JP2020145891A - Electric railway active filter, control method thereof, and power conversion device and railway vehicle equipped with the same - Google Patents

Abstract

To provide a power conversion device equipped with an electric railway active filter that reduces an amount of noise current flowing out to a feeder wire while avoiding the risk of disturbing a communication signal for vehicle control.SOLUTION: An electric railway active filter includes; a transformer equipped with a smoothing capacitor and connected to an input side of an inverter that drives a vehicle acceleration/deceleration motor; an arm circuit composed of a series circuit of a semiconductor switching elements; a harmonic filter circuit connected in series between the arm circuit and the transformer; and a first current sensor for detecting first current flowing through between the harmonic filter circuit and the transformer. A switching signal of the arm circuit is controlled based on a detection signal of the first current.SELECTED DRAWING: Figure 1

Description

The present invention relates to an active filter for electric railways provided in a power conversion device for electric railway vehicles and a control method thereof.

Electric railway vehicles receive electric power from substations via electric wires and rails, and the received electric power is frequency-converted by an inverter to drive a motor for vehicle acceleration / deceleration. Further, the vehicle control communication signal from the operation management system is transmitted via the rail which is the power receiving path of the inverter.

Therefore, if the noise current flowing out from the inverter becomes excessive, it causes hindering the transmission and reception of the vehicle control communication signal. Therefore, the motor drive inverter system mounted on a vehicle traveling in a DC feeder section includes a DC capacitor that absorbs noise current and a DC reactor that suppresses noise current flowing in a rail. These electric devices are often mounted under the floor of a vehicle, but on the other hand, there is also a demand for expanding the vehicle space to improve passenger comfort, so there is a great need for miniaturization.

Among them, the DC reactor is a large and heavy component. Patent Document 1 discloses a configuration in which the noise reduction effect of the DC reactor is assisted by an active filter using an inverter technique.

The active filter is connected to an electric circuit via a transformer, detects the terminal voltage pulsation component of the DC smoothing capacitor of the motor drive inverter, amplifies this detection signal with an amplifier, and then outputs it to the secondary terminal of the transformer. It has a configuration.

However, Patent Document 1 does not disclose the main circuit configuration of the amplifier, and further, since the signal amplifier generally has a small output capacitance, noise flowing out from an inverter rated at several hundred kW due to insufficient capacitance is suppressed. Is difficult.

Further, as a large-capacity active filter, as disclosed in Patent Document 2, a configuration having a built-in inverter is known.

Japanese Unexamined Patent Publication No. 61-026401 Japanese Unexamined Patent Publication No. 11-69627

When the active filter is composed of an inverter, the high-frequency noise current generated by the switching of the inverter flows out to the electric wire, which causes inductive interference. High-frequency noise current can be suppressed by installing a harmonic filter circuit in the active filter, but the resonance circuit is composed of this harmonic filter, the transformer for wire interconnection, and the DC smoothing capacitor of the motor drive inverter. This resonance may cause disturbance in the vehicle control communication signal.

The present invention provides a power conversion device provided with an active filter for electric railways that reduces the amount of noise current flowing out to a wire while avoiding the possibility of disturbing a vehicle control communication signal.

The electric railway active filter according to the present invention includes a transformer connected to the input side of an inverter for driving a vehicle acceleration / deceleration motor provided with a smoothing capacitor, an arm circuit composed of a series circuit of semiconductor switching elements, and an arm circuit. A first current sensor that detects a first current that energizes between the harmonic filter circuit and the transformer, and a first harmonic filter circuit that is connected in series between the and the transformer. It is characterized in that the switching signal of the arm circuit is controlled based on the detection signal of the current of.

According to the present invention, it is possible to prevent the vehicle control communication signal from being disturbed by a resonance phenomenon from a power conversion device provided with an active filter for electric railways.

