JP6457354B2 - Power converter - Google Patents

Description

  The present invention relates to a power converter that converts a single-phase high-frequency current into a three-phase voltage.

  As a conventional power conversion device, for example, a device that generates a single-phase high-frequency current using a resonance circuit and performs power conversion using this as a current source is aimed at increasing the efficiency of a transformer that constitutes an insulation circuit. (For example, refer to Patent Document 1). Further, for example, one that performs three-phase AC-AC direct conversion using a matrix converter is also known.

  Here, for example, it is assumed that a single-phase high-frequency current from a current source as disclosed in Patent Document 1 is converted into a three-phase voltage using a single-phase three-phase matrix converter. In this case, as shown in FIG. 3, the single-phase three-phase matrix converter includes single-phase input terminals h and l for inputting a single-phase high-frequency current from a single-phase high-frequency current source 301, and three-phase output terminals u, v, It has six bidirectional semiconductor switches SW1 to SW6 that are connected to w.

  Each of the bidirectional semiconductor switches SW1 to SW6 is configured by connecting two reverse conducting semiconductor switch elements in series in different directions or by connecting two reverse blocking semiconductor switch elements in different directions in parallel. . FIG. 3 illustrates a case where two reverse conducting semiconductor switch elements are connected in series in different directions. Each of the bidirectional semiconductor switches SW1 to SW6 has an open state in which both semiconductor switches are turned off and two diode operations in which one semiconductor switch is turned on and the other semiconductor switch is turned off in response to a command from the control unit. The four states of the state and the short-circuit state in which both semiconductor switches are turned on can be switched.

  The single-phase three-phase matrix converter shown in FIG. 3 connects three-phase high-frequency currents from a single-phase high-frequency current source 301 by connecting three-phase capacitors and three-phase loads to the three-phase output terminals u, v, and w. It becomes possible to configure a power converter that can convert the phase voltage to supply the phase voltages of Vu, Vv, and Vw to the three-phase load.

JP2013-226002A

  By the way, in the single-phase three-phase matrix converter shown in FIG. 3, the combination of the states that can be taken by the bidirectional semiconductor switches SW1 to SW6 can take four states by one bidirectional semiconductor switch. There are 4096 streets. Therefore, it is necessary to determine an optimal switching procedure for safely switching the current path from a specific path to another path from among the 4096 patterns.

  This invention is made | formed in view of this viewpoint, and it is providing the power converter device which can convert a single phase high frequency current into a three-phase voltage safely.

The power conversion device according to the present invention that achieves the above object is as follows.
A single-phase three-phase matrix converter having six bidirectional semiconductor switching elements connected between a single-phase high-frequency current source and a three-phase load;
A current detector for detecting a single-phase high-frequency current input from the single-phase high-frequency current source to the single-phase three-phase matrix converter;
A voltage detector for detecting a three-phase voltage applied to the three-phase load from the single-phase three-phase matrix converter;
A control unit for controlling the connection state of the six bidirectional semiconductor switching elements based on a detection current detected by the current detector and a three-phase detection voltage detected by the voltage detector;
The controller does not open the connection state of the six bidirectional semiconductor switching elements from the single-phase high-frequency current source side, and does not short-circuit from the three-phase load side. In addition, switching near the zero point of the single-phase high-frequency current to control the current path of the single-phase three-phase matrix converter,
Is.

  According to the present invention, it is possible to safely convert a single-phase high-frequency current into a three-phase voltage.

It is a block diagram which shows the principal part structure of the power converter device which concerns on one Embodiment. It is explanatory drawing which shows the example of 1 operation | movement of FIG. It is a figure which shows the structure of a single phase three phase matrix converter.

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

  FIG. 1 is a block diagram showing a main configuration of a power conversion device according to an embodiment. The power conversion device according to the present embodiment includes a single-phase three-phase matrix converter 100, a current detector 110, a voltage detector 120, and a control unit 130.

  The single-phase three-phase matrix converter 100 has six bidirectional semiconductor switching elements as in FIG. In the single-phase three-phase matrix converter 100, a single-phase high-frequency current source 200 that outputs a single-phase high-frequency current of, for example, 20 kHz is connected to a single-phase input terminal, and a three-phase capacitor 210 and, for example, a commercial frequency three-phase output terminal are connected to the three-phase output terminal. A three-phase load 220 driven by a phase voltage is connected.

  The current detector 110 is connected to the input side of the single-phase three-phase matrix converter 100 and detects a single-phase high-frequency current input from the single-phase high-frequency current source 200 to the single-phase three-phase matrix converter 100. The detected current detected by the current detector 110 is supplied to the control unit 130.

