JP5501996B2 - Ripple voltage suppression device and power conversion device - Google Patents

Description

  The present invention relates to a ripple voltage suppression device and a power conversion device.

  As a ripple voltage suppression device in a power conversion device that converts AC power into DC power, a DC reactor device having an iron core, a main winding and an auxiliary winding wound around the iron core, the main winding is a three-phase bridge rectifier It is provided so as to be inserted between the load and the current flowing through the main winding is detected using a DC current detection circuit, and the compensation voltage for compensating the DC ripple of the main winding is compensated by the voltage source in the auxiliary winding. There is a high-frequency suppression control device that applies and generates a magnetic flux in a direction that cancels a DC ripple in an iron core to cancel the DC ripple of a main winding (see, for example, Patent Document 1).

JP 2002-272113 A (paragraph numbers 0036 to 0071, FIGS. 1 and 6)

  Since the conventional ripple voltage suppression device is configured as described above and detects the load current flowing through the main winding using the DC current detection circuit, a DC current detection circuit such as a DC current transformer is separately required. In addition, since a load current flows through the DC current transformer, the power loss increases. In addition, since the number of devices through which the load current flows is increased, the ripple voltage suppression device as a whole is limited in size.

  The present invention has been made to solve the above-described problems, and an object thereof is to obtain a ripple voltage suppressing device and a power conversion device that can reduce power loss and can be reduced in size.

In the ripple voltage suppressing device according to the present invention,
A second electric device having a voltage detecting means, a filter, a voltage amplifier, a voltage compensating transformer, and a ripple voltage corresponding turns ratio changing means, and connected to a first electric device and a DC terminal of the first electric device; A ripple voltage suppression device inserted between the device,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding in all SANYO compensation voltage for reducing the ripple voltage is generated,
The ripple voltage corresponding turns ratio changing means changes the turns ratio between the main winding and the auxiliary winding of the voltage compensating transformer according to the ripple voltage.

And in the ripple voltage suppression device according to the present invention,
A voltage detecting means, a filter, a voltage amplifier, a voltage compensating transformer, an input electric quantity detecting means, and an input electric quantity corresponding winding ratio changing means; and a first electric device and a DC terminal of the first electric device A ripple voltage suppressing device inserted between a second electrical device to be connected,
The first electric device is an AC-DC converter,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The input electric quantity detection means detects input current or input power of the first electric device,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding A compensation voltage for reducing the ripple voltage is generated in
The input electric quantity corresponding turn ratio changing means changes the turn ratio between the main winding and the auxiliary winding of the voltage compensating transformer according to the input current or the input power.

Furthermore, in the ripple voltage suppression device according to the present invention,
A voltage detecting means, a filter, a voltage amplifier, a voltage compensating transformer, an input electric quantity detecting means, and an input electric quantity corresponding control means, and connected to the first electric device and a DC terminal of the first electric device; A ripple voltage suppression device inserted between the second electrical device and
The first electric device is an AC-DC converter,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The input electric quantity detection means detects input current or input power of the first electric device,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding A compensation voltage for reducing the ripple voltage is generated in
The input electric quantity correspondence control means stops the operation of the voltage amplifier when the input current or the input power is equal to or lower than a predetermined set value.

  In the ripple voltage suppression device according to the present invention,
A voltage detection means, a filter, a voltage amplifier, a voltage compensation transformer, and a first detection voltage correspondence control means; a second electrical device connected to the first electrical device and a DC terminal of the first electrical device; A ripple voltage suppression device inserted between the electrical device,
The second electric device is capable of regenerating electric energy,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding A compensation voltage for reducing the ripple voltage is generated in
The first detection voltage correspondence control means stops the operation of the voltage amplifier when the detection voltage becomes larger than a predetermined first value due to regeneration of the electric energy from the second electric device. It is something to be made.

And in the ripple voltage suppression device according to the present invention,
A voltage detection means, a filter, a voltage amplifier, a voltage compensation transformer, a capacitor, and a second detection voltage correspondence control means; a first electrical device and a first terminal connected to the DC terminal of the first electrical device; A ripple voltage suppression device inserted between two electrical devices,
The first electric device is capable of regenerating electric energy to the input side,
The second electric device is capable of regenerating electric energy,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding A compensation voltage for reducing the ripple voltage is generated in
The capacitor is connected in parallel with the second electric device,
The second detection voltage correspondence control means is a voltage input to the filter when the detection voltage becomes larger than a predetermined second value due to regeneration of the electric energy from the second electric device. Is switched from the detection voltage to the voltage of the capacitor.

And in the power converter device concerning this invention,
A power conversion device comprising the first electric device and a ripple voltage suppressing device provided at a DC terminal of the first electric device,
The ripple voltage suppression device is described above, and stops operation when the input current of the first electric device is smaller than a prescribed value .

Furthermore, in the power converter according to the present invention,
A power conversion device comprising the first electric device and a ripple voltage suppressing device provided at a DC terminal of the first electric device,
The first electric device is an AC-DC converter,
The ripple voltage suppression device is the one described above.

Furthermore, in the power converter according to the present invention,
A power conversion device comprising the first electric device and a ripple voltage suppressing device provided at a DC terminal of the first electric device,
The first electric device is a DC-DC converter or a DC power source,
The ripple voltage suppression device is the one described above.