It is a figure which shows an example of the system structure of the power conversion apparatus which includes the active filter for electric iron which concerns on this invention. It is a figure which shows the block structure in the control device of the active filter which concerns on Example 1. FIG. It is a figure which shows the equivalent circuit of the system configuration shown in FIG. It is a figure which shows the equivalent circuit which deformed the circuit shown in FIG. 3 paying attention to a fluctuation component. It is a figure which shows the equivalent circuit when the output current of the active filter shown in FIG. 4 is K times the electric wire current. It is a figure which shows an example of the frequency characteristic of the transfer function from the output voltage of an arm circuit to the output current of an active filter. It is a figure which shows the change of the frequency characteristic of a transfer function when only the inductance of a feeder system is changed. It is a figure which shows an example of the system configuration of the power conversion apparatus including the modification of the active filter shown in FIG. It is a figure which shows the block structure in the control device of the active filter which concerns on Example 2. FIG. It is a figure explaining the output voltage of the arm circuit during a dead time period. It is a figure which shows the graph when the gate signal is created by the common carrier wave. It is a figure which shows the graph in the case of using the carrier wave which gave the phase difference by a two-phase arm.

Hereinafter, a system configuration of a power conversion device to which the present invention is applied will be first shown, and then Examples 1 and 2 will be described with reference to the drawings as modes for carrying out the present invention. Those having the same reference number in each embodiment are shown as the same configuration requirements or configuration requirements having similar functions.
The configurations described below are presented as examples only, and the embodiments according to the present invention are not limited to the following examples.

FIG. 1 is a diagram showing an example of a system configuration of a power conversion device including an active filter for electric railways according to the present invention. In the following, the "active filter for electric railways" will be abbreviated as "active filter".
FIG. 1 shows a system of a power conversion device mounted on a railroad vehicle 500 traveling in a DC feeder section. The feeder system 200 is represented by an equivalent circuit as a series circuit of a DC power supply Vsys and an electric circuit (inductance component Ls). Further, the railroad vehicle 500 is electrically connected to the feeder system 200 via the pantograph 501 and the wheels 502.

The vehicle electric circuit 80 mounted on the railway vehicle 500 is mainly composed of a motor drive inverter 50 for driving the vehicle acceleration / deceleration motor 60, a smoothing capacitor 70, and an active filter 1. The active filter 1 is a motor drive inverter 50. Is connected in series with.

The active filter 1 has a transformer 7, a harmonic filter circuit 30, and an arm circuit 10 as main circuits, and a DC power supply 3 is connected to a DC portion of the arm circuit 10.
Further, the active filter 1 is connected to the electric circuit via the transformer 7. The harmonic filter circuit 30 is an LC filter composed of a reactor 5 and a filter capacitor 6.

Further, the active filter 1 includes a current sensor 20 for detecting the wire current Is and a current sensor 21 for detecting the output current Iout of the active filter 1 as a detection system. The detected values from the current sensors 20 and 21 are input to the control device 100 of the active filter 1.

The control device 100 calculates the output current command value of the active filter 1 based on the detected value of the current sensor 20, and reduces the deviation between the output current command value and the detected value from the current sensor 21. The gate signal of each semiconductor switching element in the U-phase arm 10u and the V-phase arm 10v in 10 is calculated.

Further, each of the U-phase arm 10u and the V-phase arm 10v in the arm circuit 10 is composed of a series circuit of IGBTs including diodes connected in antiparallel to form a single-phase inverter. However, although the semiconductor switching element included in each phase arm is shown as an IGBT, the present invention is not limited to this, and other self-extinguishing switching elements such as MOS can be used.

Next, as an embodiment of the present invention, the control device 100 that controls the active filter 1 will be described.
FIG. 2 is a diagram showing a block configuration (specific configuration including an arithmetic unit and the like) in the control device 100 of the active filter 1 according to the first embodiment.

