Power conversion equipment for railway vehicles

Abstract

In the case of this power conversion device for a railroad car, a converter control section (242) provided in a control device (240) comprises: a counter voltage computation unit (501) for computing a counter voltage to be used as a reference for current control of a converter (210) on the basis of a detected value of an overhead-line voltage; and a voltage phase estimation unit (502) for estimating the phase of an alternating-current voltage to be applied to an auxiliary power supply device (107) during an unpowered period on the basis of the counter voltage. The counter voltage computation unit (501) comprises: a phase difference estimation part (810) for estimating a phase difference between a first phase, that is, the phase of a first voltage which is an overhead-line voltage detected by an ACPT (102) after the unpowered period is ended, and a second phase, that is, the phase of an alternating-current second voltage estimated by the voltage phase estimation unit (502) on the basis of an overhead-line voltage detected by the ACPT (102) before the start of the unpowered period; and a switching part (820) for switching the sign of a frequency correction amount by which to correct the frequency of the second voltage on the basis of the estimated phase difference, that is, the value estimated for the phase difference.

Description

[Technical field]

[0001] The present disclosure relates to a power conversion device for a railway vehicle that runs on AC power supplied from an AC overhead line. [Background technology]

[0002] In an AC-electrified railway line, the feeder section, which is the range where one substation supplies power, is limited, and the voltage phase of the AC power differs for each substation. For this reason, in a railway line, there is a section at the boundary between the feeder sections where power cannot be supplied. This section is called a "dead section." Therefore, when a railway vehicle that runs by receiving AC power supplied from an AC overhead line passes through a dead section, the power supply from the AC overhead line is interrupted. On the other hand, at this time, by supplying regenerative power from a propulsion motor for driving the railway vehicle to the auxiliary equipment mounted on the railway vehicle, the power supply to the auxiliary equipment can be continued in the same way as during normal running. This operation is called "pump back." Note that the auxiliary equipment is a name that refers to the equipment mounted on the railway vehicle and supplied with power, other than the propulsion motor. Power is supplied to the auxiliary equipment by a power conversion device called an auxiliary power supply unit.

[0003] When power supply from the overhead line resumes after passing the dead section, the circuit breaker at the power receiving section is closed to switch to normal overhead line power supply. If the overhead line is an AC overhead line, the circuit breaker must be closed to match the voltage phase between the voltage applied to the main transformer before the switch and the overhead line voltage applied after the switch in order to prevent excessive current from flowing. In particular, in the case of a circuit configuration in which the auxiliary power supply unit is connected to the tertiary winding of the main transformer, the phase is matched while continuing to apply AC voltage to the main transformer.

[0004] Against the above technical background, Patent Document 1 below discloses a technology for directly determining the overhead line voltage phase, which is the phase of the overhead line voltage, and achieving phase synchronization between the converter voltage and the overhead line voltage by increasing the frequency so that the converter voltage phase catches up with this overhead line voltage phase. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6510060 Summary of the Invention [Problem to be solved by the invention]

[0006] However, a specific method for directly calculating the overhead line voltage phase is not described in the above Patent Document 1. In addition, the method of directly calculating the overhead line voltage phase as in Patent Document 1 has problems in that when the overhead line voltage frequency deviates from the rated value, phase detection is difficult and the phase synchronization time for matching the converter voltage phase with the overhead line voltage phase becomes long.

[0007] The present disclosure has been made in consideration of the above, and aims to provide a power conversion device for a railway vehicle that can suppress an increase in the time required for phase synchronization even if the overhead line voltage frequency deviates from the rated value. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems and achieve the object, a power conversion device for railway vehicles according to the present disclosure is mounted on a railway vehicle including a main transformer, a switch, and a voltage detector. The main transformer has a primary winding connected to an overhead line via a power receiving unit, the switch electrically connects or disconnects the main transformer and the overhead line, and the voltage detector is provided between the overhead line and the switch and detects the overhead line voltage applied from the overhead line. The power conversion device for railway vehicles includes a first power conversion device, a second power conversion device, and a control device. The first power conversion device is connected to a secondary winding of the main transformer, includes a converter that converts an AC voltage applied via the main transformer into a DC voltage, and is connected to a traction motor for driving the railway vehicle. The second power conversion device is connected to a tertiary winding of the main transformer, and supplies power to an auxiliary machine mounted on the railway vehicle. The control device controls the operation of the switch and the first and second power conversion devices. The control device includes a converter control unit that controls the converter to supply regenerative power generated by the traction motor to the second power conversion device via the main transformer during a power-loss period when no power is supplied from the overhead line. The converter control unit includes a reference voltage calculation unit and a voltage phase estimation unit. The reference voltage calculation unit calculates a reference voltage that is a reference for current control of the converter based on a detected value of the overhead line voltage. The voltage phase estimation unit estimates the phase of an AC voltage to be applied to the second power conversion device during the power-loss period based on the reference voltage. The reference voltage calculation unit includes a phase difference estimation unit and a switching unit. The phase difference estimation unit estimates a phase difference between a first phase that is the phase of the first voltage and a second phase that is the phase of the second voltage. The first voltage is the overhead line voltage detected by the voltage detector after the end of the power-loss period. The second voltage is the AC voltage estimated by the voltage phase estimation unit based on the overhead line voltage detected by the voltage detector before the start of the power-loss period. The switching unit switches the sign of a frequency correction amount for correcting the frequency of the second voltage based on an estimated phase difference that is an estimate of the phase difference. Effect of the Invention

[0009] Advantageous Effects of Invention According to the railway vehicle power conversion device according to the present disclosure, an effect is achieved in that an increase in the time required for phase synchronization can be suppressed even if the overhead line voltage frequency deviates from the rated value. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of an electrical system of a railway vehicle system including a railway vehicle power conversion device according to an embodiment; [Diagram 2] FIG. 2 is a diagram showing a configuration example of the main converter shown in FIG. 1. [Diagram 3] FIG. 2 is a diagram for explaining an energy flow during normal operation in the power conversion device for a railway vehicle according to the embodiment; [Figure 4] FIG. 2 is a diagram for explaining an energy flow during a non-power-feeding period in a railway vehicle power conversion device according to an embodiment. [Diagram 5] 1 is a time chart for explaining an operation during pump back in an embodiment; [Figure 6] FIG. 2 is a block diagram showing a configuration example of a converter control unit according to an embodiment; [Figure 7] A diagram for explaining a conventional method using a PLL. [Figure 8] FIG. 1 is a block diagram showing an example of the configuration of a counter voltage calculation unit according to an embodiment; [Figure 9] FIG. 13 is a diagram for explaining the effect of shortening the time required for phase synchronization when the counter voltage calculation unit according to the embodiment is used; [Figure 10] FIG. 13 shows voltage waveforms and current waveforms of key parts in a comparative example when the actual voltage phase difference is 180°. [Figure 11] FIG. 13 is a diagram showing PLL operation waveforms in a comparative example when the actual voltage phase difference is 180°. [Figure 12] The figure shows the voltage and current waveforms of the main parts of this method when the actual voltage phase difference is 180[°]. [Figure 13] A diagram showing the PLL operation waveform in this method when the actual voltage phase difference is 180[°]. [Figure 14] The figure shows the voltage and current waveforms of the main parts of this method when the actual voltage phase difference is 150[°]. [Figure 15] A diagram showing the PLL operation waveform in this method when the actual voltage phase difference is 150[°]. [Figure 16]FIG. 2 is a block diagram showing an example of a hardware configuration for implementing the functions of a converter control unit according to the embodiment; [Figure 17] FIG. 1 is a block diagram showing another example of a hardware configuration for implementing the functions of a converter control unit according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A railway vehicle power conversion device according to an embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings. Note that in the following description, no distinction will be made between physical connection and electrical connection, and the term "connection" will be used. In other words, the term "connection" includes both cases in which components are directly connected to each other and cases in which components are indirectly connected to each other via other components.

