JPS6117234B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a power supply system for a linear motor, and particularly to a power supply system for reducing harmonic components of a power supply side current and reducing reactive power during operation of a power conversion device. Concerning an optimal linear motor power supply system.

[Conventional technology]

As a power supply system for the linear motor of a superconducting magnetic levitation type ultrahigh-speed railway, a method is used in which power is supplied from an AC power supply to a propulsion coil on the track side via a variable frequency output power converter.

The output voltage of the power converter is proportional to the speed of the moving object; when the speed of the moving object is low, the output voltage of the power converter is small, and as the speed of the moving object increases, the output voltage of the power converter increases. Become.

In this way, if the output voltage of the power converter can be adjusted over the entire speed range when the speed of the moving object varies from 0 to the rated speed, the small output voltage of the power converter in the low speed range of the moving object can be adjusted. In this range, the power factor is poor and the reactive power is large.

FIG. 1 is a block diagram showing a conventional example of a power supply system for an ultra-high-speed railway using a cyclone converter as a power conversion device. 3-phase AC power system
Power converter CC ₁ configured as a cyclone converter via power transformers T ₁ and T ₂ to SS,
The input side of CC ₂ is connected to this power converter
Feeder wires F ₁ and F ₂ are connected to the output sides of CC ₁ and CC ₂ . Then, a power switching switch receives the power from the feeder lines F ₁ and F ₂ and supplies it to the desired power feeding section of the propulsion coils LM ₁ to _{LM 6} on the track side.
Among SW ₁ to _{SW 6} , step-up transformers T 11 to T ₁₁ are connected in series with the power switching switches SW ₂ to SW ₆ and have different transformation ratios corresponding to the speed range of the traveling body T in each power supply section.
Insert each T ₁₅ .

[Problem that the invention seeks to solve]

With this circuit configuration, feeder wires F ₁ , F ₂
The power converters CC ₁ and CC ₂ that supply power to each power supply section have almost the same small control delay angle and can operate with a narrow control range and output voltage, so there is no problem of deterioration of power factor and increase of reactive power. It has the advantage of being able to significantly reduce
However, since step-up transformers T ₁₁ to _{T 15} having different transformation ratios are connected in series with each power switching switch SW ₂ to SW ₆ , there are problems such as an increase in cost and a large-sized ground equipment.

In a circuit in which the input side of a power conversion device is connected to an AC power source via a power transformer, the present invention provides a device that can vary the secondary voltage of the power transformer in accordance with the speed of a running body to generate reactive power. The purpose is to reduce the

〔Example〕

Hereinafter, the present invention will be described in detail based on specific examples.

FIG. 2 is a block diagram showing an embodiment of the present invention.

In Fig. 2, the propulsion coil of the linear motor is divided into propulsion coil units LM ₁ to LM ₆ for each section, respectively, and the feeder wires F ₁ and F ₂ are alternately and repeatedly connected to each other by power switching switches SW ₁ to SW ₆ . Connected. Power converters CC ₁ and CC ₂ are connected to each feeder line, and input sides of power converters CC ₁ and CC ₂ are connected to the AC power supply SS via transformers T ₁ and T ₂ .

Here, the operation of the circuit shown in FIG. 2 in the case where the filters FL ₁ , FL ₂ , the switching device S ₁ and the opening/closing command circuit G ₁ of the switching device S ₁ are not provided will be described.

SD is a speed detection device that detects the speed of _the traveling body T carrying the field F _; This is a small electric motor that varies the output voltage in proportion to Vn.

Assuming that the running body T is started from the first propulsion coil LM ₁ , the odd-numbered propulsion coils LM _{1 ,} LM ₃ , LM ₅ . . . counting from the propulsion coil LM 1 are power switching switches SW ₁ , SW _{3 ,} respectively. _, SW ₅ . . . , and _the even-numbered propulsion coils _{LM 2} , LM ₄ , _{LM 6 .} and receive power from the other feeder line _F2 .

The power switching switches SW ₁ to SW ₆ . . . are opened and closed depending on the position of the traveling body T so that power is supplied to only one or two propulsion coils where the traveling body T is present each time.