The electric wire current Is detected by the current sensor 20 is input to the bandpass filter 1001. The band-passing filter 1001 extracts a frequency band component including a communication frequency band in the traveling section of the railway vehicle 500 from the detected value of the wire current Is, and outputs the frequency band component to the multiplier 1002. The multiplier 1002 multiplies the output of the passband filter 1001 by a positive constant, and outputs the product to the subtractor 1003 as an output current command value of the active filter 1.

The detected value of the output current Iout of the arm circuit 10 detected by the current sensor 21 is input to the subtractor 1003, and is input to the current controller 1004 in order to reduce the deviation from the output current command value, and the current controller 1004 is used. It works to reduce the deviation. In the first embodiment, the current controller 1004 is shown as a multiplier, but other compensating calculators such as a proportional / integrator and a differential / proportional / integrator may be used.

The output of the current controller 1004 is an output voltage command value of the active filter 1, and is input to the U-phase PWM calculator 1005U and the V-phase PWM calculator 1005V. Since the active filter 1 is a single-phase inverter composed of two-phase arms, an output voltage command value whose sign is inverted by the multiplier 1007 is input to the V-phase PWM calculator 1005V.

In the PWM calculators 1005U and 1005V, the input output voltage command value and the carrier wave calculator 1006 are compared in magnitude, and the gate signals (Gate UP and UN and Gate VP and VN) output to the U-phase arm 10u and the V-phase arm 10v are compared. ) Is calculated and output.

As described above, the active filter 1 according to the present invention operates in the current control system while being connected in series with the motor drive inverter 50 which is a noise source.

Next, a mechanism by which the motor drive inverter 50 can reduce the noise current flowing out to the feeder system 200 according to the present invention will be described with reference to FIGS. 3 and 4.

FIG. 3 is a diagram showing an equivalent circuit of the system configuration shown in FIG. In order to avoid complication of the explanation, here, the turns ratio of the transformer 7 is set to 1: 1.
The motor drive inverter 50 is expressed as a current source Iinv that outputs a noise current.

The transformer 7 is represented as a T-type equivalent circuit having leakage inductances L1 and L2 and mutual inductance Lm. That is, L1 is the leakage inductance of the feeder circuit side winding (primary winding), L2 is the leakage inductance of the secondary winding, and Lm is the mutual inductance of the transformer 7.
Ls is the inductance of the feeder system 200, Cfc is the capacitance of the smoothing capacitor 70, Lf is the inductance of the reactor 5, and Cf is the capacitance of the filter capacitor.
Further, the output voltage Vuv of the arm circuit 10 is expressed as a controllable voltage source.

The circuit shown in FIG. 3 is rearranged and deformed focusing on the variable component, and the result is shown as an equivalent circuit in FIG.
ΔVuv and ΔIinv are fluctuation components of the output voltage Vuv of the arm circuit 10 and noise components output from the motor drive inverter 50, respectively. The voltage source Vsys of the feeder system 200 was kept constant, and was deleted because it was not shown in FIG.

FIG. 5 shows an equivalent circuit when the output current Iout of the active filter 1 shown in FIG. 4 is K times the wire current Is. The voltage drop generated by the mutual inductance Lm of the transformer 7 is (1 + K) times as large as that in the case where only the wire current Is flows through Lm. This is equivalent to the mutual inductance Lm being (1 + K) times when the active filter 1 is expected from the feeder system 200 side. Therefore, the impedance is increased, and the same effect as suppressing the noise current from flowing out to the feeder can be obtained, and the noise current flowing out to the feeder system 200 can be suppressed. This is the principle of noise reduction by the active filter 1 according to the present invention.

As described above, if the active filter 1 can output a current K times that of the frequency band component to be noise-suppressed by the feeder current Is, the noise current flowing out to the feeder system 200 according to the above principle. Can be suppressed.

However, in reality, since the resonance circuit is formed by the harmonic filter circuit 10 in the active filter 1, the transformer 7, and the smoothing capacitor 70, the resonance in this resonance circuit may destabilize the current control. There is a risk that the noise current having a resonance frequency component will be amplified.

