JP2010213514A - Device for switching power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To completely remove a voltage fluctuation by a dead time without correcting a commutation signal in a device for switching a power supply. <P>SOLUTION: The device for switching the power supply is composed of a current-polarity detector detecting the polarity of a load current, a current commutation-signal generator using an output from the current-polarity detector, a voltage comparator detecting the magnitude of the voltage of a voltage source and a voltage commutation-signal generator using the output from the voltage comparator. The device for switching the power supply is further composed of a sharing appliance selecting the output from the current commutation-signal generator and the output from the voltage commutation-signal generator so as to reach the same ratio within a predetermined time and for output to a bidirectional switch. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a device that can freely control an input voltage of a load by switching a plurality of voltage sources and connecting to a load, such as a matrix converter.

  The matrix converter has a configuration in which a three-phase voltage source and a three-phase load are connected by nine bidirectional switches, and an arbitrary voltage can be applied to the three-phase load by controlling the bidirectional switches. In addition, the power conversion device can easily realize power regeneration and a current flowing through the three-phase voltage source as a sine wave having a power factor of 1.

  The matrix converter controls the average voltage applied to the load by switching the voltage source connected to the load with a bidirectional switch, but when switching (hereinafter referred to as commutation), the switching target is due to the switch operating delay, etc. In order to prevent the two voltage sources from being short-circuited or to open the load, the bidirectional switch is sequentially turned on / off with a predetermined delay time.

  FIG. 2 is a circuit diagram for explaining the commutation operation. Two voltage sources 31 and 32, and bidirectional switches (bidirectional switches composed of reverse conducting switches) 1 and 2 connected thereto, respectively. The load 4 connected to the other of the bidirectional switches, the current polarity detector 5 for detecting the polarity of the negative overcurrent IL, and the output of the current polarity detector and the commutation command S are input bidirectionally. The current commutation signal generator 8 outputs a switch control signal. The bidirectional switch 1 composed of a reverse conduction switch has a configuration in which reverse conduction switches 11 and 12 are connected in series in the reverse direction, and two control signals Ga1 and Ga2 for controlling the reverse conduction switches 11 and 12 respectively are inputted. Yes. Similarly, the bidirectional switch 2 composed of reverse conduction switches also receives two control signals Gb1 and Gb2 for controlling the reverse conduction switches 21 and 22, respectively.

  FIG. 5 shows a commutation sequence when the voltage source connected to the load 4 is switched from the voltage source 31 of the voltage Va to the voltage source 32 of the voltage Vb in the circuit of FIG. The change of the control signal of each switch produced | generated is shown. Before the time t1, the commutation signal S = Sa is in a state in which the bidirectional switch 1 comprising the reverse conducting switch is turned on and the bidirectional switch 2 comprising the reverse conducting switch is turned off. The control signals Ga1 and Ga2 of the reverse conduction switches 11 and 12 of the directional switch 1 are both on, and the control signals Gb1 and Gb2 of the bidirectional switch 2 comprising the reverse conduction switches are both off and the load 4 The voltage VL is the voltage Va of the voltage source 31. The commutation sequence starts by changing to a commutation signal S = Sb at time t1. When the negative overcurrent IL is positive, as shown on the left side of FIG. 5, Ga1 is first turned off at time t1, Gb2 is turned on at time t2 after the lapse of dead time td, and at time t3 after the lapse of time td. When Ga2 is turned off and Gb1 is turned on at time t4 after elapse of td, commutation is completed. The reason for setting the dead time td in this manner and sequentially turning on and off is to prevent the voltage source from being short-circuited or the load from being released due to a delay in the operation of the switch. The load voltage is actually switched at time t3 when Va> Vb, and at time t2 when Va <Vb.

  When the load current IL is negative, the commutation sequence shown on the right side of FIG. 5 is performed, and the load voltage is actually switched at time t2 when Va> Vb, and at time t3 when Va <Vb. Become.

  That is, depending on the polarity of the load current, the load voltage between t2 and t3 is a higher voltage source voltage when IL> 0, and a lower voltage source voltage when IL <0.

  FIG. 3 is a circuit diagram for explaining a commutation operation by a method different from that in FIG. The difference from FIG. 2 is that instead of the current polarity detector 5, the voltage comparator 6 detects and outputs the magnitude relationship between the voltage Va of the voltage source 31 and the voltage Vb of the voltage source 32, and the current commutation signal generator The voltage commutation signal generator 7 outputs the control signal of the bidirectional switch by inputting the output of the voltage comparator 6 and the commutation command S instead of 8.