Transformers T ₁ and T ₂ with induced voltage regulators
The respective secondary side voltage V ₂ and the speed V of the traveling body T
The characteristics with respect to changes are as shown in FIG. The secondary side small output voltage V ₂ min of each of the transformers T ₁ and T ₂ is a voltage enough to start the traveling body T, and after the traveling body T has started, it is approximately proportional to the speed V of the traveling body T. The speed detection device is configured such that the secondary voltage V ₂ of each of the transformers T ₁ and T ₂ is varied.
The small electric motor A is varied by the output voltage Vn of the SD.

On the other hand, linear motor (propulsion coil LM ₁ ~ LM ₆ )
The induced voltage is generated in proportion to the speed V of the traveling body T.

That is, when the speed V of the traveling body T is low, the secondary voltage V ₂ of each of the transformers T ₁ and T ₂ is also low.
Therefore, the output voltage of the power converter CC ₁ or CC ₂ becomes approximately the same as the induced voltage of the linear motor, so the power factor is significantly increased compared to the state where the secondary voltage V ₂ of each transformer T ₁ and T ₂ is not varied. It is possible to significantly reduce reactive power.

In addition, in Figure 1, there is one less transformer with a different transformation ratio than the propulsion coil divided into multiple pieces, whereas in Figure 2, an induced voltage regulator is used as transformers T ₁ and T ₂ . Since it is only used, the installation on the ground becomes small and inexpensive.

As described above in detail, according to the embodiment of the present invention shown in FIG. 2, the power switching device
Since the output voltage of CC ₁ or CC ₂ becomes comparable to the induced voltage of the linear motor (propulsion coil), it has the effect of significantly reducing reactive power and improving the power factor.

In the embodiment shown in FIG. 2, when the traveling body is running astride two propulsion coils, that is, when the tip of the traveling body T is at time _t1 , the traveling body T is present in the propulsion coil _LM1 . Therefore, it is natural that power converter CC ₁ is operating, but power converter CC ₂ is also operated in order to prepare for the traveling body T to enter the next propulsion coil LM ₂ . Most of the power supplied from the power converter CC ₂ to the propulsion coil LM ₂ becomes reactive power, and there are problems such as the inability to compensate for this.

A second embodiment of the present invention devised to solve this problem is shown in FIG. A ₁ and A ₂ are small electric motors used to vary the induced voltage regulators when they are used as transformers _{T 1} and _{T 2 ,} respectively. is given, the transformers T ₁ and T ₂ rotate forward to increase their respective secondary voltages V ₂ ,
Also, if a command is given to the input 2 side, the transformer
A circuit configuration that rotates in reverse to reduce the secondary voltage V ₂ of each of T ₁ and T ₂ , and when commands are given to both input 1 and 2 sides, the command given to input 2 side takes priority. And so.

B ₁ and B ₂ are voltage detection devices for detecting the secondary side voltages V ₂ of the transformers T ₁ and T ₂ , _respectively . It is shown in Figure 5. C ₁ and C ₂ are AND circuits that output when both inputs are 1, and do not output otherwise. D ₁ is an even-numbered propulsion coil LM ₂ , LM ₄ , LM ₆ ... and the next propulsion coil
LM ₃ , LM ₅ ..., that is, the even-numbered propulsion coil for the length of the traveling body T from the section crossing.
LM ₂ , LM ₄ , LM ₆ ... Period from the point of approach to section crossing, that is, t ₃ to _{t 4} , t ₉ to t ₁₀ , t ₁₅ to _{t 16}
Although not shown in the figure, this is a signal circuit that outputs an output based on a signal generated from the track side. D ₂ is the period from the activation command of the power converter CC ₂ for feeding power to the even-numbered propulsion coils LM ₂ , LM ₄ , LM ₆ . . . to the length of the traveling body T, that is, t ₁ to t ₂ , t ₇ ~ _t8 ,
Although not shown, this is a signal circuit that outputs an output using a signal generated from the track side during periods t ₁₃ , t ₁₄ . . . . _D3
is the crossing between the odd-numbered propulsion coils LM ₁ , LM ₃ , LM _{5 .} . . and the next propulsion coils LM ₂ , LM ₄ , LM ₆ . ₁ , LM ₃ , LM ₅ ...The period from the point of approach to the crossing of the section, that is, t ₀ ~
Although not shown, this is a signal circuit that outputs an output based on a signal generated from the track side during periods t ₁ , t ₆ to t ₇ , t ₁₂ , t ₁₃ . _D4 is the odd-numbered propulsion coil LM ₁ , LM ₃ ,
The period from the activation command of the power converter CC ₁ for supplying power to LM ₅ to the length of the traveling body T, that is,
Although not shown, this is a signal circuit that outputs an output using a signal generated from the track side during the periods _t4 to _t5 , _t10 to _t11 , _t16 , _t17 , . . . E ₁ and E ₂ are subtractors, and SD' is the secondary voltage V of each of the transformers T ₁ and T ₂ when the propulsion coils LM ₁ to LM ₆ ... cross sections according to the speed of the traveling body T. ₂ to the characteristic shown by the broken line in FIG. 3, and the characteristic of its output voltage V ₂ '' with respect to changes in the speed v of the traveling body R is shown by the broken line in FIG. d ₁ to _{d 4} are diodes, and other signals are shown with the same symbols as in the respective circuits of FIG. 1 and FIG. 2, so their explanation will be omitted.