In the ripple voltage suppressing device according to the present invention,
A second electric device having a voltage detecting means, a filter, a voltage amplifier, a voltage compensating transformer, and a ripple voltage corresponding turns ratio changing means, and connected to a first electric device and a DC terminal of the first electric device; A ripple voltage suppression device inserted between the device,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding in all SANYO compensation voltage for reducing the ripple voltage is generated,
The ripple voltage corresponding turns ratio changing means is for changing the turns ratio between the main winding and the auxiliary winding of the voltage compensating transformer according to the ripple voltage.
A ripple voltage suppressing device that can reduce power loss and can be reduced in size can be obtained.

And in the ripple voltage suppression device according to the present invention,
A voltage detecting means, a filter, a voltage amplifier, a voltage compensating transformer, an input electric quantity detecting means, and an input electric quantity corresponding winding ratio changing means; and a first electric device and a DC terminal of the first electric device A ripple voltage suppressing device inserted between a second electrical device to be connected,
The first electric device is an AC-DC converter,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The input electric quantity detection means detects input current or input power of the first electric device,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding A compensation voltage for reducing the ripple voltage is generated in
The input electric quantity corresponding turn ratio changing means changes the turn ratio between the main winding and the auxiliary winding of the voltage compensating transformer according to the input current or the input power.
A ripple voltage suppressing device that can reduce power loss and can be reduced in size can be obtained.

Furthermore, in the ripple voltage suppression device according to the present invention,
A voltage detecting means, a filter, a voltage amplifier, a voltage compensating transformer, an input electric quantity detecting means, and an input electric quantity corresponding control means, and connected to the first electric device and a DC terminal of the first electric device; A ripple voltage suppression device inserted between the second electrical device and
The first electric device is an AC-DC converter,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The input electric quantity detection means detects input current or input power of the first electric device,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding A compensation voltage for reducing the ripple voltage is generated in
Since the input electric quantity corresponding control means stops the operation of the voltage amplifier when the input current or the input power is equal to or lower than a predetermined set value,
A ripple voltage suppressing device that can reduce power loss and can be reduced in size can be obtained.

In the ripple voltage suppression device according to the present invention,
A voltage detection means, a filter, a voltage amplifier, a voltage compensation transformer, and a first detection voltage correspondence control means; a second electrical device connected to the first electrical device and a DC terminal of the first electrical device; A ripple voltage suppression device inserted between the electrical device,
The second electric device is capable of regenerating electric energy,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding A compensation voltage for reducing the ripple voltage is generated in
The first detection voltage correspondence control means stops the operation of the voltage amplifier when the detection voltage becomes larger than a predetermined first value due to regeneration of the electric energy from the second electric device. So that
A ripple voltage suppressing device that can reduce power loss and can be reduced in size can be obtained.

And in the ripple voltage suppression device according to the present invention,
A voltage detection means, a filter, a voltage amplifier, a voltage compensation transformer, a capacitor, and a second detection voltage correspondence control means; a first electrical device and a first terminal connected to the DC terminal of the first electrical device; A ripple voltage suppression device inserted between two electrical devices,
The first electric device is capable of regenerating electric energy to the input side,
The second electric device is capable of regenerating electric energy,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding A compensation voltage for reducing the ripple voltage is generated in
The capacitor is connected in parallel with the second electric device,
The second detection voltage correspondence control means is a voltage input to the filter when the detection voltage becomes larger than a predetermined second value due to regeneration of the electric energy from the second electric device. Is switched from the detection voltage to the voltage of the capacitor,
A ripple voltage suppressing device that can reduce power loss and can be reduced in size can be obtained.

And in the power converter device concerning this invention,
A power conversion device comprising the first electric device and a ripple voltage suppressing device provided at a DC terminal of the first electric device,
Since the ripple voltage suppressing device is described above and stops operating when the input current of the first electric device is smaller than a specified value ,
It is possible to obtain a power conversion device that can reduce power loss and can be miniaturized.

Furthermore, in the power converter according to the present invention,
A power conversion device comprising the first electric device and a ripple voltage suppressing device provided at a DC terminal of the first electric device,
The first electric device is an AC-DC converter,
Since the ripple voltage suppression device is described above,
It is possible to obtain a power conversion device that can reduce power loss and can be miniaturized.

Furthermore, in the power converter according to the present invention,
A power conversion device comprising the first electric device and a ripple voltage suppressing device provided at a DC terminal of the first electric device,
The first electric device is a DC-DC converter or a DC power source,
Since the ripple voltage suppression device is described above,
It is possible to obtain a power conversion device that can reduce power loss and can be miniaturized.

It is a circuit diagram which shows the structure of the ripple voltage suppression apparatus and power converter device which are Embodiment 1 of this invention. It is a circuit diagram which shows the structure of the modification of the ripple voltage suppression apparatus and power converter device of FIG. It is a circuit diagram which shows the structure of another modification of the ripple voltage suppression apparatus and power converter device of FIG. It is a circuit diagram which shows the structure of the ripple voltage suppression apparatus and power converter device which are Embodiment 2 of this invention. It is a circuit diagram which shows the structure of the ripple voltage suppression apparatus and power converter device which are Embodiment 3 of this invention. It is a circuit diagram which shows the structure of the ripple voltage suppression apparatus and power converter device which are Embodiment 4 of this invention. It is a circuit diagram which shows the structure of the ripple voltage suppression apparatus and power converter device which are Embodiment 5 of this invention. It is a circuit diagram which shows the structure of the ripple voltage suppression apparatus and power converter device which are Embodiment 6 of this invention. It is a circuit diagram which shows the structure of the ripple voltage suppression apparatus and power converter device which are Embodiment 7 of this invention. It is a circuit diagram which shows the structure of the ripple voltage suppression apparatus and power converter device which are Embodiment 8 of this invention. It is a circuit diagram which shows the structure of the ripple voltage suppression apparatus and power converter device which are Embodiment 9 of this invention. It is a circuit diagram which shows the structure of the ripple voltage suppression apparatus and power converter device which are Embodiment 10 of this invention.

