WO2017208322A1

WO2017208322A1 - Power converter cell and power conversion device

Info

Publication number: WO2017208322A1
Application number: PCT/JP2016/065967
Authority: WO
Inventors: 充弘門田; 泰明乗松; 杉山　由一; 輝米川
Original assignee: 株式会社日立製作所
Priority date: 2016-05-31
Filing date: 2016-05-31
Publication date: 2017-12-07

Abstract

Provided is a power converter cell and a power conversion device capable of high-speed communication by a low cost communication system while ensuring high voltage insulation. The power converter cell is provided with a main circuit including a first converter and a second converter, a first control circuit for controlling the first converter, and a second control circuit for controlling the second converter, and is operated by a control signal supplied from a central control device to the first control circuit and the second control circuit. The power converter cell is characterized in that: a first board and a second board are fixedly arranged at mutually opposing positions by supports, said first board being mounted with some or all of the constituents of the first control circuit, said second board being mounted with some or all of the constituents of the second control circuit; the control signal from the central control device is supplied to the first control circuit, and thereby the first converter is controlled by the first control circuit; and the control signal is further transmitted to the second control circuit by wireless communication between the first control circuit and the second control circuit, and thereby the second converter is controlled by the second control circuit.

Description

Power converter cell and power converter

The present invention relates to a power converter cell and a power converter.

In a high voltage or large capacity power converter, a power converter in which a plurality of power converter cells are connected in series or in parallel is used. As such a power converter, there is a direct high-voltage inverter device described in Patent Document 1. In the direct high-voltage inverter device, the outputs of a plurality of single-phase inverters (corresponding to power converter cells) are connected in series to obtain a three-phase high-voltage output. In this configuration, the high voltage motor can be directly driven without using a large low frequency step-up transformer.

On the other hand, the introduction of natural energy power generation such as solar power generation and wind power generation is expanding worldwide. There is a PCS (Power Conditioning System) as a power conversion device for converting electric power obtained from natural energy and outputting it to an electric power system. Also in this PCS, it is considered effective to use a plurality of power converter cells as in the above-described power converter when dealing with higher voltages and larger capacities.

JP 2009-033943 A

A power converter provided with a plurality of power converter cells is provided with a central control device for controlling each power converter cell. Each power converter cell is provided with a control circuit for driving the converter and detecting the state. With this configuration, the central control device performs an operation for controlling the output of the power converter, and transmits a control signal generated as a result to the control circuit of each power converter cell to control the power converter cell. .

Here, when each power converter cell is connected in series, the ground potential of the control circuit (reference potential at which the circuit operates) is different for each power converter cell. Therefore, when communicating between the central controller and the control circuit of each power converter cell, wired communication using electric wires cannot be used, and it is necessary to perform communication while ensuring electrical insulation. In particular, when the power converter is used for driving a high-voltage motor or a PCS for a high-voltage distribution system, a withstand voltage exceeding 5 kV is required as a communication withstand voltage.

Explain issues other than insulation for communication of control signals. Since the central control apparatus must communicate with a plurality of control circuits within a predetermined control period, high-speed communication is required. Further, in order to improve the responsiveness of the output control, it is necessary to set the control cycle short. High-speed communication is important for improving controllability by making it possible to shorten the time required for communication, and hence the control cycle.

Lowering the cost of communication systems is also an important issue. Conventionally, optical fiber communication has been used as a high-speed communication method with excellent insulation. However, in optical fiber communication, components such as optical fiber cables and optical transceivers are expensive.

Based on the above, in the present invention, a power converter cell and power conversion that can be communicated at high speed by a low-cost communication system while ensuring high withstand voltage insulation from the central controller to the control circuit of each power converter cell. An object is to provide an apparatus.

From the above, in the present invention, the main circuit including the first converter and the second converter, the first control circuit for controlling the first converter, and the second control circuit for controlling the second converter are provided. A power converter cell that is activated by receiving a control signal from a central control device for the first control circuit and the second control circuit, and that implements part or all of the components of the first control circuit. The first substrate and the second substrate on which a part or all of the components of the second control circuit are mounted are fixedly arranged at positions facing each other by the support material, and the control signal from the central control device is the first control. The first converter is controlled by the first control circuit, and the control signal is transmitted to the second control circuit by wireless communication between the first control circuit and the second control circuit. The second converter is controlled.

In the power converter of the present invention, the external connection terminals of the first converter of the main circuit of the plurality of sets of power converter cells are connected in parallel, and the second converter of the main circuit of the plurality of sets of power converter cells. The external connection terminals are connected in series, and a control signal from the central control device is given to the plurality of first control circuits, and the corresponding first converter is controlled by the first control circuit. The signal is transmitted from each first control circuit to the corresponding second control circuit by wireless communication, and the second converter is controlled by the second control circuit.

According to the present invention, high-speed communication can be performed from the central control device to the control circuit of each power converter cell by the low-cost power converter cell and the power conversion device while ensuring high voltage insulation.