[0012] Embodiment FIG. 1 is a diagram showing an example of the configuration of an electric system of a railway vehicle system including a railway vehicle power converter according to an embodiment. The railway vehicle system according to the embodiment is configured to include a power receiving unit 101, an ACPT (Alternating Current Potential Transformer) 102 which is a voltage detector, a switch 103, a main transformer 104, a main converter 105, a traction motor 106, and an auxiliary power supply 107. Note that FIG. 1 shows a configuration in which four main converters 105 and four traction motors 106 are provided, but this is only an example, and the number of motors may be different. Also, FIG. 1 shows a configuration in which one traction motor 106 is connected to one main converter 105, but a configuration in which multiple traction motors 106 are connected to one main converter 105 may be used. Also, FIG. 1 shows a configuration in which one auxiliary power supply 107 is connected to the main transformer 104, but a configuration in which multiple auxiliary power supplies 107 are connected to the main transformer 104 may be used. In FIG. 1, main converter 105 and auxiliary power supply 107 constitute a power converter for a railway vehicle according to the embodiment.

[0013] The power receiving unit 101 is a device that allows the railway vehicle to receive AC power from the overhead line 100. Examples of the power receiving unit 101 include a pantograph, a current collecting shoe, etc. It is assumed that power is supplied to the railway vehicle by a pantograph attached to the top of the railway vehicle, but it may also be a third rail installed next to the track.

[0014] The switch 103 is a device that electrically switches between the main transformer 104 and the overhead line 100. One example of the switch 103 is a circuit breaker, and a vacuum circuit breaker (VCB) is often used for railway vehicles. Note that the switch 103 does not have to be a circuit breaker as long as it is a device that can electrically switch between the main transformer 104 and the overhead line 100, i.e., disconnect and connect.

[0015] The ACPT 102 is a device that measures the receiving voltage of the power receiving unit 101. The ACPT 102 is provided between the overhead line 100 and the switch 103, and detects the overhead line voltage applied from the overhead line 100.

[0016] The main transformer 104 includes a primary winding 141, a secondary winding 142, and a tertiary winding 143. The primary winding 141 is connected to the overhead line 100 via the power receiving unit 101 and the switch 103. The secondary winding 142 is connected to the main converter 105, and the tertiary winding 143 is connected to the auxiliary power supply 107. An overhead line voltage is applied to the primary winding 141, and a voltage determined by the turn ratio between the primary winding 141 and the secondary winding 142 and the tertiary winding 143 is generated in the primary winding 141. The secondary windings 142 are provided in the same number as the main converters 105, and the tertiary windings 143 are provided in the same number as the auxiliary power supply 107. Basically, each winding is connected to each device one-to-one, but a configuration in which one winding is connected to multiple devices via a reactor may be used. The voltage applied to the primary winding 141 is a reference voltage that is a reference for current control of the converter 210. In this document, this reference voltage is called a "counter voltage." In this document, the counter voltage is calculated.

[0017] The main conversion device 105 includes a converter 210 and an inverter 230. The converter 210 is connected to the secondary winding 142 of the main transformer 104, and converts the AC voltage applied via the main transformer 104 into a DC voltage. The inverter 230 is connected to the traction motor 106, and converts the DC voltage applied from the converter 210 into a drive voltage for the traction motor 106 and applies it to the traction motor 106. Note that in this document, the main conversion device 105 may be referred to as the "first power conversion device."

[0018] The propulsion motor 106 is a motor for driving a railway vehicle. The railway vehicle runs by obtaining driving force from the rotation of the propulsion motor 106. Furthermore, the railway vehicle accelerates or decelerates by the torque generated by the propulsion motor 106.

[0019] The auxiliary power supply 107 is connected to the tertiary winding 143 of the main transformer 104, and supplies power to the above-mentioned auxiliary devices. Examples of the auxiliary devices include interior lighting, door opening and closing devices, air conditioning devices, safety devices, compressors, batteries, and control power supplies. In this document, the auxiliary power supply 107 may be referred to as the "second power conversion device."

[0020] Fig. 2 is a diagram showing an example of the configuration of the main conversion device 105 shown in Fig. 1. The main conversion device 105 includes a converter 210, a smoothing capacitor 220, an inverter 230, and a control device 240. The control device 240 also includes a converter control unit 242 and an inverter control unit 244.

[0021] The converter 210 includes a primary terminal 211 and a secondary terminal 212. The converter 210 can convert between a single-phase AC voltage applied to the primary terminal 211 and a DC voltage applied to the secondary terminal 212. This operation is controlled by the converter control unit 242. The converter 210 controls the power supplied to the inverter 230 by adjusting the voltage of the primary terminal 211. In addition, a current sensor 213 is disposed in one of the primary terminals 211. The current sensor 213 detects a current flowing in the primary side of the converter 210. Note that, although FIG. 2 illustrates a three-level converter having three secondary terminals 212 and capable of outputting three types of potential to the secondary side, the present invention is not limited to this example. The number of secondary terminals 212 may be two, or may be four or more. A configuration having two secondary terminals 212 is called a two-level converter.

[0022] The inverter 230 includes a primary terminal 231 and a secondary terminal 232. The inverter 230 can convert between a DC voltage applied to the primary terminal 231 and an AC voltage applied to the secondary terminal 232. This operation is controlled by the inverter control unit 244. The inverter 230 controls the output torque of the propulsion motor 106 by adjusting the voltage of the secondary terminal 232. When the propulsion motor 106 is a three-phase AC motor, the voltage output to the secondary terminal 232 is a three-phase AC voltage. Note that, in FIG. 2, a two-level inverter having two primary terminals 231 and capable of outputting two types of potential to the primary side is illustrated as an example, but is not limited to this example. The number of primary terminals 231 may be three or more. A configuration having three primary terminals 231 is called a three-level inverter.

[0023] The smoothing capacitor 220 is connected between the secondary terminal 212 of the converter 210 and the primary terminal 231 of the inverter 230, and has a function of suppressing fluctuations in the DC voltage. When the converter 210 and the inverter 230 are both configured as two levels, only one smoothing capacitor 220 may be used. In addition, a voltage sensor 221 is arranged in parallel with the smoothing capacitor 220. The voltage sensor 221 detects a capacitor voltage, which is a voltage across the smoothing capacitor 220.

