JP2011250669A - Power conversion apparatus and controller of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion apparatus and a controller of the same having a simple constitution and corresponding to both AC power and DC power system.SOLUTION: The power conversion apparatus includes: a switching part having four diodes consisting of a bridge circuit, and two switching elements concurrently connected to each of the two diodes whose cathodes are connected to the bridge circuit's diagonal vertices set as an input side, and setting the other diagonal vertices of the bridge circuit as an output side; a reactor being provided between either of the bridge circuit's diagonal vertices set as an input side of the switching part and input terminals; and a smoothness capacitor concurrently connected to the switching part and connected to the other diagonal vertices of the bridge circuit that are set as an output side of the switching part. When input voltage is determined as AC, a controller of the power conversion apparatus controls the two switching elements for switching. When input voltage is determined as DC, one of the two switching elements is set as on-state and the other is controlled for switching.

Description

  The present invention relates to a power conversion device and a control device for the power conversion device corresponding to both systems of an AC power source and a DC power source.

  FIG. 8 is a diagram illustrating a circuit configuration of the power supply device disclosed in Patent Document 1. In FIG. The power supply device shown in FIG. 8 is used as a charging device for a mobile phone installed in an evacuation site or the like at the time of a disaster, and can charge the mobile phone without an AC adapter.

  The power supply device shown in FIG. 8 includes a power plug 21 that is plugged into an outlet of a commercial AC power supply AC100V, a connector 22 that is connected to a DC power supply DC12V, a power conversion device 20, and a male connector 24 that is plugged into a mobile phone. Is provided. The power converter 20 includes an AC / DC circuit 26, a DC / DC circuit 27 (27a, 27b, 27c, 27d), and a changeover switch 25.

  The AC / DC circuit 26 includes a switching regulator circuit, for example, and converts the commercial AC power supply AC100V supplied from the power plug 21 into a predetermined DC voltage DC12V. The DC / DC circuit 27 is configured by a DC / DC switching power supply circuit, and a DC voltage DC12V is a predetermined DC voltage required for the mobile phone, for example, a 5V system (5.6V, 5.8V, etc.), a 3V system (3. 7V etc.). The changeover switch 25 is a switch for selectively using one of two systems of commercial AC power supply AC100V and DC power supply DC12V.

JP 2004-364347 A

  However, since the power conversion device 20 included in the power supply device of Patent Document 1 corresponds to two systems of commercial AC power supply AC100V and DC power supply DC12V, an AC / DC circuit 26 and a DC / DC circuit 27 are provided as shown in FIG. These two types of power conversion circuits are provided, and a changeover switch 25 is also provided. In general, as the number of parts increases, the cost of the apparatus increases and the size increases. Therefore, it is considered that the power supply device disclosed in Patent Document 1 has a high cost and a large size.

  The objective of this invention is providing the power converter device of the simple structure corresponding to both the system | strain of AC power supply and DC power supply, and its control apparatus.

  In order to solve the above problems and achieve the object, the power conversion device according to the first aspect of the present invention includes four diodes constituting the bridge circuit (for example, the diodes D1 and D2 and the freewheeling diode in the embodiment) ) And two switching elements (for example, transistors S1, S2 in the embodiment) connected in parallel to each of two diodes each having a cathode connected to the diagonal vertex of the bridge circuit set on the input side ), And the other diagonal vertex of the bridge circuit is set on the output side (for example, the switching unit 100 in the embodiment), and is set on the input side of the switching unit A reactor (for example, a reactor L in the embodiment) provided between one of the diagonal vertices of the bridge circuit and the input terminal, and the switching unit. A smoothing capacitor (for example, a smoothing capacitor C in the embodiment) connected to another diagonal vertex of the bridge circuit set on the output side of the switching unit, and two switching elements of the switching unit A switching control unit (for example, the switching control unit 203 in the embodiment) that controls the switching control unit, when the DC voltage is applied to the input side, of the two switching elements, One of the features is that one is turned on and the other is subjected to switching control.

