component contained in the overhead line voltage detected by the overhead line voltage detection unit. The regenerative operation determination unit calculates the ratio between the overhead line voltage detected by the overhead line voltage detection unit and the ripple voltage detected by the ripple voltage detection unit, and determines whether the electric car is performing regenerative operation based on the calculated ratio.

This disclosure has the effect of improving the accuracy of determining whether an electric vehicle is performing regenerative operation.

FIG. 1 includes a functional configuration diagram of a station power supply device according to a first embodiment. FIG. 1 is a diagram showing a change in overhead line voltage according to the first embodiment. FIG. 1 is a diagram showing a relationship between a change in overhead line voltage, a change in ripple voltage, and a change in a regeneration determination index value according to the first embodiment; FIG. 1 is a diagram illustrating an example of a configuration of a station power supply device according to a first embodiment. FIG. 1 is a diagram showing a relationship between the change over time of the overhead line voltage, the ripple voltage, and the regeneration determination index value and the regeneration determination by the regeneration operation determination unit according to the first embodiment; FIG. 1 is a diagram for explaining a determination process performed by a regenerative operation determination unit according to the first embodiment; FIG. 13 is a diagram showing an example of a histogram showing a relationship between a regeneration determination index value and an overhead line voltage according to the first embodiment; A flowchart showing an example of a regeneration determination process by a regeneration operation determination unit of a station power supply operation panel according to the first embodiment. A flowchart showing an example of a first threshold determination process by a threshold determination unit of a station power supply control panel according to the first embodiment. A flowchart showing an example of a second threshold determination process by a threshold determination unit of a station power supply control panel according to the first embodiment. FIG. 1 is a diagram illustrating an example of a hardware configuration of a station building power supply control panel of a station building power supply device according to a first embodiment.

The station building power supply device, regeneration determination method, and regeneration determination program according to the embodiments are described in detail below with reference to the drawings.

Embodiment 1.
Fig. 1 is a diagram including a functional configuration diagram of a station building power supply device according to embodiment 1. The station building power supply device 10 shown in Fig. 1 converts regenerative power generated on an overhead line 2 due to, for example, a deceleration operation of an electric car 1 connected to the overhead line 2 from DC power to AC power and outputs the power to a station building 7.

The station building power supply device 10 executes an overhead line voltage detection process to detect the overhead line voltage, which is the voltage of the overhead line 2 connected to the electric car 1, and a ripple voltage detection process to detect the ripple voltage, which is the voltage of the ripple component contained in the overhead line voltage detected by the overhead line voltage detection process.

The station building power supply device 10 then uses the ratio of the overhead line voltage detected by the overhead line voltage detection process to the ripple voltage detected by the ripple voltage detection process as a regeneration determination index value, and performs a regeneration operation determination process to determine whether the electric car 1 is performing regenerative operation based on this determination index value. This allows the station building power supply device 10 to improve the accuracy of determining whether the electric car 1 is performing regenerative operation.

Then, when the station building power supply device 10 determines in the regenerative operation determination process that the electric car 1 is performing regenerative operation, it performs a power conversion process to convert the regenerative power generated on the overhead line 2 from DC power to AC power and output it to the station building 7.

Here, the relationship between the overhead line voltage and the ripple component contained in the overhead line voltage will be explained. Figure 2 is a diagram showing the change in the overhead line voltage in the first embodiment. In Figure 2, the horizontal axis indicates time, and the vertical axis indicates the overhead line voltage of the overhead line 2. The graph shown in Figure 2 shows the change in the overhead line voltage as it progresses from a no-load state to a powering operation state in which the electric car 1 accelerates, etc., to a no-load state, to a regenerative operation state in which the electric car 1 decelerates, etc., and back to the no-load state. The no-load state is a state in which neither power is supplied from the overhead line 2 to the electric car 1 nor from the electric car 1 to the overhead line 2.

The magnitude of the overhead line voltage shown in Figure 2 indicates the instantaneous value in each state, and in the no-load state, the overhead line voltage actually contains a ripple component. The waveform in the no-load state is shown in box A. Power is supplied to the overhead line 2 from a substation (not shown in Figure 1), and the overhead line voltage contains a ripple component due to the influence of the substation rectifier. The rectifier in the substation is, for example, a 6-pulse rectifier or a 12-pulse rectifier.

When the electric car 1 on the overhead line 2 transitions from a no-load state to a regenerative operation state, the overhead line voltage rises due to the regenerative power generated by the electric car 1. As the overhead line voltage rises, the valleys of the ripple component are pushed up and become shallower. Box B shows the waveform in the state of transition from a no-load state to regenerative operation. When the overhead line voltage increases further, the overhead line voltage and the peak of the ripple component become the same voltage. Box C shows the state at this point. When the overhead line voltage increases further due to regenerative operation, the overhead line voltage becomes higher than the peak of the ripple component.

Fluctuations in the overhead line voltage and ripple voltage detected by the station building power supply device 10 may not be linked due to load fluctuations, which poses a problem in terms of the accuracy of estimating the no-load voltage calculated from the overhead line voltage and ripple voltage. Therefore, if the regeneration determination voltage for determining the regenerative operation of the electric car 1 is set to a value obtained by adding an additional value to the no-load voltage value calculated from the overhead line voltage when it is determined that the overhead line voltage does not contain a ripple component, the additional value is set to a value that prevents the regeneration determination value from falling below the actual no-load voltage.

When using such a regeneration judgment value, the greater the difference between the estimated no-load voltage and the actual no-load voltage, the greater the discrepancy between the timing at which it is judged that the electric vehicle 1 has started regenerative operation and the timing at which the electric vehicle 1 actually starts regenerative operation, reducing the accuracy of the judgment as to whether the electric vehicle 1 is performing regenerative operation.