The figure which shows the structural example of the power converter device in Example 1, and its communication system. The figure which shows the three-dimensional structure of the power converter cell in Example 1. FIG. The figure which looked at the three-dimensional structure of FIG. 2 from the front. The figure which looked at the three-dimensional structure of FIG. 2 from the right. The figure which shows the circuit structural example of a power converter cell. The figure which shows an example of a synthetic | combination output voltage waveform. The figure which shows the three-dimensional structure of the power converter cell in Example 2. FIG. The figure which looked from the front in the state which inserted the shield member 532 in the board | substrate about the three-dimensional structure of FIG. The figure seen from the front in the state which attached the

shield members

532 and 533 about the three-dimensional structure of FIG. FIG. 10 is a view showing a cross section when the one-dot chain line A-A ′ in FIG. 9 is taken as a cutting line; The figure seen from the right in the state which attached the

shield members

532 and 533 about the three-dimensional structure of FIG. FIG. 12 is a view showing a cross section when a dashed line B-B ′ in FIG. 11 is taken as a cutting line. The figure which shows the three-dimensional structure of the power converter cell in Example 3. FIG. The figure seen from the front in the state which attached the infrared communication part 540 about the three-dimensional structure of FIG. The figure which shows the cross section when the dashed-dotted line C-C 'of FIG. 14 is made into a cutting line. The figure which shows the structure of the power converter device in Example 4, and its communication system. The figure which shows the structure of the power converter device in Example 5, and its communication system.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a configuration example of a power conversion device and a communication system thereof according to Embodiment 1 of the present invention.

In FIG. 1, the power conversion apparatus 1000 converts the power input from the external power supply 300 and outputs it to the external load 400. The power conversion apparatus 1000 includes a plurality of power converter cells 101 to 104 and a central control apparatus 200 that controls them. Although FIG. 1 shows an example in which four power converter cells are connected, the number is arbitrary.

The power converter cells 101 to 104 include first converters 141 to 144 connected to the external power supply 300 side, first control circuits 211 to 214 for controlling them, and a second converter connected to the external load 400 side. Converters 151 to 154, second control circuits 221 to 224 for controlling them, and transformers 131 to 134 connected between the first converters 141 to 144 and the second converters 151 to 154, respectively. . Hereinafter, the first converters 141 to 144 and the first control circuits 211 to 214 are collectively defined as primary side circuits 111 to 114, respectively. Further, the second converters 151 to 154 and the second control circuits 221 to 224 are collectively defined as secondary side circuits 121 to 124, respectively. The transformers 131 to 134 are so-called insulating transformers that electrically insulate the primary side circuits 111 to 114 and the secondary side circuits 121 to 124, respectively. A more detailed configuration of the power converter cell will be described later.

The power converter cells 101 to 104 are connected to the power supply 300 in parallel. Therefore, the input voltages of power converter cells 101-104 are all equal. The power converter cells 101 to 104 convert the voltage of the power supply 300 to generate output voltages Vo1 to Vo4, respectively.

A description will be given of how the power converter cell 101 generates the output voltage Vo1. First, the first converter 141 converts the voltage of the power supply 300 into an AC voltage and applies it to the primary winding of the transformer 131. The first control circuit 211 performs calculation / processing for controlling the AC voltage and drives the first converter 141. Next, the second converter 151 converts the voltage generated in the secondary winding of the transformer 131 to generate the output voltage Vo1. The second control circuit 221 performs calculation / processing for controlling the output voltage Vo <b> 1 and drives the second converter 151. For power converter cells 102 to 104, output voltages Vo2 to Vo4 are generated in the same manner.

The output terminals of the power converter cells 101 to 104 are connected in series. The output voltage of the power converter 1000 is a voltage obtained by synthesizing the output voltages Vo1 to Vo4. Hereinafter, a voltage obtained by combining the output voltages of the power converter cells 101 to 104 is defined as a combined output voltage Vos (= Vo1 + Vo2 + Vo3 + Vo4). The combined output voltage Vos corresponds to the output voltage of the power conversion apparatus 1000. With the above configuration, the power conversion apparatus 1000 can output a high voltage.

The central control device 200 controls the output voltage Vo1 to Vo4 to a predetermined value, thereby controlling the combined output voltage Vos or the output current of the power converter 1000 to a predetermined value. In FIG. 1, assuming that the output current of the power conversion apparatus 1000 is controlled, the current detector 230 is installed on the path through which the output current flows. In this case, the central controller 200 detects the output current by the current detector 230 and uses this for calculation such as feedback control. When the central control device 200 controls the output voltage of the power conversion device 1000, a voltage detector for detecting this may be additionally installed in FIG.

In order to control the output voltages Vo1 to Vo4 of each power converter cell to a predetermined value, the first converters 141 to 144 and the second converters 151 to 154 need to be cooperatively controlled. Therefore, the central controller 200 outputs control signals to the first control circuits 211 to 214 and the second control circuits 221 to 224 of each power converter cell. Here, the control signal is a signal representing the target value of the control amount, and also includes a signal for instructing start and stop. Details of the control signal will be described later.

Here, a case where the central control device 200 transmits a control signal to the second control circuit 221 of the power converter cell 101 will be described. When the central control device 200 transmits a control signal to the other second control circuits 222 to 224, it can be transmitted in the same manner.

First, the central control device 200 once transmits a control signal to the second control circuit 221 to the first control circuit 211 once. That is, relaying using the first control circuit 211 is performed. In FIG. 1, communication paths in this communication are indicated by solid arrows. The primary side circuits 111 to 114 of each power converter cell are connected to the power supply 300 in parallel. Therefore, the ground potentials (reference potentials at which the circuits operate) of the first control circuits 211 to 214 are all common. Further, the ground potential of the central control device 200 and the first control circuits 211 to 214 can be shared. With this configuration, the communication from the central controller 200 to the first control circuits 211 to 214 does not require insulation, and wired communication using electric wires can be applied.

Next, the first control circuit 211 transmits the received control signal to the second control circuit 221. In FIG. 1, the communication path in this communication is indicated by a broken-line arrow. Since the secondary side circuits 121 to 124 of each power converter cell are connected in series, the ground potentials of the second control circuits 221 to 224 are different. The ground potentials of the first control circuits 211 to 214 and the second control circuits 221 to 224 are also different. Therefore, the communication from the first control circuit 211 to the second control circuit 221 requires insulation.

