JP5412856B2 - Bidirectional converter - Google Patents

Description

  The present invention relates to a bidirectional converter including a voltage conversion unit including a switching element and a control unit thereof.

  In recent years, various large-capacity power storage devices have been developed against the background of power electronics technology. Such a large-capacity power storage device is applied to a use of accumulating natural energy such as solar power generation and discharging and using it. These large-capacity power storage devices must be equipped with a converter that controls charging and discharging of power.

  Here, the two functions of charging and discharging in such a converter have heretofore been realized by their dedicated circuit networks and have been switched and used. However, in recent years, since the converter is required to be small and light, a bidirectional converter in which the above two functions are realized by one circuit network has been proposed (for example, Patent Documents 1 and 2). ).

  Such a bidirectional converter includes a reactor, a capacitor, and at least four or more semiconductor switches. Selection of charging and discharging and adjustment of an output voltage value or current value are performed by the semiconductor switch. It is done by opening and closing.

  On the other hand, a plug-in hybrid electric vehicle (PHEV) has been proposed as a use application of the above-described large-capacity power storage device. In this PHEV, when charging, electric power is supplied from a commercial power supply (AC power supply) to a battery mounted on the vehicle via a converter that functions as a charger. On the other hand, at the time of discharging, electric power is supplied from the battery to a commercial power source via a converter that functions as an AC outlet.

  Here, in order to obtain electric power from a commercial power supply, it is required by the standard that the harmonic current on the input side is reduced to some extent. Therefore, in order to cope with this (in order to increase the power factor), a converter for PHEV is generally equipped with a power factor correction circuit (PFC (Power Factor Correction) circuit).

  On the other hand, a booster function or a step-up / step-down function is required for a PHEV converter circuit. The AC outlet power conversion circuit requires a step-down inverter function.

  On the other hand, for example, in Patent Documents 3 to 5, a front-stage inverter / converter using a reactor, a capacitor, and four or more semiconductor switches, and a DC / DC converter using a transformer and eight or more semiconductor switches are used. A bidirectional AC / DC converter using a two-stage converter has been proposed.

JP 2006-87197 A JP 2007-274778 A JP 2001-37226 A JP 2007-110856 A JP 2008-54473 A

  By the way, in these converters, a drive power supply unit for driving a control unit that controls the AC / DC power conversion unit (supplying power as a power source) is required. However, this drive power supply unit can obtain power only from the commercial power supply (when operating as a charger) or only from the battery (when operating as an AC outlet) at least during startup.

  Therefore, conventionally, it is difficult to share a drive power source between the commercial power source side and the battery side, and the drive power source is provided separately between the commercial power source side and the battery side. At the time of startup, the control unit is driven by only one of the commercial power supply side and the battery side (mainly the input side) drive power supply. However, since two drive power sources that can supply sufficient power to the control unit are provided separately, the bidirectional converter as a whole has been increased in size and weight. Therefore, it has been particularly desired to reduce the size and weight of the bidirectional converter and the like for use in PHEVs mounted on vehicles.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a bidirectional converter that can be reduced in size and weight as compared with the conventional one.

The bidirectional converter of the present invention outputs an output voltage from the other input / output terminal pair based on an input voltage input from one of the first and second input / output terminal pairs. A voltage conversion unit configured to include a switching element and generate the output voltage by performing voltage conversion based on the input voltage, a control unit for controlling the operation of the switching element, and the first Including a first drive power source connected to the input / output terminal pair side and a second drive power source connected to the second input / output terminal pair side. And a drive power supply unit that supplies electric power. Here, in the normal operation period of the voltage conversion unit, the control unit is supplied with power by at least a main drive power source which is a drive power source having a larger power supply capability of the first and second drive power sources. It is comprised so that. Of the first and second drive power supplies, the drive power supply to which the input voltage is input is the drive power supply having the smaller power supply capability of the first and second drive power supplies. In the case of the sub-drive power supply, power is supplied only by the sub-drive power supply during the start-up period of the voltage conversion unit, and the power consumption of the control unit is lower than that in the normal operation period. . Note that the first and second drive power sources are not limited to being configured using a single drive power source, and each may be configured using a plurality of drive power sources. .

In the bidirectional converter of the present invention, during forward operation, an input voltage is input from the first input / output terminal pair, and voltage conversion is performed in the voltage converter. Thus, an output voltage is generated based on this input voltage and is output from the second input / output terminal pair. On the other hand, during reverse operation, an input voltage is input from the second input / output terminal pair, and voltage conversion is performed in the voltage converter. Thus, an output voltage is generated based on this input voltage and is output from the first input / output terminal pair. At this time, the operation of the switching element in the voltage conversion unit is controlled by the control unit, and the power serving as the power source of the control unit is supplied by the driving power source unit including the first and second driving power sources. Here, in the forward operation or the reverse operation, when the drive power on the input voltage input side (input side) of the first and second drive power supplies is the sub drive power supply. In the start-up period of the voltage conversion unit, power is supplied from the drive power supply unit to the control unit only by the sub drive power supply, and the power consumption of the control unit is set lower than in the normal operation period. The Therefore, the voltage conversion operation of the voltage conversion unit is performed under the control of the control unit, and power is supplied to the second input / output terminal pair side. As a result, the other drive power supply (the main drive power supply) on the output voltage output side (output side) of the first and second drive power supplies starts the power supply operation, and the normal voltage conversion unit Transition to the operation period. On the other hand, when the drive power supply on the input side is the main drive power supply, for example, the normal operation period is immediately shifted without passing through such a startup period. In this normal operation period, power is supplied from the drive power supply unit to the control unit by at least the main drive power supply. In this way, when the drive power supply on the input side is the sub drive power supply, power is supplied to the control unit only by the sub drive power supply during the start-up period and the control unit consumes power compared to the normal operation period. Since the power is set to be low and power is supplied to the control unit by at least the main drive power supply during the normal operation period, a drive power supply with high power supply capability is provided on both the input side and the output side, and always. Compared to the conventional case where power is supplied to the control unit only by one drive power source on the input side, at least one side (sub drive power source side) has a lower power supply capability. In the case where the drive power supply on the input side is the main drive power supply, the normal operation period may be started after the start-up period.

