JPWO2010004738A1 - Rectifier and solar power generation system including the same - Google Patents

Abstract

The first MOSFET (4) is connected between the two terminals of the anode terminal (2) and the cathode terminal (3) with the source electrode on the anode terminal side, and the control voltage (V1) is applied from the applied voltage between the two terminals. A power supply circuit (5) to be generated, a first drive control circuit (6), and a detection circuit (7) for detecting a current direction between two terminals are provided. The detection circuit (7) includes a current limiting resistor (71) connected to the output of the power supply circuit (5), and a diode having an anode connected to the current limiting resistor (71) and a cathode connected to the cathode terminal (3). (72), the current direction is detected based on the anode potential (V2) of the diode (72), and the first drive control circuit (6) uses the control voltage (V1) to detect the anode potential ( The first MOSFET (4) is driven and controlled based on V2).

Description

  The present invention relates to a rectifier that is connected between two external terminals and that allows a current to flow only in one direction and prevents a reverse current, and a photovoltaic power generation system including such a rectifier.

  A diode that is a rectifier connected between two external terminals, when a voltage is applied in the forward direction, causes a current to flow in one direction from the anode side to the cathode side, and reverses when a reverse voltage is applied. The operation to block the current that is going to flow is performed. These general diodes are used for redundant power supplies, rectifier circuits, and the like. However, a forward voltage is generated in the diode when conducting, and a relatively large conduction loss occurs due to the product of this voltage and the forward current. In particular, when a plurality of redundant systems are used in series connection, there is a problem that the loss increases by the number of diodes connected.

Conventionally, a synchronous rectification method has been used for a rectifier with low conduction loss. However, it is necessary to detect a power source for driving the rectifier and a direction of a current flowing through the synchronous signal or the rectifier.
In the conventional rectifier, the cathode of the diode is connected to the drain of the synchronous rectifier MOSFET, the current supply means for supplying power from the outside is connected to the anode, and a resistor is connected between the anode of the diode and the source of the MOSFET. Connect and detect the voltage across it. Then, the voltage across the resistor is compared with the reference voltage, the output signal is amplified, and the gate voltage is obtained via the gate driving means, so that the gate voltage is applied to the MOSFET during most of the period in which the current flows in the MOSFET ( For example, see Patent Document 1).

  Further, in the conventional rectifier according to another example, the drain electrode of the field effect transistor is used as an AC input terminal, the source electrode is used as a DC output terminal, the gate electrode is connected to the output of the operational amplifier, and one input of the operational amplifier is input as an AC input. Connect to the terminal and connect the other to the DC output terminal. When the operational amplifier detects the potential difference between the AC input terminal and the DC output terminal and the input voltage is applied in the reverse direction, the field effect transistor is turned off and the input voltage is applied in the forward direction Enables rectification by making the field effect transistor conductive (see, for example, Patent Document 2).

JP 2004-32937 A Japanese Patent Laid-Open No. 11-122929

In the conventional rectifier shown in Patent Document 1, a current supply means is connected to the anode of a diode in which the cathode is connected to the drain of the MOSFET to detect the direction of the current flowing through the MOSFET, and between the anode and the source of the MOSFET. The voltage across the resistor connected to was detected. However, in order to apply to a rectifier having two external terminals, an anode terminal and a cathode terminal, it is necessary to generate a current supply means for supplying a constant current separately from the driving power source of the MOSFET inside the rectifier. Was not applicable.
In the conventional rectifier shown in Patent Document 2, the drain-source voltage is detected by the operational amplifier for detection of the direction of the current flowing through the MOSFET. However, in order to improve the reliability, the operational amplifier has an input offset voltage. ing. For this reason, there has been a problem that an operational amplifier manufactured to supply an input offset voltage from an external power source or to have an input offset voltage is required.

The present invention has been made to solve the above-described problems, and a rectifier comprising a MOSFET having a reduced loss during conduction and connected between two external terminals is provided with a further terminal and An object is to eliminate the need for an external power source and to easily replace the diode with a two-terminal diode, and to easily and reliably detect the direction of the current flowing through the MOSFET.
It is a second object of the present invention to provide a solar power generation system that includes such a rectifier and can improve power generation efficiency with a simple configuration and with high reliability.

  In the rectifier according to the present invention, an external terminal is an anode terminal and a cathode terminal, and a first MOSFET connected between the two terminals with a source electrode on the anode terminal side is connected between the two terminals. A power supply circuit that generates and outputs a predetermined control voltage from the applied voltage, and a first drive control circuit that outputs a drive signal to the gate electrode of the first MOSFET using the control voltage from the power supply circuit; A current limiting resistor connected to the output of the power supply circuit, and a detection circuit for detecting an anode potential of the diode, having a diode having an anode connected to the current limiting resistor and a cathode connected to the cathode terminal; Is provided. The first drive control circuit outputs the drive signal in accordance with the anode potential of the diode detected by the detection circuit.

  The solar power generation system according to the present invention generates power using one or more solar panels. Each of the solar panels includes a plurality of solar power generation cells connected in series, and an external terminal serving as an anode terminal and a cathode terminal. And two rectifiers connected in parallel to the respective photovoltaic power generation cells. Each rectifier generates a predetermined control voltage from the first MOSFET connected between the two terminals with the source electrode on the anode terminal side and the voltage applied between the two terminals. A power supply circuit for outputting, a first drive control circuit for outputting a drive signal to the gate electrode of the first MOSFET using a control voltage from the power supply circuit, and a current limiting circuit connected to the output of the power supply circuit And a detection circuit that includes a diode having an anode connected to the current limiting resistor and a cathode connected to the cathode terminal, and detecting an anode potential of the diode. The first drive control circuit detects an abnormality of the connected photovoltaic power generation cell from the anode potential of the diode detected by the detection circuit, turns on the first MOSFET, and The solar power generation cell is bypassed by a rectifier.

  The rectifier according to the present invention includes a power supply circuit that generates a predetermined control voltage from a voltage applied between two terminals. Further, a current limiting resistor is connected to the output of the power supply circuit, and a diode is inserted between the current limiting resistor and the cathode terminal to detect the anode potential of the diode. Since the anode potential that changes depending on the direction of the current flowing through the first MOSFET is detected, the direction of the current flowing through the first MOSFET can be easily and reliably detected. In addition, the control voltage output from the power supply circuit can be used not only to control the first MOSFET, but also to operate the rectifier using a voltage for detecting the anode potential of the diode. Therefore, it is possible to realize a low-loss and high-reliability rectifier that can be easily replaced with a two-terminal diode with a simple circuit configuration.

  Moreover, the photovoltaic power generation system by this invention connects a rectifier in parallel with each photovoltaic power generation cell of the several photovoltaic power generation cell connected in series. And this rectification | straightening apparatus can bypass this solar power generation cell with low loss and reliability at the time of abnormality of each solar power generation cell by simple circuit structure. For this reason, the photovoltaic power generation system can improve the power generation efficiency with a simple configuration with high reliability.

It is a figure which shows the circuit structure of the rectifier by Embodiment 1 of this invention. It is a figure which shows the circuit structure of the rectifier by Embodiment 2 of this invention. It is a figure which shows the circuit structure of the rectifier by Embodiment 3 of this invention. It is a figure which shows the circuit structure of the rectifier by Embodiment 4 of this invention. It is a figure which shows the circuit structure of the rectifier by Embodiment 5 of this invention. It is a figure explaining the operating characteristic of the rectifier by Embodiment 5 of this invention. It is a figure explaining the switching state of each MOSFET in the rectifier by Embodiment 5 of this invention. It is a figure which shows the circuit structure of the rectifier by Embodiment 6 of this invention. It is a figure explaining operation | movement of the rectifier by Embodiment 6 of this invention. It is a figure which shows the circuit structure of the rectifier by Embodiment 7 of this invention. It is a figure which shows the circuit structure of the rectifier by Embodiment 8 of this invention. It is a figure which shows the circuit structure of the rectifier by Embodiment 9 of this invention. It is a figure explaining the operating characteristic of the rectifier by Embodiment 10 of this invention. It is a figure explaining the switching state of each MOSFET in the rectifier by Embodiment 10 of this invention. It is a figure which shows the circuit structure of the rectifier by Embodiment 11 of this invention. It is a figure which shows the rectifier and peripheral circuit structure by Embodiment 13 of this invention. It is a figure which shows the main circuit structure of the solar energy power generation system by Embodiment 14 of this invention.

Embodiment 1 FIG.
A rectifier according to Embodiment 1 of the present invention will be described below with reference to the drawings.
1 is a diagram showing a circuit configuration of a rectifier according to Embodiment 1 of the present invention.
As shown in the figure, the rectifier 1 is an n-channel power MOSFET having two terminals, an anode terminal 2 serving as an anode terminal and a cathode terminal 3 serving as a cathode terminal, as external terminals connected between the two terminals. 1 MOSFET 4, a power supply circuit 5 that generates a predetermined control voltage V 1, a first drive control circuit 6 that drives and controls the first MOSFET 4 using the control voltage V 1 output from the power supply circuit 5, And a current direction detection circuit 7 as a detection circuit for detecting the direction of the current flowing through the MOSFET 4. The first MOSFET 4 incorporates a parasitic diode 4 a between the source and drain, and connects the source electrode to the anode terminal 2 and the drain electrode to the cathode terminal 3.

The power supply circuit 5 includes a diode 51, a capacitor 52, and a voltage adjusting circuit 53 configured by, for example, a chopper circuit, and has a reverse polarity voltage (hereinafter referred to as a reverse voltage) applied between the anode terminal 2 and the cathode terminal 3. The capacitor 52 is charged via the diode 51, and a predetermined voltage with the anode terminal 2 as a potential reference is generated from the charging voltage of the capacitor 52 as the control voltage V 1 of the first MOSFET 4. The voltage adjustment circuit 53 employs a step-up type or a step-down type depending on the magnitude of the reverse voltage, and generates a stable control voltage V1 regardless of the magnitude of the reverse voltage.
The current direction detection circuit 7 includes a current limiting resistor 71 connected to the output of the power supply circuit 5, and a diode 72 having an anode connected to the current limiting resistor 71 and a cathode connected to the cathode terminal 3. The anode potential V2 of the diode 72 is detected using the anode terminal 2 as a potential reference.