In the present invention, for communication between the first control circuits 211 to 214 and the second control circuits 221 to 224, communication is performed while ensuring electrical insulation by applying wireless communication. Here, wireless communication in the present invention is defined as communication using electromagnetic waves including infrared rays and visible light. Among wireless communication, infrared communication is a promising method in that it can be realized at low cost, and an infrared communication method (standard) such as IrDA (Infrared Data Association) can be used. In the case of wireless communication, the ground potential is greatly different between the first control circuit 211 and the second control circuit 221. Even if a withstand voltage exceeding 5 kV is required, structural measures such as maintaining the distance between the transmitter and the receiver appropriately Communication is possible while ensuring insulation.

Incidentally, the power converter cells 101 to 104 may transmit a physical quantity such as voltage, current, and temperature of each power converter cell and a state quantity such as the presence / absence of abnormality to the central controller 200. Signals representing these physical quantities and state quantities are defined as detection signals, and in the present invention, the detection signals are also considered as part of the control signals. For communication of the detection signal, a communication path indicated by an arrow in FIG. 1 is used, and the signal may be transmitted in the direction opposite to the arrow. For example, when the second control circuit 221 communicates a detection signal related to the second converter 151 to the central control device 200, the second control circuit 221 transmits the first control circuit 211 from the second control circuit 221 to the first control circuit 211 by wireless communication. May be transmitted to the central control device 200 via wired communication.

Supplementary matters about the configuration in FIG. First, a configuration in which a part of the first control circuits 211 to 214 plays the role of the central control device 200 is also conceivable. That is, a configuration in which a part of the power converter cells 101 to 104 plays the role of master in the master / slave system and the rest plays the role of slave. The power supply 300 may be either a DC power supply or an AC power supply. As an example, when the power conversion apparatus 1000 is applied to a PCS for photovoltaic power generation, the power supply 300 is a solar battery. Examples of the load 400 include a high voltage motor and other electric power equipment. As in the case where the power conversion apparatus 1000 is applied to a PCS for photovoltaic power generation, the load 400 may be a power system. Further, the power conversion apparatus 1000 may include elements such as a protection component (relay, fuse, etc.) and a filter component (reactor, capacitor) in addition to the configuration described above.

As described above, in the present invention, wireless communication is used to secure insulation between the first control circuits 211 to 214 and the second control circuits 221 to 224. Wireless communication can be realized at a lower cost than optical fiber communication. In particular, infrared communication is used for home appliances and the like, and can be said to be an advantageous method for cost reduction. Although the communication speed of wireless communication depends on the method and standard, it is slower when the method is selected with priority on cost. However, since wireless communication is performed in parallel for each power converter cell, even if a wireless communication method with a low communication speed is selected with priority given to cost, the time required for communication can be shortened and within a desired control cycle. You can complete the communication.

FIG. 2 is a diagram showing a three-dimensional structure of the power converter cell. The three-dimensional structure of the power converter cell in FIG. 2 can be applied to all of the power converter cells 101 to 104. The power converter cells 101 to 104 have a box shape with a two-layer structure, and the low layer and the high layer are supported by support members 510 to 513. A primary circuit board 501 on which the first converters 141 to 144 and the first control circuits 211 to 214 are mounted is disposed in the lower layer, and the second converters 151 to 154 and the second control circuit 221 to are mounted in the higher layer. A secondary circuit board 502 on which 224 is mounted is arranged. In FIG. 2, most of components mounted on the primary circuit board 501 and the secondary circuit board 502, and main circuit wiring for connecting to the power supply 300 and other power converter cells are omitted. Show.

The transformer 503 in FIG. 2 corresponds to any of the transformers 131 to 134 in FIG. FIG. 2 shows a configuration in which the transformer 503 is installed separately from the primary circuit board 501 and the secondary circuit board 502. In addition, an example in which the conductor 503 (bus bar) 601 and 602 is wired between the transformer 503 and the secondary circuit board 502 is shown. The wiring connecting the transformer 503 and the primary circuit board 501 will be described later. The transformer 503 may be mounted on the primary circuit board 501 or the secondary circuit board 502 as a component.

As shown in FIG. 2, the low-layer primary circuit board 501 and the high-layer secondary circuit board 502 are arranged to face each other with a gap between the support members 510 to 513. That is, the first control circuit and the second control circuit are mounted on the substrates facing each other. In FIG. 2, all the components of the first control circuits 211 to 214 and all the components of the second control circuits 221 to 224 are mounted on the primary circuit board 501 and the secondary circuit board 502, respectively. showed that. However, a structure in which some components of the first control circuits 211 to 214 and some components of the second control circuits 221 to 224 are mounted on substrates facing each other may be employed.

The primary side circuit board 501 and the secondary side circuit board 502 are provided with

wireless communication transceivers

504 and 505, respectively. That is, the

transceivers

504 and 505 are mounted on the

circuit boards

501 and 502 on opposite circuit boards. In FIG. 2, since the transceiver 505 is installed on the back side of the secondary circuit board 502, the transceiver 505 is indicated by a dotted line. The

transceivers

504 and 505 perform transmission and reception of wireless signals in the above-described wireless communication. When infrared communication IrDA is used as wireless communication, a commercially available IrDA module can be used as a transceiver. In the present invention, the

transceivers

504 and 505 are considered to be components (parts) of the first control circuits 211 to 214 and the second control circuits 221 to 224, respectively.