  In the bidirectional converter of the present invention, it is preferable that the control unit stops the operation of the sub drive power supply during the normal operation period so that power is supplied only from the main drive power supply. When configured in this manner, power consumption is reduced and noise due to switching, for example, is also suppressed.

  In the bidirectional converter of the present invention, each of the first and second drive power supplies includes a switching element, and the control unit includes a switching element in the voltage conversion unit and a switching element in the main drive power supply. Are preferably controlled so as to perform on / off operations in synchronization with each other. When configured in this way, for example, when the control unit captures an input voltage, an input current, an output voltage, an output current, or the like, the influence of switching noise can be suppressed.

  In the bidirectional converter of the present invention, the first drive power supply and the second drive power supply are insulated from each other, and an insulating transformer is provided between the sub drive power supply and the control unit. It is preferable to do this. When configured in this way, the power used in this insulating transformer can be small, so when applied to an insulating bidirectional converter between the input side and the output side, it is more effective as a whole. Small and lightweight.

In the bidirectional converter according to the present invention, when the control unit includes a digital arithmetic unit (DSP), the operating frequency of the DSP is lower than the normal operation period in the start-up period. It is possible. In such a configuration, by DSP operating frequency is lower than the normal operation period in the start-up period, the starting period, the power consumption of the control unit is lower than a normal operation period.

  In this case, the DSP may output a prescribed pulse signal for controlling the switching element in the voltage converter during the startup period. In such a configuration, since the operation as the control unit is minimized, the power consumption of the control unit is lower in the startup period than in the normal operation period.

  In the bidirectional converter of the present invention, relays are respectively provided between the first input / output terminal pair and the first drive power source, and between the second input / output terminal pair and the second drive power source. It is preferable that the relay on the side where the output voltage is output is turned off during the startup period. When configured in this way, it is avoided that uncontrolled power during the startup period is output to the output side, and safety on the output side is ensured.

  In the bidirectional converter of the present invention, the voltage conversion unit is an AC / DC conversion unit that performs voltage conversion between a DC voltage and an AC voltage, and functions as a bidirectional AC / DC converter. Is possible. In such a configuration, during forward operation, an AC input voltage is input from the first input / output terminal pair, and the AC / DC converter generates a DC output voltage based on the AC input voltage. Output from the I / O terminal pair. On the other hand, during reverse operation, a DC input voltage is input from the second input / output terminal pair, and an AC output voltage is generated on the basis of the DC input voltage in the AC / DC conversion unit. Is output from.

  According to the bidirectional converter of the present invention, when the drive power supply on the input side is the sub drive power supply, power is supplied to the control unit only by the sub drive power supply in the start-up period and the control unit is compared with the normal operation period. The power is supplied to the control unit by at least the main drive power supply during the normal operation period, so that at least one side (sub drive power supply side) is supplied compared to the conventional power supply. The ability is low. Therefore, the drive power supply unit can be reduced in size and weight, and the bidirectional converter as a whole can be reduced in size and weight as compared with the conventional one.

It is a block diagram showing the structure of the bidirectional | two-way converter which concerns on one embodiment of this invention. FIG. 2 is a circuit diagram illustrating a configuration example of a main part in the bidirectional converter illustrated in FIG. 1. FIG. 2 is a circuit diagram illustrating a configuration example of a drive power source illustrated in FIG. 1. FIG. 2 is a circuit diagram for explaining a basic operation during a forward operation in the bidirectional converter shown in FIG. 1. FIG. 2 is a circuit diagram for explaining a basic operation during a forward operation in the bidirectional converter shown in FIG. 1. FIG. 2 is a circuit diagram for explaining a basic operation at the time of reverse operation in the bidirectional converter shown in FIG. 1. FIG. 2 is a circuit diagram for explaining a basic operation at the time of reverse operation in the bidirectional converter shown in FIG. 1. It is a timing chart showing an example of the relationship between the ON / OFF timing of the switching element in the AC / DC converter and the main drive power supply and the detection signal capture timing in the controller. It is a block diagram showing the structure and operation | movement of a bidirectional | two-way converter which concerns on a comparative example. It is a flowchart showing an example of operation | movement of the drive power supply and control part which concern on embodiment. It is a flowchart showing other examples of operation of a drive power supply and a control part concerning an embodiment. It is a block diagram for demonstrating operation | movement of the starting period at the time of the forward operation in the bidirectional | two-way converter which concerns on embodiment, and a normal operation period. It is a block diagram for demonstrating the operation | movement of the starting period at the time of reverse operation and the normal operation period in the bidirectional | two-way converter which concerns on embodiment. It is a block diagram showing the structure of the bidirectional | two-way converter which concerns on the modification of this invention. It is a block diagram showing the structure of the bidirectional | two-way converter which concerns on the other modification of this invention. It is a block diagram for demonstrating operation | movement of the normal operation period at the time of the forward direction operation | movement and the reverse direction operation | movement in the bidirectional | two-way converter which concerns on the other modification of this invention.

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

(Example of overall configuration of bidirectional converter)
FIG. 1 shows a block configuration of a bidirectional converter (bidirectional converter 1) according to an embodiment of the present invention. The bidirectional converter 1 functions as an AC / DC converter that is applied to, for example, an automobile, and includes input / output terminals T1 and T2 on the alternating current (AC) side and input / output terminals T3 and T4 on the direct current (DC) side. And. The bidirectional converter 1 also includes an AC / DC converter 2, two voltage detection circuits 311 and 321, two current detection circuits 312 and 322, a control unit 4, two drive power supplies 51 and 52, and a diode. D51 and D52.

  The AC / DC converter 2 includes a switching element to be described later, and performs voltage conversion between an AC voltage V1 between the input / output terminals T1 and T2 and a DC voltage V2 between the input / output terminals T3 and T4. Is what you do. The detailed configuration of the AC / DC converter 2 will be described later (FIG. 2).