Next, the filters FL ₁ ,
FL ₂ , switchgear S ₁ and switchgear S ₁ switching command circuit
The operation of the circuit shown in FIG. 4 when G ₁ is not provided will be explained. First, the converter quantity E ₁ that subtracts the output voltage of the setting circuit SD' and the output voltage of each of the voltage detection devices B ₁ and B ₂ will be explained. and explain the operation of E ₂ .

For example, when the traveling body T reaches time t ₀ , it is assumed that the traveling body T is accelerating to some extent, and the subtracter
To explain the operation of E ₂ , the secondary voltage V ₂ of each of the transformers T ₁ and T ₂ is set according to the speed of the traveling body T until the traveling body T reaches time t ₀ , so that the traveling body T is propelled. Since the output voltage of power converter CC ₁ feeding power to coil LM ₁ and the induced voltage of propulsion coil LM ₁ are approximately the same, voltage detection devices B ₁ and B ₂
The output voltage V ₂ ' has the characteristics shown by the solid line in FIG.

On the other hand, since the output voltage V ₂ '' of the setting circuit SD' has the characteristics shown by the broken line in Figure 5, the voltage detection device
Since a deviation occurs between the output voltages V ₂ ' of B ₁ and B ₂ , the subtracters E ₁ and E ₂ output their respective outputs.

In this state, when the traveling body T reaches time t ₀ , the signal circuit D ₃ outputs an output in response to a signal from the track side (not shown), and the AND circuit C ₂ outputs _an output. Since the command is given, the small electric motor A ₂ rotates in reverse so as to reduce the secondary voltage V ₂ of the transformer T ₂ .

Then, the small electric motor _A2 continues to rotate in reverse until the traveling body T reaches the time _t1 , and stops when the traveling body T reaches the time _t1 , and the signal circuit _D3 does not output any output after that. Since no command is given from the output of the AND circuit AC ₂ on the 2 side of the small motor A ₂ , the output voltage Vn of the speed detection device SD causes the small motor A ₂ to
rotates in the forward direction, increasing the secondary voltage V ₂ of the transformer T ₂ .

Here, to explain why the output voltage V ₂ '' of the setting circuit SD' is set as shown by the broken line in FIG. In order to reduce the reactive power of the power converter that supplies power to the propulsion coil from just before the traveling body T enters the propulsion coil, compared to the case where the secondary side voltage of each of the main voltage regulators _T1 and _T2 is not varied at the time of section crossing. It is a means.

When the output voltage of the setting circuit SD′ is set to V ₂ min′,
Although the reactive power during section crossing becomes smaller,
The effective power required to run the traveling body T decreases, the thrust pulsation during section crossing increases, and when the speed V of the traveling body T is high, each of the transformers T ₁ and T ₂ is Next side voltage V ₂ ′
Problems arise such as the impossibility of reducing to V ₂ min.

When the traveling body T reaches time _t1 , the signal circuit _D2 outputs an output in response to a signal from the track side (not shown), and the AND circuit _C1 outputs an output, so the small electric motor _A1
Since a command is given to the second side of the motor _A1 , the small electric motor _A1 rotates in the opposite direction so as to reduce the secondary voltage _V2 of the transformer T1. Then, the small electric motor _A1 continues to rotate in reverse until the traveling body T reaches time _t2 , and stops when the traveling body R reaches time _t2 , and from then on, the small electric motor A1 continues to rotate in reverse until the traveling body T reaches time _t2.
does not output any output, so the small electric motor A ₁ rotates in the forward direction due to the output voltage Vn of the speed detection device SD, and the transformer T ₁
Increase the secondary voltage V ₂ of .