The first drive control circuit 6 uses a control voltage V1 from the power supply circuit 5 to output a drive signal 6a to the gate electrode of the first MOSFET 4, and a voltage for generating a reference voltage V3 from the control voltage V1. And an adjustment circuit 62. Then, the drive circuit 61 compares the anode voltage V2 (hereinafter referred to as the detection voltage V2) of the diode 72 detected by the current direction detection circuit 7 with the reference voltage V3, and compares the magnitude of the gate voltage of the first MOSFET 4 A drive signal 6a for turning on / off the first MOSFET 4 is output to the electrode. Here, when the detection voltage V2 is lower than the reference voltage V3, the first MOSFET 4 is turned on.
The detection voltage V <b> 2 is a voltage between the anode of the diode 72 and the anode terminal 2.

Next, the operation of the rectifier 1 will be described.
In the power supply circuit 5, a reverse voltage applied between the anode terminal 2 and the cathode terminal 3 is charged to the capacitor 52 through the diode 51, and the anode terminal 2 is used as a potential reference from the charging voltage of the capacitor 52, for example, 15V. Is generated as the control voltage V1 of the first MOSFET 4. Therefore, the predetermined control voltage V1 can be generated regardless of the magnitude of the reverse voltage. In this case, the voltage VCA between the cathode terminal 3 and the anode terminal 2 (hereinafter referred to as cathode-anode voltage VCA) is the voltage between the drain and source of the first MOSFET 4 and is reverse when a reverse voltage is applied. The magnitude of the voltage is the cathode-anode voltage VCA.

  When the reverse voltage (cathode-anode voltage VCA) is higher than the control voltage V1, in the current direction detection circuit 7, no current flows from the output terminal of the power supply circuit 5 that outputs the control voltage V1 to the cathode terminal 3, and the detection voltage V2 Is equivalent to the control voltage V1. The drive circuit 61 compares the reference voltage V3 set to, for example, 0.7V and the detection voltage V2, and turns on the first MOSFET 4 when the detection voltage V2 is lower than the reference voltage V3. In this case, since the detection voltage V2 is as high as the control voltage V1, the first MOSFET 4 is turned off, and the rectifier 1 prevents conduction of the current i.

  When the reverse voltage becomes lower than the control voltage V1, the control voltage V1 is higher than the cathode-anode voltage VCA. Therefore, in the current direction detection circuit 7, the current limiting resistor 71 and the diode are connected from the output terminal of the power supply circuit 5 to the cathode terminal 3. A current flows through 72. At this time, the current limiting resistor 71 limits the current and suppresses the discharge of the output of the power supply circuit 5. A voltage value obtained by adding the forward voltage Vf of the diode 72 to the cathode-anode voltage VCA is detected as the detection voltage V2. As the cathode-anode voltage VCA decreases, the detection voltage V2 also decreases. However, when the reverse voltage is applied, the detection voltage V2 is higher than the forward voltage Vf (about 0.6 to 0.7 V) of the diode 72, and thus the reference voltage. By appropriately setting V3, the detection voltage V2 becomes equal to or higher than the reference voltage V3, the first MOSFET 4 is turned off, and the rectifier 1 prevents conduction of the current i.

  When the cathode-anode voltage VCA decreases and the detection voltage V2 becomes lower than the reference voltage V3, the drive circuit 61 outputs a drive signal 6a for turning on the first MOSFET 4, and the first MOSFET 4 is turned on from off. . When the first MOSFET 4 is turned on, a current i through the first MOSFET 4 flows in the forward direction from the anode terminal 2 to the cathode terminal 3, and a voltage drop due to the current i and the on-resistance of the first MOSFET 4 occurs. The cathode-anode voltage VCA becomes negative. In the current direction detection circuit 7, a current flows from the output terminal of the power supply circuit 5 to the cathode terminal 3 through the current limiting resistor 71 and the diode 72. A voltage value obtained by adding the forward voltage Vf of the diode 72 to the cathode-anode voltage VCA is detected as the detection voltage V2. In this case, the detection voltage V2 is a voltage value obtained by subtracting the on-voltage (= −VCA) between the drain and source of the first MOSFET 4 from the forward voltage Vf of the diode. The on-voltage is a voltage corresponding to a voltage drop generated by the on-resistance when the MOSFET is turned on and a current flows.

The reference voltage V3 used in the drive circuit 61 is set to 0.7 V, for example. However, the forward voltage Vf of the diode 72 is subtracted from the on-voltage between the drain and source of the first MOSFET 4, and the forward voltage It is set between the direction voltage Vf and the voltage value obtained by adding the ON voltage. More precisely, the on-voltage when subtracting is the on-voltage when current flows in the first MOSFET 4 in the forward direction, and the on-voltage when adding is the current flowing in the reverse direction in the first MOSFET 4. ON voltage in case of
As described above, when the first MOSFET 4 is turned on and the current i flows through the first MOSFET 4 in the forward direction, the detection voltage V2 is generated between the forward voltage Vf of the diode 72 and the drain-source of the first MOSFET 4. The voltage value is obtained by subtracting the ON voltage, and is lower than the reference voltage V3. As a result, the drive circuit 61 turns on the first MOSFET 4 and the rectifier 1 continues to conduct the current i.

  When the cathode-anode voltage VCA is inverted from negative to positive, that is, at the initial stage of reverse voltage application, the first MOSFET 4 is in an on state, so that the current from the cathode terminal 3 to the anode terminal 2 via the first MOSFET 4 i flows in the reverse direction, and a voltage drop due to the current i and the on-resistance of the first MOSFET 4 occurs in the reverse direction. In the current direction detection circuit 7, a current flows from the output terminal of the power supply circuit 5 to the cathode terminal 3 through the current limiting resistor 71 and the diode 72. A voltage value obtained by adding the forward voltage Vf of the diode 72 to the cathode-anode voltage VCA is detected as the detection voltage V2. In this case, the detection voltage V2 has a voltage value obtained by adding the on-voltage between the drain and source of the first MOSFET 4 to the forward voltage Vf of the diode, and is equal to or higher than the reference voltage V3. As a result, the drive circuit 61 turns off the first MOSFET 4 and the rectifier 1 prevents conduction of the current i.

As described above, in this embodiment, the reverse voltage applied between the two terminals of the rectifier 1 is charged in the capacitor 52, and the voltage adjustment circuit 53 controls the control voltage of the first MOSFET 4 from the charged voltage of the capacitor 52. V1 is generated. Therefore, the predetermined control voltage V1 can be generated regardless of the magnitude of the reverse voltage, and the predetermined control voltage V1 can be secured stably, and the rectifier 1 can be operated. In addition, the withstand voltage of the element used for the first drive control circuit 6 does not need to be greater than the magnitude of the reverse voltage.
Further, when the cathode-anode voltage VCA is higher than the control voltage V1, the diode 72 in the current direction detection circuit 7 is not turned on, and a high reverse voltage can be prevented from being applied to the first drive control circuit 6. . Further, the detection voltage V2 does not become higher than the control voltage V1, and the voltage applied to each element for detection can be suppressed.

In addition, the current direction detection circuit 7 detects a voltage value obtained by adding the forward voltage Vf of the diode 72 to the cathode-anode voltage VCA, unless the reverse voltage exceeds the control voltage V1, as the detection voltage V2. Since the forward voltage Vf of the diode 72 is substantially constant and the cathode-anode voltage VCA changes depending on the direction of the current i between the cathode and the anode, the direction of the current i between the cathode and the anode is detected by the detection voltage V2. it can. In this way, detection of the direction of the current flowing through the first MOSFET 4 can be easily and reliably realized. Further, even when the reverse voltage is applied and the current i between the cathode and the anode is interrupted, the detection voltage V2 that is equal to or higher than the reference voltage V3 can be detected.
Then, the drive circuit 61 generates the drive signal 6a according to the detection voltage V2, so that when the reverse voltage is applied between the two terminals of the rectifier 1, the first MOSFET 4 is turned off and the current is blocked. When the forward voltage is applied, the first MOSFET 4 can be turned on and the two terminals of the rectifier 1 can be conducted.

  Further, since the control voltage V1 from the power supply circuit 5 is used not only for the drive voltage of the first MOSFET 4 but also for obtaining the detection voltage V2, it is easy to replace with a two-terminal diode with a simple circuit configuration. A highly reliable rectifier can be realized.

  Further, the reference voltage V3 used in the drive circuit 61 is obtained by adding the forward voltage Vf and the on-voltage to the voltage value obtained by subtracting the on-voltage between the drain and source of the first MOSFET 4 from the forward voltage Vf of the diode 72. Set between voltage values. As a result, when a forward voltage is applied between the two terminals of the rectifier 1, the first MOSFET 4 is turned on to ensure conduction between the two terminals of the rectifier 1, and the change in the current direction when the reverse voltage is applied. Can be detected quickly and reliably, the first MOSFET 4 is turned off, and the two terminals of the rectifier 1 can be quickly disconnected.

Embodiment 2. FIG.
2 is a diagram showing a circuit configuration of a rectifier according to Embodiment 2 of the present invention.
As shown in the figure, in the rectifier according to the first embodiment shown in FIG. 1, the diode 72 of the current direction detection circuit 7 is provided with a temperature detection line 73 as means for detecting the element temperature, and the detected element temperature. Is input to the voltage adjustment circuit 62 of the first drive control circuit 6. The voltage adjustment circuit 62 adjusts the reference voltage V <b> 3 according to the element temperature of the diode 72. Other configurations are the same as those of the first embodiment.
The temperature detection line 73 is, for example, a temperature detection line such as a thermocouple from the voltage adjustment circuit 62 or a temperature data line from which the diode 72 outputs its temperature to the voltage adjustment circuit 62.