FIG. 6 is a diagram showing an example of the frequency characteristics of the transfer function from the output voltage Vuv of the arm circuit 10 to the output current Iout of the active filter 1.
Assuming that the railroad vehicle 500 is located in the immediate vicinity of the substation, the values shown in Table 1 are used as the numerical values of the circuit constants. Here, Rf, R2, and R1 indicate the resistance value of the reactor 5, and the resistance values of the secondary winding and the primary winding of the transformer 7, respectively. The numerical values shown in Table 1 are for explanatory purposes, and the present invention is not limited to these numerical values.

As can be seen from FIG. 6, the transfer function exhibits a characteristic having two resonance frequencies (resonance frequency 1 and resonance frequency 2). The resonance frequency 1 is a resonance frequency determined by the inductance Lf of the reactor 5, the leakage inductances L1 and L2 of the transformer 7, and the capacitance Cfc of the smoothing capacitor 70. The resonance frequency 2 is a resonance frequency determined by the inductance Lf of the reactor 5, the capacitance Cf of the filter capacitor 6, the leakage inductances L1 and L2 of the transformer 7, and the inductance Ls of the electric current system 200.

That is, assuming that the resonance frequency 1 is fr1 [Hz] and the resonance frequency 2 is fr2 [Hz], the following equation holds.
2πfr1 ≒ [1 / {(L1 + L2 + Lf + Ls) × Cfc}] ^0.5 (1)
2πfr2 ≒ [(L1 + L2 + Ls + Lf) / {(L1 + L2 + Ls) × Lf × Cf}] ^0.5 (2)

From the equation (1), the circuit constant of the active filter 1 according to the present invention is the resonance frequency 1 (fr1) when the inductance Ls = 0 of the feeder system 200 (for example, when the railroad vehicle is located directly under the substation). ) Is lower than the lower limit of the frequency band of the vehicle control communication signal, and the above L1, L2, Lf and Cfc are designed. By designing in this way, it is possible to avoid the problem of disturbance to the communication signal for vehicle control due to circuit resonance.

Further, it is also conceivable to set the resonance frequency 1 (fr1) higher than the frequency band of the vehicle control communication signal to avoid the disturbance to the vehicle control communication signal due to resonance, but the position of the railroad vehicle is As the distance from the substation increases, the two resonance frequencies (resonance frequency 1 and resonance frequency 2) both change.

FIG. 7 is a diagram showing changes in the frequency characteristics of the transfer function from Vuv to Iout when only the inductance Ls of the constant-constant electric system 200 used in FIG. 6 is changed. The solid line is the characteristic when Ls = 0 mH, the broken line is Ls = 2 mH, and the dotted line is Ls = 5 mH.

As can be seen from FIG. 7, as Ls increases, both the resonance frequency 1 (fr1) and the resonance frequency 2 (fr2) change to lower values. Since the transmission gain is maximized when the resonance frequency is 1 (fr1), in order to avoid disturbance to the vehicle control communication signal, the resonance frequency 1 (fr1) is the vehicle even if the position of the railcar changes. It is desirable that it does not overlap with the frequency band of the control communication signal. Therefore, under the condition of Ls = 0, the resonance frequency 1 (fr1) represented by the equation (1) may be lower than the lower limit of the frequency band of the vehicle control communication signal.

As described above, the active filter 1 according to the first embodiment has an effect of reducing the amount of noise current flowing out to the electric wire while avoiding the active filter itself from disturbing the vehicle control communication signal. is there.
In FIG. 1, the active filter 1 according to the present invention has been described as a single-phase inverter including two arms, but the active filter according to the present invention is not limited to the configuration of the single-phase inverter, for example. As shown in FIG. 8, the output wiring may be connected to the midpoint of the DC power supply (the connection point between the DC power supplies 3a and 3b). Even with this configuration, the same effect as described above can be obtained.