As the traveling body T advances, the signal circuits D ₁ to _{D 4} individually output outputs when crossing sections to vary the secondary voltage V ₂ of the transformers T ₁ and T ₂ , as shown in FIG. 6. This is the operating waveform diagram.

As explained in detail above, according to the embodiment shown in FIG. 4, the secondary voltage of the transformer is varied according to the speed of the traveling body, and even when crossing sections, the secondary voltage of the transformer is controlled by a signal from the track side. Since the voltage is varied according to the set voltage, the reactive power under normal running conditions is significantly reduced, the power factor is improved, and fluctuations in reactive power during section crossing can be reduced. be.

The circuits in Figures 2 and 4 also include filters FL ₁ and
The operation in the case where FL ₂ etc. are not provided has been explained, but the operation in that part when these are provided will be explained next.

First, use the circuits shown in Figures 2 and 4 to connect the filter FL _1.
To explain the problems when not installing FL ₂ , etc., there are cases where power is supplied directly from a commercial frequency AC power supply to the propulsion coil on the orbit side via a power conversion device, and when power is supplied from a dedicated AC generator to a power conversion device. In either case, the AC input power source of the power converter modulates the amplitude by the output current, producing many fractional harmonics and harmonics in addition to the fundamental wave. It is well known that the filters FL 1 and FL 2 are not provided, and if the filters FL ₁ and FL ₂ are not provided, these harmonic currents will flow out to the power supply side, causing problems such as induction disturbances in communication lines and the like.

Frequency fh of harmonic current generated by power converter
is generally expressed as:

fh=kf ₁ ±2nf. ...(1) However, f ₁ : Power supply frequency f ₀ : Output frequency k: 1 and 6m±1, m=1,2,
… n: 0, 1, 2, … When the power conversion device operates, as is known from the second term on the right side of equation (1), irregular harmonics of the power supply frequency appear, and the output frequency f ₀ is It is necessary to consider that the frequency spectrum of harmonics changes continuously because it changes depending on the speed of the harmonic.

When a dedicated AC power supply is used as an AC power source for a power converter, the harmonic frequency shown by equation (1)
The rotor is the part that most affects the operating limits of the alternator when the fh current flows out to the AC power supply side during power converter operation, and the rotor is also the part that has the greatest effect on the operating limit of the alternator. Since the current at the harmonic frequency fh shown in equation (1) is regulated by The loss due to negative sequence current is calculated as follows. That is, loss due to harmonic current = ΣKfh/fp・Ih ² … (2) Loss due to negative sequence current = Kfp′/fp・I′p ₂ … (3) where, K: constant fh: harmonic frequency ((1 ) formula) fp: Fundamental frequency Ih: Harmonic current fp': Frequency for negative phase component (generally twice the fundamental frequency fp) Ip': Negative sequence current (=I'peq) In the formula (2), If each equation in equation (3) is equal and fp′=2fp(2), substituting it into each equation (3) and rearranging it, ΣKfh/fp・Ih ² =K2fp/fp・I′peq ² …(4
) From the formula, the equivalent negative sequence current I'peq is expressed as I'peq=Σ( ⁴ kf ₁ ±2nf ₀ /2fp·Ih) ² .

On the other hand, when a commercial frequency is used as the AC power source for a power converter, if the current at the harmonic frequency fh shown in equation (1) flows to the AC power source during operation of the power converter, it may cause inductive disturbances in communication lines, etc. The equivalent disturbance current Jp expressed by the following equation is used as a relational expression to consider the occurrence. That is, Jp=Σ(SnIn) ² (6) where Sn: Noise evaluation coefficient of voltage at frequency fn In: Represented by current component at frequency fn.

In other words, when a dedicated AC generator is used as an AC power source, disturbances due to harmonic currents on the AC power supply side that occur during the operation of a power converter are evaluated by the equivalent negative sequence current I'peq; When using , it is evaluated by the equivalent disturbance current Jp.