[0024] FIG. 3 is a diagram for explaining the energy flow in the railway vehicle power conversion device according to the embodiment during normal operation. FIG. 4 is a diagram for explaining the energy flow in the railway vehicle power conversion device according to the embodiment during a non-power-feeding period. Note that the normal operation refers to a state in which power from the overhead line 100 is normally applied to the main transformer 104. The non-power-feeding period is a concept that includes a period in which the railway vehicle actually passes through a dead section, and further includes a period before and after that in which the switch is in an open state. In other words, the non-power-feeding period is a period in which the main transformer 104 and the overhead line 100 are electrically disconnected, and power is not supplied from the overhead line 100 to the main transformer 104.

[0025] Under normal circumstances, the power required to drive the railway vehicle is supplied to a main converter 105 and an auxiliary power supply 107 via a power receiving unit 101, a switch 103, and a main transformer 104. The main converter 105 converts the supplied power into drive power for a propulsion motor 106 to drive the propulsion motor 106. The auxiliary power supply 107 converts the supplied power into drive power for the auxiliary machinery to operate the auxiliary machinery.

[0026] During the power-off period, power cannot be supplied from the overhead line 100. Therefore, the converter control unit 242 provided in the control device 240 performs pump-back, which regenerates the kinetic energy of the traction motor 106 and supplies the regenerated power to the auxiliary power supply 107 via the main converter 105 and the main transformer 104. In the following description, when the main converter 105 is mentioned, it refers to the main converter 105 performing pump-back. Note that the main converter 105 performing pump-back is one for each main transformer 104. By having one main converter 105 perform pump-back, it is possible to prevent the regenerative power supplied to the main transformer 104 from becoming unstable. The one main converter 105 performing pump-back may be determined in advance, or may be designated by a train information management device that manages train information. The power-off period associated with passing through a dead section is short, and the amount of power consumed by the auxiliary power supply 107 during this period is sufficiently smaller than the kinetic energy of the traction motor 106 and the railway vehicle. Therefore, even if only one main converter 105 performs pump back, it is possible to prevent the train from suddenly decelerating.

[0027] Fig. 5 is a time chart for explaining the operation during pump back in the embodiment. The horizontal axis of Fig. 5 represents time. The vertical axis of Fig. 5 shows, from the top, the detection waveform of ACPT 102, the dead section passage warning signal, the torque pattern, the pump back status signal, the status signal of the switch 103, and the voltage waveform used for converter control.

[0028] Before the railway vehicle passes through the dead section, a dead section passing warning signal is output. Specifically, in the example of FIG. 5, the dead section passing warning signal is output at time t1, and the output of the dead section passing warning signal is released at time t10. Regeneration starts at time t2, and pump-back starts at time t3. The switch 103 is opened at time t4, and the open state continues until time t11. The period from time t5 to time t6 is the period during which the railway vehicle actually passes through the dead section. During the period from time t7 to time t8, control is performed to match the output voltage waveform of the converter 210 to the detected waveform of the ACPT 102. Pump-back ends at time t9, and the transition from regeneration to powering occurs at time t12.

[0029] Next, the behavior of the main transformer 104 and the main converter 105 will be described with reference to the time chart of Fig. 5. First, when power is supplied from the overhead line 100, the converter 210 operates so that the capacitor voltage is constant. The main transformer 104 outputs a single-phase AC voltage to a primary terminal 211 of the converter 210 so that the converter 210 can receive the necessary power. The converter 210 outputs a DC voltage to a secondary terminal 212 so that the smoothing capacitor 220 can follow the voltage as commanded. On the other hand, the inverter 230 outputs a voltage to a secondary terminal 232 so that the traction motor 106 can output a torque as commanded.

[0030] At time t1, a dead section passage warning signal is output, and upon receiving this signal, the inverter 230 reduces the powering torque and then stops supplying current to the traction motor 106. This causes the traction motor 106 to rotate by inertia, and the railway vehicle enters a coasting state. When the operation switches to pump-back at time t3, the inverter 230 operates to regenerate from the traction motor 106 the power required to maintain the capacitor voltage. After the start of pump-back, when the regenerated power from the main converter 105 and the power consumption of the auxiliaries connected to the auxiliary power supply 107 approximately match, the current flowing through the switch 103 approaches zero. This makes it possible to open the switch 103 at time t4.

[0031] During the period from time t5 to time t6 when the vehicle is actually passing through the dead section, the overhead line voltage cannot be measured. Therefore, from time t4 when the state signal of the switch 103 is turned OFF, that is, from time t4 before time t5, the control is switched to one that does not refer to the overhead line voltage. Specifically, the converter 210 outputs a voltage of a constant amplitude and frequency to the primary side terminal 211 without referring to the overhead line voltage. Here, the power supplied by the converter 210 depends on the load of the auxiliary power supply 107, so the capacitor voltage cannot be controlled. Therefore, the inverter control unit 244 is responsible for the capacitor voltage control at this time. The inverter control unit 244 controls the inverter 230 so that the torque command to the traction motor 106 becomes the regenerative torque amount required to obtain the power required to maintain the capacitor voltage. The control that does not refer to the overhead line voltage continues until time t7 after the vehicle has passed through the dead section.

[0032] After time t6 when the railcar passes through the dead section, the ACPT 102 resumes measuring the overhead line voltage. However, since the overhead line voltage and the voltage generated by the converter 210 are out of phase, if the switch 103 is closed at this time, an excessive inrush current may flow through the main transformer 104. To prevent this excessive current, the converter 210 performs control to gradually match the generated voltage to the waveform detected by the ACPT 102. Specifically, the converter 210 controls the frequency of the generated voltage to be gradually changed so that the phase of the generated voltage is synchronized with the phase of the overhead line voltage while continuing to supply power to the auxiliary power supply 107. FIG. 5 shows an example in which the phase of the generated voltage and the phase of the overhead line voltage are synchronized at time t8, pump-back ends at the following time t9, and the switch 103 is closed at the following time t11. After time t11, power supply from the overhead line 100 is resumed, the converter 210 returns to DC voltage control, and the inverter 230 returns to motor torque control.

[0033] In this document, the overhead line voltage detected by ACPT102 after the end of the power-free period is referred to as the "first voltage," and the phase of this first voltage is sometimes referred to as the "first phase." In addition, in this document, the AC voltage generated by converter control unit 242 during the power-free period based on the overhead line voltage detected by ACPT102 before the start of the power-free period is referred to as the "second voltage," and the phase of this second voltage is sometimes referred to as the "second phase."

[0034] 6 is a block diagram showing an example of the configuration of converter control unit 242 according to the embodiment. Converter control unit 242 according to the embodiment includes a counter voltage calculation unit 501, a voltage phase estimation unit 502, a current control unit 503, a voltage command calculation unit 504, and a converter drive signal generation unit 505, as shown in FIG.

[0035] The counter voltage calculation unit 501 calculates a counter voltage command value V2, which is a command value for the counter voltage V2, based on the overhead line voltage V1 acquired from the ACPT 102. * When the switch 103 is closed, V1 = V2 * However, when switch 103 is open, the voltages are essentially different.