Therefore, in the station building power supply device 10 according to the first embodiment, the regeneration determination index value is used to determine whether the electric car 1 is performing regenerative operation. This allows the station building power supply device 10 to accurately determine whether the electric car 1 is performing regenerative operation. The regeneration determination index value is described in detail below.

Figure 3 is a diagram showing the relationship between the change in overhead line voltage, the change in ripple voltage, and the change in the regeneration judgment index value in the first embodiment. In Figure 3, the horizontal axis indicates time, and the vertical axis indicates the overhead line voltage, the ripple voltage, or the regeneration judgment index value. In the example shown in Figure 3, the regeneration judgment index value is a value expressed as the ratio of the overhead line voltage to the ripple voltage. In other words, the regeneration judgment index value is a value obtained by dividing the overhead line voltage by the ripple voltage.

As shown in Figure 3, in the powered operating state, the overhead line voltage is lower than in the no-load state, and in the regenerative operating state, the overhead line voltage is higher than in the no-load state. Also, in the powered operating state, the ripple voltage is higher than in the no-load state, and in the regenerative operating state, the ripple voltage is lower than in the no-load state. Therefore, the regeneration judgment index value, which is a value expressed as the ratio of the overhead line voltage to the ripple voltage, is smaller in the powered operating state than in the no-load state, and larger in the regenerative operating state than in the no-load state.

As shown in FIG. 3, the regeneration determination index value increases rapidly when transitioning from a no-load state to regenerative operation. Therefore, even in cases where fluctuations in the overhead line voltage and fluctuations in the ripple voltage are not linked due to load fluctuations, the accuracy of determining whether or not the electric vehicle 1 is performing regenerative operation can be improved by determining whether or not the electric vehicle 1 is performing regenerative operation from changes in the regeneration determination index value.

The configuration and processing of the station building power supply device 10 will be specifically described below. FIG. 4 is a diagram showing an example of the configuration of the station building power supply device according to the first embodiment. As shown in FIG. 4, the station building power supply device 10 includes a main circuit unit 11 that converts regenerative power generated on the overhead line 2 due to factors such as deceleration of the electric car 1 from DC power to AC power and outputs the power to the station building 7, and a station building power supply operation panel 12 that controls the operation of the main circuit unit 11.

The main circuit unit 11 includes a power conversion unit 20, an overhead line voltage detection unit 21, and a ripple voltage detection unit 22. In the example shown in FIG. 4, the power conversion unit 20 converts the regenerative power generated in the overhead line 2 from DC (Direct Current) 1500V system direct current power to AC (Alternating Current) 210V system alternating current power and outputs it to the station building 7. Note that the voltage of the overhead line 2 may be a voltage other than the DC 1500V system, and the voltage of the station building 7 may be a voltage other than the AC 210V system.

The overhead line 2 is supplied with DC 1500V DC power from a substation 8. As shown in FIG. 4, the substation 8 includes a transformer 81 and an n-pulse rectifier 82 that rectifies the three-phase voltage. n is, for example, a multiple of 6, and is 6 or 12, but may be 18 or 24. The six-pulse rectifier includes, for example, a three-phase full-wave rectifier that performs three-phase full-wave rectification. The 12-pulse rectifier includes, for example, two transformers with different connections and two three-phase full-wave rectifiers that are each connected to a corresponding one of the two transformers. The 12-pulse rectifier generates two three-phase AC voltages with a phase difference of 30 degrees using the two transformers, and performs three-phase full-wave rectification on each of the two generated three-phase AC voltages using the corresponding three-phase full-wave rectifier.

The transformer 81 steps down the 6600V AC voltage supplied from the high-voltage distribution system 6. The n-pulse rectifier 82 rectifies the AC voltage output from the transformer 81 and converts it to a DC 1500V voltage, and supplies the converted DC 1500V voltage to the overhead line 2 via a feeder wire (not shown).

The station building 7 also includes a transformer 71 and a station load 72. The transformer 71 converts the 6600V AC voltage supplied from the high-voltage distribution system 6 into an AC 210V voltage, and supplies the converted 210V AC voltage to station equipment 73 ₁ , 73 ₂ , ..., 73 _m . The station load 72 includes station equipment 73 ₁ , 73 ₂ , ..., 73 _m . The station equipment 73 ₁ , 73 ₂ , ..., 73 _m are, for example, air conditioning equipment, lighting equipment, elevators, etc. installed in the station.

The overhead line voltage detection unit 21 detects the DC 1500V overhead line voltage between the overhead line 2 and the rail 3 at a preset period Ts, and outputs information on the overhead line voltage value, which is the instantaneous value of the detected overhead line voltage. Hereinafter, the overhead line voltage value may be referred to as the overhead line voltage Vs. The overhead line voltage detection unit 21 has a filter that removes noise, and detects the overhead line voltage value from which noise has been removed as the overhead line voltage Vs.

The ripple voltage detection unit 22 detects a ripple voltage, which is the voltage of the ripple component contained in the voltage of the overhead line 2, based on the overhead line voltage Vs detected by the overhead line voltage detection unit 21 each time the overhead line voltage detection unit 21 detects the overhead line voltage Vs at a preset cycle Ts, and outputs information on the detected ripple voltage. The ripple voltage detection unit 22 analyzes the frequency components of the voltage of the overhead line 2 detected by the overhead line voltage detection unit 21. Specifically, the ripple voltage detection unit 22 analyzes the frequency components for the nth frequency of the power supply frequency, which is the frequency of the 6600V AC voltage output from the high-voltage distribution system 6. The ripple voltage detection unit 22 analyzes the frequency components by, for example, Fourier transform processing or wavelet transform that performs a time discrete Fourier transform or a fast Fourier transform.