The inventors used a large-scale power converter to keep the current command signal constant, and analyzed the frequency spectrum of continuous harmonics from the current waveform on the power supply side of the power converter during power running of a linear motor, and calculated the equivalent disturbance current.
As a result of calculating Jp, as shown in Fig. 7, it becomes large in the low speed range and high speed range, and becomes minimum in the medium speed range.

Here, the reason why the equivalent disturbance current Jp becomes large in the low speed range is because the induced voltage of the linear motor is small, so the current supplied from the AC power supply to the power converter increases, and each harmonic current increases accordingly. Also, the reason why the equivalent disturbance current Jp became large in the high-speed range is because the sideband currents of the fundamental frequency fp and integer harmonics became large due to the influence of the induced voltage of the linear motor. .

In order to reduce the current at the harmonic frequency fh shown in equation (1) above, connect a high-order reduction filter, such as the one shown in Figure 8, which is used in DC transmission systems, to the AC power supply side, for example. Although it is necessary, it is uneconomical to connect the high-order reduction filter shown in Fig. 8 until the operating state where the traveling body straddles two propulsion coils with the characteristics shown in Fig. 7 is uneconomical. .

Specific examples for solving this problem are circuits such as filters FL ₄ and FL ₂ shown in FIGS. 2 and 4, and the operations of these circuits will be explained.

Harmonic current on the AC power supply side SS when at least two power converters CC ₁ and CC ₂ operate alternately to supply power to multiple sections of propulsion coils LM ₁ to LM ₆ via switches SW ₁ to SW ₅ A first reduction filter FL ₁ ,
When the traveling body is traveling astride two propulsion coils, at least two power converters CC ₁ ,
CC ₂ is equipped with a second filter FL ₂ for reducing harmonic current of the AC power supply side SS when the CC 2 operates simultaneously and supplies power to different propulsion coils, the first filter FL ₁ is always operated, and the second filter The filter FL ₂ is an economical and efficient filter that operates only when the propulsion coil section crosses, and is a circuit system that can reduce harmonic current on the AC power supply side.

The switching command circuit G ₁ issues a command to close the switching device S ₁ when each of the power converters CC ₁ and CC ₂ issues a gate start command, and the power converter
This circuit issues a command to open/close switchgear _S1 when either CC ₁ or CC ₂ issues a gate block command, and opens/closes switchgear _S1 when switching command circuit _G1 outputs an output. Filter FL ₂ is connected to the AC power supply side SS, and when the switching command circuit G ₁ does not output an output, the switching device S ₁ is opened and the filter FL ₂ is not connected to the AC power supply side SS, and the filter FL ₂ is The filter is economical because it is activated only when the section crosses, and its efficient filter structure has the effect of reducing harmonic current on the AC power supply side.

Figure 7 shows the characteristics of the equivalent disturbance current Jp when a commercial frequency is used as the AC power supply SS, and the equivalent negative sequence current I'peq when a dedicated AC generator is used as the AC power supply SS. It goes without saying that the circuits of FIGS. 2 and 4 can reduce the equivalent negative-sequence current I'peq since the characteristics are similar to those of FIG. 7.

In each of the embodiments shown in FIGS. 2 and 4, a first filter that operates at all times regardless of the current command signal and the speed of the traveling object, and a second filter that operates only when crossing sections are installed to convert power. We have described the circuit configuration that reduces harmonic current on the AC power supply side during device operation, but as shown by the solid and broken lines in Figure 7, the equivalent disturbance current Jp changes approximately in proportion to the magnitude of the current command signal. Therefore, in a range where the current command signal is small, problems arise such as the capacities of each of the first and second filters becoming large.

Other embodiments of the present invention for solving this problem are shown in FIGS. 9 and 10. The circuit configuration for reducing reactive power in Figure 10 is the same as the circuit in Figure 2, and the circuit configuration for reducing reactive power in Figure 10 is the same as the circuit in Figure 4. The explanation of the operation will be omitted.