  The voltage detection circuit 311 is disposed between the connection lines H1 and L1 connected to the input / output terminals T1 and T2, detects the AC voltage V1 between both ends, and a detection signal corresponding to the detected AC voltage V1. S (V1) is output into the control unit 4. Similarly, the voltage detection circuit 321 is disposed between the connection lines H2 and L2 connected to the input / output terminals T3 and T4, detects the DC voltage V2 between both ends, and corresponds to the detected DC voltage V2. The detection signal S (V2) to be output is output to the control unit 4. As a specific circuit configuration of these voltage detection circuits 311, 321, for example, a voltage is detected by a voltage dividing resistor (not shown) arranged between connection lines, and a voltage corresponding to this is generated. Things.

  The current detection circuit 312 is disposed between the voltage detection circuit 311 and the AC / DC converter 2 on the connection line H1, and detects the AC current I1 flowing on the connection line H1. The detection signal S (I1) corresponding to the alternating current I1 is output into the control unit 4. Similarly, the current detection circuit 322 is disposed on the connection line H2 between the voltage detection circuit 321 and the AC / DC conversion unit 2, and detects the DC current I2 flowing on the connection line H2. A detection signal S (I2) corresponding to the detected DC current I2 is output into the control unit 4. A specific circuit configuration of these current detection circuits 312 and 322 includes, for example, a circuit including a current transformer.

  The control unit 4 controls the operation of each switching element to be described later in the AC / DC conversion unit 2, and includes an oscillator 41, a frequency divider 42, and a digital control device 43.

  The oscillator 41 generates and outputs a basic clock signal CLK0 used in the control unit 4. The frequency divider 42 controls the frequency division ratio by dividing the basic frequency in the basic clock signal CLK0 according to the control from the digital control device 43, and the frequency division signal used in the digital control device 43. (System clock signal) CLK1 is generated and output. Thereby, it is possible to perform switching control of the operating frequency in the digital control device 43. Such switching control of the operating frequency may be performed by switching multiples of the fundamental frequency using a PLL (Phase Locked Loop) circuit instead of using the frequency dividing circuit 42. Further, by using a digital control device 43 having these functions, the digital control device 43 may be used.

  The digital control device 43 includes detection signals S (V1) and S (V2) supplied from the voltage detection circuits 311 and 321 and detection signals S (I1) and S (I2) supplied from the current detection circuits 312 and 322. The timing control signals Sa and Sb are generated by performing arithmetic processing based on the above and supplied to the AC / DC converter 2. Each of these timing control signals Sa and Sb is a control signal for performing switching driving by pulse width modulation (PWM) to a switching element to be described later in the AC / DC converter 2. The detection signals S (V1), S (V2), S (I1), and S (I2) are converted into digital signals via an A / D (analog / digital) conversion unit (not shown) in the control unit 4, respectively. Then, it is supplied to the digital control unit 43.

  Further, the digital control device 43 supplies a disable signal Dis for stopping the operation of the drive power supply 51 to the drive power supply 51, and a predetermined synchronization signal Sync to be described later to the drive power supply 52. It comes to supply.

  The functions of the digital control device 43 are configured by software, and all processing in the digital control device 43 is performed by a digital signal processing device. Such a digital signal processing device is preferably constituted by, for example, a logic circuit group or a microcomputer, and is preferably constituted by a single DSP (Digital Signal Processor). This is because the functions of the control unit 4 can be integrated, and the bidirectional converter 1 can be reduced in size and weight. For example, functions of communication, AC / DC power control, DC / AC power control, and PFC control can be incorporated into one DSP.

  The drive power supply 51 is a power supply that operates by receiving power supply from the DC voltage V1 between the input / output terminals T1 and T2 by being connected to the input / output terminals T1 and T2. The drive power supply 51 is configured to have a power supply capability smaller than that of the drive power supply 52, and operates as a sub drive power supply. On the other hand, the drive power supply 52 is a power supply that operates by receiving power supply from the AC voltage V2 between the input / output terminals T3 and T4 by being connected to the input / output terminals T3 and T4. The drive power supply 52 is configured to have a power supply capability larger than that of the drive power supply 51, and operates as a main drive power supply.

  These drive power supplies 51 and 52 are for supplying electric power to the control unit 4 via the diode D51 or the diode D52. However, in the present embodiment, the driving power source 52 (main driving power source) has a power supply capability sufficient to drive the control unit 4, while the driving power source 51 (sub driving power source) drives the control unit 4. It does not have enough power supply capacity to do. Further, in the present embodiment, the control unit 4 described above is supplied with power only by the drive power source 51 that is the main drive power source during the normal operation period of the AC / DC conversion unit 2. On the other hand, when the drive power supply on the side (input side) to which the input voltage is input from the input / output terminals T1, T2 or the input / output terminals T3, T4 is the drive power supply 51 (sub drive power supply) (during forward operation described later) ), During the start-up period of the AC / DC converter 2, the control unit 4 is supplied with power to the control unit 4 only by the drive power source 51, and its power consumption is lower than that in the normal operation period. It is configured as follows. Further, in this start-up period, when the digital control device 43 is configured using a DSP, the operating frequency of the DSP is configured to be lower than that in the normal operation period. Thereby, although details will be described later, the power consumption in the control unit 4 is lower in the startup period than in the normal operation period. The detailed configuration of the drive power supplies 51 and 52 will be described later (FIG. 3).

(Detailed configuration example of AC / DC converter)
Next, the detailed configuration of the AC / DC conversion unit 2 will be described with reference to FIG. FIG. 2 is a circuit diagram showing the detailed configuration of the AC / DC converter 2. In FIG. 2, in the bidirectional converter 1, the voltage detection circuits 311 and 321, the current detection circuits 312 and 322, the drive power supplies 51 and 52, and the diodes D51 and D52 are not illustrated.

  The AC / DC converter 2 has a two-stage configuration of an AC / DC converter 2A and a DC / DC converter 2B.

  The AC / DC converter 2A performs AC / DC (AC / DC) conversion between the AC voltage V1 between the input / output terminals T1 and T2 and the DC voltage on the DC / DC converter 2B side. . The AC / DC converter 2 includes capacitors C1 and 25C, inductors 24L1 and 24L2 and switching elements SW21 to SW24 that function as a synchronous rectifier circuit or an inverter circuit having a PFC function.

  The DC / DC converter 2B performs DC / DC (DC / DC) conversion between the DC voltage V2 between the input / output terminals T3 and T4 and the DC voltage on the AC / DC converter 2A side. . The DC / DC converter 2B includes switching elements SW31 to SW34 and switching elements SW41 to SW44 that function as an inverter circuit or a synchronous rectification circuit, a transformer 22, and a capacitor 26C.