For example, when the n-pulse rectifier 82 of the substation 8 is a 6-pulse rectifier and the substation 8 is located in an area with a power supply frequency of 50 Hz, the ripple voltage detection unit 22 calculates the ripple voltage for the sixth frequency of 300 Hz. The ripple voltage detection unit 22 outputs ripple information, which is information on the calculated ripple voltage. The ripple voltage is expressed as the voltage value from the valley of the ripple component to the peak of the ripple component, the amplitude of the ripple component, or the effective voltage value of the ripple component. The valley of the ripple is also called the bottom, and the peak of the ripple is also called the peak. Note that the ripple voltage is not limited to the above-mentioned example, and may be any value that indicates the magnitude of the voltage of the ripple component. Hereinafter, the ripple voltage may be referred to as ripple voltage Vn.

In addition, when the n-pulse rectifier 82 of the substation 8 is a 12-pulse rectifier and the location of the substation 8 is in an area where the power frequency is 50 Hz, the ripple voltage detection unit 22 calculates the ripple voltage Vn for the 12th frequency of 600 Hz and outputs ripple information that is information on the calculated ripple voltage Vn.

The ripple voltage detection unit 22 can determine whether the n-pulse rectifier 82 of the substation 8 is a 6-pulse rectifier or a 12-pulse rectifier based on the magnitude of the ripple voltage Vn at the 6th frequency and the magnitude of the ripple voltage Vn at the 12th frequency. Based on the result of the determination, the ripple voltage detection unit 22 can output ripple information, which is information on the ripple voltage Vn at the nth frequency.

The station building power supply operation panel 12 includes a regenerative operation determination unit 30, a memory processing unit 31, a memory unit 32, a threshold determination unit 33, a control unit 34, and a display unit 35. The control unit 34 can cause the display unit 35 to display the determination result by the regenerative operation determination unit 30, and can cause the display unit 35 to display information stored in the memory unit 32.

The regenerative operation determination unit 30 calculates the ratio between the overhead line voltage Vs detected by the overhead line voltage detection unit 21 and the ripple voltage Vn detected by the ripple voltage detection unit 22 at a preset period Ts as a regenerative determination index value, and determines whether the electric vehicle 1 is performing regenerative operation based on the calculated regenerative determination index value. The regenerative operation determination unit 30 includes an index value calculation unit 40, a comparison unit 41, and a determination result output unit 42.

The index value calculation unit 40 calculates the ratio of the overhead line voltage Vs detected by the overhead line voltage detection unit 21 to the ripple voltage Vn detected by the ripple voltage detection unit 22 at a preset period Ts as the regeneration determination index value Vr. The regeneration determination index value Vr is, for example, the ratio of the overhead line voltage Vs to the ripple voltage Vn.

When the ripple voltage Vn is zero, the index value calculation unit 40 calculates the regeneration judgment index value Vr using the ripple voltage Vn that was last detected as a non-zero value among the ripple voltages Vn detected by the ripple voltage detection unit 22.

The comparison unit 41 compares the regeneration judgment index value Vr calculated by the index value calculation unit 40 with a preset first regeneration judgment threshold value Vr_th, and outputs the comparison result to the judgment result output unit 42. The comparison unit 41 also compares the overhead line voltage Vs detected by the overhead line voltage detection unit 21 with a preset second regeneration judgment threshold value Vs_th, and outputs the comparison result to the judgment result output unit 42.

The judgment result output unit 42 judges whether the electric vehicle 1 is performing regenerative operation based on the comparison result by the comparison unit 41. Specifically, the judgment result output unit 42 judges that the electric vehicle 1 is performing regenerative operation when the regenerative judgment index value Vr is equal to or greater than the first regenerative judgment threshold Vr_th and the overhead line voltage Vs is equal to or greater than the second regenerative judgment threshold Vs_th.

In addition, the judgment result output unit 42 judges that the electric vehicle 1 is not performing regenerative operation if the regeneration judgment index value Vr is not equal to or greater than the first regeneration judgment threshold Vr_th, or if the overhead line voltage Vs is not equal to or greater than the second regeneration judgment threshold Vs_th.

Here, the regeneration judgment index value Vr being equal to or greater than the first regeneration judgment threshold Vr_th does not necessarily mean that one regeneration judgment index value Vr is equal to or greater than the first regeneration judgment threshold Vr_th. For example, the regeneration judgment index value Vr being equal to or greater than the first regeneration judgment threshold Vr_th includes the moving average of the regeneration judgment index value Vr being equal to or greater than the first regeneration judgment threshold Vr_th, or two or more of three or more consecutive regeneration judgment index values Vr being equal to or greater than the first regeneration judgment threshold Vr_th.

Furthermore, the overhead line voltage Vs being equal to or greater than the second regeneration judgment threshold Vs_th does not necessarily mean that one overhead line voltage Vs is equal to or greater than the second regeneration judgment threshold Vs_th. For example, the overhead line voltage Vs being equal to or greater than the second regeneration judgment threshold Vs_th includes the moving average of the overhead line voltage Vs being equal to or greater than the second regeneration judgment threshold Vs_th, or the regeneration judgment index values Vr of two or more of three or more consecutive overhead line voltages Vs being equal to or greater than the second regeneration judgment threshold Vs_th.

Figure 5 is a diagram showing the relationship between the change over time of the overhead line voltage, ripple voltage, and regeneration judgment index value in the first embodiment and the regeneration judgment by the regeneration operation judgment unit. In the graph shown in Figure 5, the horizontal axis is time, and the vertical axis is the overhead line voltage Vs, the ripple voltage Vn, or the regeneration judgment index value Vr.