First, to explain the symbols of the circuits in FIGS. 9 and 10, E ₃ to E ₅ are subtracters, H is subtracters E ₄ and E ₅
An OR circuit that outputs an output when one or both output, If is the current value of the current command signal, Ip is the reference current, and _C3 is the output from both the subtracter _E3 and the OR circuit H. _G2 is an AND circuit that outputs an output when _{C3 outputs} an output, and does not output otherwise. When C ₃ does not output, the opening/closing command circuit of the switching device S ₂ issues a command to open the circuit of the switching device S _2. Vn ₁ is the speed v of the traveling body T.
is the reference voltage corresponding to the case where, for example, v ₁ is shown in FIG. 7, Vn ₂ is the reference voltage corresponding to the case where the speed v of the traveling object T is, for example, v ₂ shown in FIG. 7, d ₅ , d ₆ is a diode, and FL ₃ is a filter that can be connected to or disconnected from the AC power supply SS by opening and closing the switchgear S _2. Other symbols are shown with the same symbols as the circuits in Figures 2 and 4, so they will not be confused with each other. Explanation will be omitted.

Since the harmonic current reduction circuit configurations in FIGS. 9 and 10 are the same, the operation of the circuit in FIG. 9 will be explained.

As shown by the broken line in Fig. 7, the filter FL ₁ has a capacity sufficient to keep the equivalent disturbance current Jp or the equivalent negative sequence current I'peq below the permissible value in the speed range _v1 to _v2 of the traveling body T. and filter FL ₂ is the second
As with the respective circuits in Figures and Figure 4, the capacity is set to a level that suppresses the increase in equivalent disturbance current J or equivalent negative sequence current I'peq due to the increase in power supply current during section crossing, and the current value If is the rated value. Set by current.

On the other hand, filter FL ₃ is used when the speed v of the traveling body T is less than v ₁ or more than v ₂ , and the current value If is 50% of the rated current.
% or more (if the current value If is less than 50%, as shown by the solid line in Fig. 7, filter FL ₁ reduces the equivalent disturbance current Jp or equivalent negative sequence current Ipeq and the traveling body T).
The capacity can be set to such an extent that the equivalent disturbance current Jp or the equivalent negative sequence current I'peq in the shaded range in FIG. 7 can be controlled to be below the allowable value in the entire speed range.

To explain the operation of the circuit shown in Fig. 9 when the filters FL ₂ to FL ₃ are set as described above, if 50% of the rated current is given as the reference current Ip, the current value If becomes 50% of the rated current. % or less, the subtracter E ₃ does not output, so even if the OR circuit H outputs an output, the AND circuit C ₃ does not output, so the open/close command circuit G ₂ outputs no output. I don't give out. Therefore, the switchgear S ₂ is not closed, but the filter FL ₁ , which is constantly operating in this state,
Therefore, it is safe because the equivalent disturbance current Jp or the equivalent negative sequence current I' becomes less than the allowable value.

In addition, when the traveling body T enters the section crossing between the two propulsion coils in this state, the switching device _S1 is closed by the output of the opening/closing command circuit _G1 , so the filter _FL2 is connected to the AC power supply SS, and the section crossing Due to the increase in current of AC power supply SS at
It is safe because the increase in Jp or I'peq is controlled by the filter FL ₂ to keep Jp or I'peq below the allowable value.

On the other hand, if the current value If is 50% or more of the rated current,
If the speed v of the traveling body T is less than _v1 , the output voltage Vn of the speed detection device SD is lower than the reference voltage _Vn1 , so the subtractor _E4 outputs an output, so the OR circuit H outputs an output, and the current Since the value If is greater than the reference current Ip, the subtracter E ₃ outputs an output, so the AND circuit C ₃
outputs an output, so the switching device S ₂ is closed by the switching command circuit G ₂ , so the filter FL ₃ is connected to the AC power supply SS.
It is safe because Jp or I′peq will be below the allowable value. In this state, when the traveling body T enters when crossing the section, the switching device S ₁ is closed by the output of the opening/closing command circuit G ₁ , so that the filter FL ₂ is connected to the AC power supply SS, and when crossing the section Jp
Or, when I′peq is made below the allowable value and the traveling body T moves to the next propulsion coil, the opening/closing command circuit G ₁
Even if the opening/closing device S ₁ is opened or closed, it is safe because the filters FL ₁ and FL ₃ keep Jp or I'peq below the allowable value.

In this state, when the speed v of the traveling body T falls within the range of v ₁ to _{v 2} , the output voltage Vn of the speed detection device SD is higher than the reference voltage Vn ₁ and lower than the reference voltage Vn ₂ , so the subtracter E ₄ Since neither E5 nor _E5 output, the OR circuit H does not output an output, so the AND circuit
Since C ₃ no longer outputs output, switchgear S ₂ is opened, but Jp or I'peq is maintained at the allowable value by filter FL ₁ , which is always active, and by propulsion coils FL ₁ and FL ₂ during section crossing. It is safe because it is as follows.