Embodiment 1 FIG.
FIG. 1 is a circuit diagram showing a configuration of a ripple voltage suppression device and a power conversion device according to Embodiment 1 for carrying out the present invention. 2 is a circuit diagram showing a configuration of a variation of the ripple voltage suppression device and the power conversion device of FIG. 1, and FIG. 3 is a circuit diagram showing a configuration of another variation of the ripple voltage suppression device and the power conversion device of FIG. is there. In FIG. 1, a rectifier 2 serving as a first electric device and an AC-DC converter is connected to a three-phase AC power source 1. In this embodiment, the rectifier 2 is constituted by a diode bridge. A voltage divider 3 as voltage detecting means is connected to terminals 2a and 2b as DC terminals on the DC side of the rectifier 2. The detection voltage detected by the voltage divider 3 is input to the voltage amplifier 5 through the filter 4 and amplified. Specifically, the voltage divider 3 is constituted by a voltage dividing resistor. The transformer 6 as a voltage compensating transformer has a main winding 6a and an auxiliary winding 6b, and the turn ratio of the main winding 6a and the auxiliary winding 6b is 1: 1 in this embodiment. Yes.

  A smoothing capacitor 7 is connected to the rectifier 2 via a transformer 6. The resistor 8 as the second electric device is similarly connected to the rectifier 2 via the transformer 6. That is, one terminal of the resistor 8 is connected to the terminal 2 a on the positive electrode side of the rectifier 2 via the main winding 6 a of the transformer 6. The other terminal of the resistor 8 is connected to the negative terminal 2b of the rectifier 2, one terminal of the auxiliary winding 6b is connected to the output terminal of the voltage amplifier 5, and the other terminal is a negative terminal of the rectifier 2. 2b. In this embodiment, the voltage amplifier 5 adjusts the gate voltage or base current of a switching element or a circuit that adjusts the output voltage by switching with a semiconductor switching element such as a MOSFET (not shown). And a regulation circuit for adjusting the output voltage. The voltage divider 3, the filter 4, the voltage amplifier 5, and the transformer 6 constitute the ripple voltage suppressing device of the present invention. Moreover, the power converter of this invention is comprised by the rectifier 2 and the ripple voltage suppression apparatus.

  Next, the operation will be described. The alternating current input from the three-phase alternating current power source 1 is rectified into direct current by the rectifier 2. The voltage divider 3 detects the bus voltage V1, which is a DC output voltage of the rectifier 2, divides the voltage, multiplies the amplitude by 1 / N, and outputs the detected voltage V2 to the filter 4. The filter 4 receives the detection voltage V 2, extracts an AC component (ripple voltage) V 3 as a ripple voltage in the detection voltage V 2, and outputs it to the voltage amplifier 5. The voltage amplifier 5 receives the AC component V3, amplifies it N times, applies it as the inter-terminal voltage V4 to the auxiliary winding 6b of the transformer 6, and generates a compensation voltage V5 across the main winding 6a. As a result, a voltage having the same magnitude as the AC component of the bus voltage V1 of the rectifier 2 is generated at both ends of the main winding 6a of the transformer 6 as the compensation voltage V5. For this reason, the ripple voltage on the DC side of the rectifier 2 is canceled, and a DC voltage having almost no ripple voltage is applied to the capacitor 7 and the resistor 8.

  In this way, the detection voltage V2 detected at 1 / N times by the voltage divider 3 is applied to the filter 4 to extract the AC component V3, and the AC component V3 is multiplied by N by the voltage amplifier 5 to obtain the terminal voltage V4. Application is made in series with the resistor 8 via the transformer 6. As a result, a voltage is applied in a direction in which the ripple voltage on the DC side of the rectifier 2 is canceled, and a DC voltage from which the ripple voltage is almost removed is applied to the resistor 8.

  As described above, only the bus voltage V1 of the rectifier 2 is sufficient for removing the ripple voltage on the DC side, and no current information is required. Therefore, the current detection is not required, and the three-phase AC power source 1 has a simple configuration. The harmonic current flowing through the rectifier 2 can be reduced, and the ripple voltage of the DC output of the rectifier 2 can be reduced. Further, since it is not necessary to provide a conventional DC current transformer, the power loss can be reduced by the amount of power loss of the DC current transformer, and further the size of the entire apparatus can be reduced.

  Note that the harmonic current of the three-phase AC power supply 1 is reduced, and the AC current component flowing through the main winding 6a of the transformer 6 is greatly reduced, so that the smoothing operation of the capacitor 7 is facilitated. For this reason, the electrostatic capacitance of the capacitor 7 can be reduced, and the apparatus can be miniaturized. In addition, since the capacitance of the capacitor 7 can be reduced, a film capacitor, a ceramic capacitor, or the like that has a low temperature dependency of the lifetime other than the electrolytic capacitor can be used as the capacitor 7. As a result, the temperature dependence related to the life of the electrolytic capacitor can be eliminated, and the reliability can be improved. Moreover, you may use the kind of capacitor | condenser with a smaller equivalent internal resistance than an electrolytic capacitor. By using a capacitor having a small equivalent internal resistance, the voltage drop inside the capacitor is reduced, so that the ripple voltage can be further reduced.