  The voltage detector 120 is connected to the output side of the three-phase matrix converter 100 and detects a three-phase voltage applied from the three-phase matrix converter 100 to the three-phase load 220. In the present embodiment, voltage detector 120 detects a three-phase line voltage between three-phase capacitor 210 and three-phase load 220. The three-phase detection voltage detected by the voltage detector 120 is supplied to the control unit 130.

  The control unit 130 includes six bidirectional semiconductor switching elements constituting the single-phase three-phase matrix converter 100 based on the detected current detected by the current detector 110 and the three-phase detected voltage detected by the voltage detector 120. Control the connection status of. Specifically, the control unit 130 does not open the connection state of the six bidirectional semiconductor switching elements when viewed from the single-phase high-frequency current source 200 side, and short-circuits when viewed from the three-phase load 220 side. The current path of the single-phase three-phase matrix converter 100 is controlled by switching near the zero point of the single-phase high-frequency current so as not to enter the state.

  In the present embodiment, the control unit 130 includes a vector operation unit 131 and a logic operation unit 132. The vector calculation unit 131 includes six bidirectional semiconductor switches of the single-phase three-phase matrix converter 100 based on the detection current detected by the current detector 110 and the three-phase detection voltage detected by the voltage detector 120. Current command value vectors respectively indicating the state before and after switching are calculated.

  The logic operation unit 132 is based on the current command value vector calculated by the vector operation unit 131 and the three-phase detection voltage detected by the voltage detector 120, and the six bidirectional semiconductors of the single-phase three-phase matrix converter 100. A current command value vector indicating an intermediate state from the state before switching to the state after switching is calculated.

  In the present embodiment, a current command value vector Sk indicating the state of six bidirectional semiconductor switches each having two semiconductor switches is defined as shown in the following equation (1), and the conduction state of each semiconductor switch is defined. 1. The blocking state is 0.

Sk = (Skuph, Skvph, Skwph, Skunh, Skvnh, Skwnh,
Skupl, Skvpl, Skwpl, Skunl, Skvnl, Skwnl) (k = 0,1,…, 4) (1)

  The subscripts u, v, and w in the above equation (1) represent semiconductor switches that are connected to the three-phase output terminals u, v, and w in FIG. The subscript p represents a semiconductor switch that controls a current in a direction from the input side to the output side. The subscript n represents a semiconductor switch that controls a current in a direction from the output side to the input side. The subscript h represents a semiconductor switch connected to the input terminal h (upper arm). The subscript l represents a semiconductor switch connected to the input terminal l (lower arm).

  Based on the detected current detected by the current detector 110 and the three-phase detected voltage detected by the voltage detector 120, the vector calculation unit 131 performs the state S0 and switching of the semiconductor switch before switching according to the equation (1). The state S4 of the subsequent semiconductor switch is calculated. Information on the state S0 and the state S4 is supplied to the logic operation unit 132.

  The logical operation unit 132 calculates the current command value vectors S0R, S0L, S4R, and S4L obtained by changing the bit arrays of the state S0 and the state S4 from the vector operation unit 131 according to the following equations (2) and (3). In addition, the logical operation unit 132 sets the case where each line voltage of the three-phase detection voltage detected by the voltage detector 120 is positive according to the following equation (4), and sets the negative case as 0. And voltage code vectors VsR and VsL shown in (6) are defined. Then, the logic operation unit 132 uses the calculated current command value vectors S0R, S0L, S4R, S4L and the defined voltage code vectors VsR, VsL based on the bits shown in the following equations (7), (8), and (9). Current command value vectors S1, S2, and S3 are calculated by calculation to indicate sequential intermediate states from the semiconductor switch state S0 before switching to the semiconductor switch state S4 after switching.

SkR = (Skwnh, Skuph, Skvph, Skwph, Skunh, Skvnh,
Skwnl, Skupl, Skvpl, Skwpl, Skunl, Skvnl) (k = 0,4) (2)
SkL = (Skvph, Skwph, Skunh, Skvnh, Skwnh, Skuph,
Skvpl, Skwpl, Skunl, Skvnl, Skwnl, Skupl) (k = 0,4) (3)

Vsuv = {1 (Vu <Vv), 0 (Vu> Vv)}
Vsvw = {1 (Vv <Vw), 0 (Vv> Vw)}
Vswu = {1 (Vw <Vu), 0 (Vw> Vu)}
... (4)
However, Vsuv, Vsvw, and Vswu indicate line voltages of the three-phase outputs u, v, and w, and Vu, Vv, and Vw indicate phase voltages.
VsR = (Vsuv, Vsvw, Vswu, not Vsuv, not Vsvw, not Vswu, Vsuv, Vsvw, Vswu,
not Vsuv, not Vsvw, not Vswu) (5)
VsL = (Vswu, Vsuv, Vsvw, not Vswu, not Vsuv, not Vsvw, Vswu, Vsuv, Vsvw,
not Vswu, not Vsuv, not Vsvw) (6)
However, not indicates logical negation.