As explained in detail above, FIGS. 9 and 10
According to the embodiment shown in the figure, the first filter for reducing harmonic current of an AC power supply when at least two power converters are operating independently, and the running body running astride two propulsion coils. a second filter for reducing harmonic current of the AC power supply when at least two power converters operate simultaneously to supply power to different propulsion coils, and a traveling body at a certain speed or below or above a certain speed. and the third harmonic current reduction of the AC power supply when the current command signal is running at a certain current value or more.
The first filter is always activated, the second filter is activated only when crossing a section, and the third filter is activated only within a certain speed range of the traveling object and within a certain current command signal range. This is an economical and efficient filter that reduces harmonic current on the AC power supply side and allows equivalent disturbance current or equivalent negative sequence current in the entire speed range of the traveling vehicle and in all operating conditions of the power converter. It has the effect of being able to be lower than the value.

Furthermore, the high-order reduction filters shown in FIG. 8 are used as the filters FL ₁ and FL ₂ of the circuits in FIGS. 2 and 4, and the filters FL ₁ to FL ₃ of the circuits in FIGS. 9 and 10, respectively. , and one filter is provided for each phase on the power supply side of the power conversion device. However, the present invention is not limited to this, and various filter circuits or a plurality of filters may be used. It goes without saying that the present invention is also applicable to such a case.

In the embodiment shown in FIG. 2, since the secondary voltage of the transformer is varied according to the speed of the traveling object, the reactive voltage is significantly reduced, the power factor is improved, and the first filter is constantly activated. The second filter is activated only when crossing the section, making it economical.
Moreover, it has the effect of reducing harmonic current of the AC power source with an efficient filter configuration. In addition, in the embodiment shown in Fig. 4, the secondary voltage of the transformer is varied according to the speed of the traveling body, and the secondary voltage of the transformer is also varied according to the set voltage when crossing sections, so that normal running is possible. It is economical and efficient because the first filter is activated all the time and the second filter is activated only when the section is crossed. A good filter configuration has the effect of reducing harmonic current of an AC power supply.

Furthermore, in the embodiment shown in FIG. 9, since the secondary voltage of the transformer is varied according to the speed of the traveling object, reactive power is significantly reduced and the power factor is improved. A filter, a second filter that is activated only when crossing sections, and a third filter that is activated only within a certain speed range of the traveling object and within a certain current command signal range, making it economical.
In addition, the highly efficient filter configuration has the effect of reducing harmonic current of the AC power supply. Also the first
In the embodiment shown in Fig. 0, the secondary voltage of the transformer is varied according to the speed of the traveling body, and the secondary voltage of the transformer is also varied according to the set voltage when crossing sections, so that it can be used in both normal running conditions and A first filter that significantly reduces reactive power when crossing sections and improves the power factor, and is always activated, a second filter that is activated only when crossing sections, and a traveling body within a certain speed range. In addition, the third filter, which is activated only within a certain range of current command signal, has the effect of reducing the AC harmonic current of the AC power source with an economical and efficient filter configuration.

That is, Figures 2, 4, 9 and 10
According to each of the embodiments in the figures, it is possible to reduce reactive power and improve the power factor with a simple circuit configuration, and also to reduce harmonic current on the AC power supply side with an economical and effective filter. There are effects such as

The above describes the case where the present invention is applied to a power supply system for a linear motor of an ultra-high-speed railway.
The present invention is not limited only to ultra-high-speed railways, but can also be widely applied to power supply devices that require variable frequency AC output and circuit configurations that eliminate adverse effects on AC power systems, such as voltage flicker.

In addition, in each embodiment, an example was shown in which power is supplied directly from a commercial power supply to the propulsion coil on the track side via the power converter, but in other cases, a dedicated AC generator is used to feed the propulsion coil via the power converter. The present invention can also be applied to a power feeding system.