  Furthermore, in the power converter of the invention according to claim 2, a switching element (for example, provided between one of the other diagonal vertices of the bridge circuit set on the output side of the switching unit and the output terminal) The current output prevention unit (for example, the current output prevention unit 121 in the embodiment) including the transistor S3) in the embodiment is provided.

  Furthermore, in the power conversion device according to the third aspect of the present invention, on the output side of the switching unit, in parallel with the switching unit, a step-down unit (for example, a transistor S3 in the embodiment) (for example, The step-down unit 131) according to the embodiment is provided.

  Further, a control device according to a fourth aspect of the invention is a control device (for example, the control device 200 in the embodiment) that controls the power conversion device according to any one of the first to third aspects. The input voltage applied to the input terminal of the power converter includes an input voltage determination unit (for example, the input voltage determination unit 201 in the embodiment), the switching control unit, When the input voltage determination unit determines that the input voltage is alternating current, the two switching elements are controlled to switch, and when the input voltage determination unit determines that the input voltage is direct current, , One is turned on, and the other is switching-controlled.

  Furthermore, in the control device according to claim 5, the input voltage determination unit determines the polarity of the input voltage when the input voltage is DC, and the switching control unit is controlled by the input voltage determination unit. When the input voltage is determined to be DC, and the input terminal to which the reactor of the power converter is connected is positive, the reactor is connected among the diagonal vertices of the bridge circuit set on the input side A switching element connected in parallel with a diode whose cathode is connected to a vertex that is not connected, and switching control of the switching element connected in parallel to a diode whose cathode is connected to the vertex that is connected to the reactor, When the input terminal to which the reactor is connected is a negative electrode, among the diagonal vertices of the bridge circuit set on the input side, the The switching element connected in parallel with the diode connected to the cathode at the apex to which the reactor is connected is turned on, and the switching element connected in parallel to the diode connected to the cathode at the apex not connected to the reactor is controlled to be switched. It is characterized by doing.

  Furthermore, in the control device of the invention according to claim 6, the switching control unit is a current output prevention unit provided in the power conversion device according to claim 2, during the determination operation of the input voltage by the input voltage determination unit. The switching element included in is controlled to be off.

  Furthermore, in the control device according to the seventh aspect of the present invention, the switching control unit performs switching control of a switching element included in the step-down unit included in the power conversion device according to the third aspect.

  Furthermore, in the control device according to claim 8, the input voltage determination unit determines the polarity of the input voltage after determining that the input voltage is alternating current, or by determining that the input voltage is direct current. Thereafter, no determination is made while the input voltage is applied to the input terminal.

According to the power conversion device of the invention described in claims 1 to 3 and the control device of the invention described in claims 4 to 8, the power conversion device corresponds to both systems of an AC power source and a DC power source with a simple configuration. Can do. Therefore, the cost of the power conversion device can be reduced and the size can be reduced.
Moreover, according to the power converter device of the invention described in claims 1 to 3 and the control device of the invention described in claims 5 to 8, it is possible to easily cope with a change in polarity of the input voltage.
According to the power converter of the invention described in claim 2 and the controller of the invention described in claim 6, to the load connected to the output terminal until the determination of the input voltage by the input voltage determination unit is completed. Current output can be prevented.
According to the power converter of the invention described in claim 3 and the controller of the invention described in claim 7, the power converter can output a DC voltage at a level corresponding to the load.