As shown in FIG. 5, the index value calculation unit 40 determines that the electric vehicle 1 is performing a regenerative operation when the regeneration determination index value Vr is equal to or greater than the first regeneration determination threshold Vr_th and the overhead line voltage Vs is equal to or greater than the second regeneration determination threshold Vs_th. The index value calculation unit 40 also determines that the electric vehicle 1 is not performing a regenerative operation when the regeneration determination index value Vr is not equal to or greater than the first regeneration determination threshold Vr_th or when the overhead line voltage Vs is not equal to or greater than the second regeneration determination threshold Vs_th.

Figure 6 is a diagram for explaining the judgment process by the regeneration operation judgment unit according to the first embodiment. In the graph shown in Figure 6, the horizontal axis is time and the vertical axis is voltage. As shown in Figure 6, the overhead line voltage Vs and the no-load voltage fluctuate. The no-load voltage is the overhead line voltage Vs when the overhead line 2 is in an unloaded state. The regeneration judgment value is the value of the overhead line voltage Vs when it is assumed that the electric car 1 performs regenerative operation due to the station power supply device 10 and the regeneration judgment index value Vr becomes the first regeneration judgment threshold value Vr_th.

As described above, the station building power supply device 10 determines that the electric car 1 is performing regenerative operation when the regeneration determination index value Vr is equal to or greater than the first regeneration determination threshold value Vr_th, and can therefore accurately determine regenerative operation. Therefore, as shown in FIG. 6, more regenerative power can be converted and supplied to the station building 7 compared to when the regenerative operation start voltage value is set to the overhead line voltage Vs obtained by adding an additional value to the no-load voltage, and the amount of regenerative power available can be increased.

Also, as shown in FIG. 6, in the station building power supply device 10, the second regeneration judgment threshold Vs_th is set to a value greater than the maximum value of the no-load voltage. Therefore, in the station building power supply device 10, when the overhead line voltage Vs is equal to or less than the no-load voltage, power conversion is prevented from being performed by the power conversion unit 20.

The regeneration judgment index value Vr calculated by the index value calculation unit 40 may be the ratio of the ripple voltage Vn to the overhead line voltage Vs. In other words, the regeneration judgment index value Vr may be a value obtained by dividing the ripple voltage Vn by the overhead line voltage Vs. In this case, the judgment result output unit 42 judges that the electric vehicle 1 is performing a regenerative operation when the regeneration judgment index value Vr is equal to or less than the first regeneration judgment threshold Vr_th and the overhead line voltage Vs is equal to or greater than the second regeneration judgment threshold Vs_th. Furthermore, the judgment result output unit 42 judges that the electric vehicle 1 is not performing a regenerative operation when the regeneration judgment index value Vr is not equal to or less than the first regeneration judgment threshold Vr_th or when the overhead line voltage Vs is not equal to or greater than the second regeneration judgment threshold Vs_th.

The determination result output unit 42 outputs determination result information indicating the result of determining whether or not the electric car 1 is performing regenerative operation to the power conversion unit 20 of the main circuit unit 11. When the determination result information indicates that the electric car 1 is performing regenerative operation, the power conversion unit 20 converts the regenerative power from DC to AC and supplies the 210V system AC voltage to the station facilities _73-1 , _73-2 , ..., 73- _m . When the determination result information indicates that the electric car 1 is not performing regenerative operation, the power conversion unit 20 does not perform power conversion operation.

The memory processing unit 31 generates detection information at a preset period Ts, in which information on the overhead line voltage Vs, information on the ripple voltage Vn, and information on the regeneration judgment index value Vr are associated with time information. The time information is, for example, the time when the overhead line voltage Vs is detected by the overhead line voltage detection unit 21 or the time when the detection information is generated. The memory processing unit 31 stores the generated detection information in the memory unit 32.

The memory processing unit 31 also stores information relating to the overhead line voltage Vs when the regenerative operation determination unit 30 determines that the electric vehicle 1 is performing regenerative operation, in the memory unit 32 as threshold determination information.

The threshold determination unit 33 determines the first regeneration judgment threshold Vr_th and the second regeneration judgment threshold Vs_th based on the detection information stored in the memory unit 32. The first regeneration judgment threshold Vr_th is an example of a first threshold, and the second regeneration judgment threshold Vs_th is an example of a second threshold.

The threshold determination unit 33 determines the first regeneration judgment threshold Vr_th and the second regeneration judgment threshold Vs_th based on the detection information stored in the memory unit 32 during the operation period before the previous operation period among the detection information stored in the memory unit 32, for example, before the start of the next operation period. Note that the operation period is the period during which the electric vehicle 1 operates, for example, from 5:00 to 23:30.

The threshold determination unit 33 sets the determined first regeneration determination threshold Vr_th and second regeneration determination threshold Vs_th in the comparison unit 41 of the regeneration operation determination unit 30. The threshold determination unit 33 also stores the determined first regeneration determination threshold Vr_th and second regeneration determination threshold Vs_th in the storage unit 32.

The threshold determination unit 33 generates histogram information showing the relationship between the regeneration judgment index value Vr and the overhead line voltage Vs based on the history of detection information stored in the memory unit 32. For example, the threshold determination unit 33 generates a histogram showing the distribution of the average value of the overhead line voltage Vs in increments of preset voltage values within the range of the overhead line voltage Vs for each period divided by a preset division width during which a voltage is supplied to the overhead line 2 in one day. The preset division width is, for example, 1 hour or 2 hours, and the preset voltage value is, for example, 5 V or 10 V.