  The capacitor C1 is disposed between the connection lines H1 and L1, and functions as a smoothing capacitor. Specifically, it is for smoothing and reducing noise and the like during switching operations by switching elements SW21 to SW24 described later.

  The inductor 24L1 is inserted on the connection line H1, and the inductor 24L2 is inserted on the connection line L1.

  The switching elements SW21 to SW24 constitute a full bridge type inverter circuit and a rectifier circuit. Each of the switching elements SW21 to SW24 is configured by, for example, a field effect transistor (MOS-FET), a bipolar transistor, an IGBT (Insulated Gate Bipolar Transistor), or the like. Here, the switching elements SW21 to SW24 are each configured by an N-channel MOS-FET. Here, the gate of the switching element SW21 is connected to the signal line of the timing control signal Sa, the source is connected to the drain of the switching element SW22, and the drain is connected to the connection line H3. The gate of the switching element SW22 is connected to the signal line of the timing control signal Sa, the source is connected to the connection line L3, and the drain is connected to the source of the switching element SW21. The gate of the switching element SW23 is connected to the signal line of the timing control signal Sa, the source is connected to the drain of the switching element SW24, and the drain is connected to the connection line H3. The gate of the switching element SW24 is connected to the signal line of the timing control signal Sa, the source is connected to the connection line L3, and the drain is connected to the source of the switching element SW23. The source of the switching element SW21 is connected to the connection line H1, and the source of the switching element SW23 is connected to the connection line L1.

  The capacitor 25C is disposed between the connection lines H3 and L3 and functions as a smoothing capacitor.

  The switching elements SW31 to SW34 constitute a full bridge type inverter circuit and a rectifier circuit. Each of these switching elements SW31 to SW34 is configured by, for example, a MOS-FET, a bipolar transistor, an IGBT, or the like. Here, the switching elements SW31 to SW34 are each configured by an N-channel MOS-FET. Here, the gate of the switching element SW31 is connected to the signal line of the timing control signal Sb, the source is connected to the drain of the switching element SW32, and the drain is connected to the connection line H3. The gate of the switching element SW32 is connected to the signal line of the timing control signal Sb, the source is connected to the connection line L3, and the drain is connected to the source of the switching element SW31. The gate of the switching element SW33 is connected to the signal line of the timing control signal Sb, the source is connected to the drain of the switching element SW34, and the drain is connected to the connection line H3. The gate of the switching element SW34 is connected to the signal line of the timing control signal Sb, the source is connected to the connection line L3, and the drain is connected to the source of the switching element SW33. The source of the switching element SW31 and the drain of the switching element SW32 are connected to one end of a winding 221 in the transformer 22 described later, and the source of the switching element SW33 and the drain of the switching element SW34 are connected to the other end of the winding 221. It is connected.

  The transformer 22 has windings 221 and 222 that are insulated from each other. One end of the winding 222 is connected to the connection line H2, and the other end is connected to the connection line L2. The transformer 22 transforms an AC voltage input from the switching elements SW31 to SW34 side or the switching elements SW41 to SW44 side, and generates an AC voltage at both ends of the other winding. In this case, the degree of transformation is determined by the turn ratio between the winding 221 and the winding 222.

  The switching elements SW41 to SW44 constitute a full bridge type inverter circuit and a rectifier circuit. Each of these switching elements SW41 to SW44 is configured by, for example, a MOS-FET, a bipolar transistor, or an IGBT. Here, the switching elements SW41 to SW44 are each configured by an N-channel MOS-FET. Here, the gate of the switching element SW41 is connected to the signal line of the timing control signal Sb, the source is connected to the drain of the switching element SW42, and the drain is connected to the connection line H2. The gate of the switching element SW42 is connected to the signal line of the timing control signal Sb, the source is connected to the connection line L2, and the drain is connected to the source of the switching element SW41. The gate of the switching element SW43 is connected to the signal line of the timing control signal Sb, the source is connected to the drain of the switching element SW44, and the drain is connected to the connection line H2. The gate of the switching element SW44 is connected to the signal line of the timing control signal Sb, the source is connected to the connection line L2, and the drain is connected to the source of the switching element SW43.

  The capacitor 26C is disposed between the connection lines H2 and L2, and functions as a smoothing capacitor.

(Detailed configuration example of the drive power supply unit)
Next, the detailed configuration of the drive power supplies 51 and 52 will be described with reference to FIG. 3A is a circuit diagram showing the detailed configuration of the drive power supply 51, and FIG. 3B is a circuit diagram showing the detailed configuration of the drive power supply 52. As shown in FIG.

  The drive power supplies 51 and 52 are capacitors C1 and C2, a control IC (Integrated Circuit) 50, a switching element SW51 (or switching element SW52) constituted by an N-channel MOS-FET, a transformer T5, and a diode D50, respectively. And resistors R51 and R52.

  One end of the capacitor C1 is connected to the connection line L51 connected to the connection line H1 (H2), and the other end is connected to the connection line L1 (L2). One end of the winding T51 in the transformer T5 is connected to the connection line L51, and the other end is connected to the drain of the switching element SW51 (SW52). One end of the winding T52 in the transformer T5 is connected to the anode of the diode D50, and the other end is connected to the connection line L1 (L2). The switching control signal S51 (S52) from the control IC 50 is input to the gate of the switching element SW51 (SW52), and the source is connected to the connection line L1 (L2). The cathode of the diode D50 is connected to one end of the resistor R51 on the connection line L52, the other end of the resistor R51 is connected to one end of the resistor R52, and the other end of the resistor R52 is connected to the connection line L1 (L2). It is connected. One end of the capacitor C2 is connected to the connection line L52, and the other end is connected to the connection line L1 (L2). The control IC 50 is supplied with the AC voltage V1 or the DC voltage V2 via the connection line H1 (H2), and also supplied with the voltage V5 on the connection line L52 divided by the resistors R51 and R52. Thus, feedback control is performed. Further, the drive power supply 51 supplies a disable signal Dis to the control IC 50, while the drive power supply unit 52 supplies a synchronization signal Sync to the control IC 50.