S1 = S0 or (S4 and S0R and VsR) or (S4 and S0L and VsL) (7)
S2 = (S4 and S0) or (S4 and S0R and VsR) or (S4 and S0L and VsL) or (S0 and S4R
and VsR) or (S0 and S4L and VsL) (8)
S3 = S4 or (S0 and S4R and VsR) or (S0 and S4L and VsL) (9)
Where or is logical sum, and and is logical product.

  The logic operation unit 132 may include a dedicated combinational logic circuit that executes each bit operation described above.

  Then, the control unit 130 sequentially switches the connection state of the six bidirectional semiconductor switches of the single-phase three-phase matrix converter 100 from the state S0 before switching to the state S4 after switching through the intermediate states S1, S2, and S3. As a result, the single-phase high-frequency AC input current from the single-phase high-frequency current source 200 can be converted into a three-phase voltage and supplied to the three-phase load 220.

  Here, the state S0 at a certain moment of the single-phase three-phase matrix converter 100 is in the conductive state between the terminals hu and l-w in FIG. 3, and this is the next state S4 between h-v and l. The case of switching to the conductive state between −w will be specifically described. It is assumed that the phase voltage at this time is Vu> Vv> Vw.

  First, the above state is made into a bit arrangement as follows according to the equations (1) to (6).

S0 = (100100 001001)
S4 = (010010 001001)
VsR = (001110 001110)
VsL = (100011 100011)
S0R = (010010 100100)
S0L = (001001 010010)
S4R = (001001 100100)
S4L = (100 100 010010)

  Next, intermediate expressions necessary for calculating the intermediate states S1, S2, and S3 are calculated as follows.

(S4 and S0R and VsR) = (010010 001001) and
(010010 100100) and
(001110 001110)
= (000010 000000)
(S4 and S0L and VsL) = (010010 001001) and
(001001 010010) and
(100011 100011)
= (000000 000000)
(S4 and S0) = (010010 001001) and
(100100 001001)
= (000000 001001)
(S0 and S4R and VsR) = (100100 001001) and
(001001 100100) and
(001110 001110)
= (000000 000000)
(S0 and S4L and VsL) = (100100 001001) and
(100100 010010) and
(100011 100011)
= (100000 000000)

  Thereafter, sequential intermediate states S1, S2, and S3 are obtained as follows.

S1 = S0 or (S4 and S0R and VsR) or (S4 and S0L and VsL)
= (100100 001001) or
(000010 000000) or
(000000 000000)
= (100110 001001)
S2 = (S4 and S0) or (S4 and S0R and VsR) or (S4 and S0L and VsL)
or (S0 and S4R and VsR) or (S0 and S4L and VsL)
= (000000 001001) or
(000010 000000) or
(000000 000000) or
(000000 000000) or
(100000 000000)
= (100010 001001)
S3 = S4 or (S0 and S4R and VsR) or (S0 and S4L and VsL)
(010010 001001) or
(000000 000000) or
(100000 000000)
= (110010 001001)

The above states S0, S1, S2, S3, and S4 are arranged in the switching order as follows.
S0 = (100100 001001)
S1 = (100110 001001)
S2 = (100010 001001)
S3 = (110010 001001)
S4 = (010010 001001)

  FIG. 2 conceptually shows the state of the semiconductor switch in this case. In FIG. 2, a white arrow from the three-phase output terminal v to u indicates that the u-phase voltage is higher than the v-phase voltage.

  As described above, according to the power conversion device of the present embodiment, the connection state of the six bidirectional semiconductor switching elements of the single-phase three-phase matrix converter 100 is in an open state when viewed from the single-phase high-frequency current source 200 side. In addition, the current path of the single-phase three-phase matrix converter 100 can be switched by controlling near the zero point of the single-phase high-frequency current so as not to be short-circuited when viewed from the three-phase load 220 side. Therefore, it is possible to safely convert the single-phase high-frequency current into a three-phase voltage.

  The present invention can be applied to a power conversion device that includes a single-phase three-phase matrix converter and converts a single-phase high-frequency current into a three-phase voltage of a commercial frequency.