FIG. 9 is a diagram showing a block configuration (specific configuration including an arithmetic unit and the like) in the control device 100'of the active filter 1 according to the second embodiment. The difference between the active filter 1 according to the second embodiment and the active filter 1 according to the first embodiment on the left is only the configuration of the control device 100.

The difference between the arithmetic unit configuration of the control device 100 ′ adopted in the second embodiment and the control device 100 adopted in the first embodiment is that the control device 100 ′ of the second embodiment includes the delay circuit 1008, so that the U-phase PWM is provided. The point is that the carrier wave to the arithmetic unit 1005U and the carrier wave to the V-phase PWM arithmetic unit 1005V are out of phase.

With the above configuration, the output current distortion when the voltage amplitude output from the arm circuit 10 is small and the amplitude of the arm current Ic is near zero can be reduced, and as a result, the noise current flowing out to the wire can be increased. It can be avoided.

Next, the cause of the distortion of the output current and the mechanism capable of improving the distortion of the output current by the configuration of the second embodiment will be described.
Each of the U-phase arm 10u and the V-phase arm 10v has a configuration in which an IGBT and two diodes connected in antiparallel to the IGBT are connected in series. The IGBT has a finite time when switching the switching state. Therefore, in order to avoid a circuit short circuit via a DC circuit, dead time control is generally used, and an off command is input to both IGBTs, and after the IGBT that was in the ON state has surely transitioned to OFF, the other IGBT is used. It controls to send a short circuit command.

FIG. 10 is a diagram illustrating an output voltage of the arm circuit 10 during the dead time period. Since the off command is input to both the upper and lower IGBTs of the arm, the diode to be energized changes depending on the polarity of the current flowing out to the arm circuit 10, and as a result, the output voltage of the arm circuit 10 also changes.
For example, when the current flowing out from the arm circuit 10 is positive, the N-side diode is energized and the output voltage of the arm circuit 10 becomes negative (left figure in FIG. 10). On the contrary, when the flowing current is negative, the P-side diode is energized and the output voltage of the arm circuit 10 becomes positive (right figure in FIG. 10). When the outflow current is zero, both diodes are not energized, and the arm circuit 10 is in a high impedance state (center view of FIG. 10).

Since the output voltage of the active filter 1 according to the present invention depends on the noise current, the output voltage command of the arm circuit 10 also becomes a small value when the noise current is small.

Next, when the gate signals of the U-phase arm 10u and the V-phase arm 10v are calculated by a common carrier wave as in Example 1 and when calculated by a carrier wave having a phase difference as in Example 2. The output state of the arm circuit of the above will be described. FIG. 11 shows a case where a common carrier wave is used, and FIG. 12 shows a case where a carrier wave having a phase difference is used.

FIG. 11 is a diagram showing a graph when a gate signal is created with a common carrier wave.
From the top of the graph, the carrier wave, the modulated wave (U-phase modulated wave: Uref, V-phase modulated wave: Vref), the U-phase arm output voltage Vu, the V-phase arm output voltage Vv, and the output current i.

When the amplitude of the output voltage is small, Uref and Vref are values near zero. Therefore, for most of the time, the U-phase arm circuit output voltage Vu and the V-phase arm circuit output voltage Vv are equal.

It is assumed that the output current i is slightly flowing in the positive direction at time t0. The P-side IGBT is on for the U-phase and V-phase assemblies. Since the current is positive, the P-side voltage that is lower by the voltage drop in the IGBT is output to Vu, and the P-side voltage that is higher by the voltage drop of the diode is output to Vv. Therefore, the current i decreases toward the time t1.
When the current i becomes zero, no voltage drop occurs in the IGBT or diode. Since Vu and Vv are equal, the current is maintained at zero.