〔Effect of the invention〕

As is clear from the above, according to the present invention, it is possible to reduce the reactive power and harmonic current of the power supply system.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional linear motor power supply system, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a characteristic diagram of a transformer according to the present invention.
FIG. 4 is a block diagram showing another embodiment of the present invention;
Fig. 5 is a characteristic diagram of the voltage detection device and setting circuit in the embodiment shown in Fig. 4, Fig. 6 is an operation waveform diagram of each part in the embodiment shown in Fig. 4, and Fig. 7 is an equivalent disturbance current with respect to a change in the current command signal. Fig. 8 is a circuit diagram of a general high-order resistance filter, Fig. 9 is a block diagram showing a third embodiment of the present invention, and Fig. 10 is a fourth embodiment of the present invention. FIG. A, A ₁ , A ₃ ... Small electric motor, B ₁ , B ₂ ... Voltage detection device, C ₁ to _{C 3} ... AND circuit, D ₁ to D ₄ ...
Signal circuit, CC ₁ ~ CC ₂ ... Power converter, E ₁ ~ E ₅
...Subtractor, F ₁ ~ F ₂ ... Feeder line, FL ₁ ~ FL ₃ ...
Filter, G ₁ , G ₂ ... Opening/closing command circuit, H ... OR circuit, LM ₁ to _{LM 6} ... Propulsion coil, SS ...
AC power supply, SW ₁ to SW ₆ ... Power switching switch, S ₁ ,
S ₂ ...Switching device, SD...Speed detection device, SD′...
Setting circuit, T...running body, _T1 , _T2 ...transformer.

Claims (1)

[Claims] 1. A multi-section propulsion coil installed on the track side,
A switch is connected to each of these propulsion coils, and the propulsion coils of the plurality of divisions are divided into at least two groups, odd-numbered and even-numbered, and each of these is connected to a transformer connected to an AC power source, and the transformer is connected to a switch. In a power supply system for a linear motor that connects a system consisting of a power converter connected to a power converter, alternately energizes the propulsion coils of the multiple sections, and supplies power to the range where the traveling body is present by the switch, the AC power source a first filter connected to;
A second connected to the AC power source via a switchgear
a command to close the switchgear when the two power converters are activated, and a command to open the switchgear when either of the two power converters is gated off. a speed detection device for detecting the speed of the traveling body; and a second means for varying the secondary voltage of the transformer according to the output voltage of the device. Features a linear motor power supply system. 2. In the power supply system for a linear motor according to claim 1, the second means is a circuit that can simultaneously vary the secondary voltage of each of the at least two transformers according to the speed of the traveling body. A power supply system for a linear motor characterized by the following configuration. 3. In the power supply system for a linear motor according to claim 1, the second means is configured to supply power to the propulsion coil while sequentially switching the switches, and to supply power to each of the at least two transformers. A power supply system for a linear motor characterized by a circuit configuration that allows side voltages to be individually varied. 4 A multi-section propulsion coil installed on the track side, a switch connected to each of these propulsion coils, and dividing the multi-section propulsion coil into at least two groups, odd-numbered and even-numbered, and each of these A system consisting of a transformer connected to an AC power supply and a power conversion device connected to the transformer is connected to the transformer, and the propulsion coils of the multiple sections are alternately energized, and the switch is used to close the range where the traveling object is present. In a power supply system for a linear motor that supplies power to a linear motor, a first filter connected to the AC power supply;
A second filter connected to the AC power source via the first switching device, a third filter connected to the AC power source via the second switching device, and the two power converters. When started, the above first
a first means for issuing a command to close the first switching device and a command to open the first switching device when either of the two power converters is gated off; A speed detection device for detecting the speed, a second means for varying the secondary voltage of the transformer according to the output voltage of the device, and a first comparison device for comparing the output voltage of the speed detection device with a reference voltage. a second comparison device that compares a current command signal for controlling the output current of the power converter with a reference current command; and a second comparison device that compares the output current of the first comparison device and the second comparison device. A linear motor comprising an AND circuit that outputs an output when the AND circuit outputs an output, and third means that issues a command to close the second switching device only when the AND circuit outputs an output. power supply system. 5. In the power supply system for a linear motor according to claim 4, the second means is a circuit that can simultaneously vary the secondary voltage of each of the at least two transformers according to the speed of the traveling body. A power supply system for a linear motor characterized by the following configuration. 6. In the power supply system for a linear motor according to claim 4, when the second means is used to supply power to the propulsion coil while sequentially switching the switches, each of the at least two transformers is A power supply system for a linear motor characterized by a circuit configuration that allows the next-side voltage to be individually varied.