DESCRIPTION OF SYMBOLS 100 Single phase three phase matrix converter 110 Current detector 120 Voltage detector 130 Control part 131 Vector operation part 132 Logic operation part 200 Single phase high frequency current source 210 Three phase capacitor 220 Three phase load SW1-SW6 Bidirectional semiconductor switch

Claims (4)

A single-phase three-phase matrix converter having six bidirectional semiconductor switching elements connected between a single-phase high-frequency current source and a three-phase load;
A current detector for detecting a single-phase high-frequency current input from the single-phase high-frequency current source to the single-phase three-phase matrix converter;
A voltage detector for detecting a three-phase voltage applied to the three-phase load from the single-phase three-phase matrix converter;
A control unit for controlling the connection state of the six bidirectional semiconductor switching elements based on a detection current detected by the current detector and a three-phase detection voltage detected by the voltage detector;
The controller does not open the connection state of the six bidirectional semiconductor switching elements from the single-phase high-frequency current source side, and does not short-circuit from the three-phase load side. In addition, switching near the zero point of the single-phase high-frequency current to control the current path of the single-phase three-phase matrix converter,
Power conversion device. The power conversion device according to claim 1,
The controller is
Based on the detection current and the three-phase detection voltage, a vector calculation unit that calculates current command value vectors respectively indicating a state before switching and a state after switching of the six bidirectional semiconductor switches;
Based on the current command value vector calculated by the vector calculation unit and the three-phase detection voltage, an intermediate state from the state before switching to the state after switching of the six bidirectional semiconductor switches is shown. A logic operation unit for calculating a current command value vector,
The connection state of the six bidirectional semiconductor switches is sequentially switched from the state before switching to the state after switching through the intermediate state.
The power converter characterized by the above-mentioned. The power conversion device according to claim 2,
When the current command value vector indicating the state before the switching of the six bidirectional semiconductor switches is S0 and the current command value vector indicating the state after the switching is S4, the logical operation unit is represented by the following formula (1 ) And VsR indicating the direction of the three-phase detection voltage defined by (2), VsR and VsL are calculated, and based on these VsR and VsL and S0 and S4, the following equations (3), (4 ) And (5) to calculate current command value vectors S1, S2 and S3 indicating the sequential intermediate state from S0 to S4.
The power converter characterized by the above-mentioned.
VsR = (Vsuv, Vsvw, Vswu, not Vsuv, not Vsvw, not Vswu, Vsuv, Vsvw, Vswu,
not Vsuv, not Vsvw, not Vswu) (1)
VsL = (Vswu, Vsuv, Vsvw, not Vswu, not Vsuv, not Vsvw, Vswu, Vsuv, Vsvw,
not Vswu, not Vsuv, not Vsvw) (2)
However,
Vsuv = {1 (Vu <Vv), 0 (Vu> Vv)}
Vsvw = {1 (Vv <Vw), 0 (Vv> Vw)}
Vswu = {1 (Vw <Vu), 0 (Vw> Vu)}
Vsuv, Vsvw and Vswu are the line voltages of the three-phase outputs u, v and w, Vu, Vv and Vw are the phase voltages, and not is a logic negation.
S1 = S0 or (S4 and S0R and VsR) or (S4 and S0L and VsL) (3)
Where or is logical sum, and and is logical product.
S2 = (S4 and S0) or (S4 and S0R and VsR) or (S4 and S0L and VsL) or (S0 and S4R
and VsR) or (S0 and S4L and VsL) (4)
S3 = S4 or (S0 and S4R and VsR) or (S0 and S4L and VsL) (5)
However,
Sk = (Skuph, Skvph, Skwph, Skunh, Skvnh, Skwnh,
Skupl, Skvpl, Skwpl, Skunl, Skvnl, Skwnl) (k = 0,1,…, 4)
SkR = (Skwnh, Skuph, Skvph, Skwph, Skunh, Skvnh,
Skwnl, Skupl, Skvpl, Skwpl, Skunl, Skvnl) (k = 0,4)
SkL = (Skvph, Skwph, Skunh, Skvnh, Skwnh, Skuph,
(Skvpl, Skwpl, Skunl, Skvnl, Skwnl, Skupl) (k = 0,4)
It is. Subscripts u, v, and w are semiconductor switches connected to the three-phase output terminals u, v, and w, subscript p is a semiconductor switch that controls current in the direction from the input side to the output side, and subscript n is the output side. Switch for controlling the current in the direction from the input side to the input side, the suffix h is a semiconductor switch connected to one of the input terminals (upper arm), and the suffix l is connected to the other of the input terminals (lower arm) Each represents a semiconductor switch, and is “1” when conducting and “0” when interrupting. The power conversion device according to claim 3,
The logical operation unit has a dedicated combinational logic circuit,
The power converter characterized by the above-mentioned.

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