At time t2, since the V-phase modulated wave Vref intersects the carrier wave, both the P-side and N-side IGBTs of the V-phase are turned off during the dead time period Td. As described in FIG. 10, when the current i = 0, the assembly becomes high impedance during the dead time period.

At time t3, the V-phase dead time ends, but the U-phase becomes the dead time. Similarly, since the current i = 0 in the U phase, the U phase also has high impedance during the dead time period from the time t3.

The phenomenon of t1 to t3 is repeated at times t4 to t6. Therefore, even if the output voltage command value of the inverter is not 0, the current does not increase at all at time t0 to t6. This is the cause of the distortion of the output current due to the vicinity of the current zero cross of the active filter 1. When the output current of the active filter 1 remains zero, the noise current flowing out to the feeder system 200 increases.

At time t6, the output voltage was increased. As a result, the current i increases after the V-phase dead time (time t7-t8). In this way, current control can be realized only when the modulated wave is large without being affected by the current distortion.

FIG. 12 is a diagram showing a graph when a carrier wave having a phase difference between two-phase arms is used.
Since the output voltages of the U-phase arm 10u and the V-phase arm 10v occur at different times, the arm output current increases or decreases, and the zero current state does not continue. Since the modulated wave (Uref) of the U-phase arm is positive and the modulated wave (Vref) of the V-phase arm is negative, the current flowing from the U-phase to the V-phase increases. From this, it can be seen that a positive voltage is applied as the U-V line voltage as expected. From the above, the active filter 1 can avoid distortion of the output current.

Further, as shown in FIG. 12, by giving the carrier wave used in the two-phase arm a phase difference, the ripple current due to the switching frequency increases in the current flowing through the active filter 1. Therefore, if the arm circuit current Ic is used for the output current feedback for the current control performed by the control device 100', the output current command value also fluctuates with a ripple component, and further, the ripple of the arm circuit current Ic occurs. The current increases and the current control performance deteriorates.

In order to avoid this, in the output current control of the active filter 1, the current sensor 21 for detecting the active filter output current Iout is provided at the position shown in FIG. 1 instead of the output end of the arm circuit 10. Therefore, it is desirable to construct a current control system using the detected value of the current sensor 21.

As described above, the active filter 1 according to the second embodiment also reduces the amount of noise current flowing out to the electric wire while avoiding the active filter itself from disturbing the vehicle control communication signal, as in the first embodiment. It has an effect that can be reduced.

Further, in the control device 100', even when the output voltage amplitude of the arm circuit 10 is small and the output current of the arm circuit 10 is small by providing a phase difference between the carriers for the U-phase and V-phase arm circuit currents, The influence of output current distortion can be avoided, and the noise current flowing out to the electric wire due to the dead time of the active filter can be suppressed.

As shown in FIGS. 1 and 8, the active filter according to the present invention has a configuration in which it is connected to the wire side of the motor drive inverter. As a connection mode as an active filter, a configuration in which the motor drive inverter is directly connected to the rail side can be considered, but for the following reasons, a configuration in which the motor drive inverter is connected to the wire side as in the present invention is used. It is also desirable to surely achieve the desired effect of the present invention.

That is, the motor drive inverter is electrically directly connected to the vehicle acceleration / deceleration motor having a large stray capacitance with respect to the wheels directly connected to the rail. When the active filter is connected to the rail side of the motor drive inverter, the main circuit of the motor drive inverter has a potential different from that of the rail. Therefore, the risk that the switching element in the inverter via the stray capacitance described above causes a false call increases. In order to avoid such a risk, it is desirable to connect the active filter to the wire side of the motor drive inverter.