In general, in a diode, the higher the temperature, the smaller the forward voltage for the same forward current. For this reason, in the voltage adjustment circuit 62, when the element temperature of the diode 72 becomes high, the reference voltage V3 is adjusted low.
When the element temperature of the diode 72 increases, the detection voltage V2 from the current direction detection circuit 7 decreases. However, by adjusting the reference voltage V3 to be low as described above, the first drive control circuit 6 has a high reliability. One MOSFET 4 can be driven and controlled.

Embodiment 3 FIG.
FIG. 3 is a diagram showing a circuit configuration of a rectifier according to Embodiment 3 of the present invention.
As shown in the figure, in the rectifier according to the first embodiment shown in FIG. 1, an adjustment resistor 74 is inserted between the diode 72 of the current direction detection circuit 7 and the detection point of the detection voltage V2. Other configurations are the same as those of the first embodiment.

  As in the first embodiment, in the current direction detection circuit 7, when the cathode-anode voltage VCA is lower than the control voltage V1, the diode 72 is turned on and current flows from the output terminal of the power supply circuit 5 to the cathode terminal 3. . In this embodiment, since the adjustment resistor 74 is inserted between the diode 72 and the detection point of the detection voltage V2, the detection voltage V2 is the cathode-anode voltage VCA, the forward voltage Vf of the diode 72, and the adjustment resistor 74. The voltage value is obtained by adding the inter-terminal voltage. Thereby, the detection voltage V2 can be shifted to a high region.

  When the first MOSFET 4 is turned on and a change in the direction of the current i flowing through the first MOSFET 4 is detected when a reverse voltage is applied, the current i is a small current region. In the configuration in which the adjustment resistor 74 is not inserted between the diode 72 and the detection point of the detection voltage V2, the detection voltage V2 is detected because the detection voltage V2 obtained by adding the forward voltage Vf of the diode 72 to the cathode-anode voltage VCA is detected. Becomes a relatively small voltage level near the forward voltage Vf. In the first embodiment, it is necessary for the drive circuit 61 to detect such a voltage change at a relatively small voltage level. In this embodiment, since the detection voltage V2 can be shifted to a high region, the current direction can be detected accurately even with the current i in a small current range.

In addition, when the first MOSFET 4 is on and the current i flowing through the first MOSFET 4 increases, the on-voltage of the first MOSFET 4 increases and the detection voltage V2 decreases. In this embodiment, since the detection voltage V2 can be shifted to a high region, the detection voltage V2 can be prevented from becoming a negative voltage. In order for the first drive control circuit 6 to handle a negative voltage, a negative control power source or the like is required, and the circuit configuration becomes complicated at each stage. In this embodiment, with a simple circuit configuration in which the adjustment resistor 74 is inserted between the diode 72 and the detection point of the detection voltage V2, the detection voltage V2 can be shifted to a high region and the direction of the current i can be detected with high reliability. .
As described above, the current i can be detected in the current direction with high accuracy in both a small current range and a large current range, and the detectable current range is expanded.

Embodiment 4 FIG.
4 is a diagram showing a circuit configuration of a rectifier according to Embodiment 4 of the present invention.
In the third embodiment, the adjustment resistor 74 is inserted between the diode 72 and the detection point of the detection voltage V2. However, as shown in FIG. 4, a Zener diode 75 as a constant voltage means is used instead of the adjustment resistor 74. It may be used. In this case, the detection voltage V2 can be shifted to a high region with a constant voltage width, and the fluctuation range of the detection voltage V2 does not change without being divided by the resistance value. For this reason, the current direction can be detected with higher accuracy when the current i flowing through the first MOSFET 4 is in a small current range.

Further, as shown in FIG. 4, the drive circuit 61 may include a hysteresis circuit 63, and the reference voltage V3 may be provided with a hysteresis width. Thereby, the reference voltage for turning on the first MOSFET 4 from off and the reference voltage for turning off from on are changed.
When the cathode-anode voltage VCA decreases and the detection voltage V2 becomes lower than the reference voltage V3, the first MOSFET 4 is turned on. At this time, a forward current flows through the first MOSFET 4 to cause a cathode-anode voltage. Even if VCA fluctuates, it is possible to prevent the drive circuit 61 from malfunctioning.
In addition, the structure which provides the hysteresis circuit 63 in this way can be similarly applied to each of the first to third embodiments, and the same effect can be obtained.

  Further, the configuration using the adjustment resistor 74 and the Zener diode 75 of the third and fourth embodiments can be applied not only to the first embodiment but also to the second embodiment, and the same effect can be obtained.

Embodiment 5 FIG.
Next, a rectifier according to Embodiment 5 of the present invention will be described with reference to the drawings.
FIG. 5 is a diagram showing a circuit configuration of a rectifier according to Embodiment 5 of the present invention.
As shown in the figure, in the same way as in the first embodiment, the rectifier 1 uses the two terminals of the anode terminal 2 and the cathode terminal 3 as external terminals, and generates a control voltage V1 and a first drive. A control circuit 6 and a current direction detection circuit 7 are provided. The configurations and operations of the power supply circuit 5, the first drive control circuit 6, and the current direction detection circuit 7 are the same as those in the first embodiment.

In parallel with the first MOSFET 4 whose source electrode is connected to the anode terminal 2, the second MOSFET 10 connected in series to the first MOSFET 4, and the series circuit of the first MOSFET 4 and the second MOSFET 10. A third MOSFET 12 to be connected and a third diode 13 having an anode connected to the anode terminal 2 and a cathode connected to the cathode terminal 3 are provided between the two terminals. In addition, a shunt resistor 11 is connected in parallel to the second MOSFET 10, and an on-voltage adjusting circuit 14 is configured by these elements 10 to 13.
Note that the third diode 13 may also be a parasitic diode built in the third MOSFET 12.
In addition, a second drive control circuit 20 that operates with the control voltage V1 from the power supply circuit 5 is provided, and the second drive control circuit 20 performs the second and third in accordance with the detection voltage V2 from the current direction detection circuit 7. Drive signals 21 and 22 to the MOSFETs 10 and 12 and a limit signal 23 to the first drive control circuit 6 are output.

As shown in the first embodiment, when the first MOSFET 4 is turned on, the current i through the first MOSFET 4 flows from the anode terminal 2 to the cathode terminal 3 in the forward direction. This current i and the first MOSFET 4 A voltage drop occurs due to the on-resistance.
The second drive control circuit 20 determines the combination of MOSFETs to be turned on from the first MOSFET 4 and the second and third MOSFETs 10 and 12 according to the detection voltage V2, and controls the MOSFETs 4, 10, and 12. As a result, the on-resistance between the terminals when the current i flows from the anode terminal 2 to the cathode terminal 3 in the forward direction is changed stepwise. This is a control to change the on-resistance to decrease as the current i increases, and thereby suppresses an increase in the on-voltage that is a voltage drop due to the on-resistance due to the increase in the current i.

  FIG. 6 shows the operating characteristics of the rectifier 1 according to this embodiment, and is a diagram showing the anode-cathode voltage VAC (= −VCA) that changes according to the current i. FIG. 7 shows the switching state of each MOSFET corresponding to the current i. The on-voltage is indicated by an anode-cathode voltage VAC (= −VCA) when the anode-cathode is conductive. Further, 31 is a range of the anode-cathode voltage VAC in the range of the detection voltage V2 in which the current direction can be detected by the current direction detection circuit 7, and 32 is an output characteristic of the third diode 13 connected between the anode and the cathode. Is shown. In the state of the first MOSFET 4 and the second and third MOSFETs 10 and 12, SW indicates a state that is switched in synchronization with the drive signal 6 a from the drive circuit 61.

  When a change in the direction of the current i flowing through the first MOSFET 4 is detected when a reverse voltage is applied when the first MOSFET 4 is on, the change in the detection voltage V2 is small in the region where the current i is small and is used for the drive circuit 61. In some cases, it is difficult to detect with a comparator or operational amplifier, or the driving power for driving the first MOSFET 4 is larger than the conduction loss when flowing through the diode. In such a range of the current i (i1 or less), the second drive control circuit 20 selects to turn off all the MOSFETs 4, 10, and 12, and sends the limit signal 23 for adjusting the reference voltage V3 to the first signal. The voltage is output to the voltage adjustment circuit 62 in the drive control circuit 6. The limit signal 23 is a signal for limiting the drive signal 6a in order to turn off the first MOSFET 4, whereby the first MOSFET 4 is turned off.

When the cathode-anode voltage VCA decreases and the detection voltage V2 becomes lower than the reference voltage V3, and the current i when the first MOSFET 4 is turned on becomes i1, the second drive control circuit 20 Then, it is selected that only the first MOSFET 4 is turned on, and the limit signal 23 is released. The first drive control circuit 6 turns on the first MOSFET 4 by the drive signal 6a, and the current i of i1 flows.
This current i flows between the anode and the cathode via the first MOSFET 4 and the shunt resistor 11, and the anode-cathode voltage VAC (= −VCA) becomes small. The on-resistance at this time is the sum of the on-resistance of the first MOSFET 4 and the shunt resistor 11.

  When the current i increases in this state, the on-voltage, that is, the anode-cathode voltage VAC increases. When the value of the current i reaches i2, the second MOSFET 10 is turned on. At this time, the second drive control circuit 20 selects the MOSFET for turning on the first MOSFET 4 and the second MOSFET 10 and outputs a drive signal 21 for turning on the second MOSFET 10. This drive signal 21 is output at a voltage based on the potential of the source electrode of the second MOSFET 10, and is charged by the second drive control circuit 20 from the control voltage V1 when the first MOSFET 4 is turned on. Generate. When the second MOSFET 10 is turned on, the current i flowing through the shunt resistor 11 is commutated to the second MOSFET 10. As a result, the current i flows between the anode and the cathode via the first MOSFET 4 and the second MOSFET 10. The on-resistance at this time is the sum of the on-resistance of the first MOSFET 4 and the on-resistance of the second MOSFET 10, and the on-resistance decreases because the on-resistance decreases.