  With such a configuration, in the drive power supplies 51 and 52, when the AC voltage V1 or the DC voltage V2 supplied via the connection line H1 (H2) becomes equal to or higher than a predetermined threshold (specified value described later), the drive power is supplied from the control IC 50. The on / off control operation of the switching element SW51 (SW52) is started by the switching control signal S51 (S52). Thereby, the voltage V5 transformed by the transformer T5 is generated on the connection line L52 and supplied to the diode D51 (D52). Further, in the drive power supply 51, the operation of the control IC 50 (power supply operation of the entire drive power supply 51) can be stopped by the disable signal Dis. In the drive power supply 52, the operation of the control IC 50 (the timing of the on / off operation of the switching element SW52) is controlled by the synchronization signal Sync.

  Here, the input / output terminals T1 and T2 correspond to a specific example of the “first input / output terminal pair” in the present invention, and the input / output terminals T3 and T4 correspond to the “second input / output terminal pair” in the present invention. This corresponds to a specific example. The AC / DC converter 2 corresponds to a specific example of “voltage converter” and “AC / DC converter” in the present invention. The driving power source 51 (sub driving power source) corresponds to a specific example of “first driving power source” in the present invention, and the driving power source 52 (main driving power source) corresponds to one example of “second driving power source” in the present invention. Corresponding to a specific example, the drive power supplies 51 and 52 and the diodes D51 and D52 correspond to a specific example of the “drive power supply unit” in the present invention.

  Next, the operation and effect of the bidirectional converter 1 of the present embodiment will be described.

(Example of basic operation of bidirectional converter)
First, the basic operation of the bidirectional converter 1 will be described with reference to FIGS. 4 to 7 illustrate the state of basic operation of the bidirectional converter 1 using circuit diagrams. 4 and 5 show the forward operation (charging operation from the AC commercial power supply 10 to the DC battery 60), and FIGS. 6 and 7 show the backward operation (from the DC battery 60). AC voltage output operation to the load 70 on the AC side). 4 to 7, in the bidirectional converter 1, the voltage detection circuits 311 and 321, current detection circuits 312 and 322, the drive power supplies 51 and 52, and the diodes D51 and D52 are not illustrated. . Also, “ON” and “OFF” in the figure represent the on state and off state of each switching element, and the arrows in the figure represent the path and direction of current flow.

  First, during the forward operation shown in FIGS. 4 and 5, the operation state shown in FIG. 4 and the operation state shown in FIG. 5 are alternately repeated. Specifically, when an AC input voltage Vacin (commercial voltage) input from the commercial power supply 10 via the input / output terminals T1 and T2 is supplied to the AC / DC converter 2A, a synchronous rectifier circuit having a PFC function is obtained. A DC voltage is generated between the connection lines H3 and L3 by the functioning inductors 24L1 and 24L2 and the switching elements SW21 to SW24. Next, in the DC / DC conversion unit 2B, when this DC voltage is supplied from the AC / DC conversion unit 2A, a pulse voltage is generated by the switching elements SW31 to SW34 functioning as an inverter circuit, and the winding 221 of the transformer 22 is generated. Is applied between both ends. This pulse voltage is transformed by the transformer 22, and the transformed pulse voltage is generated across the winding 222. Then, the transformed pulse voltage is rectified by the switching elements SW41 to SW44 functioning as a rectifier circuit, and a DC output voltage Vdcout is generated. Thereby, the battery 60 is charged by the DC output voltage Vdcout and the DC output current flowing through the connection lines H2 and L2.

  On the other hand, during the backward operation shown in FIGS. 6 and 7, the operation state shown in FIG. 6 and the operation state shown in FIG. 7 are alternately repeated. Specifically, when the DC input voltage Vdcin input from the battery 60 via the input / output terminals T3 and T4 is supplied to the DC / DC converter 2B, the pulse voltage is generated by the switching elements SW41 to SW44 functioning as an inverter circuit. Is generated and applied across the winding 222 of the transformer 22. This pulse voltage is transformed by the transformer 22, and the transformed pulse voltage is generated across the winding 221. The transformed pulse voltage is rectified by the switching elements SW31 to SW34 functioning as a rectifier circuit, and a DC voltage is generated. Next, in the AC / DC conversion unit 2A, when this DC voltage is supplied from the DC / DC conversion unit 2B, the inductors 24L1 and 24L2 functioning as inverter circuits having a PFC function and the switching elements SW21 to SW24 connect the connection line. An AC output voltage Vacout is generated between H1 and L1. Thus, the load 70 is driven via the input / output terminals T1 and T2 by the AC output voltage Vacout and the AC output current flowing through the connection lines H1 and L1.

  At this time, the ON / OFF operation of the switching elements SW21 to SW24, SW31 to SW34, and SW41 to SW44 in the AC / DC converter 2 is performed in the digital in the controller 4 during both forward operation and reverse operation. Control is performed by timing control signals Sa and Sb output from the control device 43. In addition, power as a power source for the control unit 4 is supplied from the drive power sources 51 and 52 to the control unit 4 via the diodes D51 and D52.

  Here, in the present embodiment, the control unit 4 causes the switching elements SW21 to SW24 and the like in the AC / DC conversion unit 2 and the switching element SW52 in the drive power source 52 to synchronize with each other as shown in FIG. Thus, it is preferable to control the timing control signals Sa and Sb and the switching control signal S52 using the synchronization signal Sync so that the on / off operation is performed. Note that the timings t1 to t6 in the drawing represent the timings of the on / off operations of the switching elements SW21 to SW24 or the switching element SW52, respectively. In this embodiment, as shown in FIG. 8, the digital control unit 43 detects the detection signals S (V1), S (V2), and the like via an A / D conversion unit (not shown) in the control unit 4. The fetching (sampling) timings ts1 to ts3 when fetching S (I1) and S (I2) are made different from the timing of the on / off operation of the switching elements SW21 to SW24 and the switching element SW52. Is preferred. In particular, as shown in FIG. 8, the capture timings ts1 to ts3 are synchronized with the on / off operation timings of the switching elements SW21 to SW24 and the switching element SW52, and the on / off states of these switching elements are More preferably, the timing is different from the timing of the off operation. With these configurations, when such detection signals S (V1), S (V2), S (I1), and S (I2) are taken in, the influence of switching noise caused by the switching elements SW21 to SW24 and the switching element SW52 is affected. It is because it can be suppressed.