Even when the ground potential differs greatly between the primary circuit board 501 and the secondary circuit board 502 and a withstand voltage exceeding 5 kV is required, communication can be performed while ensuring insulation by adjusting the distance between the boards. . Further, since the two transmitters /

receivers

504 and 505 are opposed to each other and there is no obstacle between them, a radio signal can be accurately transmitted / received between the transmitter /

receivers

504 and 505. Further, if infrared communication is selected as the wireless communication system and a transceiver having high infrared directivity is selected, the amount of infrared light leaking outside the power converter cell is reduced. As a result, even when each power converter cell performs infrared communication in parallel (simultaneously) as described above, infrared light transmitted by a certain power converter cell leaks to the outside and is transmitted to other power converter cells. It is possible to prevent erroneous reception. From the above, it is possible to achieve both high-speed communication in which each power converter cell performs communication in parallel and highly reliable communication without communication interference between the power converter cells.

The connector 506 mounted on the primary side circuit board 501 and the electric wire 507 connected thereto are used for connecting the primary side circuit board 501 and the central controller 200. In FIG. 2, although two electric wires are shown as the electric wires 507, the number of electric wires is arbitrary.

When the control signal is transmitted from the central controller 200 to the second control circuits 221 to 224, the control signal is transmitted to the primary side circuit board 501 through the electric wire 507, and the first control circuit 211 of the primary side circuit board 501 is transmitted. ... 214 receive a control signal once. Thereafter, the first control circuits 211 to 214 output this control signal to the transceiver 504. The control signal is converted into a radio signal (an electromagnetic wave signal including infrared rays and visible light) by the transceiver 504 and transmitted from the transceiver 504 of the primary circuit board 501 to the transceiver 505 of the secondary circuit board 502. Is done. Through the above flow, the second control circuits 221 to 224 can receive the control signal from the central controller 200.

The primary circuit board 501 and the secondary circuit board 502 are supported by support materials 510 to 513. A screw can be used for fixing the substrate and the support material, but this is not shown. By applying an insulating material as a material for these supporting materials and screws, it is possible to ensure insulation between the primary circuit board 501 and the secondary circuit board 502. In addition, when infrared communication is used as a wireless communication method, infrared rays are shielded by the support members 510 to 513, infrared rays transmitted from a certain power converter cell leak to the outside, and are erroneously received by other power converter cells. Can be prevented. That is, more reliable infrared communication can be realized by shielding infrared rays with the support members 510 to 513. The configuration in which infrared rays are shielded by the support material is particularly effective when the distance between the substrates is long and the directivity of infrared communication is low.

In FIG. 2, the primary circuit board 501 is disposed on the lower side and the secondary circuit board 502 is disposed on the upper side. However, the primary circuit board 501 is disposed on the upper side and the secondary circuit board 502 is disposed on the lower side. May be arranged respectively.

FIG. 3 is a view of the three-dimensional structure of FIG. 2 as viewed from the front, that is, with the transformer 503 on the back side. In FIG. 3, since the transformer 503 comes to the back, the illustration of the transformer 503 and the

conductor rods

601 and 602 that connect the transformer 503 and the power converter cell are omitted. In FIG. 3, the

components

520 and 521 of the first converters 141 to 144 and the

components

522 and 523 of the second converters 151 to 154 are shown. These components include capacitors or switching elements and heat radiation fins for cooling them. As shown in FIG. 3, parts taller than the transceiver are arranged around the transceiver. Such component arrangement has an effect of shielding wireless signals (signals of electromagnetic waves including infrared rays and visible light) in wireless communication, as in the case of the support members 510 to 513, and is effective in increasing the reliability of wireless communication.

FIG. 4 is a view of the three-dimensional structure of FIG. 2 viewed from the right, that is, the transformer 503 is on the right side. However, in order to show the structure arrange | positioned in the back of the support material 512, illustration about the support material 512 was abbreviate | omitted. In FIG. 4,

transceivers

504 and 505 for wireless communication are arranged in the back of the part 521 of the first converters 141 to 144 and the part 523 of the second converters 151 to 154, respectively. Therefore, these are indicated by broken lines in FIG.

FIG. 4 shows a conductor rod 600 for wiring the primary circuit board 501 and the transformer 503 and a conductor rod 601 for wiring the secondary circuit board 502 and the transformer 503. Also, a conductor bar 603 for wiring the primary side circuit board 501 and the power supply 300 is shown, and a conductor bar 604 for wiring the secondary side circuit board 502 and the load 400 or other power converter cell. The

conductor rods

600, 601, 603 and 604 are fixed to the substrate using terminal blocks 610 to 613, respectively. The members (screws and the like) that connect the conductor rod and the terminal block are not shown. An electric wire may be used instead of the conductor rod. Note that the

conductor rods

600, 603, and 604 and the terminal blocks 610 to 613 are omitted in FIGS.

2 to 4, the first converters 141 to 144 and the first control circuits 211 to 214, the second converters 151 to 154, and the second control circuits 221 to 224 are mounted on the same substrate. The first converters 141 to 144 and the second converters 151 to 154 are also mounted on opposing substrates and wired as shown in FIG. 4 to reduce the size of the power converter cell. Also, the insulation between the first converters 141 to 144 and the second converters 151 to 154 can be ensured by adjusting the distance between the substrates.

FIG. 5 is a circuit configuration example of the power converter cell 101. In FIG. 5, it is assumed that the power source 300 is a DC power source and the power conversion apparatus 1000 outputs AC power to the load 400. The same configuration can be applied to the other power converter cells 102 to 104.

The circuit configuration of the first converter 141 in the power converter cell 101 will be described. The first converter 141 includes a filter capacitor 10 in parallel with the input terminal. A first inverter including four switching elements (MOSFETs in FIG. 5) 11 to 14 is provided. A capacitor 10 is connected to the DC input side of the first inverter. Between the output terminals of the first inverter, a series resonance circuit in which the coil 15, the capacitor 16, and the primary winding of the transformer 131 are connected in series is connected.