  FIG. 6 shows a commutation sequence when the voltage source connected to the load 4 is switched from the voltage source 31 of the voltage Va to the voltage source 32 of the voltage Vb in the circuit of FIG. The change of the control signal of each switch produced | generated is shown. Before the time t1, since the commutation signal S = Sa is in a state in which the bidirectional switch 1 is turned on and the bidirectional switch 2 is turned off, the control signals Ga1 of the reverse conducting switches 11 and 12 of the bidirectional switch 1 are set. And Ga2 are both in the on state, the control signals Gb1 and Gb2 of the bidirectional switch 2 are both in the off state, and the voltage VL of the load 4 is the voltage Va of the voltage source 31. The commutation sequence starts by changing to a commutation signal S = Sb at time t1. When Va> Vb, as shown on the left side of FIG. 6, Gb2 is first turned on at time t1, Ga2 is turned off at time t2 after elapse of the dead time td, and Gb1 is turned on at time t3 after elapse of td. Then, when Ga1 is turned off at time t4 after td has elapsed, commutation is completed. The reason for setting the dead time td in this manner and sequentially turning on and off is to prevent the voltage source from being short-circuited or the load from being released due to a delay in the operation of the switch. The load voltage is actually switched at time t2 when IL> 0, and at time t3 when IL <0.

  When Va <Vb, the commutation sequence shown on the right side of FIG. 6 is performed, and the load voltage is actually switched at time t3 when IL> 0 and at time t2 when IL <0.

  That is, depending on the polarity of the load current, the load voltage between t2 and t3 is a higher voltage source voltage when IL <0, and a lower voltage source voltage when IL> 0.

  Even when the current commutation signal generator depending on the polarity of the load current shown in FIG. 2 is used or when the voltage commutation signal generator based on the magnitude relation of the power supply voltage shown in FIG. Since the load voltage depends only on the dead time at the time of commutation according to the polarity, a commutation signal S in which the voltage fluctuation of the load due to the dead time is corrected in advance according to the polarity of the load current is generated, A technique for applying a desired voltage has been proposed.

JP 2005-20799 A

  The problem to be solved can be corrected by correcting the commutation signal timing for the load voltage fluctuation due to the dead time. For this purpose, it is necessary to know the accurate dead time. However, since the actual dead time changes according to the operation delay time of the photocoupler and the switching element that insulate and transmit the signal, it is difficult to accurately grasp the dead time.

According to the first aspect of the present invention, a plurality of reverse conducting switches each composed of two reverse conducting switches each composed of a switching element capable of switching a unidirectional current and a diode connected in reverse parallel to the switching element are connected in series in a reverse direction. A voltage source is connected to each terminal of the bidirectional switch and the bidirectional switch, and all the terminals of the bidirectional switch not connected to the voltage source are short-circuited and connected to the load. The two bidirectional switches that perform different switching operations in the bidirectional switch are defined as a bidirectional switch A and a bidirectional switch B, respectively, and the voltage source connected to the bidirectional switch A Is the voltage source A, the voltage source connected to the bidirectional switch B is the voltage source B, and the current polarity for detecting the polarity of the current flowing through the load A state in which the load is connected to either the voltage source A or the voltage source B without short-circuiting the voltage source A and the voltage source B by inputting the output of the output device and the current polarity detector A current commutation signal generator for generating and outputting a signal for controlling the two switching elements of the bidirectional switch A and a signal for controlling the two switching elements of the bidirectional switch B so as to maintain A voltage comparator that detects the magnitude relationship between the voltages of the voltage source A and the voltage source B, and an output of the voltage comparator are input so that the voltage source A and the voltage source B are not short-circuited. A signal for controlling the two switching elements of the bidirectional switch A and the two switching elements of the bidirectional switch B are controlled so as to maintain a state of being connected to either the voltage source A or the voltage source B. Signal In the power switching device comprising a voltage commutation signal generator to form an output,
Sharing the output of the current commutation signal generator and the output of the voltage commutation signal generator so as to have the same ratio within a predetermined time and outputting them to the bidirectional switch A and the bidirectional switch B It is a power supply switching device characterized by comprising a device.

  According to the invention of claim 2, the power supply according to claim 1, wherein the power supply is a bidirectional switch configured by connecting two reverse blocking switches that can switch a unidirectional current and block a reverse current in antiparallel. It is a switching device.

  That is, in order to solve the above problem, the present invention does not correct the load voltage fluctuation due to dead time by correcting the commutation signal timing, but the output of the current commutation signal generator and the voltage commutation. It is characterized by comprising a divider that selects the output of the signal generator to be the same ratio within a predetermined time and outputs it to each bidirectional switch.

  In the present invention, since the load voltage fluctuation due to the dead time is not corrected by correcting the commutation signal timing, there is an advantage that the actual dead time required for the correction is not required.

It is explanatory drawing which showed the commutation operation | movement of this invention. (Example 1) It is a circuit diagram for demonstrating the commutation operation | movement using a current commutation signal generator. It is a circuit diagram for demonstrating the commutation operation | movement using a voltage commutation signal generator. It is explanatory drawing which showed the bidirectional | two-way switch by a reverse blocking switch. 3 is an explanatory diagram showing a commutation sequence when a voltage source connected to a load 4 is switched from a voltage source 31 having a voltage Va to a voltage source 32 having a voltage Vb in the circuit of FIG. 4 is an explanatory diagram showing a commutation sequence when a voltage source connected to a load 4 is switched from a voltage source 31 having a voltage Va to a voltage source 32 having a voltage Vb in the circuit of FIG.