  Moreover, in this Embodiment, although the case where the three-phase alternating current power supply 1 was provided via the rectifier 2 in the input side of the ripple voltage suppression apparatus was demonstrated, direct current power supply may be provided in the input side. For example, as shown in the modified example of FIG. 2, the ripple voltage is suppressed via terminals 202a and 202b having a direct current power source 201 composed of a solar cell or the like as a first electric device and a smoothing capacitor 202 as a direct current power source. The ripple voltage of the DC output of the smoothing capacitor 202 can be reduced even when connected to the apparatus. As another modified example, as shown in FIG. 3, a DC power supply 201 uses a DC / DC converter 203 as a first electric device and a DC-DC converter as a ripple voltage via terminals 203a and 203b as DC terminals. The ripple voltage of the DC output of the DC / DC converter 203 can be reduced even when connected to the suppression device. Moreover, DC power supplies, such as a storage battery and a solar cell, are used as a 1st electric apparatus, and the terminal for DC output as a DC terminal of these DC power supplies may be connected to a ripple voltage suppression apparatus.

Embodiment 2. FIG.
FIG. 4 is a circuit diagram illustrating a configuration of the ripple voltage suppression device and the power conversion device according to the second embodiment. In FIG. 4, the difference from the first embodiment is that the voltage dividing ratio of the voltage divider 23 is the same at 1 / N, but the voltage rating is low and the current rating is large, and the filter 24 has a low voltage rating and a large current rating. The amplification factor of the voltage amplifier 25 is N / M times (M will be described later), and the relationship between the number of turns n1 of the main winding 26a and the number of turns n2 of the auxiliary winding 26b of the transformer 26 as a voltage compensating transformer. N1 / n2 = M (M is an integer greater than 1), and a voltage V5 that is M times larger than the input voltage V4 of the auxiliary winding 26b is generated at both ends of the main winding 26a. is there. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given to the corresponding components and the description thereof is omitted. The voltage divider 23, the filter 24, the voltage amplifier 25, and the transformer 26 constitute the ripple voltage suppressing device of the present invention. Moreover, the power converter of this invention is comprised by the rectifier 2 and the ripple voltage suppression apparatus.

  Next, the operation will be described. The voltage amplifier 25 receives the AC component V3 through the filter 24, amplifies it by N / M times, and applies it to the auxiliary winding 26b of the transformer 26 as the inter-terminal voltage V4. When the transformer 26 receives the inter-terminal voltage V4 from the auxiliary winding 26b, the main winding 26a is configured with M times the number of turns of the auxiliary winding 26b, and thus the inter-terminal voltage V4 at both ends of the main winding 26a. M times the compensation voltage V5. As a result, a compensation voltage V5 having the same magnitude as the AC component of the bus voltage V1 of the rectifier 2 is generated at both ends of the main winding 26a of the transformer 26. Thus, a DC voltage having almost no ripple voltage is applied to the capacitor 7 and the resistor 8.

  Thus, when the number of turns n1 of the main winding 26a is larger than the number of turns n2 of the auxiliary winding 26b, that is, when the turn ratio M (= n1 / n2)> 1, the voltage is amplified by the transformer 26 to M times the turn ratio. Therefore, the filter 24 and the voltage amplifier 25 can be composed of components and elements having a lower rated voltage than those of the first embodiment.

Embodiment 3 FIG.
FIG. 5 is a circuit diagram illustrating a configuration of the ripple voltage suppressing device and the power conversion device according to the third embodiment. In FIG. 5, the difference from the first embodiment is that the voltage dividing ratio of the voltage divider 33 is the same at 1 / N, but the voltage rating is high and the current rating is small, and the filter 34 is high in voltage rating and low in current rating. The voltage amplifier 35 has an amplification factor of N · S (S will be described later), and the number n1 of turns of the main winding 36a and the number of turns n2 of the auxiliary winding 36b of the transformer 36 as a voltage compensating transformer. The relationship is n1 / n2 = 1 / S times (S is an integer greater than 1) so that a voltage V5 of 1 / S times is generated at both ends of the main winding 26a with respect to the input voltage V4 of the auxiliary winding 26b. It is configured. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given to the corresponding components and the description thereof is omitted. The above voltage divider 33, filter 34, voltage amplifier 35, and transformer 36 constitute the ripple voltage suppression device of the present invention. Moreover, the power converter of this invention is comprised by the rectifier 2 and the ripple voltage suppression apparatus.

  Next, the operation will be described. The voltage amplifier 35 receives the AC component V3 through the filter 34, amplifies it by N · S times, and applies it to the auxiliary winding 36b of the transformer 36 as the inter-terminal voltage V4. When the transformer 36 receives the inter-terminal voltage V4 from the auxiliary winding 36b, the main winding 36a is configured with 1 / S times the number of turns of the auxiliary winding 36b. A compensation voltage V5 that is 1 / S times the voltage V4 is generated. As a result, a compensation voltage V5 having the same magnitude as the AC component of the bus voltage V1 of the rectifier 2 is generated at both ends of the main winding 36a of the transformer 36. Thus, a DC voltage having almost no ripple voltage is applied to the capacitor 7 and the resistor 8.

  Thus, when the number of turns n1 of the main winding 36a is smaller than the number of turns n2 of the auxiliary winding 36b, that is, when the turns ratio 1 / S (= n1 / n2) <1, the voltage is 1 / S times at the transformer 36. Therefore, the voltage amplitude output from the voltage amplifier 35 must be increased. However, since the rated current of the filter 34 and the voltage amplifier 35 can be reduced (can be reduced to 1 / S), the voltage divider 33 and the voltage amplifier 35 are Compared to the first embodiment, it can be configured with parts and elements having a smaller rated current.