When the current i further increases, the on-voltage increases, but when the value of the current i becomes i3, the third MOSFET 12 is turned on. At this time, the second drive control circuit 20 selects the first MOSFET 4 and the second and third MOSFETs 10 and 12 as MOSFETs to be turned on, and outputs a drive signal 21 to turn on the second MOSFET 10 and A drive signal 22 for turning on the third MOSFET 12 is output. The drive signal 22 is input to the AND circuit 63 together with the drive signal 6 a to the first MOSFET 4, and the drive signal 24 a is output from the AND circuit 63 to the gate electrode of the third MOSFET 12. For this reason, the third MOSFET 12 is switched in synchronization with the drive signal 6a.
Since the third MOSFET 12 connected in parallel to the path formed by the first MOSFET 4 and the second MOSFET 10 is turned on, the on-resistance between the anode and the cathode is reduced, and the on-voltage is lowered.

When the current i further increases, the on-voltage increases, but when the value of the current i becomes i4, the first MOSFET 4 and the third MOSFET 12 are turned off and the second MOSFET 10 is turned on. At this time, the second drive control circuit 20 selects the MOSFET for turning on the second MOSFET 10, outputs the drive signal 21 for turning on the second MOSFET 10, and sets the drive signal 22 to low so that the third MOSFET 12. And a limit signal 23 for adjusting the reference voltage V3 is output to the voltage adjustment circuit 62 in the first drive control circuit 6. The limit signal 23 is a signal for limiting the drive signal 6a in order to turn off the first MOSFET 4, whereby the first MOSFET 4 is turned off.
The current i flows through the path formed by the parasitic diode of the first MOSFET 4 and the second MOSFET 10, the path through the parasitic diode of the third diode 13, and the path through the third diode 13, and the current i further increases. Even so, the on-state voltage hardly changes.

  As described above, the second drive control circuit 20 switches the combination of MOSFETs that are turned on when the current i increases so as to reduce the on-resistance, thereby suppressing an increase in the on-voltage. Actually, the switching is performed when the detection voltage V2 becomes a voltage value corresponding to each of the current values i1 to i4. Further, as shown in FIG. 6, the on-resistance is controlled to be minimum within the voltage range 31 of the on-voltage in which the current direction can be detected.

In this embodiment, a second MOSFET 10 connected in series to the first MOSFET 4, a third MOSFET 12 connected in parallel, a shunt resistor 11 connected in parallel to the second MOSFET 10, and a third An on-voltage adjusting circuit 14 including a diode 13 is provided, and the on-voltage is increased by stepwise changing the on-resistance between the anode and the cathode when the current i flows from the anode terminal 2 to the cathode terminal 3 in the forward direction. Suppressed to do. Thereby, the conduction | electrical_connection loss of the rectifier 1 can be reduced and the rectifier suitable for energy saving with high efficiency is realizable.
In addition, in the range of the current i in which it is difficult to detect the change in the current direction (i1 or less), control for limiting the drive signal 6a to the first MOSFET 4 is performed, so that malfunction of the rectifier 1 can be prevented.

Two or more second MOSFETs 10 may be connected in series to the first MOSFET 4, and the number of parallel third MOSFETs 12 connected in parallel may be two or more. The second MOSFET 10 and the third MOSFET 12 may include only one of them. Further, the shunt resistor 11 and the third diode 13 may not be provided, and a plurality thereof may be provided.
In this embodiment, the first MOSFET 4 and the third MOSFET 12 are simultaneously switched. However, the present invention is not limited to this. First, only the first MOSFET 4 is turned on as the current i increases so that the power for driving the MOSFET and the on-voltage are reduced and the sum of losses during rectification is minimized. Alternatively, the MOSFET to be driven may be selected step by step such that only the first MOSFET 4 and the third MOSFET 12 are simultaneously turned on.
In addition, the first MOSFET 4 and the third MOSFET 12 may be different types of elements, for example, the third MOSFET 12 may be an element having a smaller on-resistance value than the first MOSFET 4. In this way, the type of element to be used according to the value of the current i so that the ON voltage is reduced within the range in which the current direction can be detected and the sum of the conduction loss during rectification and the MOSFET drive loss is minimized. The number may be changed.
In either case, the on-resistance is changed stepwise in accordance with the detection voltage V2 so that the on-resistance is minimized within the voltage range 31 of the on-voltage in which the current direction can be detected.

  In this embodiment, the second drive control circuit 20 is provided separately from the first drive control circuit 6 for driving the first MOSFET 4. However, the first drive control circuit 6 and the second drive control circuit are provided. A drive control circuit having functions of 20 and the AND circuit 24 may be used. In this case, the first MOSFET 4, the second MOSFET 10 connected in series to the first MOSFET 4, and the third MOSFET 12 connected in parallel are provided, and the gates of the MOSFETs 4, 10, 12 are connected from the drive control circuit. By outputting drive signals to the electrodes, the same control as in the fifth embodiment is performed.

Embodiment 6 FIG.
Next, a rectifier according to Embodiment 6 of the present invention will be described with reference to the drawings.
FIG. 8 is a diagram showing a circuit configuration of a rectifier according to Embodiment 6 of the present invention.
As shown in the figure, the rectifier 1 includes an anode terminal 2 as an anode terminal and a cathode terminal 3 as a cathode terminal as external terminals, a first MOSFET 4 connected between the two terminals, A power supply circuit 5c that generates the control voltage V1, a first drive control circuit 6 that drives and controls the first MOSFET 4 with the control voltage V1, and a current direction detection circuit 7 that detects the direction of the current flowing through the first MOSFET 4. With. The first MOSFET 4 incorporates a parasitic diode 4 a between the source and drain, and connects the source electrode to the anode terminal 2 and the drain electrode to the cathode terminal 3.

  The power supply circuit 5c includes a first power supply circuit 5a and a second power supply circuit 5b. The first power supply circuit 5 a includes a first diode 51, a first capacitor 52, and a first voltage adjustment circuit 53 configured by, for example, a chopper circuit or a charge pump, and includes an anode terminal 2 and a cathode terminal 3. The first capacitor 52 is charged with the reverse voltage applied to the first capacitor 51 via the first diode 51, and the first voltage adjustment circuit 53 determines the potential of the anode terminal 2 from the charged voltage of the first capacitor 52. The control voltage V1 is generated. The second power supply circuit 5b includes a second diode 55, a second capacitor 56, and a second voltage adjusting circuit 57 configured by, for example, a chopper circuit, a charge pump, a cockcroft circuit, etc. A positive voltage applied to the cathode terminal 3 (hereinafter referred to as a forward voltage) is charged to the second capacitor 56 via the second diode 55, and the second voltage adjusting circuit 57 is connected to the second voltage adjusting circuit 57. A control voltage V1 based on the potential of the anode terminal 2 is generated from the charging voltage of the capacitor 56. The first and second voltage adjustment circuits 53 and 57 are connected to the output terminal of the entire power supply circuit 5c via diodes 54 and 58 arranged on the output side, respectively. The power supply circuit 5c is connected to the anode terminal 2 The control voltage V1 is output regardless of the voltage polarity applied between the cathode terminal 3 and the cathode terminal 3.

The current direction detection circuit 7 includes a current limiting resistor 71 connected to the output of the power supply circuit 5 c, and a diode 72 whose anode is connected to the current limiting resistor 71 and whose cathode is connected to the cathode terminal 3. Then, the current direction detection circuit 7 detects the anode potential V2 of the diode 72 using the anode terminal 2 of the rectifier 1 as a potential reference, and sets the detected voltage V2.
The first drive control circuit 6 uses a control voltage V1 from the power supply circuit 5c to output a drive signal 6a to the gate electrode of the first MOSFET 4, and a voltage for generating a reference voltage V3 from the control voltage V1. And an adjustment circuit 62. Then, the drive circuit 61 compares the detection voltage V2 from the current direction detection circuit 7 with the reference voltage V3 and outputs a drive signal 6a for turning on / off the first MOSFET 4 to the gate electrode of the first MOSFET 4. Output. Here, when the detection voltage V2 is lower than the reference voltage V3, the first MOSFET 4 is turned on.

Next, the operational characteristics of the rectifier 1 will be described.
The relationship between the cathode-anode voltage VCA between the cathode terminal 3 and the anode terminal 2 and the characteristics of the current i flowing from the anode terminal 2 to the cathode terminal 3 through the first MOSFET 4 and the operation of the first MOSFET 4 is shown. 9 shows. In FIG. 9, 33 indicates the operating state of the first MOSFET 4, 34 indicates the characteristics of the cathode-anode voltage VCA, and 35 indicates the characteristics of the current i with the forward direction being positive. The cathode-anode voltage VCA is the drain-source voltage of the first MOSFET 4.
As shown in the figure, when the cathode-anode voltage VCA is positive, that is, when a reverse voltage is applied between the cathode and the anode, the first MOSFET 4 is turned off and the cathode-anode is cut off. . Further, in the conduction period A in which the first MOSFET 4 is turned on and the cathode and the anode are conducted, the cathode-anode voltage VCA is negative.

In the cut-off period B, the reverse voltage applied between the anode terminal 2 and the cathode terminal 3 is charged to the first capacitor 52 via the first diode 51 of the first power supply circuit 5a. In the conduction period A, the cathode-anode voltage VCA is charged to the second capacitor 56 via the second diode 55 of the second power supply circuit 5b.
The first voltage adjustment circuit 53 generates a control voltage V1 of, for example, 15V based on the potential of the anode terminal 2 from the charging voltage of the first capacitor 52. The second voltage adjustment circuit 57 generates a similar control voltage V <b> 1 from the charging voltage of the second capacitor 56.
Since the power supply circuit 5c outputs the control voltage V1 from both the first and second power supply circuits 5a and 5b, the reverse voltage is applied regardless of the voltage polarity applied between the anode terminal 2 and the cathode terminal 3. The predetermined control voltage V1 can be output regardless of the magnitude of.