Figure 7 is a diagram showing an example of a histogram showing the relationship between the regeneration judgment index value and the overhead line voltage in the first embodiment. In Figure 7, the horizontal axis is the overhead line voltage Vs, and the vertical axis is the regeneration judgment index value Vr. In Figure 7, the period from 4:00 to 24:00 is divided into two-hour intervals. Specifically, the period from 4:00 to 24:00 is divided into the following periods: 4:00 to 6:00, 6:00 to 8:00, 8:00 to 10:00, 10:00 to 12:00, 12:00 to 14:00, 14:00 to 16:00, 16:00 to 18:00, 18:00 to 20:00, 20:00 to 22:00, and 22:00 to 24:00.

In the example shown in FIG. 7, the threshold determination unit 33 calculates the average value of the regeneration judgment index value Vr for each divided period in the range of 1500V to 1700V in increments of 10V, and generates the histogram shown in FIG. 7. For example, the regeneration judgment index value Vr of 1560V is the average value of the regeneration judgment index value Vr between 155V or more and less than 1565V.

The threshold determination unit 33, for example, determines the overhead line voltage Vs at which the average value of the regeneration judgment index value Vr in the generated histogram begins to change rapidly as the second regeneration judgment threshold Vs_th. For example, when the difference between the average value of the regeneration judgment index value Vr in the earlier time of two consecutive periods and the average value of the regeneration judgment index value Vr in the later time is equal to or greater than a preset threshold, the threshold determination unit 33 determines the average value of the regeneration judgment index value Vr in the later time as the second regeneration judgment threshold Vs_th.

In the example shown in FIG. 7, the average value of the regeneration judgment index value Vr in the latter of the two consecutive periods is 1670 V, and the threshold determination unit 33 determines 1670 V as the second regeneration judgment threshold Vs_th.

The threshold determination unit 33 can determine the result of multiplying the maximum value or average value of the regeneration judgment index value Vr at the second regeneration judgment threshold Vs_th by a preset coefficient k as the first regeneration judgment threshold Vr_th. Note that the coefficient k can be set to a different value when the n-pulse rectifier 82 is a 6-pulse rectifier and when the n-pulse rectifier 82 is a 12-pulse rectifier, for example. In the example shown in FIG. 7, the maximum value of the regeneration judgment index value Vr at 1670 V is "140", and the preset value α is "100". Therefore, the threshold determination unit 33 can determine "240", which is the result of adding the preset value α "100" to "140", as the first regeneration judgment threshold Vr_th.

Instead of the above process, the threshold determination unit 33 can determine the second regeneration determination threshold Vs_th by regression analysis using the regeneration determination index value Vr and the overhead line voltage Vs. For example, the threshold determination unit 33 can determine the inflection point of a regression curve calculated by performing a bivariate analysis of the regeneration determination index value Vr and the overhead line voltage Vs as the second regeneration determination threshold Vs_th.

For example, the threshold determination unit 33 performs a bivariate analysis of the average value of the regeneration determination index value Vr at the overhead line voltage Vs in increments of 5 V or 10 V and the overhead line voltage Vs, and calculates a regression analysis curve with the average value of the regeneration determination index value Vr at the overhead line voltage Vs in increments of 5 V or 10 V on the vertical axis and the overhead line voltage Vs on the horizontal axis. The threshold determination unit 33 determines the inflection point of the regression analysis curve as the second regeneration determination threshold Vs_th.

Here, an example of the process of determining the second regeneration determination threshold Vs_th by regression analysis will be specifically described. The data string shown in the following formula (1) includes, for example, the average value of the regeneration determination index value Vr for each period obtained by dividing the period from 4:00 to 24:00 into two-hour intervals. For example, data _X1 is the average value of the regeneration determination index value Vr from 4:00 to 6:00, and data _Xn is the average value of the regeneration determination index value Vr from 22:00 to 24:00, where n=10.

If the change point of the average value of the regeneration determination index value Vr is v, the threshold value determination unit 33 uses, for example, a k-th order autoregressive model as the data string model. This autoregressive model is a model in which the conditional probability density function of x _i when the following formula (2) is given is given by the following formula (3).

In the above formula (3), "ω _v " is expressed by the following formula (4): The threshold determination unit 33 estimates the parameters of the following formula (4) shown in the following formula (5) by using, for example, a maximum likelihood method.

Here, if the estimated value of _ωv calculated by the above formula (4) is "ω^ _v ", the threshold determination unit 33 performs the calculation of the following formula (6). When v ^* , which is the minimum value for v, satisfies the following formula (7), "v ^* " is regarded as an inflection point, and the inflection point is determined as the second regeneration determination threshold Vs_th. In the following formula (7), "δ" is a threshold value.

The process of determining the second regeneration judgment threshold Vs_th by regression analysis is not limited to the above example. The threshold determination unit 33 can also determine the second regeneration judgment threshold Vs_th using a learning model generated by machine learning based on a data set including multiple combinations of the data sequence shown in the above formula (1) and the overhead line voltage Vs generated by regenerative power. In this case, the data sequence shown in the above formula (1) is input to the learning model, and the learning model outputs a determination result as to whether or not the electric vehicle 1 is performing regenerative operation. The learning model is, for example, a neural network.

The threshold determination unit 33 also compares the no-load voltage, which is the overhead line voltage Vs before the start of the next operation period, with the second regeneration determination threshold Vs_th based on the information stored in the memory unit 32. If the difference between the second regeneration determination threshold Vs_th and the no-load voltage is equal to or less than a preset value, the threshold determination unit 33 can determine the second regeneration determination threshold Vs_th to be the value obtained by adding a preset value to the no-load voltage.

Furthermore, based on the information stored in the memory unit 32, the threshold determination unit 33 can determine the second regeneration determination threshold Vs_th to be the value obtained by adding a preset value to the no-load voltage when the value obtained by subtracting the second regeneration determination threshold Vs_th determined previously from the second regeneration determination threshold Vs_th determined currently is equal to or less than a preset value. The second regeneration determination threshold Vs_th determined previously is the second regeneration determination threshold Vs_th determined in the operation period two days ago or the average value of the second regeneration determination threshold Vs_th determined in each operation period up to the past three days or more.