[0036] The voltage phase estimation unit 502 estimates the counter voltage command value V2 * Based on this, the estimated voltage phase θ S The counter voltage command value V2 is estimated. * is a single-phase sine wave, and the voltage phase estimation unit 502 normally calculates V1=V2 * The counter voltage command value V2 is * Based on the estimated voltage phase θ S Specifically, the voltage phase estimation unit 502 calculates the counter voltage command value V2 * is regarded as a sine wave, and the counter voltage command value V2 * The timing at which the instantaneous voltage of V2 changes from negative to positive is detected, and the phase is set to 0° at that timing. * is required to be a sine wave with little ripple.

[0037] The current control unit 503 normally controls the capacitor voltage V dc The capacitor voltage command value V dc * During pump back, the output voltage V2 is corrected to follow the counter voltage command value V2 * Specifically, the current control unit 503 performs output voltage correction so as to follow the load power P m and the capacitor voltage V detected by the voltage sensor 221. dc Based on the detected value of and the capacitor voltage V dc The capacitor voltage command value V dc * Then, the current control unit 503 calculates the current amplitude required to make the voltage follow the calculated current amplitude and the estimated voltage phase θ output from the voltage phase estimation unit 502. S Based on this, the voltage drop V in the main transformer 104 is tr On the other hand, during pump back, the current control unit 503 calculates the current I S The current sensor 213 detects the current I S Based on the detected value of tr Calculate the following.

[0038] The voltage command calculation unit 504 calculates the counter voltage command value V2 * and the voltage drop V in the main transformer 104 tr Based on this, the primary voltage command V ac * Specifically, the voltage command calculation unit 504 calculates the counter voltage command value V2 * Voltage drop V tr By subtracting ac * Calculate the following.

[0039] The converter drive signal generator 505 generates a voltage command V ac * , estimated voltage phase θ S and the capacitor voltage V dc Based on the detection value ofc The generated switching command S c The converter 210 outputs a switching command S to the converter 210. Although not shown in the figure, the converter 210 includes a plurality of switching elements that are bridge-connected. c is a command to turn on or off each of the multiple switching elements at a desired timing. c The switching command S can be generated using a known control method, for example, a PWM method. c As a result, a voltage command V ac * A voltage according to the input signal is output.

[0040] Next, the problems with the conventional method will be described. As described above, the counter voltage calculation unit 501 calculates the counter voltage command value V2, which is a command value for the counter voltage V2, based on the overhead line voltage V1 acquired from the ACPT 102. * The counter voltage command value V2 is calculated. * A PLL (Phase Locked Loop) is generally used for the calculation of the above. The PLL is also called a phase-locked loop, and is a method for calculating a desired phase by feedback control that matches the phase difference between the phase of an input signal and the phase of an output signal. The railway vehicle power conversion device of the present disclosure also uses a PLL, but the conventional method has the following problems. FIG. 7 is a diagram for explaining the conventional method using a PLL.

[0041] In FIG. 7, the sine wave shown by the solid line is a curve used for phase estimation. The horizontal axis represents the actual voltage phase difference θ1-θ2, which is the actual voltage phase difference, and the vertical axis represents the estimated phase difference Δθ in the conventional method. The dashed line is a straight line showing the relationship in which the estimated phase difference Δθ coincides with the actual voltage phase difference θ1-θ2, and in the control of phase estimation, the difference between the actual and dashed lines appears as an error component of the estimated phase difference Δθ. Here, in the conventional method, when the value of the actual voltage phase difference θ1-θ2 is small, the value of sin(θ1-θ2) is used to calculate the estimated phase difference Δθ, utilizing the fact that (θ1-θ2)≒sin(θ1-θ2). However, as shown in FIG. 7, the difference between θ1-θ2 and sin(θ1-θ2) increases when the absolute value of the actual voltage phase difference θ1-θ2 exceeds 30[°], and becomes rapidly larger when it exceeds 90[°]. Therefore, when the actual voltage phase difference θ1-θ2 is large, the estimated phase difference Δθ is estimated to be smaller than the actual one, which causes the problem that phase synchronization takes time. In particular, when the absolute value of the actual voltage phase difference θ1-θ2 is 180[°], sin(θ1-θ2)=0 occurs, and the PLL does not work sufficiently, which causes the fatal problem that the voltage phase cannot be corrected.

[0042] Next, a control method capable of solving the above-mentioned problem will be described. Fig. 8 is a block diagram showing a configuration example of the counter voltage calculation unit 501 according to the embodiment. As shown in Fig. 8, the counter voltage calculation unit 501 according to the embodiment includes gain providing units 601 and 605, a cosine calculation unit 602, multiplication units 603, 610, 801, and 804, low-pass filters (LPFs) 604 and 802, switches 606, 611, and 805, an adder 607, an integrator 608, a sine calculation unit 609, a band-pass filter (BPF) 612, and a sign determination unit 803. In addition, in FIG. 8, the cosine calculation unit 602, the multiplication unit 603, and the LPF 604 configure a phase difference estimation unit 810, and the multiplication units 801 and 804, the LPF 802, the sign determination unit 803, and the switch 805 configure a changeover unit 820.

[0043] Next, the operation of the counter voltage calculation unit 501 shown in Fig. 8 will be described. First, in the gain applying unit 601, a gain N is applied to the overhead line voltage V1 taken in from the ACPT 102. As a result, the voltage V output from the gain applying unit 601 is b The voltage value of is converted to a voltage equivalent to that of the secondary winding 142 of the main transformer 104. The gain N is determined by dividing the number of turns of the primary winding 141 of the main transformer 104 by the number of turns of the secondary winding 142.

[0044] Next, in the cosine calculation unit 602, a cosine value cos θ is calculated using the current voltage phase θ generated inside the counter voltage calculation unit 501. This process corresponds to a process of advancing the voltage waveform by 90° and generating a voltage waveform with a peak value of ±1. Here, the current voltage phase θ is expressed by the following formula (1) using the angular frequency ω0 and the phase θ2 at time 0 [s]. Also, the voltage V output from the gain applying unit 601 is b is expressed by the following equation (2) using frequency ω0 and phase θ1 at time 0 [s].

[0045]

number

number

[0046] In the above formula (2), V S * is the rated voltage amplitude, which is the rated value of the overhead line voltage V1. In the multiplication unit 603, the output of the gain providing unit 601 and the output of the cosine calculation unit 602 are multiplied together, and the multiplication result is expressed by the following equation (3).

[0047]

number

[0048] The right side of the above equation (3) is the sum of a voltage component that changes with time and a voltage component that pulsates at an angular frequency twice that of the voltage. For this reason, LPF 604 is provided to leave only the former component and remove the latter component. The transfer function of LPF 604 is set, for example, as shown in the following equation (4). By using LPF 604 set in this way, it is possible to sufficiently remove the component with an angular frequency of 2ω0.

[0049]

number

[0050] From LPF604, V S * As described above, in the case of the conventional method, it is assumed that the difference between θ1 and θ2 is sufficiently small, and the output of the LPF 604 is "V S * It is treated as being approximately equal to "(θ1-θ2) / 2".

[0051] The gain adding unit 605 applies a gain K PLL is applied. Through this process, the output of the gain application unit 605 is converted into a frequency correction amount Δω. The frequency correction amount Δω is input to the switch 606 via the switch 805. The operation of the switch 805 will be described later.