(Example of power supply operation by the drive power supply)
Next, with reference to FIGS. 9 to 13, the power supply operation to the control unit 4 by the drive power supplies 51 and 52, which is one of the characteristic parts of the present invention, will be described in detail in comparison with the comparative example. . FIG. 9 is a block diagram showing the configuration and operation of a conventional bidirectional converter (bidirectional converter 101) according to a comparative example. FIGS. 10 and 11 are flowcharts showing examples of operations of the drive power supplies 51 and 52 and the control unit 4 of the present embodiment. FIG. 12 is a block diagram showing the operation state during forward operation in the bidirectional converter 1 of the present embodiment, where (A) shows the operation state during the start-up period, and (B) shows the normal operation. Each operation state in the period is shown. FIG. 13 is a block diagram showing an operation state at the time of reverse operation in the bidirectional converter 1 of the present embodiment, and shows an operation state in a normal operation period.

  First, in the comparative example shown in FIG. 9, similarly to the present embodiment, the AC side driving power source 105 </ b> A and the DC side driving power source 105 </ b> B are provided separately. However, in this comparative example, a control unit 104 that outputs a timing control signal S101 of the switching element to the AC / DC conversion unit 2 is provided instead of the control unit 4 of the present embodiment. When the AC / DC converter 2 is activated, the controller 104 is driven only by one (mainly, the input side) of the two drive power supplies 105A and 105B. That is, at the time of forward operation indicated by an arrow P301 in the figure, as indicated by an arrow P101 in the figure, the power serving as the power source is supplied to the control unit 104 mainly by the drive power source 105A on the input side. Is done. On the other hand, at the time of the reverse operation indicated by the arrow P302 in the figure, as indicated by the arrow P102 in the figure, the power serving as the power supply is supplied to the control unit 104 mainly by the input side drive power supply 105B. Is done. However, in this comparative example, two drive power supplies that can supply sufficient power to the control unit 104 are separately provided (drive power supplies 105A and 105B), so that the bidirectional converter 101 as a whole is increased in size and weight. Will be caused.

  On the other hand, in the present embodiment, first, the control unit 4 determines whether or not the input-side drive power supply is the drive power supply 52 (main drive power supply) (in this case, during the reverse operation). (Step S10 in FIG. 10, step S20 in FIG. 11).

(Start-up period using sub-drive power supply)
Here, when it is determined that the drive power supply on the input side is the drive power supply 51 (sub drive power supply) (steps S10 and S11: N), the activation period using the drive power supply 51 that is the sub drive power supply is entered. . That is, in the start-up period using this drive power supply 51, electric power is supplied to the control unit 4 by only one drive power supply (drive power supply 51) on the input side among the two drive power supplies 51 and 52. In the start-up period using the drive power supply 51, the operating frequency (driving frequency) fa of the DSP constituting the digital control device 43 is the operating frequency (driving frequency) during the normal operating period of the AC / DC converter 2 described later. It is set to be lower than fb (steps S11 and S21: fa <fb).

  Next, the digital control device 43 in the control unit 4 determines that the output voltage (DC output voltage Vdcout or AC output voltage Vacout) from the AC / DC converter 2 is a predetermined specified value (control in the drive power supplies 51 and 52). It is determined whether or not it is equal to or higher than the operation start voltage of the IC 50 (steps S12 and S22).

  Here, when the output voltage has not yet reached the specified value (steps S12, S22: N), for example, an operation state as shown in FIG. 12A (during forward operation) is obtained. That is, at the time of forward operation indicated by an arrow P31 in FIG. 12A, as indicated by an arrow P1 in the figure, only the driving power supply 51 on the input side serves as the power supply for the control unit 4. Power is supplied.

  At this time, when PWM control is performed in the start-up period using the drive power supply 51 (step S13 in FIG. 10), as described above, the operating frequency fa of the DSP constituting the digital control device 43 is a normal operation period described later. Is set to be lower (fa <fb), the power consumption in the control unit 4 is lower in the startup period using the drive power supply 51 than in the normal operation period. This is because most DSPs are composed of MOS transistors, and the power consumption is almost proportional to the operating frequency. Further, when an IGBT is used as a semiconductor switch in the DSP, for example, the power consumed for charging and discharging the gate capacitance is proportional to the switching frequency. Therefore, when the operating frequency of the DSP is lowered and the switching frequency is lowered, The driving power can also be lowered. Note that the ratio of the operating frequency between the normal operation period and the start-up period using the drive power supply 51 is preferably set to 2 or more. This is because the power ratio between the drive power supplies 51 and 52 can be set to 1: 1 or more.

  On the other hand, in the start-up period using this drive power supply 51, the operating frequency fa of the DSP constituting the digital control device 43 is set to be lower than that in the normal operation period, and the switching element SW21 in the AC / DC converter 2 is set. Only a prescribed pulse (predetermined pulse signal with a fixed duty ratio and waveform etc.) for controlling SW24 and the like may be output (step S23 in FIG. 11). This is due to the following reason. That is, since the power control by the DSP requires a plurality of calculation processes, it takes time to complete the calculation. Therefore, since this time depends on the operating frequency, if the operating frequency decreases, the calculation may not be in time. Therefore, in the start-up period using the drive power supply 51, the operation frequency is lowered and the calculation is simplified, and the switching elements SW21 to 24 are controlled to be turned on / off by a prescribed pulse signal. In such a configuration, since the operation as the control unit 4 is minimized, the power consumption of the control unit 4 is lower in the startup period using the drive power supply 51 than in the normal operation period.

  Note that the two controls shown in steps S13 and S23 may be switched at any time. Further, after such an operation of step S13 or step S23, the process returns to step S12 or step S22 again.

  Here, the voltage conversion operation of the AC / DC conversion unit 2 is performed by the control by the control unit 4 in this way, and power is supplied to the output side. As a result, when the output voltage subsequently reaches a specified value or more (steps S12, S22: Y), the output-side drive power supply 52 (main drive power supply) also starts the power supply operation to the control unit 4. Thus, the normal operation period starts.