The circuit configuration of the second converter 151 in the power converter cell 101 will be described. The second converter 151 includes a diode bridge composed of diodes 21 to 24, and the AC input side of the diode bridge is connected between the secondary windings of the transformer 131. The first inverter, the series resonance circuit, and the diode bridge described above constitute a resonance type converter that is a kind of isolated DC-DC converter.

A smoothing capacitor 20 and a voltage detector 25 are connected between the DC output terminals of the diode bridge. Further, the second converter 151 includes a second inverter composed of four switching elements (MOSFETs in FIG. 5) 31 to 34. A capacitor 20 and a voltage detector 25 are connected to the DC input side of the second inverter. The output terminal of the second inverter becomes the output terminal of the power converter cell 101. From the above circuit configuration, it can be said that each power converter cell includes a resonant converter (hereinafter referred to as a converter) and a second inverter (hereinafter referred to as an inverter).

The converter converts the voltage input to the power converter cell 101 to generate the DC link voltage Vdc1. Although details are omitted, Vdc1 can be controlled to a predetermined value by the on / off operation of the four switching elements. Similarly, power converter cells 102 to 104 include converters, and generate DC link voltages Vdc2 to Vdc4, respectively. Here, the DC link voltages Vdc1 to Vdc4 of the power converter cells may all be controlled to the same value or may be controlled to different values. In FIG. 5, a resonant converter is shown, but any specific circuit system may be used as long as it is an isolated DC-DC converter. When the power supply 300 is an AC power supply, a rectifier circuit (AC-DC converter) may be added before the converter of FIG.

The inverter converts the DC link voltage Vdc1 to generate the output voltage Vo1 of the power converter cell 101. Similarly, power converter cells 102 to 104 include inverters, and convert DC link voltages Vdc2 to Vdc4 to generate output voltages Vo2 to Vo4, respectively. Although not described in detail, the inverter can control the output voltage Vo1 (its instantaneous value) to any of + Vdc1, 0, and −Vdc1 by the on / off operation of the four switching elements.

PWM (pulse width modulation) can be applied to control the inverter. The inverter can output an arbitrary voltage satisfying −Vdc1 ≦ Vo1 ≦ + Vdc1 as an average voltage in the PWM cycle. That is, if the target value of the output voltage Vo1 is within the above range, the PWM cycle (or a half of the time) is set as the control cycle, and the output voltage Vo1 (average value) in each control cycle is set according to the target value. Can be controlled. Since PWM itself is a known technique, details are omitted.

The first control circuit 211 receives control signals related to the first converter 141 and the second converter 151, that is, control signals related to the converter and the inverter, from the central controller 200 (not shown in FIG. 5). Specific examples of control signals related to the converter and the inverter include a target value for the DC link voltage Vdc1 and a target value for the output voltage Vo1.

The first control circuit 211 performs an operation for controlling the DC link voltage Vdc1 according to the target value, and outputs a drive signal for the switching element included in the converter based on the result. Since the calculation performed by the first control circuit 211 is a simple feedback control calculation and PWM processing, a detailed description thereof will be omitted. The first control circuit 211 also receives an inverter detection signal transmitted from the second control circuit 221, specifically, a detection value of the DC link voltage Vdc1, and uses this for control of the DC link voltage Vdc1. . Further, the first control circuit 211 transmits a control signal related to the second converter 151, that is, a target value of the output voltage Vo <b> 1 to the second control circuit 221.

The second control circuit 221 performs an operation for controlling the output voltage Vo1 according to the target value, and outputs a drive signal for the switching element included in the inverter based on the result. Since the calculation performed by the second control circuit 221 is a simple PWM process, a detailed description thereof will be omitted. Further, the second control circuit 221 transmits the detected value of the output voltage Vdc1 detected by the voltage detector 25 to the first control circuit 211. The first control circuits 212 to 214 and the second control circuits 222 to 224 of the power converter cells 102 to 104 operate in the same manner.

In FIG. 5, in order to distinguish between a control signal transmitted from the first control circuit 211 to the second control circuit 221 and a detection signal transmitted from the second control circuit 221 to the first control circuit 211, a broken arrow is used. Two were shown.

FIG. 6 is an example of a composite output voltage (Vos) waveform. 6 assumes a case where the power conversion apparatus 1000 outputs an AC voltage using the configuration of the power conversion apparatus 1000 shown in FIG. 1 and the circuit configuration of the power converter cells 101 to 104 shown in FIG. did. Further, it is assumed that the DC link voltages Vdc1 to Vdc4 of the power converter cells 101 to 104 are all controlled to the same value “Vdc”, and PWM is applied to the inverter control of the power converter cells 101 to 104. A sine wave indicated by a broken line in FIG. 6 is a fundamental wave component included in the combined output voltage Vos. This fundamental wave component may be considered as the target value of the combined output voltage Vos, that is, the target value of the output voltage of the power conversion apparatus 1000.

The inverter of each power converter cell 1000 can output + Vdc, 0, or −Vdc as an instantaneous value. Therefore, the instantaneous value of the combined output voltage Vos is any of −4Vdc, −3Vdc,..., 0,..., + 3Vdc, and + 4Vdc. The power converter can control the combined output voltage Vos to an arbitrary value satisfying −4 Vdc ≦ Vos ≦ + 4 Vdc as an average value in the PWM cycle. In other words, if the target value of the composite output voltage Vos is within the above range, the composite cycle voltage Vos (average value) in each control cycle is set to the target value with the PWM cycle (or half the time) as the control cycle. Can be controlled on the street. By changing the target value into a sine wave shape, the synthetic output voltage Vos having a pseudo sine wave shape shown in FIG. 6 can be generated. The combined output voltage Vos waveform of FIG. 6 can be said to be stepped, and the voltage of one step of the staircase becomes the DC link voltage Vdc.