Embodiment 4 FIG.
FIG. 6 is a circuit diagram illustrating a configuration of the ripple voltage suppressing device and the power conversion device according to the fourth embodiment. In FIG. 6, the AC component V <b> 3 is input from the filter 4 to the ripple voltage corresponding tap switching means 41. Further, the ripple voltage corresponding tap switching means 41 is connected to a tap selector 42. The transformer 46 has a main winding 46a and an auxiliary winding 46b with a tap. The output side of the voltage amplifier 5 is connected to the auxiliary winding 46b via the tap selector 42. Although the details of the tap selector 42 are not shown, the tap is switched using a semiconductor switch. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given to the corresponding components and the description thereof is omitted. The ripple voltage corresponding tap switching means 41 and the tap selector 42 are the ripple voltage corresponding turns ratio changing means of the present invention. Further, the voltage divider 3, the filter 4, the voltage amplifier 5, the ripple voltage corresponding tap switching means 41, the tap selector 42, and the transformer 46 constitute the ripple voltage suppressing device of the present invention. Moreover, the power converter of this invention is comprised by the rectifier 2 and the ripple voltage suppression apparatus. By detecting the magnitude of the input voltage and changing the turn ratio between the main winding 46a and the auxiliary winding 46b of the transformer 46 according to the magnitude, the voltage amplification factor in the transformer 46 is changed, and the magnitude is small. The input ripple voltage is such that the output voltage of the voltage amplifier 5 corresponds to a large ripple voltage or the output voltage of the large voltage amplifier 5 corresponds to a small ripple voltage to reduce the current output from the voltage amplifier 5. A desired compensation voltage V5 is generated in the main winding 46a by adjusting the turns ratio of the transformer 46 in accordance with the size of the main winding 46a.

  Next, the operation will be described. In FIG. 6, the ripple voltage corresponding tap switching means 41 determines the magnitude of the input AC component V3 and controls the tap selector 42 according to the magnitude to switch the number of turns of the auxiliary winding 46b. Specifically, for example, when the AC component V3 is large, the ripple voltage corresponding tap switching means 41 controls the tap selector 42 to switch the tap of the auxiliary winding 46b to a tap with a small number of turns. Then, since the turn ratio n1 / n2 between the main winding 46a and the auxiliary winding 46b of the transformer 46 is increased, the compensation voltage V5 generated in the main winding 46a is large even if the output voltage of the voltage amplifier 5 is the same. Become. Thereby, even when the load of the rectifier 2 is large and the ripple voltage is large, the ripple voltage can be effectively reduced. In addition, the amplification factor of the voltage amplifier 5 can be set to an appropriate value, and can be manufactured inexpensively and easily.

Embodiment 5 FIG.
FIG. 7 is a circuit diagram showing configurations of the ripple voltage suppressing device and the power conversion device according to the fifth embodiment. In FIG. 7, instrument current transformers 1 a and 1 c as input electric quantity detection means are provided on the output side of the three-phase AC power source 1, and an AC input current as an input current from the three-phase AC power source 1 to the rectifier 2. Jac is detected and input to the AC side current corresponding tap switching means 51 as the input electricity quantity corresponding tap switching means. The AC-side current corresponding tap switching means 51 is connected to the tap selector 42. Since other configurations are the same as those of the fourth embodiment shown in FIG. 6, the corresponding components are denoted by the same reference numerals and description thereof is omitted. The AC side current-capable tap switching means 51 and the tap selector 42 are the input electric quantity corresponding winding ratio changing means of the present invention. Further, the voltage divider 3, the filter 4, the voltage amplifier 5, the AC side current corresponding tap switching means 51, the tap selector 42, and the transformer 46 constitute the ripple voltage suppressing device of the present invention. Moreover, the power converter of this invention is comprised by the rectifier 2 and the ripple voltage suppression apparatus.

In FIG. 7, the AC side current corresponding tap switching means 51 determines the magnitude of the input AC input current Jac of the rectifier 2 and controls the tap selector 42 in accordance with the magnitude, thereby controlling the auxiliary winding 46b. Switch the number of turns. Specifically, for example, when the AC input current Jac is large, the AC side current corresponding tap switching unit 51 controls the tap selector 42 to switch the tap of the auxiliary winding 46b to a tap having a large number of turns. Then, since the turn ratio n1 / n2 between the main winding 46a and the auxiliary winding 46b of the transformer 46 is reduced, the compensation voltage V5 generated in the main winding 46a is large even if the output current of the voltage amplifier 5 is the same. Become. Thereby, even when the load of the rectifier 2 is large, the ripple voltage can be effectively reduced by the voltage amplifier 5 having a small current capacity.
Instead of measuring the AC input current Jac of the rectifier 2, the AC side input power as the input electric quantity is measured, and the tap of the auxiliary winding 46b is set according to the magnitude by the AC side electric quantity corresponding tap switching means. It may be switched.

Embodiment 6 FIG.
FIG. 8 is a circuit diagram showing configurations of the ripple voltage suppressing device and the power conversion device according to the sixth embodiment. In FIG. 8, the AC side current corresponding control means 61 as the AC side electric quantity corresponding control means has an output terminal 61d. The AC input current Jac from the instrument current transformers 1a and 1c and the detection voltage V2 from the voltage divider 3 are input to the AC side current corresponding control means 61. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given to the corresponding components and the description thereof is omitted. The voltage divider 3, the filter 4, the voltage amplifier 5, the transformer 6, and the AC side current corresponding control means 61 constitute the ripple voltage suppressing device of the present invention. Moreover, the power converter of this invention is comprised by the rectifier 2 and the ripple voltage suppression apparatus.