In the above-described process, the threshold determination unit 33 determines the result of multiplying the average value of the regeneration determination index value Vr by a preset coefficient k when the overhead line voltage Vs is the second regeneration determination threshold Vs_th as the first regeneration determination threshold Vr_th, but the first regeneration determination threshold Vr_th may be a fixed value. For example, when the n-pulse rectifier 82 is a 6-pulse rectifier, the threshold determination unit 33 determines the result of multiplying the setting value for the 6-pulse rectifier by a preset coefficient k1 as the first regeneration determination threshold Vr_th. Also, when the n-pulse rectifier 82 is a 12-pulse rectifier, the threshold determination unit 33 determines the result of multiplying the setting value for the 12-pulse rectifier by a preset coefficient k2 as the first regeneration determination threshold Vr_th.

Furthermore, based on the information stored in the memory unit 32, if the value obtained by subtracting the first regeneration judgment threshold Vr_th determined currently from the first regeneration judgment threshold Vr_th determined previously is equal to or less than a preset value, the threshold determination unit 33 can determine the first regeneration judgment threshold Vr_th as the first regeneration judgment threshold Vr_th by adding a preset value to the first regeneration judgment threshold Vr_th determined currently or the first regeneration judgment threshold Vr_th determined previously. The first regeneration judgment threshold Vr_th determined previously is the first regeneration judgment threshold Vr_th determined on the previous day or the day before that, or the average value of the first regeneration judgment threshold Vr_th determined on each day up to two days ago.

By performing the above-described processing, the threshold determination unit 33 can prevent, for example, setting incorrect values as the first regeneration judgment threshold Vr_th and the second regeneration judgment threshold Vs_th due to the influence of noise.

Next, the processing by the station power supply control panel 12 will be explained using a flowchart. Figure 8 is a flowchart showing an example of a regeneration determination process by the regeneration operation determination unit of the station power supply control panel according to the first embodiment. The regeneration operation determination unit 30 of the station power supply control panel 12 repeatedly executes the process shown in Figure 8.

As shown in FIG. 8, the regenerative operation determination unit 30 of the station power supply operation panel 12 acquires information on the overhead line voltage Vs and information on the ripple voltage Vn from the main circuit unit 11 (step S10). Next, the regenerative operation determination unit 30 calculates the regenerative determination index value Vr by dividing the overhead line voltage Vs by the ripple voltage Vn (step S11). Then, the regenerative operation determination unit 30 stores the information on the overhead line voltage Vs and the regenerative determination index value Vr in the memory unit 32 (step S12).

Next, the regenerative operation determination unit 30 determines whether the regenerative judgment index value Vr is equal to or greater than the first regenerative judgment threshold Vr_th and whether the overhead line voltage Vs is equal to or greater than the second regenerative judgment threshold Vs_th (step S13). If the regenerative operation determination unit 30 determines that the regenerative judgment index value Vr is equal to or greater than the first regenerative judgment threshold Vr_th and that the overhead line voltage Vs is equal to or greater than the second regenerative judgment threshold Vs_th (step S13: Yes), it determines that regenerative operation is occurring and outputs the determination result to the power conversion unit 20 (step S14). In addition, the regenerative operation determination unit 30 stores information on the overhead line voltage Vs when the regenerative judgment index value Vr is equal to or greater than the first regenerative judgment threshold Vr_th in the storage unit 32 (step S15).

If the regeneration operation determination unit 30 determines that the regeneration determination index value Vr is not equal to or greater than the first regeneration determination threshold Vr_th, or if it determines that the overhead line voltage Vs is not equal to or greater than the second regeneration determination threshold Vs_th (step S13: No), or if the processing of step S15 is completed, the processing shown in FIG. 8 is terminated.

Figure 9 is a flowchart showing an example of a first threshold determination process by the threshold determination unit of the station power supply control panel according to the first embodiment. The threshold determination unit 33 of the station power supply control panel 12 executes the threshold determination process shown in Figure 9, for example, before the start of the next operation period.

As shown in FIG. 9, the threshold determination unit 33 of the station power supply operation panel 12 acquires information on the overhead line voltage Vs and the regeneration determination index value Vr during the past operation period from the memory unit 32 (step S20). Next, the threshold determination unit 33 generates a histogram showing the relationship between the overhead line voltage Vs and the regeneration determination index value Vr (step S21). The histogram generated by the processing of step S21 is, for example, the histogram shown in FIG. 7.

Next, the threshold determination unit 33 determines the second regeneration judgment threshold Vs_th based on the histogram generated in step S21 (step S22). When the process of step S22 is completed, the threshold determination unit 33 ends the process shown in FIG. 9.

Figure 10 is a flowchart showing an example of a second threshold determination process by the threshold determination unit of the station power supply control panel according to the first embodiment. The threshold determination unit 33 of the station power supply control panel 12 executes the threshold determination process shown in Figure 10, for example, before the start of the next operation period.

As shown in FIG. 10, the threshold determination unit 33 of the station power supply operation panel 12 acquires information on the overhead line voltage Vs and the regeneration judgment index value Vr during the previous operation period from the memory unit 32 (step S30). Next, the threshold determination unit 33 calculates a regression curve between the overhead line voltage Vs and the regeneration judgment index value Vr (step S31), and determines a second regeneration judgment threshold Vs_th based on the inflection point of the calculated regression curve (step S32). When the processing of step S32 is completed, the threshold determination unit 33 ends the processing shown in FIG. 10.