The control performed by the central control device 200 and the contents of communication in the case of generating the composite output voltage (Vos) waveform in FIG. 6 will be described. The central controller 200 calculates a target value of the combined output voltage Vos within a range of −4 Vdc ≦ Vos ≦ + 4 Vdc for each control cycle. Suppose that the target value calculated in a certain control cycle is 2.5 Vdc. Central controller 200 transmits Vdc as the target value of DC link voltages Vdc1 to Vdc4 to first control circuits 211 to 214 of each power converter cell. In addition, the central controller sets Vdc, Vdc, 0.5Vdc, 0 as target values of the output voltages Vo1, Vo2, Vo3, Vo4 of the respective power converter cells, and sets the target values for the first control circuits 211-214. Send each. The first control circuits 211 to 214 receive the target values of the output voltages Vo1 to Vo4, respectively, and then transmit them to the second control circuits 221 to 224, respectively.

Here, it is assumed that the DC link voltage Vdc is a fixed value, and the value is recorded in both the central control device 200 and the first control circuits 211 to 214. In this case, instead of transmitting the target values of the DC link voltages Vdc1 to Vdc4 to the first control circuits 211 to 214, the central controller 200 instructs the converter of each power converter cell to start up or continue the operation. You can just send

The central controller 200 repeats the above operation every control cycle. By changing the target value of the combined output voltage Vos (average value thereof) into a sine wave shape, the combined output voltage Vos having the waveform shown in FIG. 6 is generated.

According to the first embodiment described above, high-speed communication can be performed from the central controller 200 to the control circuits of the power converter cells 101 to 104 by a low-cost communication system while ensuring high-voltage insulation.

In the second embodiment of the present invention, infrared communication is used as the wireless communication described in the first embodiment.

FIG. 7 shows a three-dimensional structure of the power converter cell in Example 2 of the present invention. The structure of FIG. 7 can be applied to all of the power converter cells 101 to 104. As a difference from the structure shown in FIG. 2, slits 530 and 531 are provided in the primary circuit board 501 and the secondary circuit board 502, respectively. FIG. 7 shows

shield members

532 and 533. These are members attached to the power converter cells 101 to 104 as components of the power converter cells 101 to 104, but FIG. 7 shows a state before being attached.

The shield member 532 is inserted from above the

substrates

501 and 502 through the

slits

530 and 531. In FIG. 7, the

slits

530 and 531 of the substrate have a “U” shape, and the shield member 532 has a “U” shape that matches the

slits

530 and 531. However, the

slits

530 and 531 may have other shapes such as “arc shape”, and the shape of the shield member 532 is not limited as long as it can be inserted into the substrate.

FIG. 8 is a front view of the power converter cells 101 to 104 with the shield member 532 inserted into the substrate. However, in FIG. 8, the shield member 533 is not attached, and the illustration of the shield member 533 is omitted. Similarly to FIG. 3, the illustration of the transformer 503 and the

conductor rods

601 and 602 is omitted, and the

parts

520 and 521 of the first converters 141 to 144 and the

parts

522 and 523 of the second converters 151 to 154 are added. Illustrated. The shield member 532 has an effect of shielding the infrared signal transmitted from the

transceivers

504 and 505 and preventing the infrared signal from leaking to the outside of the power converter cell. It is effective for reliability.

The shield member 533 is attached to the shield member 532 so as to close the opening on the front surface. As means for fixing the shield member 533 to the shield member 532, a screw may be used, or an uneven portion for fitting may be provided in each shield member. Since the shield member 532 is inserted using the slit of the substrate and the shield member 533 is simply fitted (or screwed) into the shield member 532, the work time required for the attachment can be shortened.

FIG. 9 is a view of the power converter cells 101 to 104 as viewed from the front with the

shield members

532 and 533 attached. In FIG. 9, since the

transceivers

504 and 505 are arranged behind the shield member 533, these are indicated by dotted lines. FIG. 10 is a cross-sectional view when the alternate long and short dash line A-A ′ in FIG. 9 is taken as a cutting line. FIG. 11 is a view of the

power converter cells

533, 546 to 549 as viewed from the right with the shield member 533 attached. In FIG. 11, since the

transceivers

504 and 505 are arranged behind the support member 512 and the like, these are indicated by dotted lines. FIG. 12 is a cross-sectional view when the alternate long and short dash line B-B ′ in FIG. 11 is taken as a cutting line.

As can be seen from FIG. 12, the

shield members

532 and 533 and the

substrates

501 and 502 seal the space serving as the path of the infrared signal and block the space outside the power converter cells 101 to 104. However, minute gaps that can be formed between the shield member and the slit provided in the substrate and at the joint between the shield members are allowed.

Here, depending on the place where the power conversion apparatus 1000 is installed, dust may enter the power conversion apparatus 1000, and hence the power converter cells 101 to 104. If dust that has entered the power converter cells 101 to 104 accumulates so as to cover the transceiver, infrared communication cannot be performed normally. 9 to 12 prevents dust from entering the infrared path from the outside of the power converter cells 101 to 104, and stable infrared communication even in an environment where dust can enter the power converter cells 101 to 104. To realize. Such a structure also prevents infrared rays from leaking outside the power converter cells 101 to 104, and is therefore effective for high reliability of infrared communication for the reason described in the first embodiment. Even when the shield member 533 is removed from the power converter cells 101 to 104, if the shield member 532 is attached, the amount of dust accumulated on the transceiver can be reduced.

If an insulating material such as a resin is used as the material of the

shield members

532 and 533, the above-described effects can be obtained while suppressing the influence on the insulation of the

substrates

501 and 502.