The figure which shows the circuit structure and control apparatus of the power converter device of 1st Embodiment. Since the positive terminal of the DC power source is connected to the input terminal T1 and the negative terminal is connected to the input terminal T2, the equivalent circuit diagram when the switching control unit 203 always turns on the transistor S2. Since the negative terminal of the DC power source is connected to the input terminal T1 and the positive terminal is connected to the input terminal T2, the equivalent circuit diagram when the switching control unit 203 always turns on the transistor S1. Since the negative terminal of the DC power source is connected to the input terminal T1 and the positive terminal is connected to the input terminal T2, the equivalent circuit diagram when the switching control unit 203 always turns on the transistor S1. The flowchart which shows operation | movement of the control apparatus which controls the switching part of the power converter device of 1st Embodiment. The figure which shows the circuit structure and control apparatus of the power converter device of 2nd Embodiment. The figure which shows the circuit structure and control apparatus of the power converter device of 3rd Embodiment. The figure which shows the circuit structure of the power supply device of patent document 1

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

  In the power conversion device of the embodiment described below, the input voltage is an AC voltage or a DC voltage, and the output voltage is a DC voltage. For example, a commercial AC voltage, an electric motor, or a DC power source is connected to the input-side terminal of the power converter. In addition, for example, a capacitor is connected to the output terminal of the power conversion device. As described below, the power conversion device performs AC / DC conversion or DC / DC conversion according to the type of input voltage.

(First embodiment)
FIG. 1 is a diagram illustrating a circuit configuration and a control device of the power conversion device according to the first embodiment. As shown in FIG. 1, the power conversion device of the first embodiment includes a reactor L, a switching unit 100, and a smoothing capacitor (hereinafter simply referred to as “capacitor”) C. The power conversion apparatus includes a voltage sensor 101 that detects an input voltage Vin, a current sensor 103 that detects an input current Iin, and a voltage sensor 105 that detects an output voltage Vout. In addition, the signal which shows the detected value of each sensor is input into the control apparatus 200 which controls the switching part 100 of a power converter device.

  Reactor L is a coil connected to one of the input terminals, and an input current Iin flows therethrough.

The switching unit 100 includes two transistors S1 and S2 having freewheeling diodes connected in parallel, the transistors S1 and S2, a first connection unit (point A shown in FIG. 1), and a second connection unit (shown in FIG. 1). It has diodes D1, D2 connected in series via point B).
The collector of each transistor is connected to the cathode of the freewheeling diode, and the emitter is connected to the anode of the freewheeling diode. Further, the set of the transistor S1 and the diode D1 and the set of the transistor S2 and the diode D2 are connected in parallel.
Specifically, the cathode of the diode D1 and the cathode of the diode D2 are connected via a third connection (point C shown in FIG. 1), and the emitter of the transistor S1 and the emitter of the transistor S2 are connected to the fourth connection ( They are connected via point D) shown in FIG.
The middle point (point A) of the transistor S1 and the diode D1 is connected to one of the input terminals via the reactor L, and the middle point (point B) of the transistor S2 and the diode D2 is connected to the other input terminal. . As described above, the combination of the diodes D1 and D2, each transistor, and the freewheeling diode constitutes a bridge circuit.
Therefore, the first connection part (point A) and the second connection part (point B) are diagonal vertices of the bridge circuit set on the input side of the switching unit 100. In addition, the third connection part (point C) and the fourth connection part (point D) serve as other diagonal vertices of the bridge circuit set on the output side of the switching unit 100.

  The capacitor C is connected in parallel with the set of the transistor S1 and the diode D1 and the set of the transistor S2 and the diode D2. Capacitor C smoothes the output voltage of switching unit 100.

  The control device 200 includes an input voltage determination unit 201 and a switching control unit 203. The input voltage determination unit 201 determines whether the input voltage Vin detected by the voltage sensor 101 is alternating current or direct current. The input voltage determination unit 201 determines the polarity of the input voltage Vin when the input voltage Vin is DC.

  The switching control unit 203 controls the transistors S <b> 1 and S <b> 2 of the switching unit 100 according to the determination result of the input voltage Vin by the input voltage determination unit 201. When the input voltage Vin is determined to be alternating current by the input voltage determination unit 201, the switching control unit 203 performs PWM (Pulse Width Modulation) control or PFM (Pulse Frequency Modulation) control of switching of each transistor at a predetermined duty ratio. As a result, the power conversion device of this embodiment functions as an AC / DC converter and outputs a DC voltage.