  Next, the operation will be described. In FIG. 8, the AC side current correspondence control means 61 determines the magnitude of the AC input current Jac of the rectifier 2 and controls whether or not to output the detection voltage V2 input from the voltage divider 3 from the output terminal 61d. . Specifically, the AC side current correspondence control means 61 outputs the input detection voltage V2 to the output terminal 61d as it is, for example, when the AC input current Jac is smaller than a predetermined predetermined AC input current set value. The detection voltage V2 is supplied to the filter 4. Note that the predetermined value is assumed to be a current when a current value at which magnetic flux saturation does not occur even if the voltage winding 5 side of the auxiliary winding 6b of the transformer 6 is opened. When the AC input current Jac is less than or equal to a predetermined value, the output terminal 61d and the negative side of the rectifier 2 are short-circuited, the output voltage to the filter 4 is set to zero, and the operation of the voltage amplifier 5 is substantially stopped. At this time, the output of the voltage amplifier 5 becomes high impedance, no current flows through the winding 6b of the transformer 6, and the transformer 6 operates as a reactor of the winding 6a. Instead of detecting the AC input current Jac from the three-phase AC power supply 1, it is also possible to detect whether AC power is detected and similarly to control whether the detection voltage V2 is output from the output terminal 61d. Thereby, unnecessary operation | movement of the transformer 6 can be excluded and power loss can be reduced.

Embodiment 7 FIG.
FIG. 9 is a circuit diagram showing configurations of the ripple voltage suppressing device and the power conversion device according to the seventh embodiment. In FIG. 9, a rectifier 2 is connected to a second electric device and an inverter 14 as a DC-AC converter and a regenerative resistor 16 via a transformer 6. A motor 15 is connected to the AC side of the inverter 14. The first detected voltage correspondence control means 71 has an output terminal 71d. The detection voltage V2 is input from the voltage divider 3 to the first detection voltage correspondence control means 71, and the output is output from the output terminal 71d to the filter 4. Note that the rectifier 2, the inverter 14, and the ripple voltage suppression device (the voltage divider 3, the filter 4, the voltage amplifier 5, the transformer 6, and the first detected voltage correspondence control means 71) are accommodated in one housing 78. Although not shown, the inverter 14 uses a MOSFET as a switching element and has regenerative capability. That is, regeneration of electrical energy to the three-phase AC power source 1 is enabled. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given to the corresponding components and the description thereof is omitted. The voltage divider 3, the filter 4, the voltage amplifier 5, the transformer 6, and the first detected voltage correspondence control means 71 constitute the ripple voltage suppressing device of the present invention. Moreover, the power converter of this invention is comprised by the rectifier 2 and the ripple voltage suppression apparatus, or the rectifier 2, the ripple voltage suppression apparatus, and the inverter 14. FIG.

  The detection voltage V2 is input from the voltage divider 3 to the first detection voltage correspondence control means 71, and whether or not the detection voltage V2 input from the voltage divider 3 is output from the output terminal 71d according to the magnitude of the detection voltage V2. To control. Specifically, the first detection voltage correspondence control unit 71 outputs the input detection voltage V2 to the output terminal 71d as it is, for example, when the detection voltage is equal to or lower than a predetermined first value, and the detection voltage V2 Is supplied to the filter 4. That is, when electric power is supplied from the rectifier 2 to the motor 15 via the inverter 14 and the power running operation is performed, the detection voltage V2 is small. The detected voltage V2 is supplied to the filter 4 as it is by detecting that it is less than the value. A voltage V4 between the terminals is applied from the voltage amplifier 5 to the auxiliary winding 6b, and a compensation voltage V5 is generated at both ends of the main winding 6a, thereby reducing the ripple voltage in the bus voltage V1.

  On the other hand, when the motor 15 shifts to the regenerative operation and power is regenerated from the inverter 14 to the capacitor 7 or the regenerative resistor 16, the capacitor 7 is charged by the regenerative power, so that the bus voltage V1 increases. When the bus voltage V1 rises, the first detection voltage correspondence control means 71 detects that the bus voltage V1, that is, the detection voltage V2, is greater than a predetermined first value, and the output terminal 71d and the rectifier 2 Are short-circuited with each other, the output voltage to the filter 4 is made zero, and the operation of the voltage amplifier 5 is stopped. Thereby, unnecessary operation can be eliminated and power loss can be reduced.

Embodiment 8 FIG.
FIG. 10 is a circuit diagram showing configurations of the ripple voltage suppressing device and the power conversion device according to the eighth embodiment. In FIG. 10, the second detection voltage correspondence control means 81 has an output terminal 81d. The rectifier 82 as the first electric device and the AC-DC converter is configured by an AC-DC converter circuit having a regenerative capability instead of a diode bridge. The rectifier 82 has terminals 82 a and 82 b as DC terminals, and the inverter 14 is connected to the terminals 82 a and 82 b through the transformer 6. Although not shown, the rectifier 82 uses a MOSFET as a switching element. The detection voltage V2 from the voltage divider 3 and the divided voltage V7 from the voltage divider 83 connected to the capacitor 7 are input to the second detection voltage correspondence control means 81, and any voltage from the output terminal 81d to the filter 4 is input. Is output. The divided voltage V7 is obtained by dividing the terminal voltage V6 of the capacitor 7. Further, the rectifier 82, the inverter 14, and the ripple voltage suppression device (the voltage divider 3, the filter 4, the voltage amplifier 5, the transformer 6, the second detection voltage correspondence control means 81, and the voltage divider 83) are accommodated in one housing 88. Has been.