  Embodiments of the present invention will be described below. The current commutation signal generator shown in FIG. 2 and the voltage commutation signal generator shown in FIG. 3 were only required in the prior art, but the present invention includes both, There is provided a divider for selecting and outputting the output so as to have the same ratio within a predetermined time.

  FIG. 1 is a circuit diagram of one embodiment of the present invention, which comprises a current polarity detector 5, a current commutation signal generator 8, a voltage comparator 6, and a voltage commutation signal generator 7 at the same time. The switching signal Ga1i, Ga2i, Gb1i, Gb2i output from the commutation signal generator 8 and the voltage commutation signal generator 7 are provided at the same time. The switching signals Ga1v, Ga2v, Gb1v, output from the current commutation signal generator 8 are provided. It consists of a divider 9 that selects Gb2v and outputs it to the bidirectional switches 1 and 2.

  As described above, the load voltage in the dead time period during commutation is the higher voltage source voltage when IL> 0 in the commutation using the output signal of the current commutation signal generator 8, and IL <0. In this case, the lower voltage source voltage is obtained. On the other hand, in the commutation using the output signal of the voltage commutation signal generator 7, the load voltage in the dead time period during commutation is the higher voltage source voltage when IL <0, and when IL> 0. Is the lower voltage source voltage. In other words, since the current commutation signal generator 8 and the voltage commutation signal generator 7 have completely opposite characteristics, the load voltage can be obtained by alternately using both signals by the divider 9, for example. It is possible to cancel the fluctuation amount. The divider 9 does not need to select completely alternately, and the selection ratio between the two is equal within a short period of time so that the polarity of the output current and the magnitude relation of the power supply voltage do not change and there is no influence of the output voltage fluctuation. You just have to do it.

  The present invention is directed to a reverse blocking switch 401 shown in FIG. 4 in place of the bidirectional switches 1 and 2 consisting of reverse conducting switches using the reverse conducting switches 11, 12, 21, and 22 shown in FIG. The present invention can be similarly applied to a circuit using a bidirectional switch (bidirectional switch composed of reverse blocking switches) 40 having a configuration in which 402 is connected in antiparallel.

  It is possible to completely control the load voltage fluctuation due to the dead time period without correcting the commutation signal using the dead time which is difficult to grasp accurately, so that the load voltage can be controlled accurately. Thus, a more accurate power converter can be obtained.

DESCRIPTION OF SYMBOLS 1, 2 Bidirectional switch which consists of reverse conduction switches 31, 32 Voltage source 11, 12, 21, 22 Reverse conduction switch 4 Load 5 Current polarity detector 6 Voltage comparator 7 Voltage commutation signal generator 8 Current commutation signal generation Unit 9 sharing device 40 bidirectional switch 401, 402 reverse blocking switch comprising reverse blocking switch

Claims (2)

  A plurality of bidirectional switches configured by connecting two reverse conducting switches each composed of a switching element capable of switching a unidirectional current and a diode connected in reverse parallel to the switching element in series, and the bidirectional switch Each voltage source is connected to one of the terminals, and all the terminals of the bidirectional switch that are not connected to the voltage source are short-circuited and connected to a load, Two bidirectional switches performing different switching operations in the bidirectional switch are defined as bidirectional switch A and bidirectional switch B, respectively, and the voltage source connected to the bidirectional switch A is defined as voltage source A. The voltage source connected to the switch B is the voltage source B, and a current polarity detector that detects the polarity of the current flowing through the load, and the current polarity detection The bidirectional switch so that the voltage source A and the voltage source B are not short-circuited and the load is connected to either the voltage source A or the voltage source B without being short-circuited. A current commutation signal generator for generating and outputting a signal for controlling the two switching elements of A and a signal for controlling the two switching elements of the bidirectional switch B; and the voltage source A and the voltage source B A voltage comparator for detecting the magnitude relation of the voltage, and an output of the voltage comparator are inputted to the voltage source A and the voltage source B without short-circuiting the voltage source A and the voltage source B. A voltage for generating and outputting a signal for controlling the two switching elements of the bidirectional switch A and a signal for controlling the two switching elements of the bidirectional switch B so as to maintain the state of being connected to either Commutation In the power supply switching device comprising a signal generator, the bidirectional switch A is selected by selecting the output of the current commutation signal generator and the output of the voltage commutation signal generator to be the same ratio within a predetermined time. And a power divider that outputs to the bidirectional switch B. The power supply switching device according to claim 1, wherein the switch is a bidirectional switch configured by connecting two reverse blocking switches that can switch a unidirectional current and block a reverse current.

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