In addition, each value which shows target electric power P ^* and target output voltage Vout ^* which the power converter device of this embodiment outputs is input into the control apparatus 200. FIG. The control device 200 determines the difference between the target output voltage Vout ^* and the output voltage Vout detected by the voltage sensor 105, and the difference between the target input current (= target power P ^* / input voltage Vin) and the input current Iin detected by the current sensor 103. Based on the above, the duty ratio of the switching control performed by the switching control unit 203 is determined.

  On the other hand, when the input voltage Vin is determined to be DC by the input voltage determination unit 201, the switching control unit 203 always turns on one transistor and performs PWM control of switching of the other transistor with a predetermined duty ratio. . As a result, the switching unit 100 outputs a DC voltage having a level different from that of the input voltage Vin. Note that when the input voltage is a direct current, which of the two transistors S1 and S2 is always on by the switching control unit 203 depends on the polarity of the input voltage. In the present embodiment, the switching control unit 203 always turns on a transistor whose collector is connected to the input terminal on the negative electrode side of the DC voltage.

  FIG. 2 is an equivalent circuit diagram when the switching control unit 203 always turns on the transistor S2 because the positive electrode of the DC power supply is connected to the input terminal T1 and the negative electrode is connected to the input terminal T2. In the state shown in FIG. 2, the switching control unit 203 performs PWM control of switching of the transistor S1 with a predetermined duty ratio. When the transistor S1 is on, the input current flows through the reactor L and the transistor S1. When the transistor S1 is off, the input current flows through a load such as a reactor L, a diode D1, a capacitor C or a capacitor (BATT) connected to the output terminal. As a result, the power conversion device of this embodiment functions as a DC / DC converter and outputs a DC voltage obtained by boosting the DC voltage Vin in the positive direction.

  3 and 4 are equivalent circuit diagrams when the switching control unit 203 always turns on the transistor S1 because the negative electrode of the DC power source is connected to the input terminal T1 and the positive electrode is connected to the input terminal T2. In the state shown in FIGS. 3 and 4, the switching control unit 203 performs PWM control of switching of the transistor S2 with a predetermined duty ratio. When transistor S2 is on, the input current flows through transistor S2 and reactor L. When the transistor S2 is off, the input current flows through the diode L2, a load such as a capacitor C or a capacitor (BATT) connected to the output terminal, and the reactor L. As a result, the power conversion device of this embodiment functions as a DC / DC converter and outputs a DC voltage obtained by boosting the DC voltage Vin in the negative direction.

  FIG. 5 is a flowchart illustrating the operation of the control device that controls the switching unit of the power conversion device according to the first embodiment. As illustrated in FIG. 5, the input voltage determination unit 201 of the control device 200 detects whether or not a voltage is input to the input terminal based on a signal from the voltage sensor 101 (step S <b> 101). When voltage input is detected in step S101, the input voltage determination unit 201 determines whether the input voltage is alternating current or direct current (step S103). When the input voltage is alternating current, the switching control unit 203 performs switching control on the transistors S1 and S2 of the switching unit 100 (step S105). On the other hand, when the input voltage is DC, the input voltage determination unit 201 determines the polarity of the input voltage (step S107).

  When the polarity of the input voltage is positive, the switching control unit 203 always turns on the transistor S2 of the switching unit 100 and controls the switching of the transistor S1 (step S109). On the other hand, when the polarity of the input voltage is negative, the switching control unit 203 always turns on the transistor S1 of the switching unit 100 and controls the switching of the transistor S2 (step S111). When no voltage is input to the input terminal or the voltage at the output terminal reaches a desired voltage, the input voltage determination unit 201 stops the control of the switching unit 100 by the switching control unit 203 and turns off the transistors S1 and S2. (Step S113).