(Normal operation period)
On the other hand, when it is determined in steps S10 and S20 that the driving power source on the input side is the driving power source 52 (main driving power source) (steps S10 and S20: Y), the above-described startup period is not passed. Immediately, the operation shifts to the normal operation period described below. That is, processing of steps S14 to S17 and S24 to S27 described below is performed. Also, when the start-up period using the drive power supply 51 as the sub drive power supply ends and the process shifts to the normal operation period, the processes of steps S14 to S17 and S24 to S27 described below are performed.

  In the normal operation period, the control unit 4 first sets the operation frequency fa of the DSP constituting the digital control device 43 to the operation frequency (drive frequency) fb (> fa) in the normal operation period (steps S14 and S24). ). Thereby, the power consumption in the control part 4 is changed according to the operating frequency.

  In this normal operation period, the control unit 4 stops the operation of the drive power supply 51 (sub drive power supply) using the disable signal Dis (steps S15 and S25). Therefore, in the normal operation period, for example, as shown in FIG. 12B (during forward operation) and FIG. 13 (during reverse operation), the drive power source 52 (main power) out of the two drive power sources 51 and 52, respectively. Only the drive power source) supplies power to the control unit 4.

  Thereafter, PWM control is performed during the normal operation period (steps S16 and S26). At this time, the operation frequency is switched by controlling the frequency division ratio in the frequency divider 42. Note that the transition from the startup period using the drive power supply 51 to the normal operation period is performed by detecting the detection signals S (V1), S (V2), S (I1), and the voltage detection circuits 311 and 321 and the current detection circuits 312 and 322. It is desirable to confirm the power supply to the output side by monitoring the detection signal on the input side of S (I2).

  After that, it is determined whether or not to end the entire process (steps S17 and S27). If it is determined that the process is not yet completed (steps S17 and S27: N), the process returns to step S16 or step S26 again. If it is determined that the process is to be terminated (steps S17 and S27: Y), FIG. The entire process shown in FIG. 11 is completed.

  In this way, in the present embodiment, when the driving power source on the input side is the driving power source 51 (sub driving power source), the control unit 4 is controlled only by the driving power source 51 during the start-up period of the AC / DC converting unit 2. Is set so that the power consumption of the control unit 4 is lower than that in the normal operation period. Further, during the normal operation period of the AC / DC converter 2, power is supplied to the controller 4 only by the drive power source 52 (main drive power source). As a result, a drive power supply (drive power supply 105A, 105B) having a high power supply capability is provided on both the input side and the output side, and power is always supplied to the control unit by only one drive power supply on the input side ( Compared with the comparative example, the power supply capability on one side (the drive power supply 51 side which is the sub drive power supply) can be low.

  Further, during the normal operation period, the operation of the drive power supply 51 (sub drive power supply) is stopped, and power is supplied only by the drive power supply 52 (main drive power supply), thereby reducing power consumption and driving power supply 51. Noise due to the on / off operation of the switching element SW51 and the like is also suppressed. In other words, when unnecessary circuits are stopped, extra power consumption is reduced and high efficiency is achieved. Further, when unnecessary circuits are stopped, such noise wraparound is suppressed when the control unit 4 captures the detection signals S (V1), S (V2), S (I1), and S (I2). , S / N of output is improved.

  As described above, in the present embodiment, when the driving power source on the input side is the driving power source 51 (sub driving power source), the control unit 4 is controlled only by the driving power source 51 during the start-up period of the AC / DC converter 2. Is set so that the power consumption of the control unit 4 is lower than that in the normal operation period. In the normal operation period of the AC / DC converter 2, only the drive power source 52 (main drive power source) is used. Since the power supply to the control unit 4 is performed, the power supply capability on one side (the drive power supply 51 side that is the sub drive power supply) can be lower than the conventional one. Therefore, the drive power supply 51 can be reduced in size and weight, and the bidirectional converter 1 as a whole can be reduced in size and weight compared to the conventional one.

  Further, in the normal operation period, by stopping the operation of the drive power supply 51 (sub drive power supply), power is supplied only by the drive power supply 52 (main drive power supply), so that power consumption can be reduced. In addition, noise due to the on / off operation of the switching element SW51 in the drive power supply 51 can be suppressed. Therefore, a highly efficient and highly accurate bidirectional converter can be realized.

(Modification)
While the present invention has been described with reference to the embodiment, the present invention is not limited to this embodiment, and various modifications can be made.

  For example, the configurations of the AC / DC conversion unit, the DC / DC conversion unit, the rectifier circuit, the booster circuit, the smoothing circuit, the inverter circuit, and the control unit described in the above embodiment are not limited to these, and may be other configurations. May be.

  Further, for example, like the bidirectional converter 1A shown in FIG. 14, the AC side and the DC side are insulated from each other by the transformers 22 and 27, and between the driving power source 51 and the driving power source 52 by the transformer 53. May be insulated from each other. The SW circuit unit 2C is a circuit on the AC side of the transformer 22 in the circuit configuration of the AC / DC converting unit 2 shown in FIG. The SW circuit unit 2D is a circuit on the DC side of the transformer 22 in the circuit configuration of the AC / DC converting unit 2 shown in FIG. As described above, the AC side and the DC side are insulated from each other in the AC / DC converter 2 because, for example, the voltage of the battery 60 used in the PHEV may be as high as about 350V. This is because it is a safety problem to directly connect a high-voltage battery 60 to the commercial power supply 10. In such a configuration, when the transformer 53 is used as a component for insulation between the drive power supplies 51 and 52, the power used in the transformer 53 can be reduced, so that the insulating bidirectional converter 1A as a whole is used. Thus, the size and weight can be reduced more effectively. Further, in the bidirectional converter 1A shown in FIG. 14, it is preferable to provide an insulating transformer 53 between the drive power supply 51 (sub drive power supply) and the control unit 4. When configured in this manner, the electric power used in the insulating transformer 53 can be further reduced. Therefore, the above-described insulating bidirectional converter 1A can be more effectively reduced in size and weight as a whole. Further, in the bidirectional converter 1A, a disable signal Dis1 output from the control unit 4 and a disable signal input to the drive power supply 51 are used using a photocoupler 55 including an LED (Light Emitting Diode) 551 and a phototransistor 552. Signal transmission is performed with the Able signal Dis2. As a result, it becomes possible to transmit the disable signal while completely insulating the drive power supply 51 and the control unit 4.