  Note that the first and second voltage adjustment circuits 53 and 57 need not always operate both, and either one may operate and the control voltage V1 may be output from the power supply circuit 5c. In that case, the voltages of the first and second capacitors 52 and 56, which are the input voltages of the first and second voltage adjustment circuits 53 and 57, are detected, and the first and second voltage adjustment circuits 53 and 57 are detected. However, a method of stopping the operation when the voltage cannot output the stable control voltage V1 may be used.

  When the reverse voltage is applied and the cathode-anode voltage VCA is higher than the control voltage V1, in the current direction detection circuit 7, no current flows from the output terminal of the power supply circuit 5c to the cathode terminal 3, and the detection voltage V2 is equal to the control voltage V1. It is equivalent. The drive circuit 61 compares the reference voltage V3 set to, for example, 0.7V and the detection voltage V2, and turns on the first MOSFET 4 when the detection voltage V2 is lower than the reference voltage V3. In this case, since the detection voltage V2 is as high as the control voltage V1, the first MOSFET 4 is turned off, and the rectifier 1 prevents conduction of the current i.

When the reverse voltage is applied and the cathode-anode voltage VCA becomes lower than the control voltage V1, in the current direction detection circuit 7, the output terminal of the power supply circuit 5c is connected to the cathode terminal 3 through the current limiting resistor 71 and the diode 72. Current flows. At this time, the current limiting resistor 71 limits the current and suppresses the discharge of the output of the power supply circuit 5c.
A voltage value obtained by adding the forward voltage Vf of the diode 72 to the cathode-anode voltage VCA is detected as the detection voltage V2. The detection voltage V2 also decreases as the cathode-anode voltage VCA decreases. However, when a reverse voltage is applied, the detection voltage V2 is the forward voltage Vf of the diode 72 (for example, 0.6 to 0. 0 when a PN junction diode is used). Therefore, when the reference voltage V3 is appropriately set, the detection voltage V2 becomes equal to or higher than the reference voltage V3, the first MOSFET 4 is turned off, and the rectifier 1 prevents conduction of the current i.

  When the cathode-anode voltage VCA decreases and the detection voltage V2 becomes lower than the reference voltage V3, the drive circuit 61 outputs a drive signal 6a for turning on the first MOSFET 4, and the first MOSFET 4 is turned on from off. . When the first MOSFET 4 is turned on, a current i through the first MOSFET 4 flows in the forward direction from the anode terminal 2 to the cathode terminal 3, and a voltage drop due to the current i and the on-resistance of the first MOSFET 4 occurs. The cathode-anode voltage VCA becomes negative. In the current direction detection circuit 7, a current flows from the output terminal of the power supply circuit 5 c to the cathode terminal 3 through the current limiting resistor 71 and the diode 72. A voltage value obtained by adding the forward voltage Vf of the diode 72 to the cathode-anode voltage VCA is detected as the detection voltage V2. In this case, the detection voltage V2 has a voltage value obtained by subtracting the on-voltage between the drain and source of the first MOSFET 4 from the forward voltage Vf of the diode.

The reference voltage V3 used in the drive circuit 61 is set to 0.7 V, for example. However, the forward voltage Vf of the diode 72 is subtracted from the on-voltage between the drain and source of the first MOSFET 4, and the forward voltage It is set between the direction voltage Vf and the voltage value obtained by adding the ON voltage.
As described above, when the first MOSFET 4 is turned on and the current i flows through the first MOSFET 4 in the forward direction, the detection voltage V2 is turned on between the drain and source of the first MOSFET 4 from the forward voltage Vf of the diode. The voltage value is obtained by subtracting the voltage, and is lower than the reference voltage V3. As a result, the drive circuit 61 turns on the first MOSFET 4 and the rectifier 1 continues to conduct the current i.

  When the cathode-anode voltage VCA is inverted from negative to positive, that is, at the initial stage of reverse voltage application, the first MOSFET 4 is in an on state, so that the current from the cathode terminal 3 to the anode terminal 2 via the first MOSFET 4 i flows in the reverse direction, and a voltage drop due to the current i and the on-resistance of the first MOSFET 4 occurs in the reverse direction. In the current direction detection circuit 7, a current flows from the output terminal of the power supply circuit 5 c to the cathode terminal 3 through the current limiting resistor 71 and the diode 72. A voltage value obtained by adding the forward voltage Vf of the diode 72 to the cathode-anode voltage VCA is detected as the detection voltage V2. In this case, the detection voltage V2 has a voltage value obtained by adding the on-voltage between the drain and source of the first MOSFET 4 to the forward voltage Vf of the diode, and is equal to or higher than the reference voltage V3. As a result, the drive circuit 61 turns off the first MOSFET 4 and the rectifier 1 prevents conduction of the current i.

  As described above, in this embodiment, the power supply circuit 5c is supplied with the predetermined control voltage V1 by the first voltage adjustment circuit 53 using the reverse voltage applied between the anode terminal 2 and the cathode terminal 3. The first power supply circuit 5a to be generated and the second power supply circuit 5b to generate a predetermined control voltage V1 by the second voltage adjustment circuit 57 using a forward voltage. For this reason, compared with the case where the power source is generated using only the reverse voltage, the control voltage does not fluctuate depending on the frequency of the current and the conduction rate between the two terminals, regardless of the voltage polarity applied between the two terminals. Further, the predetermined control voltage V1 can be stably output regardless of the magnitude of the reverse voltage. For this reason, it is possible to stably obtain the control voltage V1 required for the first drive control circuit 6, for example, the drive of the first MOSFET 4 and the voltage required for the elements in the first drive control circuit 6, The rectifier 1 can operate with high reliability. Further, it is not necessary to set the withstand voltage of the element used for the first drive control circuit 6 to be equal to or larger than the reverse voltage, and the first drive control circuit 6 can be configured with inexpensive elements. Further, in order to suppress the fluctuation of the control voltage V1, it is not necessary to provide a capacitor with a large capacity in the power supply circuit 5c, and the device configuration is suitable for downsizing.

Further, since the control voltage V1 from the power supply circuit 5c is used not only for the driving voltage of the first MOSFET 4 but also for obtaining the detection voltage V2 in the current direction detection circuit 7, it has a simple circuit configuration and has two terminals. The rectifier 1 that can be easily replaced with a diode, has low conduction loss, and is suitable for energy saving can be realized with high reliability.
Further, when the cathode-anode voltage VCA is higher than the control voltage V1, the diode 72 in the current direction detection circuit 7 is not turned on, and a high reverse voltage can be prevented from being applied to the first drive control circuit 6. . Further, the detection voltage V2 does not become higher than the control voltage V1, and the voltage applied to each element for detection can be suppressed.

The current direction detection circuit 7 detects, as the detection voltage V2, a voltage value obtained by adding the forward voltage Vf of the diode 72 to the cathode-anode voltage VCA when the diode 72 is conductive. Since the forward voltage Vf of the diode 72 is substantially constant and the cathode-anode voltage VCA changes depending on the direction and magnitude of the current i between the cathode and anode, the detection voltage V2 indicates the current i between the cathode and anode. Direction and size can be detected. In this way, detection of the direction of the current flowing through the first MOSFET 4 can be easily and reliably realized. Further, even when the reverse voltage is applied and the current i between the cathode and the anode is interrupted, the detection voltage V2 that is equal to or higher than the reference voltage V3 can be detected.
Then, the drive circuit 61 generates the drive signal 6a according to the detection voltage V2, so that when the reverse voltage is applied between the two terminals of the rectifier 1, the first MOSFET 4 is turned off and the current is blocked. When the forward voltage is applied, the first MOSFET 4 can be turned on and the two terminals of the rectifier 1 can be conducted.

Embodiment 7 FIG.
Next, a rectifier according to Embodiment 7 of the present invention will be described with reference to the drawings.
FIG. 10 is a diagram showing a circuit configuration of a rectifier according to Embodiment 7 of the present invention.
As shown in the figure, the rectifier 1 uses the two terminals of the anode terminal 2 and the cathode terminal 3 as external terminals as in the first and sixth embodiments, and connects the first MOSFET 4 between the two terminals. A power supply circuit 50 that generates a predetermined control voltage V 1, a first drive control circuit 6, and a current direction detection circuit 7 are provided. The configurations and operations of the first MOSFET 4, the first drive control circuit 6, and the current direction detection circuit 7 are the same as those in the first and sixth embodiments. The power supply circuit 50 will be described below.

The power supply circuit 50 includes a first power supply circuit 50a composed of the first voltage adjustment circuit 53 and a second power supply circuit 50b composed of the second voltage adjustment circuit 57, and is connected to the anode terminal 2 on the output side. A capacitor 59 as a filter circuit is provided between them. The drive signal 6 a output from the first drive control circuit 6 is input to the first and second voltage adjustment circuits 53 and 57.
The first voltage adjustment circuit 53 detects the reverse voltage applied between the anode terminal 2 and the cathode terminal 3 when the input drive signal 6a is an off signal, that is, when the first MOSFET 4 is in the off state. A control voltage V1 with the anode terminal 2 as a potential reference is generated. At this time, the first voltage adjustment circuit 53 performs a step-down operation when the reverse voltage is larger than the control voltage V1, and performs a step-up operation when the reverse voltage is smaller than the control voltage V1.
The second voltage adjustment circuit 57 is applied in the order in which the voltage is applied between the anode terminal 2 and the cathode terminal 3 when the input drive signal 6a is an on signal, that is, when the first MOSFET 4 is on. The voltage is boosted to generate a control voltage V1 with the anode terminal 2 as a potential reference.