  As described above, the power conversion device of the present embodiment functions as an AC / DC converter when the input voltage is AC, and the DC / DC converter when the input voltage is DC, according to the control of the control device 200. The switching unit 100 functioning as The switching unit 100 includes two transistors S1 and S2, a free wheel diode, and diodes D1 and D2, respectively. Thus, it is possible to deal with both AC power supply and DC power supply systems with a simple configuration. Therefore, the cost of the power conversion device can be reduced and the size can be reduced. Further, when the input voltage is a direct current, the control contents for the transistors S1 and S2 of the switching unit 100 may be reversed regardless of whether the polarity of the input voltage is positive or negative. Thus, it is possible to easily cope with a change in the polarity of the input voltage.

(Second Embodiment)
FIG. 6 is a diagram illustrating a circuit configuration and a control device of the power conversion device according to the second embodiment. The power converter of the second embodiment is different from the power converter of the first embodiment in that a current output prevention unit 121 is provided on the output side of the capacitor C. Except for this point, the second embodiment is the same as the first embodiment. In FIG. 6, the same reference numerals are given to the same components as those in FIG. 1. For this reason, the same code | symbol or an equivalent code | symbol is attached | subjected to the same or equivalent part as the power converter device of 1st Embodiment, and description is simplified or abbreviate | omitted.

  The current output prevention unit 121 includes a transistor S3 in which freewheeling diodes are connected in parallel, and a diode D3 connected in series to the transistor S3. The collector of the transistor S3 is connected to the cathode of the freewheeling diode, and the emitter is connected to the anode of the freewheeling diode. The middle point of the transistor S3 and the diode D3 is connected to one of the output terminals, and the anode of the diode D3 is connected to the other of the output terminals.

  The switching control unit 203 included in the control device 200 of the present embodiment also controls the transistor S3 included in the current output prevention unit 121 in addition to the control of the transistors S1 and S2 included in the switching unit 100. That is, the switching control unit 203 of the present embodiment controls the transistor S3 to be off during the determination operation of the input voltage Vin by the input voltage determination unit 201, and always turns on the transistor S3 after the determination is completed. The determination of the input voltage Vin includes determination of whether the input voltage Vin is alternating current or direct current and determination of the polarity of the input voltage Vin performed when the input voltage Vin is direct current.

  Thus, according to the present embodiment, output of current to the load connected to the output terminal can be prevented until the determination of the input voltage Vin by the input voltage determination unit 201 is completed.

(Third embodiment)
FIG. 7 is a diagram illustrating a circuit configuration and a control device of the power conversion device according to the third embodiment. The power converter of the third embodiment is different from the power converter of the first embodiment in that a step-down unit 131 is provided on the output side of the capacitor C. Except for this point, the second embodiment is the same as the first embodiment. In FIG. 7, the same reference numerals are given to components common to FIG. 1. For this reason, the same code | symbol or an equivalent code | symbol is attached | subjected to the same or equivalent part as the power converter device of 1st Embodiment, and description is simplified or abbreviate | omitted.

  The step-down unit 131 includes a transistor S3 having a reflux diode connected in parallel, a diode D3 connected in series to the transistor S3, a reactor Ld, and a smoothing capacitor Cd. The collector of the transistor S3 is connected to the cathode of the freewheeling diode, and the emitter is connected to the anode of the freewheeling diode. The middle point of the transistor S3 and the diode D3 is connected to one of the output terminals via the reactor Ld, and the anode of the diode D3 is connected to the other of the output terminals. The smoothing capacitor Cd is connected in parallel to the output terminal.

  The switching control unit 203 included in the control device 200 according to the present embodiment also controls the transistor S3 included in the step-down unit 131 in addition to the control of the transistors S1 and S2 included in the switching unit 100. When the switching control unit 203 performs PWM control of switching of the transistor S3 with a predetermined duty ratio, the step-down unit 131 steps down the output voltage of the switching unit 100.

  Thus, according to the present embodiment, the step-down unit 131 steps down the output voltage of the switching unit 100. Therefore, particularly when the switching unit 100 functions as an AC / DC converter, the voltage conversion unit 131 reduces the output voltage of the switching unit 100 to a desired level, so that the power conversion device generates a DC voltage at a level corresponding to the load. Can output.