[0052] Here, the behavior when the frequency correction amount Δω is used will be described. When the frequency correction amount Δω is used, the voltage V b For example, the frequency of the overhead line voltage V1 can be increased or decreased by changing the voltage phase of the overhead line voltage V1 to an estimated voltage phase θ S If it is ahead of the voltage V b By increasing the frequency of the estimated voltage phase θ S The voltage phase of the overhead line voltage V1 catches up with the estimated voltage phase θ S If it lags behind, the voltage V b By lowering the frequency of the estimated voltage phase θ Sis caught up with the voltage phase of the overhead line voltage V1.

[0053] Switch 606 is fixed ON during normal operation, turned OFF during pump-back, and turned back ON when the electric power supply through the overhead line is resumed after passing through a dead section. Therefore, a frequency correction amount Δω is input to switch 606 during normal operation, and 0 is input to switch 606 during pump-back. As a result, in the control system, when switch 606 is ON, the PLL works, and when switch 606 is OFF, the PLL does not work and a fixed frequency voltage is output to primary side terminal 211.

[0054] In the adder 607, the frequency correction amount Δω or 0 is added to the rated angular frequency ω0, which is 2π times the rated frequency of the overhead line 100, and the result is input to the downstream integration unit 608. That is, the adder 607 converts the output of the switch 606 into the frequency of the voltage to be output to the primary side terminal 211 of the converter 210. Commonly used rated frequencies for AC overhead lines electrified by AC are 16.7, 25, 50, 60 Hz, etc.

[0055] Integrator 608 integrates the output of adder 607, and outputs the integral value as the above-mentioned voltage phase θ to cosine calculator 602 and sine calculator 609. Here, during normal operation, switch 606 is controlled to be ON, so that the overhead line voltage phase is stored in integrator 608. During a non-powered period, the phase changes at the rated angular frequency based on the overhead line voltage phase stored in integrator 608, and after passing through a dead section, the PLL processing works again, resulting in a behavior that approaches the overhead line voltage phase.

[0056] In the sine calculation unit 609, a sine value sinθ is calculated using the voltage phase θ. In the multiplication unit 610, a rated voltage amplitude V S * is multiplied by the output of the sine calculation unit 609, and the multiplication result is the PLL voltage V 2p It is said.

[0057] The switch 611 is normally fixed to OFF, is turned ON during a non-powered period, and is returned to OFF after passing through a dead section. Here, since the switch 103 is normally closed, the voltage V output from the gain applying unit 601 is b is the counter voltage command value V2 * On the other hand, during the non-power-feeding period, the PLL voltage V 2p is the counter voltage command value V2 * It is used as the basis signal.

[0058] Finally, the output of the switch 611 is input to the BPF 612, which extracts the fundamental wave component and outputs the counter voltage command value V2 * Since harmonics resulting from the operation of converter 210 are superimposed on overhead line voltage V1, this is provided to remove the superimposed harmonic components.

[0059] The timing at which the switch 611 is turned from ON to OFF is determined by the counter voltage command value V2 * The time period is after the phase of the counter voltage command value V2 coincides with the phase of the overhead line voltage V1 and after the switch 103 is turned on. Note that even if the switch 611 is turned off after the switch 103 is turned on, * Since the phase of the counter voltage command value V2 coincides with the phase of the overhead line voltage V1, * does not change significantly.

[0060] Here, a method for determining whether or not phase synchronization has been completed will also be described. * Since the signal V1 is processed by the BPF 612 to be a sine wave with only the fundamental wave component with almost no distortion, the sign changes every half cycle of the fundamental wave. The overhead line voltage V1 at the moment when the sign changes is monitored, and if the instantaneous voltage is below a specified value, it is determined that phase synchronization is complete. 、 Counter voltage command value V2 *If the difference between the slope of the phase lock and the slope of the phase lock is equal to or smaller than a specified value, it may be determined that phase lock is complete. The specified value for determination may be determined based on the amount of inrush current permitted in the main transformer 104.

[0061] The following describes the operation of the switching unit 820, which has not been described above, in the counter voltage calculation unit 501. First, in the multiplication unit 801, the output of the gain providing unit 601 and the output of the sine calculation unit 609 are multiplied together, and the multiplication result is expressed by the following equation (5).

[0062]

number

[0063] The right side of the above equation (5) is the difference between a voltage component that changes with time and a voltage component that pulsates at twice the angular frequency of the voltage, and LPF 802 leaves only the former component and removes the latter component. LPF 802 may be any LPF that can sufficiently remove the component with an angular frequency of 2ω0, similar to LPF 604. Therefore, LPF 802 may be equivalent to LPF 604.

[0064] From the LPF802, V s *An output of {cos(θ1-θ2)} / 2 is obtained. θ1-θ2 corresponds to the estimated phase difference Δθ described above. When the estimated phase difference Δθ is equal to or greater than -90[°] and less than 90[°], the output of LPF 802 is a positive value, and when the estimated phase difference Δθ is less than -90[°] or more than 90[°], the output of LPF 802 is a negative value. Therefore, which of the overhead line voltage phase θ1 and the counter voltage phase θ2 is leading can be determined from the sign of the output result of LPF 802. Here, in this paper, when the overhead line voltage phase θ1 is greater than the counter voltage phase θ2, that is, when the estimated phase difference Δθ is positive, the overhead line voltage phase θ1 is defined as leading, and when the overhead line voltage phase θ1 is smaller than the counter voltage phase θ2, that is, when the estimated phase difference Δθ is negative, the overhead line voltage phase θ1 is defined as lagging. The sign determination unit 803 performs the above determination process by setting the range of the estimated phase difference Δθ to be equal to or greater than −180° and equal to or less than +180°. When the estimated phase difference Δθ is 0, the sign determination unit 803 determines whether the phase difference is positive or negative.

[0065] A multiplication unit 804 multiplies the fixed value Δω0 of the frequency correction amount by the determination result by the sign determination unit 803, i.e., either "+1" or "-1". The output of the multiplication unit 804 is input to a switch 805. The fixed value Δω0 of the frequency correction amount is a positive value, and is set to be equal to or less than the amount of frequency fluctuation permitted in the auxiliary power supply 107.

[0066] The switch 805 determines the frequency correction amount Δω. Specifically, when the output of the LPF 802 is positive, that is, when the estimated phase difference Δθ is less than 90[°], the output of the gain providing unit 605 is used as the frequency correction amount Δω. On the other hand, when the output of the LPF 802 is negative, that is, when the estimated phase difference Δθ exceeds 90[°], the input of the switch 805 is switched to the negative terminal side to accept the output of the multiplication unit 804. In this case, the frequency correction amount Δω, which is the output of the switch 805, becomes Δω=+ω0 or Δω=-ω0 according to the judgment result of the sign judgment unit 803. The reason for switching the sign of the frequency correction amount Δω is to shorten the time required for phase synchronization. Note that when the estimated phase difference Δθ is 90[°], the switch 805 may accept either the output of the gain providing unit 605 or the output of the LPF 802.