FIG. 13 shows a structure of a power converter cell in Example 3 of the present invention. The structure of FIG. 13 can be applied to all of the power converter cells 101 to 104. The infrared communication unit 540 in FIG. 13 includes components related to infrared communication such as a transceiver. The infrared communication path is configured inside the infrared communication unit 540. The infrared communication unit 540 is used in a state where it is attached to the power converter cells 101 to 104 as a component of the power converter cells 101 to 104. However, the infrared communication unit 540 is detachable by a connector described later. The state before being attached to the converter cells 101 to 104 is shown.

The infrared communication unit 540 is attached to the power converter cells 101 to 104 using a connector 514 mounted on the primary circuit board 501 and a connector 515 mounted on the secondary circuit board 502. The infrared communication unit 540 is provided with four slits according to the height of the

substrates

501 and 502. In FIG. 13, a number 541 is assigned to one of the four slits. By inserting the

substrates

501 and 502 into these slits 541, the infrared communication unit 540 is securely fixed to the power converter cells 101 to 104. Even if the infrared communication unit 540 does not have the slit 541, the infrared communication unit 540 is attached to the power converter cells 101 to 104 by a connector, so that the presence or absence of the slit is arbitrary.

FIG. 14 is a view of the power converter cells 101 to 104 viewed from the front with the infrared communication unit 540 attached to the power converter cells 101 to 104. In FIG. 14, since the

transceivers

504 and 505 are arranged behind the infrared communication unit 540, these are indicated by dotted lines. FIG. 15 is a cross-sectional view taken along the alternate long and short dash line C-C ′ in FIG.

The structure of the infrared communication unit 540 will be described with reference to FIG. A cavity surrounded by shield members 546 to 549 exists in the infrared communication unit 540. The secondary side auxiliary circuit board 542 and the secondary side auxiliary circuit board 543 are attached to the upper and

lower shield members

547 and 546 forming the cavity. A part of the first control circuits 211 to 214 and a part of the second control circuits 221 to 224 are mounted on the primary side auxiliary circuit board 542 and the secondary side auxiliary circuit board 543, respectively. As a specific example, FIG. 15 shows an example in which the transceiver 504 and the connector 544 are mounted on the primary side auxiliary circuit board 542, and the transceiver 505 and the connector 545 are mounted on the secondary side auxiliary circuit board 543, respectively.

The primary side auxiliary circuit board 542 is fixed to the shield member 546 with screws or the like. Similarly, the secondary side auxiliary circuit board 543 is fixed to the shield member 547 with screws or the like. The shield members 546 to 549 are also connected by screws or the like. Although detailed illustration is omitted, the shield member 548 is provided with an opening for letting out the connector 544 and the connector 545 to the outside.

The connector 544 of the infrared communication unit 540 is connected to the connector 514 of the primary circuit board 501, and the connector 545 of the infrared communication unit 540 is connected to the connector 515 of the secondary circuit board 502. These connectors make it possible to attach and remove the infrared communication unit 540 and the power converter cell.

Connectors

514 and 544 transmit control signals from the primary side circuit board 501 to the primary side auxiliary circuit board 542. The control signal transmitted to the primary side auxiliary circuit board 542 is transmitted as an infrared signal by the transceiver 504 of the primary side auxiliary circuit board 542. The transceiver 505 of the secondary side auxiliary circuit board 543 receives this infrared signal and converts it again into a control signal. Control signals are transmitted from the secondary side auxiliary circuit board 543 to the secondary side circuit board 502 by the

connectors

515 and 545. The second converter of the secondary circuit board 502 is controlled according to the control signal transmitted as described above.

As can be seen from FIG. 15, the infrared communication unit 540 blocks the infrared path and the external space. However, minute gaps that can be formed between the shield members 546 to 549 and the

connectors

514 and 515 and between the shield members 546 to 549 are allowed.
14 to 15 prevents dust from entering the infrared path from the outside of the power converter cells 101 to 104, and stable infrared communication even in an environment where dust can enter the power converter cells 101 to 104. Is realized. Such a structure also prevents infrared rays from leaking outside the power converter cells 101 to 104, and is therefore effective for high reliability of infrared communication for the reason described in the first embodiment.

If an insulating material such as resin is used as the material of the shield members 546 to 549, infrared rays can be shielded while minimizing the influence on the insulation of the

substrates

501, 502, 542, and 543.

FIG. 16 shows the configuration of the power conversion device and the communication system thereof according to the fourth embodiment of the present invention.

The power conversion device 2000 includes four power converter cells 105 to 108. As a difference from FIG. 1, the input terminals of the power converter cells 105 to 108 are connected in series, and the combined input terminal is connected to the external power supply 300. On the other hand, the output terminals of power converter cells 105 to 108 are connected in parallel to load 400.

The power converter cells 105 to 108 include primary side circuits 115 to 118, secondary side circuits 125 to 128, and transformers 135 to 138, respectively. Here, the primary side circuits 115 to 118 include second converters 155 to 158 and second control circuits 225 to 228 for controlling them, respectively, and the secondary side circuits 125 to 128 include the first converters 145 to 148 and If it is defined that each of the first control circuits 215 to 218 for controlling these is provided, the communication path described in the first embodiment can be applied as it is. That is, when the central controller 200 transmits a control signal to the second control circuit 225 of the power converter cell 105, the central controller 200 once transmits this control signal to the first control circuit 215. The first control circuit 215 transmits the received control signal to the second control circuit 225 by wireless communication.

With the above configuration, a high voltage power source obtained from a high voltage distribution line can be used as the power source 300, and even in that case, the effects of the present invention can be obtained.

In the fifth embodiment of the present invention, a three-phase AC output power converter is configured using the power converter and the communication system described in the first embodiment.