  In the bidirectional converter 1A shown in FIG. 14, a sub-control unit (not shown) may be provided between the drive power supply 51 and the transformer 53 to completely separate the power. In such a configuration, the switching control signals of the switching elements SW21 to SW24 and the like in the AC / DC power conversion unit 2 are the logic of the signal from the sub-control unit and the signal from the control unit 4 (positive control unit). It is desirable to be composed of sums. Further, when the operation of the drive power source 51 (sub drive power source) is stopped, it is desirable to simultaneously stop the operation of the sub control unit.

  Further, for example, as in the bidirectional converter 1B shown in FIG. 15, the relays 541 and T2 are connected between the input / output terminals T1 and T2 and the drive power supply 51, and between the input / output terminals T3 and T4 and the drive power supply 52, respectively. 542 may be provided, and the output-side relay may be turned off during the start-up period. When configured in this way, it is avoided that uncontrolled power during the startup period is output to the output side, and safety on the output side is ensured.

  In the above description, the case where the power supply is performed only by the drive power supply 52 (main drive power supply) by stopping the operation of the drive power supply 51 (sub drive power supply) in the normal operation period has been described. For example, FIG. As shown in (A) and (B), power may be supplied by both the drive power supplies 51 and 52 during the normal operation period during both the forward operation and the reverse operation.

  In addition, the case where the bidirectional converter functions as a bidirectional AC / DC converter having the AC / DC converter 2 (AC / DC converter) has been described so far. The present invention can also be applied to a device that functions as a bidirectional DC / DC converter having a DC / DC converter 2 (DC / DC converter).

  Moreover, until now, the case where the whole bidirectional | two-way converter is used as a charging / discharging apparatus with respect to a battery etc. was demonstrated, However, The bidirectional | two-way converter of this invention is other than such a charging / discharging apparatus, for example, household appliances etc. The present invention can also be applied to other uses such as a power supply device.

  In the above embodiment, the function of the digital control device 43 in the control unit 4 is configured by software. However, the function of the digital control device 43 may be configured by hardware. Good. However, when configured by hardware, the circuit scale increases, and it is difficult to correct variations in each element. Therefore, it is preferable to configure by software as in the above embodiment.

  1A, 1B ... Bidirectional converter, 10 ... Commercial power supply, 2 ... AC / DC converter, 2A ... AC / DC converter, 2B ... DC / DC converter, 2C, 2D ... SW circuit, 22, 27 ... Transformer , 311, 321 ... voltage detection circuit, 312, 322 ... current detection circuit, 4 ... control unit, 41 ... transmitter, 42 ... frequency divider, 43 ... digital control device, 51, 52 ... drive power supply, 53 ... transformer, 541, 542 ... Relay, 55 ... Photocoupler, 551 ... LED, 552 ... Phototransistor, 60 ... Battery, 70 ... Load, T1-T4 ... Input / output terminals, H1, L1, H2, L2, H3, L3 ... Connection line , I1, I2 ... current, V1, V2 ... voltage, Vacin ... AC input voltage, Vacout ... AC output voltage, Vdcin ... DC input voltage, Vdcout ... DC output voltage, S (I1), S (V1), S (I2 ) S (V2) ... detection signal, Sa, Sb ... timing control signal, S51, S52 ... switching control signal, CLK0 ... basic clock signal, CLK1 ... frequency division signal (system clock signal), D51, D52 ... diode, fa, fb ... drive frequency (operating frequency), Sync ... synchronization signal, Dis ... disable signal, t1 to t6 ... timing, ts1 to ts3 ... capture timing (sampling timing).

Claims (7)

A bidirectional converter that outputs an output voltage from the other input / output terminal pair based on an input voltage input from one input / output terminal pair of the first and second input / output terminal pairs,
A voltage converter configured to include a switching element and generate the output voltage by performing voltage conversion based on the input voltage; and
A control unit for controlling the operation of the switching element;
A first driving power source connected to the first input / output terminal pair side; and a second driving power source connected to the second input / output terminal pair side; Drive power supply section for supplying power to be used as the power supply,
The control unit includes a digital arithmetic device (DSP),
In the normal operation period of the voltage conversion unit, at least power is supplied by a main drive power source that is a drive power source having a larger power supply capability of the first and second drive power sources,
In the startup period of the voltage conversion unit, the DSP is configured such that the operating frequency of the DSP is lower than the normal operation period,
Of the first and second drive power supplies, the drive power supply on the side to which the input voltage is input is a sub-drive that is the drive power supply having the smaller power supply capability of the first and second drive power supplies. In the case of a power supply, power is supplied only by the sub-drive power supply during the start-up period of the voltage conversion unit, and the power consumption of the control unit is lower than that during the normal operation period. A bidirectional converter characterized by
2. The bidirectional converter according to claim 1, wherein the control unit supplies power only from the main drive power supply by stopping the operation of the sub drive power supply during the normal operation period. 3. Each of the first and second drive power supplies includes a switching element,
3. The control unit according to claim 1, wherein the control unit controls the switching element in the voltage conversion unit and the switching element in the main drive power supply to perform an on / off operation in synchronization with each other. Bidirectional converter as described. The first drive power source and the second drive power source are insulated from each other;
The bidirectional converter according to any one of claims 1 to 3, wherein an insulating transformer is provided between the sub-drive power source and the control unit. The bidirectional DSP according to any one of claims 1 to 4, wherein the DSP outputs a prescribed pulse signal for controlling a switching element in the voltage converter during the start-up period. converter. A relay is provided between the first input / output terminal pair and the first drive power supply, and between the second input / output terminal pair and the second drive power supply,
The bidirectional converter according to any one of claims 1 to 5 , wherein the relay on the side from which the output voltage is output is in an off state during the start-up period. The voltage conversion unit is a AC / DC conversion unit performing voltage conversion between a DC voltage and an AC voltage of claims 1 to 6, characterized in that it functions as a bi-directional AC / DC converter The bidirectional converter according to any one of claims.

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