[0067] When the above-mentioned control is viewed as the overall operation of the counter voltage calculation unit 501, when the overhead line voltage phase θ1 leads the counter voltage phase θ2 by a range of 90[°] to 180[°], the sign of the frequency correction amount Δω is set to plus, that is, Δω=+ω0, and the counter voltage command value V2 * In addition, when the overhead line voltage phase θ1 lags behind the counter voltage phase θ2 by a range of 90[°] to 180[°], the sign of the frequency correction amount Δω is set to minus, that is, Δω = -ω0, and the counter voltage command value V2 * This results in a behavior that lowers the frequency of the

[0068] Next, a description will be given of the effect of using the counter voltage calculation unit 501 according to the embodiment. Fig. 9 is a diagram for explaining the effect of shortening the time required for phase synchronization when the counter voltage calculation unit 501 according to the embodiment is used.

[0069] In Fig. 9, the horizontal axis represents the actual voltage phase difference θ1-θ2 as in Fig. 7, and the vertical axis represents the time required for phase synchronization, that is, the time required for the PLL processing to converge and phase synchronization to be completed. In Fig. 9, the solid line represents the time required for phase synchronization when this method is used, and the dashed line represents the time required for phase synchronization shown as a comparative example. Here, the comparative example is assumed to be a configuration in which the function of the switching unit 820 is removed from the configuration of the counter voltage calculation unit 501 shown in Fig. 8, that is, a configuration that does not have the function of switching the sign of the frequency correction amount Δω according to the estimated phase difference Δθ. The meaning of the dashed line shown in Fig. 9 will be described later.

[0070] 9, the overhead line voltage is 50 [Hz]. The frequency of the voltage supplied to the auxiliary power supply 107 is allowed to be up to 50±3 [Hz], and Δω0=3×2π [rad / s]. The gain K given by the gain giving unit 605 is PLL is set so that the frequency correction amount Δω when Δθ=90° coincides with Δω0. PLL =Δω0 / V S * Set to.

[0071] Moreover, the actual voltage phase difference θ1-θ2 shown on the horizontal axis in Fig. 9 is the actual voltage phase difference at the time when the overhead line voltage V1 is restored and the switch 606 is switched ON. Moreover, in Fig. 9, the time when the actual voltage phase difference θ1-θ2 becomes 0.1 [rad] or less is defined as the completion time of phase synchronization.

[0072] In the comparative example, as the actual voltage phase difference θ1-θ2 approaches 180°, the time required for phase synchronization increases rapidly, and when it is 180° in particular, it takes an infinite amount of time, making phase synchronization impossible. In contrast, in the case of this method, even if the actual voltage phase difference θ1-θ2 is 180°, it is possible to complete phase synchronization in less than 0.4 seconds.

[0073] In the above, in order to shorten the time required for phase synchronization, a configuration has been described in which the sign of the frequency correction amount Δω is switched based on the determination result of the sign determination unit 803. Since the sign determination unit 803 switches the sign at ±90°, this means that the threshold for switching the sign of the frequency correction amount Δω is ±90°. On the other hand, this threshold does not have to be ±90°, and may be set to, for example, ±150°. The reason for this will be described below with reference to FIG. 9.

[0074] In FIG. 9, a straight line is drawn as a dashed line connecting point A on the dashed line shown as a comparative example with the origin (0,0). This straight line is a tangent to point A, and is the straight line with the smallest slope among the straight lines connecting any point on the dashed line with the origin (0,0). The real voltage phase difference θ1-θ2 corresponding to point A is approximately 157[°]. Here, the slope of the straight line is "phase synchronization required time (vertical axis)" ÷ "real voltage phase difference (horizontal axis)", and increases rapidly from point A. An increase in the slope of the straight line means that the phase synchronization required time becomes longer. For this reason, 150[°] corresponding to point B, which is close to point A and located to the left of point A, is set as the sign switching threshold. Note that the curves shown in FIG. 9 are symmetrical, and the negative side of the real voltage phase difference θ1-θ2 is set to -150[°].

[0075] Therefore, the switching unit 820 included in the counter voltage calculation unit 501 compares the absolute value of the estimated phase difference Δθ with a threshold, and switches the frequency correction amount Δω to a positive value if the absolute value of the estimated phase difference Δθ is greater than the threshold and the sign of the estimated phase difference Δθ is positive. The switching unit 820 also compares the absolute value of the estimated phase difference Δθ with a threshold, and switches the frequency correction amount Δω to a negative value if the absolute value of the estimated phase difference Δθ is greater than the threshold and the sign of the estimated phase difference Δθ is negative.

[0076] In the above control, when the threshold for switching the sign of the frequency correction amount Δω is ±90[°] and the threshold for switching the sign of the frequency correction amount Δω is ±150[°], the former can share the functions of the existing controller. Therefore, the former has the effect of simplifying the configuration of the control system compared to the latter. In addition, the value of "actual voltage phase difference (horizontal axis)" ÷ "time required for phase synchronization (vertical axis)" when the vertical and horizontal relationships of the slope of the line in FIG. 9 are reversed corresponds to the difference between the average frequency during PLL operation and the frequency of the overhead line voltage, that is, the average frequency correction amount during PLL operation. Therefore, when the latter is adopted, the effect of shortening the time required for phase synchronization can be obtained while suppressing the increase in the average frequency correction amount during PLL operation.

[0077] Next, specific operation waveforms will be described with reference to the drawings of Fig. 10 to Fig. 15. Fig. 10 is a diagram showing voltage waveforms and current waveforms of main parts in a comparative example when the real voltage phase difference is 180[°]. Fig. 11 is a diagram showing PLL operation waveforms in a comparative example when the real voltage phase difference is 180[°]. Fig. 12 is a diagram showing voltage waveforms and current waveforms of main parts in this method when the real voltage phase difference is 180[°]. Fig. 13 is a diagram showing PLL operation waveforms in this method when the real voltage phase difference is 180[°]. Fig. 14 is a diagram showing voltage waveforms and current waveforms of main parts in this method when the real voltage phase difference is 150[°]. Fig. 15 is a diagram showing PLL operation waveforms in this method when the real voltage phase difference is 150[°].

[0078] 10, 12, and 14 show, from the top, waveforms of (a) overhead line voltage V1, (b) converter AC current, (c) power receiving voltage of auxiliary power supply 107, and (d) current consumption of auxiliary power supply 107. Also, each of Figs. 11, 13, and 15 shows, from the top, waveforms of (a) switch 606 closing signal, synchronization determination result, (b) overhead line voltage V1, PLL voltage V 2p , (c) Counter voltage command value V2 * , (d) Counter voltage command value V2 * Waveforms of frequencies are shown.

[0079] Figures 10 and 11 show the simulation results for the comparative example when the actual voltage phase difference is 180[°], Figures 12 and 13 show the simulation results for the present method when the actual voltage phase difference is 180[°], and Figures 14 and 15 show the simulation results for the present method when the actual voltage phase difference is 150[°].

[0080] 11, 13, and 15(a), the thick dashed line represents the input signal of the switch 606, and the thick solid line represents the synchronization determination result. Also, in each of FIGS. 11, 13, and 15(b), the thick dashed line represents the overhead line voltage V1, and the thin solid line represents the PLL voltage V 2p In addition, the overhead line voltage V1 shown in each of (a) of Fig. 10, Fig. 12 and Fig. 14, the overhead line voltage V1 and the PLL voltage V shown in each of (b) of Fig. 11, Fig. 13 and Fig. 15 2p are all secondary side converted values.