In the above-described process, the regenerative operation determination unit 30 determines that regenerative operation is occurring, for example, when the regenerative determination index value Vr is equal to or greater than the first regenerative determination threshold Vr_th and the overhead line voltage Vs is equal to or greater than the second regenerative determination threshold Vs_th, but the method of determining regenerative operation is not limited to this example. For example, the regenerative operation determination unit 30 can also determine that regenerative operation is occurring when the regenerative determination index value Vr is equal to or greater than the first regenerative determination threshold Vr_th, without comparing the overhead line voltage Vs with the second regenerative determination threshold Vs_th.

In addition, when the n-pulse rectifier 82 is a 6-pulse rectifier, the ripple voltage detection unit 22 detects the 6th frequency component as the ripple voltage Vn, and when the n-pulse rectifier 82 is a 12-pulse rectifier, the ripple voltage detection unit 22 detects the 12th frequency component as the ripple voltage Vn, but is not limited to such examples.

For example, the ripple voltage detection unit 22 can detect the 6th frequency component and the 12th frequency component as ripple voltages Vn. In this case, the regenerative operation determination unit 30 calculates the ratio between the overhead line voltage Vs and each of the two ripple voltages Vn as the regenerative determination index value Vr. The regenerative operation determination unit 30 determines that regenerative operation is occurring when either of these two regenerative determination index values Vr is equal to or greater than the first regenerative determination threshold Vr_th and the overhead line voltage Vs is equal to or greater than the second regenerative determination threshold Vs_th.

The ripple voltage detection unit 22 can also analyze frequency components of harmonic components other than the n-th harmonic component. For example, when the n-pulse rectifier 82 of the substation 8 is a 12-pulse rectifier, the ripple voltage detection unit 22 can also detect ripple voltages Vn1 and Vn2 for each of the 11th and 13th frequencies. The ripple voltage Vn1 is the ripple voltage Vn for the 11th frequency, and the ripple voltage Vn2 is the ripple voltage Vn for the 13th frequency. The regenerative operation determination unit 30 calculates the ratio between the overhead line voltage Vs and each of the two ripple voltages Vn1 and Vn2 as the regenerative determination index values Vr1 and Vr2.

The regenerative operation determination unit 30 determines that regenerative operation is occurring when these two regenerative judgment index values Vr1, Vr2 are equal to or greater than the first regenerative judgment thresholds Vr1_th, Vr2_th, and the overhead line voltage Vs is equal to or greater than the second regenerative judgment threshold Vs_th. The first regenerative judgment threshold Vr1_th is the regenerative judgment index value Vr corresponding to the regenerative judgment index value Vr1. The first regenerative judgment threshold Vr2_th is the regenerative judgment index value Vr corresponding to the regenerative judgment index value Vr2.

Figure 11 is a diagram showing an example of the hardware configuration of a station power supply control panel of a station power supply device according to embodiment 1. As shown in Figure 11, the station power supply control panel 12 of the station power supply device 10 includes a computer having a processor 101, a memory 102, an input/output interface 103, and a display 104.

The processor 101, memory 102, input/output interface 103, and display 104 can transmit and receive information to and from each other via, for example, a bus 105. The storage unit 32 is realized by the memory 102. The display unit 35 is realized by the display 104. The processor 101 executes the functions of the regenerative operation determination unit 30, the storage processing unit 31, the threshold determination unit 33, and the control unit 34 by reading and executing a program stored in the memory 102. The processor 101 is, for example, an example of a processing circuit, and includes one or more of a CPU (Central Processing Unit), a DSP (Digital Signal Processor), and a system LSI (Large Scale Integration).

The memory 102 includes one or more of RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory). The memory 102 also includes a recording medium on which a computer-readable program is recorded. Such recording medium includes one or more of non-volatile or volatile semiconductor memory, magnetic disks, flexible memories, optical disks, compact disks, and DVDs (Digital Versatile Discs). The station power supply operation panel 12 may include integrated circuits such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field Programmable Gate Arrays).

As described above, the station building power supply device 10 according to the first embodiment includes the overhead line voltage detection unit 21, the ripple voltage detection unit 22, and the regenerative operation determination unit 30. The overhead line voltage detection unit 21 detects the overhead line voltage Vs, which is the voltage of the overhead line 2 connected to the electric car 1. The ripple voltage detection unit 22 detects the ripple voltage Vn, which is the voltage of the ripple component contained in the overhead line voltage Vs detected by the overhead line voltage detection unit 21. The regenerative operation determination unit 30 calculates a regenerative determination index value Vr, which is the ratio between the overhead line voltage Vs detected by the overhead line voltage detection unit 21 and the ripple voltage Vn detected by the ripple voltage detection unit 22, and determines whether the electric car 1 is performing regenerative operation based on the calculated regenerative determination index value Vr. This allows the station building power supply device 10 to improve the accuracy of determining whether the electric car 1 is performing regenerative operation.

The regenerative operation determination unit 30 also determines whether the electric car 1 is performing regenerative operation based on the result of comparing the regenerative determination index value Vr with the first regenerative determination threshold Vr_th. The first regenerative determination threshold Vr_th is an example of a pre-set first threshold. This allows the station building power supply device 10 to easily improve the accuracy of determining whether the electric car 1 is performing regenerative operation.

The regenerative operation determination unit 30 also determines whether the electric car 1 is performing regenerative operation based on the result of comparing the regenerative determination index value Vr with the first regenerative determination threshold Vr_th and the result of comparing the overhead line voltage Vs with the second regenerative determination threshold Vs_th. The second regenerative determination threshold Vs_th is an example of a pre-set second threshold. This allows the station building power supply device 10 to prevent the overhead line voltage Vs from falling below the no-load voltage when it is determined that the electric car 1 is performing regenerative operation.