Thereby, the power supply circuit 50 can operate one of the first and second voltage adjustment circuits 53 and 57 to generate and output the predetermined control voltage V1. Since the drive signal 6a changes between on and off, the first and second voltage adjustment circuits 53 and 57 operate alternately. Then, the capacitor 59 provided on the output side suppresses the fluctuation of the control voltage V1 when the operations of the first and second voltage adjustment circuits 53 and 57 are switched.
The capacitor 59 only needs to suppress the fluctuation of the control voltage V1 when the operation of the first and second voltage adjustment circuits 53 and 57 is switched. Therefore, the capacitor 59 may be relatively small and the voltage fluctuation is within an allowable range. If it is within, the capacitor 59 may be omitted.

  Also in this embodiment, similarly to the sixth embodiment, the power supply circuit 50 is operated by the first voltage adjustment circuit 53 using the reverse voltage applied between the anode terminal 2 and the cathode terminal 3. The first power supply circuit 50a that generates the predetermined control voltage V1 and the second power supply circuit 50b that generates the predetermined control voltage V1 in the second voltage adjusting circuit 57 using the forward voltage. For this reason, compared with the case where the power source is generated using only the reverse voltage, the control voltage does not fluctuate depending on the frequency of the current and the conduction rate between the two terminals, regardless of the voltage polarity applied between the two terminals. Further, the predetermined control voltage V1 can be stably output regardless of the magnitude of the reverse voltage. For this reason, the control voltage V1 required for the first drive control circuit 6 can be stably obtained, and the rectifier 1 can operate with high reliability. Further, it is not necessary to set the withstand voltage of the element used for the first drive control circuit 6 to be equal to or larger than the reverse voltage, and the first drive control circuit 6 can be configured with inexpensive elements. In addition, in order to suppress fluctuations in the control voltage V1, it is not necessary to provide a capacitor with a large capacity in the power supply circuit 50, and the device configuration is suitable for downsizing.

In addition, since the first and second power supply circuits 50a and 50b are not provided with a capacitor for holding electric charge, the rise time of the power supply circuit 50 at the time of startup can be shortened.
The first and second voltage adjustment circuits 53 and 57 each have their own control power supply. At startup, each control power supply is started up from the voltages input to the first and second voltage adjustment circuits 53 and 57 using a voltage dividing resistor and a Zener diode. Alternatively, the control voltage V1 generated by one of the first and second voltage adjustment circuits 53 and 57 is charged to each control power supply capacitor by a charge pump.

Embodiment 8 FIG.
Next, a rectifier according to Embodiment 8 of the present invention will be described with reference to the drawings.
FIG. 11 is a diagram showing a circuit configuration of a rectifier according to Embodiment 8 of the present invention.
In the seventh embodiment, the first and second voltage adjusting circuits 53 and 57 are operated by inputting the drive signal 6a output from the first drive control circuit 6, but in the eighth embodiment, The drive signal 6a is not input to the first and second voltage adjustment circuits 53 and 57, and the first and second voltage adjustment circuits 53 and 57 are operated according to the input voltage. Other configurations and operations are the same as those in the seventh embodiment.
The first and second voltage adjustment circuits 53 and 57 generate a predetermined control voltage V1 using a cathode-anode voltage VCA applied between the anode terminal 2 and the cathode terminal 3 as an input voltage. When a reverse voltage applied between the anode terminal 2 and the cathode terminal 3 is input, the first voltage adjustment circuit 53 generates a control voltage V1 based on the potential of the anode terminal 2 from the reverse voltage. At this time, the first voltage adjustment circuit 53 performs a step-down operation when the reverse voltage is larger than the control voltage V1, and performs a step-up operation when the reverse voltage is smaller than the control voltage V1.
Further, when a forward voltage applied between the anode terminal 2 and the cathode terminal 3 is input, the second voltage adjustment circuit 57 boosts the forward voltage to control voltage with the anode terminal 2 as a potential reference. V1 is generated.

  Thereby, the power supply circuit 50 can operate one of the first and second voltage adjustment circuits 53 and 57 to generate and output the predetermined control voltage V1. When the cathode-anode voltage VCA is a reverse voltage, the drive signal 6a is turned off and the first MOSFET 4 is turned off. When the cathode-anode voltage VCA is a forward voltage, the drive signal 6a is When the output is on, the first MOSFET 4 is turned on. Therefore, the first and second voltage adjustment circuits 53 and 57 operate alternately as in the case of the seventh embodiment. Then, the capacitor 59 provided on the output side suppresses the fluctuation of the control voltage V1 when the operations of the first and second voltage adjustment circuits 53 and 57 are switched.

The power supply circuit 50 according to the eighth embodiment is the same as the seventh embodiment except that the operation of the first and second voltage adjustment circuits 53 and 57 is switched based on the input voltage. An effect is obtained.
That is, the generated control voltage does not vary depending on the frequency of current and the conduction rate between the two terminals, and the predetermined control is performed regardless of the polarity of the voltage applied between the two terminals and the magnitude of the reverse voltage. The voltage V1 can be output stably. For this reason, the control voltage V1 required for the first drive control circuit 6 can be stably obtained, and the rectifier 1 can operate with high reliability. Further, it is not necessary to set the withstand voltage of the element used for the first drive control circuit 6 to be equal to or larger than the reverse voltage, and the first drive control circuit 6 can be configured with inexpensive elements. In addition, in order to suppress fluctuations in the control voltage V1, it is not necessary to provide a capacitor with a large capacity in the power supply circuit 50, and the device configuration is suitable for downsizing.
In addition, since the first and second power supply circuits 50a and 50b are not provided with a capacitor for holding electric charge, the rise time of the power supply circuit 50 at the time of startup can be shortened.

  The power supply circuits 5c and 50 shown in the sixth to eighth embodiments can be applied in place of the power supply circuit 5 in the first to fifth embodiments. Also in this case, the same effect as each embodiment can be obtained.

  Further, in the rectifiers shown in the above-described sixth to eighth embodiments, the current direction detection circuit 7 can be configured by other configurations, for example, a Hall element or a shunt resistor for current detection. Also in this case, the output terminal of the power supply circuit 50 is connected to the current direction detection circuit, and the detection voltage V2 for detecting the current direction can be obtained using the control voltage V1.

Embodiment 9 FIG.
Next, a rectifier according to Embodiment 9 of the present invention will be described with reference to the drawings.
FIG. 12 is a diagram showing a circuit configuration of a rectifier according to Embodiment 9 of the present invention.
As shown in the figure, in the same way as in the first embodiment, the rectifier 1 uses the two terminals of the anode terminal 2 and the cathode terminal 3 as external terminals, and generates a control voltage V1 and a first drive. A control circuit 6 and a current direction detection circuit 7 are provided.
Also, a first MOSFET 4 that connects the drain electrode to the cathode terminal 3 between the two terminals of the rectifier 1, and an abnormal-time cutoff MOSFET 15 (hereinafter referred to as a cutoff MOSFET 15) connected in series to the first MOSFET 4. With. The cutoff MOSFET 15 has a source electrode connected to the source electrode of the first MOSFET 4 and a drain electrode connected to the anode terminal 2.

The configurations and operations of the power supply circuit 5, the first drive control circuit 6, and the current direction detection circuit 7 are the same as those in the first embodiment, but in this case, between the anode terminal 2 and the first MOSFET 4. Since the cutoff MOSFET 15 is inserted, the control voltage V1, the detection voltage V2, and the reference voltage V3 are generated or detected using the source electrode of the first MOSFET 4 as a potential reference. Therefore, the voltage VCA in FIG. 12 indicates the voltage between the cathode terminal 3 and the source electrode of the first MOSFET 4.
Further, the diode 16 is connected between the anode terminal 2 and the capacitor 52 in the power supply circuit 5, and the forward voltage applied between the anode terminal 2 and the cathode terminal 3 is applied to the diode 16 when the cutoff MOSFET 15 is in the OFF state. Through the capacitor 52.
Furthermore, a third drive control circuit 25 that operates with the control voltage V1 from the power supply circuit 5 is provided. The third drive control circuit 25 supplies the cutoff MOSFET 15 to the cutoff MOSFET 15 according to the detection voltage V2 from the current direction detection circuit 7. The drive signal 25a and the limit signal 25b to the first drive control circuit 6 are output.

The blocking MOSFET 15 is turned on in a steady state, and the first MOSFET 4 is turned off when the reverse voltage is applied to the rectifying device 1 to cut off the current i, as shown in the first embodiment. The current i flows only in the direction.
When the first MOSFET 4 is turned on, a current i through the first MOSFET 4 flows from the anode terminal 2 to the cathode terminal 3 in the forward direction, and a voltage drop due to the current i and the on-resistance of the first MOSFET 4 occurs. The on-voltage (= −VCA), which is a voltage corresponding to the voltage drop, increases as the current increases, and the detection voltage V2 from the current direction detection circuit 7 decreases.
Then, the third drive control circuit 25 detects that an overcurrent has occurred from the anode terminal 2 to the cathode terminal 3, and turns off the blocking MOSFET 15. Actually, the detection voltage V2 is compared with a preset cutoff reference voltage, and when the detection voltage V2 becomes lower than the cutoff reference voltage, a drive signal 25a is output to the cutoff MOSFET 15 to turn off the cutoff MOSFET 15. .

  Further, the third drive control circuit 25 outputs a limit signal 25b for adjusting the reference voltage V3 to the voltage adjustment circuit 62 in the first drive control circuit 6 at the same time when the cutoff MOSFET 15 is turned off. The limit signal 25b is a signal that limits the drive signal 6a in order to turn off the first MOSFET 4, and thereby the first MOSFET 4 is turned off. As a result, all MOSFETs 4 and 15 between the two terminals of the rectifier 1 are cut off and conduction is prevented. Since the first MOSFET 4 and the cutoff MOSFET 15 are connected in the opposite directions, the built-in parasitic diodes are also in the opposite directions, and are reliably cut off regardless of the direction of the current i.