[0081] In the operation of the comparative example when the actual voltage phase difference is 180[°], as shown in FIG. 11(b), after the overhead line voltage V1 is restored at time 4.5[s], the overhead line voltage V1 and the PLL voltage V2p It can be seen that synchronization is not completed even after another 0.4 [s] has elapsed. The reason for this is that, as described with reference to Fig. 7, when the actual voltage phase difference is 180 [°], the estimated phase difference Δθ is estimated to be substantially zero, so that the output of the gain applying unit 605 becomes a small value and the PLL does not function sufficiently.

[0082] On the other hand, in the operation of this method when the actual voltage phase difference is 180[°], as shown in Fig. 13(b), after the overhead line voltage V1 is restored at time 4.5[s], the overhead line voltage V1 and the PLL voltage V 2pIt can be seen that the voltage phase is matched with that of the auxiliary power supply 107, and phase synchronization is completed in about 0.3 [s]. When phase synchronization is completed, a closing signal is sent to the switch 103. Looking at the waveform of the power receiving voltage of the auxiliary power supply 107 shown in FIG. 12(c), it can be seen that although there are differences in the harmonic components originating from the converter 210 and the auxiliary power supply 107 between the waveform before the switch 103 is closed and the waveform after the switch 103 is closed, it can be seen that voltage is always being supplied. In addition, it can be seen that the frequency of the supplied voltage is within the range of 50±3 [Hz] as originally designed, as shown in FIG. 13(d).

[0083] In addition, in the operation examples shown in Figures 10 to 13, synchronization is achieved by increasing the frequency correction amount Δω, but in Figures 14 and 15, synchronization is achieved by decreasing the frequency correction amount Δω. In other words, it can be seen that by using the method of this method, correct operation is achieved whether the frequency correction amount Δω is increased or decreased.

[0084] Although the above describes phase synchronization between the converter voltage phase and the overhead line voltage phase when a railway vehicle passes through a dead section, the present invention is not limited to this example. For example, the present method can also be applied to phase synchronization when the overhead line experiences a momentary power outage, and the above-mentioned effects can be obtained.

[0085] As described above, in the railcar power conversion device according to the embodiment, the control device includes a converter control unit that controls the converter to supply regenerative power generated by the traction motor to the second power conversion device via the main transformer during a power-loss period when no power is supplied from the overhead line. The converter control unit includes a reference voltage calculation unit and a voltage phase estimation unit. The reference voltage calculation unit calculates a reference voltage that is a reference for current control of the converter based on a detected value of the overhead line voltage. The voltage phase estimation unit estimates the phase of the AC voltage to be applied to the second power conversion device during the power-loss period based on the reference voltage. The reference voltage calculation unit includes a phase difference estimation unit and a switching unit. The phase difference estimation unit estimates a phase difference between a first phase that is the phase of the first voltage and a second phase that is the phase of the second voltage. The first voltage is the overhead line voltage detected by the voltage detector after the end of the power-loss period. The second voltage is the AC voltage estimated by the voltage phase estimation unit based on the overhead line voltage detected by the voltage detector before the start of the power-loss period. The switching unit switches the sign of the frequency correction amount for correcting the frequency of the second voltage based on the estimated phase difference, which is an estimate of the phase difference. The railcar power conversion device configured in this manner can solve the problem that when the actual voltage phase difference is large, the estimated phase difference is estimated to be smaller than the actual one, and phase synchronization takes time. This makes it possible to suppress an increase in the time required for phase synchronization even if the overhead line voltage frequency deviates from the rated value. Note that the non-powered period referred to here may be a period including the period when the railcar passes through a dead section and the period before and after that period, or may be a period from when the overhead line experiences a momentary power outage to when the momentary power outage is restored.

[0086] In the above configuration, the converter control unit increases the frequency of the second voltage when the sign of the estimated phase difference is positive, and decreases the frequency of the second voltage when the sign of the estimated value of the estimated phase difference is negative. The switching unit compares the absolute value of the estimated phase difference with a predetermined threshold, and switches the frequency correction amount to a positive value when the absolute value of the estimated phase difference is greater than the threshold and the sign of the estimated phase difference is positive. The switching unit compares the absolute value of the estimated phase difference with a predetermined threshold, and switches the frequency correction amount to a negative value when the absolute value of the estimated phase difference is greater than the threshold and the sign of the estimated phase difference is negative. Such control is compatible with existing control systems and can be easily incorporated into existing control systems.

[0087] In the above control, the threshold value to be compared with the absolute value of the estimated phase difference can be set to, for example, 90 degrees or 150 degrees. If the threshold value is set to 90 degrees, the configuration of the control system can be simplified. Also, if the threshold value is set to 150 degrees, the time required for phase synchronization can be shortened while suppressing an increase in the average frequency correction amount during PLL operation.

[0088] Finally, a hardware configuration for realizing the functions of the converter control unit 242 described above will be described with reference to the drawings of Fig. 16 and Fig. 17. Fig. 16 is a block diagram showing an example of a hardware configuration for realizing the functions of the converter control unit 242 in the embodiment. Fig. 17 is a block diagram showing another example of a hardware configuration for realizing the functions of the converter control unit 242 in the embodiment.

[0089] When realizing some or all of the functions of converter control unit 242 in the embodiment, the configuration can include a processor 300 that performs calculations, a memory 302 in which programs read by processor 300 are stored, and an interface 304 that inputs and outputs signals, as shown in FIG. 16.

[0090] The processor 300 is a calculation means. The processor 300 may be a calculation means called a microprocessor, a microcomputer, a CPU (Central Processing Unit), or a DSP (Digital Signal Processor). Examples of the memory 302 include non-volatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), and EEPROM (registered trademark) (Electrically EPROM), magnetic disks, flexible disks, optical disks, compact disks, mini disks, and DVDs (Digital Versatile Discs). The memory 302 may be a combination of multiple storage devices, such as a RAM and an EEPROM.

[0091] A program for executing the functions of converter control unit 242 in the embodiment is stored in memory 302. Processor 300 receives and transmits necessary information via interface 304, executes the program stored in memory 302, and refers to the table stored in memory 302, thereby performing the above-mentioned processing. The calculation results by processor 300 can be stored in memory 302.

[0092] 17 may be used to realize part of the functions of converter control unit 242 in the embodiment. Processing circuit 303 may be a single circuit, a composite circuit, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination of these. Information to be input to processing circuit 303 and information to be output from processing circuit 303 can be obtained via interface 304.

[0093] Note that a part of the processing in converter control section 242 may be performed by processing circuit 303 , and the other processing not performed by processing circuit 303 may be performed by processor 300 and memory 302 .