FIG. 17 shows the configuration of the power conversion device and its communication system in the fifth embodiment. The power conversion device 3000 includes three power conversion devices 1000 described in the first embodiment. As shown in FIG. 17, one of the output terminals included in the three power conversion apparatuses 1000 constitutes a three-phase output terminal and is connected to the three-phase load 401. The other of the output terminals included in the three power converters 1000 is connected to each other to form a neutral point in a Y-connected three-phase AC circuit.

As described in the first embodiment, the power conversion device 1000 includes the control device 200. Therefore, the power conversion device 3000 of FIG. 17 includes three control devices 200, but the three control devices may be combined into one.

With the above configuration, the effect of the present invention can be obtained even in a power converter that outputs three-phase alternating current, and can be applied to an inverter that drives a three-phase high-voltage motor and a PCS for a three-phase alternating current power system.

101-104: Power converter cell, 111-114: Primary side circuit, 121-124: Secondary side circuit, 131-134, 503: Transformer, 141-144: First converter, 151-154: Second Converter: 200: Central controller, 211-214: First control circuit, 221-224: Second control circuit, 230: Current detector, 300: Power supply, 400: Load, 401: Three-phase load, 501: 1 Secondary circuit board, 502: Secondary circuit board, 504, 505: Transmitter / receiver for wireless communication, 506, 514, 515, 544, 545: Connector, 507: Electric wire, 510-513: Support material, 520, 521: Parts of the first converter, 522, 523: parts of the second converter, 530, 531: slit of the substrate, 532, 533, 546 to 549: shield member, 540: wireless communication unit, 5 1: wireless communication unit slit, 542: primary side auxiliary circuit board, 543: secondary side auxiliary circuit board, 600, 601, 603, 604: conductor rod, 610 to 613: terminal block, 10, 16, 20: Capacitors 11, 12-14, 31-34: switching elements, 15: coils, 21-24: diodes, 25: voltage detectors, 1000, 2000, 3000: power converters

Claims

A main circuit including a first converter and a second converter; a first control circuit for controlling the first converter; and a second control circuit for controlling the second converter; And a power converter cell that operates upon receiving a control signal from a central controller for the second control circuit,
A first substrate on which a part or all of the components of the first control circuit are mounted and a second substrate on which a part or all of the components of the second control circuit are mounted face each other by a support material. Fixed in place,
A control signal from the central controller is supplied to the first control circuit, and the first converter is controlled by the first control circuit, and the control signal is further transmitted from the first control circuit and the second control circuit. The power converter cell is transmitted to the second control circuit by wireless communication between the first and second converters, and the second converter is controlled by the second control circuit.
The power converter cell according to claim 1, comprising:
A part or all of the components of the first control circuit and the first converter are mounted on the first substrate, and one of the second control circuit and the second converter is mounted on the second substrate. A power converter cell in which a part or all components are mounted.
A power converter cell according to claim 1 or claim 2, wherein
The first control circuit and the second control circuit each include a transceiver for transmitting and receiving a wireless signal in the wireless communication, and the transceiver included in the first control circuit and the transceiver included in the second control circuit are A power converter cell mounted on substrates facing each other.
The power converter cell according to any one of claims 1 to 3, wherein
In the main circuit, the first converter and the second converter are coupled by a transformer, one terminal of the transformer is connected to the first substrate, and the other terminal of the transformer is A power converter cell connected to the second substrate.
The power converter cell according to any one of claims 1 to 4, wherein
The wireless communication between the first control circuit and the second control circuit is communication using an optical signal, and is formed by a light shield member between the first substrate and the second substrate facing each other. A power converter cell comprising an optical communication path.
The power converter cell according to claim 5, wherein
A power converter cell that performs infrared communication as the wireless communication.
A power converter cell according to claim 5 or claim 6, wherein
The power converter cell includes an optical shield member, and the shield member shields the optical signal.
A power converter cell according to any one of claims 5 to 7, comprising:
The light shield member is inserted into a slit provided in the first substrate and the second substrate, thereby forming an optical communication path formed by the light shield member. cell.
A power converter cell according to any one of claims 5 to 8, comprising:
The optical signal path is sealed by the optical shield member, the first substrate, and the second substrate, and the optical signal path is blocked from the space outside the power converter cell. A power converter cell characterized by.
A power converter cell according to any one of claims 5 to 9, wherein
A power converter cell, wherein a transmitter / receiver for transmitting and receiving an optical signal is detachably attached to the first substrate and the second substrate by a connector.
A power converter cell according to any one of claims 5 to 10, comprising:
The power converter cell, wherein the light shield member is an insulator.
A power converter cell according to any one of claims 5 to 11, comprising:
A transceiver that transmits and receives an optical signal is attached to the first substrate and the second substrate, and the first substrate and the second substrate on which the transceiver is mounted include A power converter cell, wherein a component taller than a transceiver is mounted, and a radio signal transmitted from the transceiver is prevented from going outside the power converter cell.
A power conversion device configured by using a plurality of power converter cells according to any one of claims 1 to 12,
External connection terminals of the first converter of the main circuit of the plurality of sets of the power converter cells are connected in parallel, and external connection terminals of the second converter of the main circuit of the plurality of sets of the power converter cells Are connected in series,
A control signal from the central control device is supplied to a plurality of the first control circuits, and the corresponding first converters are controlled by the first control circuits, and the control signals are transmitted to the respective first control circuits. A power conversion device, wherein the power is transmitted from a circuit to the corresponding second control circuit by wireless communication, and the second converter is controlled by the second control circuit.
The power conversion device according to claim 13,
The external connection terminal of the first converter is connected in parallel to an external power supply, so that the central control unit and the first control circuit of each power converter cell operate at the same ground potential, A power converter, wherein wired communication is performed between the central controller and the first control circuit of each power converter cell.