In this embodiment, a cutoff MOSFET 15 is connected to the anode terminal side of the first MOSFET 4, and the third drive control circuit 25 detects the occurrence of overcurrent based on the detection voltage V 2 from the current direction detection circuit 7. Then, the blocking MOSFET 15 is turned off. Thereby, it is possible to prevent an overcurrent from flowing through the rectifying device 1 and to improve the reliability of the rectifying device 1.
The third drive control circuit 25 can easily detect the occurrence of overcurrent based on the detection voltage V2 from the current direction detection circuit 7, and can easily cut off the overcurrent.
Furthermore, since the forward voltage applied to the rectifier 1 is charged to the capacitor 52 via the diode 16 when the cutoff MOSFET 15 is in the off state, the forward voltage at the time of the current cutoff can also be used to generate the control voltage V1, Efficiency and stabilization of control voltage generation can be achieved.

In the above embodiment, the detection voltage V2 is compared with a preset reference voltage for cutoff. However, the reference voltage for cutoff may be set and changed from the outside. In this case, as shown in FIG. 12, the third drive control circuit 25 is provided with an external terminal 25c for inputting a signal from the outside, and the value of the cutoff reference voltage is externally input by an electric signal or an optical signal. The setting is input to the third drive control circuit 25. Thereby, the reference | standard setting for interruption | blocking can be performed according to conditions, such as not only the rectifier 1 but a peripheral circuit, and the convenience improves.
Further, the period during which the blocking MOSFET 15 is turned off may be a predetermined period set in advance, or until a release signal such as an external electric signal or optical signal is input.

  Although the external terminal 25c is used for inputting a signal from the outside, the third drive control circuit 25 may be provided with an external terminal for outputting a signal to the outside. When the blocking MOSFET 15 is in an OFF state, Anomalies due to overcurrent may be notified to the outside by sound or light. The third drive control circuit 25 that detects overcurrent and is responsible for interrupting the current can be easily notified of an abnormality by providing means for notifying the outside of the abnormality.

Embodiment 10 FIG.
In the ninth embodiment, the blocking MOSFET 15 is applied to the first embodiment. However, it can be applied to the other second to eighth embodiments. In particular, the case where the blocking MOSFET 15 is applied to the fifth embodiment will be described below.
The rectifier 1 according to this embodiment has the same structure as that of the fifth embodiment shown in FIG. 5 except that the blocking MOSFET 15, the diode 16 and the third drive control circuit 25 shown in FIG. 12 of the ninth embodiment. It becomes the added composition.

That is, between the two terminals of the rectifier 1, the first MOSFET 4, the second MOSFET 10 connected in series to the first MOSFET 4, and the series circuit of the first MOSFET 4 and the second MOSFET 10 are connected in parallel. A third MOSFET 12 to be connected, a third diode 13, and a blocking MOSFET 15 connected to the anode terminal side of the first MOSFET 4 are provided. In addition, a shunt resistor 11 is connected in parallel to the second MOSFET 10, and an on-voltage adjusting circuit 14 is configured by the elements 10 to 13.
As shown in the fifth embodiment, the second drive control circuit 20 selects a combination of MOSFETs to be turned on among the first MOSFET 4 and the second and third MOSFETs 10 and 12 in accordance with the detection voltage V2. By determining and controlling each of the MOSFETs 4, 10, and 12, the on-resistance between the two terminals when the current i flows in the forward direction from the anode terminal 2 to the cathode terminal 3 is changed stepwise to increase the on-voltage. To suppress. Then, the third drive control circuit 25 detects an overcurrent and turns off the blocking MOSFET 15 as shown in the ninth embodiment.

FIG. 13 shows the operating characteristics of the rectifier 1 according to this embodiment, and is a diagram showing a voltage VAC (= −VCA) that changes according to the current i. In this case as well, the potential reference for each of the voltages V1, V2, and V3 is the source electrode of the first MOSFET 4, and the voltage VCA indicates the voltage between the cathode terminal 3 and the source electrode of the first MOSFET 4.
FIG. 14 shows the switching state of each MOSFET corresponding to the current i. Reference numeral 31a denotes a range of the voltage VAC in the range of the detection voltage V2 in which the current direction can be detected by the current direction detection circuit 7, and 32a denotes an output characteristic of the third diode 13. In the state of the first MOSFET 4 and the second and third MOSFETs 10 and 12, SW indicates a state that is switched in synchronization with the drive signal 6 a from the drive circuit 61.

The blocking MOSFET 15 continues to be in an ON state at the steady state, and the first to third MOSFETs 4, 10, and 12 are different from those in the fifth embodiment until the current value i5 (<i4) at which the current i is recognized as an overcurrent. It operates in the same way.
When the current i increases to a current value i5 and the detection voltage V2 becomes lower than the cutoff reference voltage, the third drive control circuit 25 turns off the cutoff MOSFET 15. Further, when the third drive control circuit 25 turns off the blocking MOSFET 15, at the same time, the third drive control circuit 25 outputs a limit signal 25b for adjusting the reference voltage V3 to the voltage adjustment circuit 62 in the first drive control circuit 6. 1 MOSFET 4 is turned off. At the same time, the second drive control circuit 20 turns off the second and third MOSFETs 10 and 12.

  As described above, the second drive control circuit 20 switches the combination of MOSFETs that are turned on when the current i increases so as to reduce the on-resistance, thereby suppressing an increase in the on-voltage. Then, the third drive control circuit 25 detects that an overcurrent has occurred from the anode terminal 2 to the cathode terminal 3, and turns off the blocking MOSFET 15. At this time, the other MOSFETs 4, 10, 12 are also turned off. All MOSFETs 4, 10, 12, and 15 between the two terminals of the rectifier 1 are cut off, and the current is cut off reliably.

  In this embodiment, the first, second, and third drive control circuits 6, 20, and 25 are individually provided. However, one drive control circuit that has these functions may be used.

Embodiment 11 FIG.
FIG. 15 is a diagram showing a circuit configuration of a rectifier according to Embodiment 11 of the present invention.
As shown in the figure, the rectifier according to the ninth embodiment shown in FIG. 12 includes a current limiting circuit 17 that limits the current between the two terminals of the rectifier 1. The current limiting circuit 17 includes a resistor, a reactor, a diode, and the like, and includes a bypass circuit, and is connected between the drain electrode of the first MOSFET 4 and the cathode terminal 3.

The third drive control circuit 25 detects that an overcurrent has occurred from the anode terminal 2 to the cathode terminal 3 and turns off the cutoff MOSFET 15. At this time, a predetermined transient period is provided, and the current i gradually increases. Decrease the value to cut off the current. In this case, the drive signal 25a to the blocking MOSFET 15 is controlled so that the energization rate of the blocking MOSFET 15 is gradually decreased to zero. The current limiting circuit 17 is, for example, controlled by the third drive control circuit 25, and is bypassed by a bypass circuit in a steady state. The current limiting circuit 17 limits the current by flowing the current i only during the transition period when switching on / off the blocking MOSFET 15. . The length of the transition period between when the blocking MOSFET 15 is turned on and when it is turned off may be the same or different.
Also, when the current i that has been interrupted between the two terminals of the rectifying device 1 is restored and made conductive by an external signal or the like, a predetermined transient period is provided as in the case of the interruption, and the value of the current i is gradually increased. Increase to return. Here, the drive signal 25a to the blocking MOSFET 15 is controlled so as to gradually increase the energization rate of the blocking MOSFET 15 from zero.

  In this embodiment, when the conduction / cutoff state of the current between the two terminals is switched using the cutoff MOSFET 15, it is possible to prevent the occurrence of abnormal voltage at the cutoff by slowing the change in the current value. Inrush current that flows when restoring the current between the terminals can also be prevented.

Embodiment 12 FIG.
In the eleventh embodiment, the current limiting circuit 17 is provided, and the current supply rate of the blocking MOSFET 15 is gradually increased or decreased. However, in the eleventh embodiment, the driving voltage of the driving signal 25a to the blocking MOSFET 15 is adjusted. The on-resistance of the blocking MOSFET 15 is adjusted.
In this embodiment, the current limiting circuit 17 is unnecessary, and when the current is interrupted by turning off the interrupting MOSFET 15, a predetermined transient period is provided so that the current i is gradually decreased by gradually decreasing the value of the current i. The drive voltage of the drive signal 25a to the cutoff MOSFET 15 is gradually reduced. Also, when the current i that has been interrupted between the two terminals of the rectifying device 1 is restored and made conductive by an external signal or the like, a predetermined transient period is provided as in the case of the interruption, and the value of the current i is gradually increased. The drive voltage of the drive signal 25a to the cutoff MOSFET 15 is gradually increased so as to increase and recover. During these transition periods, all the MOSFETs other than the blocking MOSFET 15 may be turned off, and a current may flow through the parasitic diode of the MOSFET.
Also in this embodiment, when switching the conduction / cutoff state of the current between the two terminals using the cut-off MOSFET 15, it is possible to prevent the occurrence of abnormal voltage at the cut-off by gradual change of the current value, Inrush current that flows when the current between the two terminals is restored can also be prevented.

Embodiment 13 FIG.
FIG. 16 is a diagram showing a simplified configuration of the rectifier 1 and peripheral circuits according to the thirteenth embodiment of the present invention. In this case, the rectifier 1 is the rectifier according to the ninth embodiment shown in FIG. 12, in which the first drive control circuit 6 and the third drive control circuit 25 are represented by one drive control circuit 26. It is. The power supply circuit 5 and the current direction detection circuit 7 are not shown.
As shown in the figure, the voltage detection circuit 27 detects the voltage of the anode terminal 2 from the external reference potential as the input voltage VIN. In the third drive control circuit 25 in the drive control circuit 26, when the signal of the input voltage VIN is received from the outside and a voltage abnormality is detected, the blocking MOSFET 15 is turned on as in the case of the overcurrent detection in the ninth embodiment. Turn off and cut off current.