[0094] 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. Various aspects of the present disclosure are summarized below as appendices. [Appendix 1] a first power conversion device connected to a secondary winding of the main transformer and connected to a propulsion motor for driving the railway vehicle, the first power conversion device having a converter that converts an AC voltage applied via the main transformer into a DC voltage and mounted on a railway vehicle having a main transformer, a primary winding of the main transformer connected to an overhead line via a power receiving unit, a switch that electrically connects or disconnects the main transformer and the overhead line, and a voltage detector that is provided between the overhead line and the switch and detects an overhead line voltage applied from the overhead line, the first power conversion device being connected to a secondary winding of the main transformer and connected to a propulsion motor for driving the railway vehicle, a second power conversion device connected to a tertiary winding of the main transformer and supplying power to auxiliary machinery mounted on the railway vehicle, and a control device that controls operation of the switch and the first and second power conversion devices, the control device includes a converter control unit that controls the converter to supply regenerative power generated by the traction motor to the second power conversion device via the main transformer during a power-loss period when power is not supplied from the overhead line, The converter control unit a reference voltage calculation unit that calculates a reference voltage serving as a reference for current control of the converter based on the detected value of the overhead line voltage; a voltage phase estimation unit that estimates a phase of an AC voltage to be applied to the second power conversion device during the non-power supply period based on the reference voltage; Equipped with The reference voltage calculation unit is a phase difference estimation unit that estimates a phase difference between a first phase, which is a phase of a first voltage when an overhead line voltage detected by the voltage detector after the end of the non-power-feeding period is defined as a first voltage, and a second phase, which is a phase of a second voltage when the AC voltage estimated by the voltage phase estimation unit based on the overhead line voltage detected by the voltage detector before the start of the non-power-feeding period is defined as a second voltage; a switching unit that switches a sign of a frequency correction amount for correcting a frequency of the second voltage based on an estimated phase difference that is an estimate of the phase difference; A power conversion device for a railway vehicle comprising: [Appendix 2] The non-powered period includes the period during which the railcar passes through the dead section and the period before and after the period. 2. A power conversion device for a railway vehicle according to claim 1. [Appendix 3] The non-power supply period is the period from when the overhead line experiences a momentary power outage to when the power is restored. 2. A power conversion device for a railway vehicle according to claim 1. [Appendix 4] The converter control unit When the sign of the estimated phase difference is positive, increasing the frequency of the second voltage; When the sign of the estimated value of the estimated phase difference is negative, the frequency of the second voltage is decreased. 4. A power conversion device for a railway vehicle according to claim 1, [Appendix 5] The switching unit compares an absolute value of the estimated phase difference with a predetermined threshold, and switches the frequency correction amount to a positive value when the absolute value is greater than the threshold and the sign of the estimated phase difference is positive. 5. A power conversion device for a railway vehicle according to claim 1, [Appendix 6] The switching unit compares an absolute value of the estimated phase difference with a predetermined threshold, and switches the frequency correction amount to a negative value when the absolute value is greater than the threshold and the sign of the estimated phase difference is negative. 5. A power conversion device for a railway vehicle according to claim 1, [Appendix 7] The threshold is 90 degrees. 7. The power conversion device for a railway vehicle according to claim 5 or 6. [Appendix 8] The threshold is 150 degrees. 7. The power conversion device for a railway vehicle according to claim 5 or 6. [Explanation of symbols]

[0095] 100 overhead line, 101 power receiving unit, 102 ACPT, 103 switch, 104 main transformer, 105 main converter, 106 propulsion motor, 107 auxiliary power supply unit, 141 primary winding, 142 secondary winding, 143 tertiary winding, 210 converter, 211, 231 primary terminal, 212, 232 secondary terminal, 213 current sensor, 220 smoothing capacitor, 221 voltage sensor, 230 inverter, 240 control device, 242 converter control unit, 244 inverter control unit, 300 processor, 302 memory, 303 processing circuit, 304 interface, 501 counter voltage calculation unit, 502 voltage phase estimation unit, 503 current control unit, 504 voltage command calculation unit, 505 converter drive signal generation unit, 601, 605 gain application unit, 602 Cosine calculation unit, 603, 610, 801, 804 multiplication units, 604, 802 LPF, 606, 611, 805 switches, 607 addition unit, 608 integration unit, 609 sine calculation unit, 612 BPF, 803 sign determination unit, 810 phase difference estimation unit, 820 switching unit.

Claims

1. a first power conversion device connected to a secondary winding of the main transformer and connected to a propulsion motor for driving the railway vehicle, the first power conversion device having a converter that converts an AC voltage applied via the main transformer into a DC voltage and mounted on a railway vehicle having a main transformer, a primary winding of the main transformer connected to an overhead line via a power receiving unit, a switch that electrically connects or disconnects the main transformer and the overhead line, and a voltage detector that is provided between the overhead line and the switch and detects an overhead line voltage applied from the overhead line, the first power conversion device being connected to a secondary winding of the main transformer and connected to a propulsion motor for driving the railway vehicle, a second power conversion device connected to a tertiary winding of the main transformer and supplying power to auxiliary machinery mounted on the railway vehicle, and a control device that controls operation of the switch and the first and second power conversion devices, the control device includes a converter control unit that controls the converter to supply regenerative power generated by the traction motor to the second power conversion device via the main transformer during a power-loss period when power is not supplied from the overhead line, The converter control unit a reference voltage calculation unit that calculates a reference voltage serving as a reference for current control of the converter based on the detected value of the overhead line voltage; a voltage phase estimator that estimates a phase of an AC voltage to be applied to the second power conversion device during the non-power supply period based on the reference voltage; Equipped with The reference voltage calculation unit is a phase difference estimation unit that estimates a phase difference between a first phase, which is a phase of a first voltage when an overhead line voltage detected by the voltage detector after the end of the non-power-feeding period is defined as a first voltage, and a second phase, which is a phase of a second voltage when the AC voltage estimated by the voltage phase estimation unit based on the overhead line voltage detected by the voltage detector before the start of the non-power-feeding period is defined as a second voltage; a switching unit that switches a sign of a frequency correction amount for correcting a frequency of the second voltage based on an estimated phase difference that is an estimate of the phase difference; A power conversion device for a railway vehicle comprising:

2. The non-powered period includes the period during which the railcar passes through the dead section and the period before and after the period.

2. The power conversion device for railcars according to claim 1 .

3. The non-power supply period is the period from when the overhead line experiences a momentary power outage to when the power is restored.

2. The power conversion device for railcars according to claim 1 .

4. The converter control unit When the sign of the estimated phase difference is positive, increasing the frequency of the second voltage; When the sign of the estimated value of the estimated phase difference is negative, the frequency of the second voltage is decreased.

4. The power converter for a railway vehicle according to claim 1, wherein the power converter is a power converter for a railway vehicle.

5. The switching unit compares an absolute value of the estimated phase difference with a predetermined threshold, and switches the frequency correction amount to a positive value when the absolute value is greater than the threshold and the sign of the estimated phase difference is positive.

2. The power conversion device for railcars according to claim 1 .

6. The switching unit compares an absolute value of the estimated phase difference with a predetermined threshold, and switches the frequency correction amount to a negative value when the absolute value is greater than the threshold and the sign of the estimated phase difference is negative.

2. The power conversion device for railcars according to claim 1 .

7. The threshold is 90 degrees.

7. The power converter for railway vehicles according to claim 5 or 6.

8. The threshold is 150 degrees.

7. The power converter for railway vehicles according to claim 5 or 6.

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