  The voltage divider 3, the filter 4, the voltage amplifier 5, the transformer 6, the second detected voltage correspondence control means 81, and the voltage divider 83 constitute the ripple voltage suppressing device of the present invention. The rectifier 82 and the ripple voltage suppression device, or the rectifier 82, the ripple voltage suppression device, and the inverter 14 constitute the power conversion device of the present invention.

  When the motor 15 shifts to the regenerative operation and the bus voltage V1 rises, the second detection voltage correspondence control means 81 detects that the bus voltage V1, that is, the detection voltage V2, is greater than a predetermined second value. Then, the output from the output terminal 81d to the filter 4 is switched from the detection voltage V2 to the divided voltage V7 of the capacitor 7. Further, when the detection voltage V2 becomes equal to or lower than the second value, the detection voltage V2 is output from the output terminal 81d to the filter 4, and the ripple voltage on the DC side of the rectifier 2 is reduced. Thereby, the ripple voltage of bus voltage V1, which is the DC voltage of rectifier 2, can be reduced, and the harmonic current for the power system during regeneration can be reduced.

In the seventh embodiment shown in FIG. 9 or the eighth embodiment shown in FIG. 10, the power is regenerated to the capacitor 7 and the regenerative resistor 16, but power regeneration is limited to these. For example, the following can also be used.
-An inverter is provided separately from the rectifier 82 to regenerate power to the three-phase AC power source 1,
-A battery or battery connected in parallel with the capacitor 7 or in place of the capacitor 7 to store power,
・ A regenerative resistor (regenerative load) 16 is stored separately as a kinetic energy by connecting an inverter and a motor as a load in parallel or in parallel with a rectifier circuit and accelerating the load connected to the motor.

Embodiment 9 FIG.
FIG. 11 is a circuit diagram illustrating a configuration of the ripple voltage suppressing device and the power conversion device according to the ninth embodiment. In FIG. 11, the control power supply device 91 has an input side connected to the output side of the rectifier 2, an output side connected to the voltage amplifier 5, and converts a DC voltage output from the rectifier 2 into a voltage necessary for the operation of the voltage amplifier 5. To the voltage amplifier 5. Capacitors 92 and 93 are connected to the output side of the control power supply 91 to reduce the AC component in the DC voltage supplied from the control power supply 91 to the voltage amplifier 5. As the control power supply device 91, a device that can adjust an input voltage such as a chopper circuit to an arbitrary voltage is used. With such a configuration, it is not necessary to supply power to the voltage amplifier 5 from the outside, and it is possible to supply high-quality DC power that does not contain AC components.

Embodiment 10 FIG.
FIG. 12 is a circuit diagram illustrating a configuration of the ripple voltage suppressing device and the power conversion device according to the tenth embodiment. In FIG. 12, the control power supply apparatus 101 has an input side connected to the three-phase AC power source 1, an output side connected to the voltage amplifier 5, and an AC voltage output from the three-phase AC power source 1 is necessary for the operation of the voltage amplifier 5. It is converted into a DC voltage and supplied to the voltage amplifier 5. Capacitors 92 and 93 are connected to the output side of the control power supply apparatus 101 to reduce the AC component in the DC voltage supplied from the control power supply apparatus 101 to the voltage amplifier 5. As the control power supply device 101, a device capable of adjusting an input AC voltage such as a converter to an arbitrary positive / negative DC voltage is used. With such a configuration, it is not necessary to supply power to the voltage amplifier 5 from the outside, and it is possible to supply high-quality DC power that does not contain AC components.

The semiconductor elements such as MOSFETs (not shown) constituting the voltage amplifier 5, the inverter 14, the rectifier 82, etc. are not limited to those formed of silicon, but may be formed of a wide band gap semiconductor having a band gap larger than that of silicon. Good. Examples of wide band gap semiconductors include silicon carbide, gallium nitride-based materials, and diamond. A semiconductor element formed of such a wide band gap semiconductor has a high voltage resistance and a high allowable current density, so that the semiconductor element can be miniaturized. By using these miniaturized semiconductor elements, A semiconductor module or device incorporating these elements can be miniaturized. Moreover, since heat resistance is also high, since the heat sink fin of the heat sink can be downsized and the water cooling part can be air cooled, further downsizing is possible. Furthermore, since the power loss is low, the efficiency of the semiconductor element can be increased, and thus the efficiency of the entire apparatus can be increased.
It should be noted that the embodiments described above can be combined as appropriate to produce a synergistic effect.

1 Three-phase AC power supply, 1a, 1c Current transformer for instrument, 2 Rectifier, 2a, 2b terminal,
3 voltage divider, 4 filter, 5 voltage amplifier, 6 transformer, 6a main winding,
6b Auxiliary winding, 6b Auxiliary winding, 7 Capacitor, 8 Resistance, 14 Inverter,
15 motor, 16 regenerative resistor, 23 voltage divider, 24 filter, 25 voltage amplifier,
26 transformer, 26a main winding, 26b auxiliary winding, 33 voltage divider, 34 filter,
35 voltage amplifier, 36 transformer, 36a main winding, 36b auxiliary winding,
41 Ripple voltage compatible tap switching means, 42 tap selector, 46 transformer,
46a main winding, 46b auxiliary winding, 46 main winding,
51 AC side current corresponding tap switching means, 61 AC side current corresponding control means,
61d output terminal, 71 detection voltage corresponding control means, 71d output terminal, 78 housing,
81 detection voltage corresponding control means, 81d output terminal, 82 rectifier,
82a, 82b terminals, 83 voltage divider, 88 housing, 201 DC power supply,
202 smoothing capacitor, 202a, 202b terminal, 203 DC / DC converter,
203a, 203b terminals.