The station building power supply device 10 also includes a threshold determination unit 33 that determines the second regeneration determination threshold Vs_th based on the relationship between the regeneration determination index value Vr previously calculated by the regeneration operation determination unit 30 and the overhead line voltage Vs previously detected by the overhead line voltage detection unit 21. This allows the station building power supply device 10 to automatically generate the second regeneration determination threshold Vs_th even if the voltage supply state to the overhead line 2 differs for each line.

The threshold determination unit 33 also generates a histogram showing the relationship between the regeneration determination index value Vr and the overhead line voltage Vs based on the regeneration determination index value Vr previously calculated by the regeneration operation determination unit 30 and the overhead line voltage Vs previously detected by the overhead line voltage detection unit 21, and determines the second regeneration determination threshold Vs_th based on the generated histogram. This allows the station building power supply device 10 to accurately determine the second regeneration determination threshold Vs_th.

The threshold determination unit 33 also determines the second regeneration determination threshold Vs_th by regression analysis using the regeneration determination index value Vr previously calculated by the regeneration operation determination unit 30 and the overhead line voltage Vs previously detected by the overhead line voltage detection unit 21. This allows the station building power supply device 10 to accurately determine the second regeneration determination threshold Vs_th.

The overhead line 2 is supplied with voltage from an n-pulse rectifier 82 that rectifies the three-phase voltage, where n is a multiple of 6. The ripple voltage detection unit 22 detects the voltage of the nth harmonic component, which is a component with a frequency that is n times the fundamental frequency of the three-phase voltage, as a ripple voltage Vn. This allows the station building power supply device 10 to improve the accuracy of determining whether the electric car 1 is performing regenerative operation.

The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies. Parts of the configurations may be omitted or modified without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 1 electric vehicle, 2 overhead line, 3 rail, 6 high voltage distribution system, 7 station building, 8 substation, 10 station building power supply device, 11 main circuit section, 12 station building power supply operation panel, 20 power conversion section, 21 overhead line voltage detection section, 22 ripple voltage detection section, 30 regenerative operation determination section, 31 memory processing section, 32 memory section, 33 threshold determination section, 34 control section, 35 display section, 40 index value calculation section, 41 comparison section, 42 determination result output section, 71, 81 transformer, 72 station load, 73 ₁ , 73 ₂ , ..., 73 _m station building equipment, 82 n pulse rectifier.

Claims (7)

an overhead line voltage detection unit that detects a voltage of an overhead line connected to an electric vehicle;
a ripple voltage detection unit that detects a ripple voltage, which is a voltage of a ripple component included in the voltage of the overhead line detected by the overhead line voltage detection unit;
a regenerative operation determination unit that calculates a ratio between the voltage of the overhead line detected by the overhead line voltage detection unit and the ripple voltage detected by the ripple voltage detection unit, and determines whether or not the electric car is performing a regenerative operation based on the calculated ratio; and
a threshold value determination unit that determines a second threshold value based on a relationship between the ratio previously calculated by the regenerative operation determination unit and a voltage of the overhead line previously detected by the overhead line voltage detection unit,
The regenerative operation determination unit is
Whether or not the electric vehicle is performing a regenerative operation is determined based on a comparison result between the ratio and a first threshold value that is set in advance and a comparison result between the ratio and a second threshold value.
A station building power supply device characterized by: The station building power supply device according to claim 1 , wherein the ratio is a ratio of the voltage of the overhead line to the ripple voltage. The threshold determination unit:
The station building power supply device according to claim 1 or 2, characterized in that a histogram showing a relationship between the ratio calculated in the past by the regenerative operation determination unit and the voltage of the overhead line detected in the past by the overhead line voltage detection unit is generated, and the second threshold is determined based on the generated histogram. The threshold determination unit:
The station building power supply device according to any one of claims 1 to 3, characterized in that the second threshold value is determined by regression analysis using the ratio previously calculated by the regenerative operation determination unit and the overhead line voltage previously detected by the overhead line voltage detection unit. The overhead line is
The voltage is supplied from an n-pulse rectifier that rectifies the three-phase voltage, where n is a multiple of 6.
The ripple voltage detection unit is
5. The station building power supply device according to claim 1 , wherein a voltage of an n-th harmonic component, which is a component with a frequency n times the frequency of the three-phase voltage, is detected as the ripple voltage. A first step of detecting a voltage of an overhead line connected to an electric vehicle;
A second step of detecting a ripple voltage, which is a voltage of a ripple component included in the voltage of the overhead line detected in the first step;
A third step of calculating a ratio between the voltage of the overhead line detected in the first step and the ripple voltage detected in the second step;
a fourth step of determining a second threshold value based on a relationship between the ratio previously calculated in the third step and a voltage of the overhead line previously detected in the first step;
and a fifth step of determining whether or not the electric vehicle is performing regenerative operation based on a comparison result between the ratio calculated in the third step and a preset first threshold value and a comparison result between the ratio calculated in the third step and a preset first threshold value and a comparison result between the ratio calculated in the third step and a preset second threshold value. A first step of detecting a voltage of an overhead line connected to an electric vehicle;
A second step of detecting a ripple voltage, which is a voltage of a ripple component included in the voltage of the overhead line detected in the first step;
A third step of calculating a ratio between the voltage of the overhead line detected in the first step and the ripple voltage detected in the second step;
a fourth step of determining a second threshold value based on a relationship between the ratio previously calculated in the third step and a voltage of the overhead line previously detected in the first step;
a fifth step of determining whether or not the electric vehicle is performing a regenerative operation based on a comparison result between the ratio calculated in the third step and a preset first threshold value and a comparison result between the ratio calculated in the third step and a preset first threshold value and a comparison result between the ratio calculated in the third step and a preset second threshold value.

Images