1 ... Active filter, 3 ... DC power supply, 5 ... Reactor, 6 ... Filter capacitor,
7 ... Transformer, 10 ... Arm circuit, 10u, 10v ... U-phase arm, V-phase arm,
20, 21 ... Current sensor, 30 ... Harmonic filter circuit, 50 ... Motor drive inverter,
60 ... motor, 70 ... smoothing capacitor, 80 ... vehicle electric circuit,
100, 100'... control device, 200 ... feeder system, 500 ... railroad vehicle,
501 ... pantograph, 502 ... wheels, 1001 ... bandpass filter,
1002, 1004, 1007 ... Multiplier, 1003 ... Subtractor, 1004 ... Current controller,
1005U, 1005V ... U-phase PWM calculator, V-phase PWM calculator,
1006 ... Carrier calculator, 1008 ... Delay circuit

Claims (13)

A transformer equipped with a smoothing capacitor and connected to the input side of the inverter that drives the vehicle acceleration / deceleration motor,
An arm circuit consisting of a series circuit of semiconductor switching elements and
A harmonic filter circuit connected in series between the arm circuit and the transformer,
A first current sensor for detecting a first current energizing between the harmonic filter circuit and the transformer is provided.
An active filter for electric railways, which controls a switching signal of the arm circuit based on the detection signal of the first current. The active filter for electric railways according to claim 1.
The transformer is an active filter for electric railways, characterized in that it is connected to a DC line from a power source of a DC feeder to an input side of the inverter. The active filter for electric railway according to claim 1 or 2.
An active electric railway characterized in that the resonance frequency of the resonance circuit composed of the transformer, the harmonic filter circuit, and the smoothing capacitor is lower than the frequency of the vehicle control communication signal for the vehicle equipped with the inverter. filter. The active filter for electric railway according to any one of claims 1 to 3.
A second current sensor for detecting a second current energizing between the direct current line and the inverter is provided.
An active filter for electric railways, characterized in that a command value with respect to an output current of the arm circuit is calculated based on the detected value of the second current. The active filter for electric railways according to any one of claims 1 to 4.
The arm circuit is composed of one or two sets of arms in which the semiconductor switching elements are connected in series as the series circuit, and receives a carrier signal for PWM control of the one or two sets of the arms by switching. An active filter for electric railways that is characterized by this. The active filter for electric railways according to claim 5.
An active filter for electric railways, characterized in that when the arm circuit is composed of the two sets of arms, the carrier signals for each of the two sets of arms are out of phase with each other. A power conversion device including the active filter for electric railways according to any one of claims 1 to 6 and the inverter. A railway vehicle equipped with the power conversion device according to claim 7. A transformer equipped with a smoothing capacitor and connected to the input side of the inverter that drives the vehicle acceleration / deceleration motor,
An arm circuit consisting of a series circuit of semiconductor switching elements and
A method for controlling an active filter for electric railways, which comprises a harmonic filter circuit connected in series between the arm circuit and the transformer.
Detecting the first current that energizes between the harmonic filter circuit and the transformer,
A method for controlling an active filter for an electric railway, which comprises controlling a switching signal of the arm circuit based on the detected value of the first current. The method for controlling an active filter for electric railways according to claim 9.
A method for controlling an active filter for electric railways, wherein the transformer is connected to a DC line from a power source of the DC feeder to an input side of the inverter. The method for controlling an active filter for electric railway according to claim 9 or 10.
An electric railway characterized in that the resonance frequency of the resonance circuit composed of the transformer, the harmonic filter circuit, and the smoothing capacitor is designed to be lower than the frequency of the vehicle control communication signal for the vehicle equipped with the inverter. How to control the active filter for. The method for controlling an active filter for electric railways according to any one of claims 9 to 11.
A second current that energizes the DC line from the power supply of the DC feeder to the input side of the inverter is detected.
A method for controlling an active filter for electric railways, which comprises calculating a command value for an output current of the arm circuit based on the detected value of the second current. The method for controlling an active filter for electric railways according to any one of claims 9 to 12.
When the arm circuit is composed of two sets of arms in which the semiconductor switching elements are connected in series as the series circuit, the switching signal for each of the two sets of arms is generated based on carrier signals having different phases from each other. A characteristic method of controlling an active filter for electric railways.

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