Claims (15)

A second electric device having a voltage detecting means, a filter, a voltage amplifier, a voltage compensating transformer, and a ripple voltage corresponding turns ratio changing means, and connected to a first electric device and a DC terminal of the first electric device; A ripple voltage suppression device inserted between the device,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding in all SANYO compensation voltage for reducing the ripple voltage is generated,
The ripple voltage corresponding turn ratio changing means changes the turn ratio between the main winding and the auxiliary winding of the voltage compensating transformer according to the ripple voltage. . A voltage detecting means, a filter, a voltage amplifier, a voltage compensating transformer, an input electric quantity detecting means, and an input electric quantity corresponding winding ratio changing means; and a first electric device and a DC terminal of the first electric device A ripple voltage suppressing device inserted between a second electrical device to be connected,
The first electric device is an AC-DC converter,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The input electric quantity detection means detects input current or input power of the first electric device,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding in all SANYO compensation voltage for reducing the ripple voltage is generated,
The input electric quantity corresponding turns ratio changing means changes the turns ratio between the main winding and the auxiliary winding of the voltage compensating transformer according to the input current or the input power. > Ripple voltage suppressor. A voltage detection means, a filter, a voltage amplifier, a voltage compensating transformer, an input electricity quantity detection means, and an input electricity quantity correspondence control means , connected to the first electrical device and a DC terminal of the first electrical device; A ripple voltage suppression device inserted between the second electrical device and
The first electric device is an AC-DC converter,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The input electric quantity detection means detects input current or input power of the first electric device,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding in all SANYO compensation voltage for reducing the ripple voltage is generated,
The ripple voltage suppressing device, wherein the input electric quantity correspondence control means stops the operation of the voltage amplifier when the input current or the input power is equal to or lower than a predetermined set value . A voltage detection means, a filter, a voltage amplifier, a voltage compensation transformer, and a first detection voltage correspondence control means ; a second electrical device connected to the first electrical device and a DC terminal of the first electrical device; A ripple voltage suppression device inserted between the electrical device,
The second electric device is capable of regenerating electric energy,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding in all SANYO compensation voltage for reducing the ripple voltage is generated,
The first detection voltage correspondence control means stops the operation of the voltage amplifier when the detection voltage becomes larger than a predetermined first value due to regeneration of the electric energy from the second electric device. A ripple voltage suppressing device. A voltage detection means, a filter, a voltage amplifier, a voltage compensation transformer, a capacitor, and a second detection voltage correspondence control means ; a first electrical device and a first terminal connected to the DC terminal of the first electrical device; A ripple voltage suppression device inserted between two electrical devices,
The first electric device is capable of regenerating electric energy to the input side,
The second electric device is capable of regenerating electric energy,
The voltage detection means detects a voltage of a DC terminal of the first electric device as a detection voltage,
The filter extracts the ripple voltage in the detection voltage when the detection voltage is input, and outputs the ripple voltage.
The voltage amplifier amplifies the ripple voltage and outputs it as an output voltage,
The voltage compensating transformer has a main winding and an auxiliary winding,
The second electrical device is connected in series to the main winding, and is connected to the first electrical device via the main winding, and the output voltage is applied to the auxiliary winding, and the main winding in all SANYO compensation voltage for reducing the ripple voltage is generated,
The capacitor is connected in parallel with the second electric device,
The second detection voltage correspondence control means is a voltage input to the filter when the detection voltage becomes larger than a predetermined second value due to regeneration of the electric energy from the second electric device. A ripple voltage suppressing device for switching the voltage from the detection voltage to the voltage of the capacitor . The voltage amplifier has an amplifying semiconductor element,
6. The ripple voltage suppressing device according to claim 1 , wherein the amplification semiconductor element is formed of a wide gap semiconductor. A power conversion device comprising the first electric device and a ripple voltage suppressing device provided at a DC terminal of the first electric device,
The ripple voltage suppression device is described in any one of claims 1 to 6 , and stops operation when an input current of the first electric device is smaller than a specified value. A power conversion device. A power conversion device comprising the first electric device and a ripple voltage suppressing device provided at a DC terminal of the first electric device,
The first electric device is an AC-DC converter,
The said ripple voltage suppression apparatus is a power converter device described in any one of Claims 1-6 . A power conversion device comprising the first electric device and a ripple voltage suppressing device provided at a DC terminal of the first electric device,
The first electric device is a DC-DC converter or a DC power source,
The said ripple voltage suppression apparatus is a power converter device as described in any one of Claim 1 or Claims 4-6 . The power converter according to claim 8 or 9 , further comprising the second electric device connected to a DC terminal of the first electric device via the ripple voltage suppressing device. The power converter according to claim 10 , wherein the second electric device is a DC-AC converter. The power converter according to claim 10 or 11 , further comprising a housing that accommodates the first electric device, the ripple voltage suppressing device, and the second electric device in common. . The power converter according to any one of claims 10 to 12 , wherein the second electric device is one that can regenerate electric energy. The power converter according to any one of claims 10 to 13 , wherein the first electric device is one that can regenerate electric energy. A capacitor connected to the opposite side of the first electrical device of the voltage compensating transformer;
The power converter according to any one of claims 7 to 14 , wherein the capacitor is of a type having an equivalent internal resistance smaller than that of an electrolytic capacitor.

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