  During the determination operation of the input voltage Vin by the input voltage determination unit 201, the transistor S3 and the diode D3 that constitute the step-down unit 131 may be used as the current output prevention unit 121 of the second embodiment. That is, the switching control unit 203 of the control device 200 controls the transistor S3 to be off during the determination operation of the input voltage Vin.

  The control device 200 of the first to third embodiments has a power frequency determining unit (not shown) that determines the frequency (for example, 50 Hz, 60 Hz) of the input voltage Vin when a commercial AC power supply is connected to the input terminal. ). Further, instead of the bipolar transistors S1 to S3, a switching element such as FET or IGBT may be used.

DESCRIPTION OF SYMBOLS 100 Switching part 101,105 Voltage sensor 103 Current sensor L, Ld Reactor C, Cd Smoothing capacitor S1, S2, S3 Transistor D1, D2, D3 Diode 200 Controller 201 Input voltage determination part 203 Switching control part 121 Current output prevention part 131 Buck unit

Claims (8)

Four diodes constituting a bridge circuit, and two switching elements connected in parallel to each of the two diodes each having a cathode connected to a diagonal vertex of the bridge circuit set on the input side A switching unit in which another diagonal vertex of the bridge circuit is set on the output side;
A reactor provided between one of the diagonal vertices of the bridge circuit set on the input side of the switching unit and the input terminal;
In parallel with the switching unit, a smoothing capacitor connected to another diagonal vertex of the bridge circuit set on the output side of the switching unit,
A switching control unit for controlling two switching elements of the switching unit,
The switching control unit is characterized in that when a DC voltage is applied to the input side, one of the two switching elements is turned on and the other is subjected to switching control. The power conversion device according to claim 1,
A power conversion device comprising a current output prevention unit including a switching element provided between one of other diagonal vertices of the bridge circuit set on the output side of the switching unit and an output terminal . The power conversion device according to claim 1 or 2,
A power conversion device comprising a step-down unit including a switching element in parallel with the switching unit on an output side of the switching unit. A control device for controlling the power conversion device according to any one of claims 1 to 3,
An input voltage determination unit that determines whether the input voltage applied to the input terminal of the power converter is alternating current or direct current;
The switching controller is
When the input voltage is determined to be alternating current by the input voltage determination unit, the two switching elements are switching-controlled,
When the input voltage is determined to be direct current by the input voltage determination unit, one of the two switching elements is turned on and the other is subjected to switching control. The control device according to claim 4,
The input voltage determination unit determines the polarity of the input voltage when the input voltage is DC,
The switching controller is
When the input voltage is determined to be direct current by the input voltage determination unit,
In the case where the input terminal to which the reactor of the power converter is connected is positive, the diode having the cathode connected to the apex to which the reactor is not connected among the diagonal apexes of the bridge circuit set on the input side The switching element connected in parallel with the diode, the cathode connected to the apex to which the reactor is connected, and the switching element connected in parallel,
When the input terminal to which the reactor is connected is negative, it is connected in parallel with a diode whose cathode is connected to the apex to which the reactor is connected among the diagonal apexes of the bridge circuit set on the input side. A control device, wherein the switching element is turned on, and the switching element connected in parallel with the diode whose cathode is connected to the apex where the reactor is not connected is controlled to switch. The control device according to claim 4 or 5,
3. The control according to claim 2, wherein the switching control unit controls the switching element of the current output prevention unit included in the power conversion device according to claim 2 to be off during the operation of determining the input voltage by the input voltage determination unit. apparatus. The control device according to any one of claims 4 to 6,
The said switching control part performs switching control of the switching element which the step-down part with which the power converter device of Claim 3 was provided is characterized by the above-mentioned. After the input voltage is determined to be alternating current, or after the input voltage is determined to be direct current and the polarity of the input voltage is determined,
The control device according to claim 5, wherein the determination is not performed while the input voltage is applied to the input terminal.

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