  In this embodiment, the third drive control circuit 25 in the drive control circuit 26 that controls the cutoff MOSFET 15 receives the external signal, detects a voltage abnormality, and shuts off the cutoff MOSFET 15. For this reason, it is possible to easily and reliably detect a voltage abnormality using the external voltage detection circuit 27 and the like, and the convenience is improved. Note that a voltage / current abnormality signal detected using another detection circuit or a signal for conducting / interrupting the current i of the rectifier 1 may be received.

  Further, the above-described Embodiments 11 and 12 may be applied to this embodiment, and the same effect can be obtained.

  Further, the semiconductor materials of the MOSFETs 4, 10, 12, and 15 used in the above embodiments are wide gap semiconductor materials such as silicon carbide, gallium nitride, and diamond semiconductor, and the loss during rectification in the rectifier 1 is reduced. What you suppress is desirable. In addition, each diode in the rectifier 1 may be of any type or material, such as a Schottky barrier diode or a fast recovery diode, but the delay times of the current direction detection circuit 7 and the drive control circuits 6, 20, 25, etc. are improved. In order to achieve this, it is desirable to use an element having a low forward voltage and a high response speed, such as silicon carbide or gallium nitride.

Embodiment 14 FIG.
Next, a solar power generation system according to Embodiment 14 of the present invention will be described with reference to the drawings.
FIG. 17 is a diagram showing a main circuit configuration of a photovoltaic power generation system according to Embodiment 14 of the present invention.
As shown in the figure, the main circuit 100 of the photovoltaic power generation system includes a plurality of (in this case, three) solar panels 80 connected in parallel, and each of the solar panels 80 has a rectifier 1a connected in parallel. A plurality of (in this case, three) solar cells 81 are connected in series. The direct-current power generated by each solar panel 80 is stored in energy storage means such as a capacitor 82 via the rectifier 1b, and then boosted by two chopper circuits 83 connected in parallel. Is output via. The chopper circuit 83 includes a switch, a reactor, and a rectifier 1c.
As the rectifiers 1a, 1b, and 1c in the main circuit 100, the rectifier 1 with low loss and high reliability having the configuration shown in the first to thirteenth embodiments is used.

In such a solar power generation system, a plurality of solar panels 80 are connected in parallel to form a redundant system circuit, and a DC voltage is reliably generated.
Moreover, in each solar panel 80, although the several photovoltaic cell 81 is connected in series, when abnormality arises in each photovoltaic cell 81, the rectifier 1a connected in parallel with the photovoltaic cell 81 which abnormality occurred Thus, the solar battery cell 81 is bypassed. For example, when some solar cells 81 are not irradiated with sunlight and cannot generate power, the impedance of the solar cells 81 is increased. Further, when the connection wiring of the solar battery cell 81 is open due to a failure of the solar battery cell 81, the power generated by the other solar battery cells 81 connected in series to the failed solar battery 81 cannot be output. When such an abnormality of the solar battery cell 81 occurs, the first drive control circuit 6 in the rectifier 1a detects the abnormality from the detection voltage V2, turns on the first MOSFET 4, and malfunctions the solar battery cell 81. The electric power generated by the other solar battery cell 81 is output.

Thus, even if the rectifier 1a is operated as a protection circuit for the solar panel 80 and an abnormality occurs in some of the solar cells 81, the solar panel 80 can output electric power. Moreover, the rectifier 1a has a device configuration that has a very low loss during current conduction as shown in the first to thirteenth embodiments, and can reduce the loss in the solar panel 80. Moreover, since the heat generation of the rectifying device 1a is small when the current of the rectifying device 1a is conducted, it is possible to suppress the heating of the other solar cells 81, and to suppress the reduction of the power generation efficiency of the other solar cells 81. it can.
Further, the first drive control circuit 6 may be provided with an external terminal, and a means for informing the outside of the conduction / cutoff state of the first MOSFET 4 may be provided, and the administrator can quickly find the location where the abnormality has occurred. .

Further, as described above, the DC voltage generated by each solar panel 80 is charged in the capacitor 82 via the rectifier 1b. When a short circuit failure occurs in any of the solar panels 80, the electric power generated by the other solar panels 80 and stored in the capacitor 82 is discharged through the failed solar panel 80. Is prevented by the rectifying device 1b. In this case, the rectifier 1b is interrupted by a reverse voltage at the time of a short circuit failure. Moreover, the rectifier 1b that conducts in a steady state has an extremely low loss when the current is conducted, as shown in the first to thirteenth embodiments, and can reduce the loss of the main circuit 100.
Also in this case, the first drive control circuit 6 in the rectifying device 1b may be provided with an external terminal and provided with means for informing the outside of the conduction / cutoff state of the first MOSFET 4, and the administrator can determine where the abnormality has occurred. Can be found promptly.

Furthermore, the boosting efficiency of the chopper circuit 83 is improved by using the rectifier 1c with extremely low loss for the rectifier element in the chopper circuit 83.
Thus, the power generation efficiency and reliability of the photovoltaic power generation system can be improved by using the low-loss and high-reliability rectifier according to the present invention for the rectifiers 1a, 1b, and 1c in the main circuit 100.

  It can be widely used for a circuit including a rectifier circuit having two external terminals, and can contribute to improvement of power conversion efficiency, particularly when used in a power converter.

In the rectifier according to the present invention, an external terminal is an anode terminal and a cathode terminal, and a first MOSFET connected between the two terminals with a source electrode on the anode terminal side is connected between the two terminals. A power supply circuit that generates and outputs a predetermined control voltage from the applied voltage, and a first drive control circuit that outputs a drive signal to the gate electrode of the first MOSFET using the control voltage from the power supply circuit; A current limiting resistor connected to the output of the power supply circuit, and a detection circuit for detecting an anode potential of the diode, having a diode having an anode connected to the current limiting resistor and a cathode connected to the cathode terminal; Is provided. The power supply circuit includes a capacitor that charges a reverse polarity voltage applied between the two terminals via a diode, and a voltage adjustment circuit that generates the control voltage based on the potential of the anode terminal from the voltage of the capacitor. And the first drive control circuit outputs the drive signal in accordance with the anode potential of the diode detected by the detection circuit.
In the rectifier according to the present invention, the power supply circuit uses a reverse polarity voltage applied between the two terminals to generate the control voltage with the anode terminal as a potential reference, and the 2 A second voltage adjusting circuit that generates the control voltage with the anode terminal as a potential reference by using a positive voltage applied between the terminals, and outputs the control voltage, and the first drive control circuit includes: The drive signal is output in accordance with the anode potential of the diode detected by the detection circuit.

The solar power generation system according to the present invention generates power using one or more solar panels. Each of the solar panels includes a plurality of solar power generation cells connected in series, and an external terminal serving as an anode terminal and a cathode terminal. And two rectifiers connected in parallel to the respective photovoltaic power generation cells. Further, each of the rectifiers is described in any one of claims 1 to 25, and the first drive control circuit is connected from an anode potential of the diode detected by the detection circuit. The detected abnormality of the photovoltaic cell is detected, the first MOSFET is turned on, and the photovoltaic cell is bypassed by the rectifier.

Claims (28)

In the rectifier with two external terminals, an anode terminal and a cathode terminal,
A first MOSFET connected between the two terminals with the source electrode on the anode terminal side;
A power supply circuit that generates and outputs a predetermined control voltage from the voltage applied between the two terminals;
A first drive control circuit that outputs a drive signal to the gate electrode of the first MOSFET using a control voltage from the power supply circuit;
A current limiting resistor connected to the output of the power supply circuit; and a detection circuit for detecting an anode potential of the diode, having a diode having an anode connected to the current limiting resistor and a cathode connected to the cathode terminal. Prepared,
The rectifier according to claim 1, wherein the first drive control circuit outputs the drive signal in accordance with an anode potential of the diode detected by the detection circuit.   The power supply circuit includes a capacitor that charges a reverse polarity voltage applied between the two terminals via a diode, and a voltage adjustment circuit that generates the control voltage based on the potential of the anode terminal from the voltage of the capacitor. The rectifier according to claim 1, wherein the control voltage is output.   The power supply circuit includes a first voltage adjusting circuit that generates the control voltage with the anode terminal as a potential reference using a reverse polarity voltage applied between the two terminals, and a positive electrode applied between the two terminals. 2. The rectifier according to claim 1, further comprising: a second voltage adjusting circuit that generates the control voltage using a positive voltage with respect to the anode terminal as a potential reference, and outputs the control voltage.   The first drive control circuit compares a reference voltage generated from the control voltage with an anode potential of the diode detected by the detection circuit, and when the anode potential is lower than the reference voltage, the first drive control circuit The rectifier according to any one of claims 1 to 3, wherein the MOSFET is turned on.   The rectifier according to any one of claims 1 to 3, wherein the detection circuit includes a resistor or a constant voltage means between an anode of the diode and an anode potential detection point.   The rectifier according to any one of claims 1 to 3, wherein the first MOSFET is a power MOSFET in which a parasitic diode is built in between a source and a drain.   The rectifier according to any one of claims 1 to 3, wherein a wide gap semiconductor such as silicon carbide, gallium nitride, or diamond is used for the first MOSFET.   The power supply circuit includes a first capacitor that charges a reverse polarity voltage applied between the two terminals via a first diode, and a positive voltage applied between the two terminals via a second diode. And the second voltage regulator circuit generates the control voltage from the voltage of the first capacitor, and the second voltage regulator circuit generates the control voltage from the voltage of the second capacitor. The rectifier according to claim 3, wherein a control voltage is generated.   9. The apparatus according to claim 8, further comprising means for detecting each voltage of the first and second capacitors, wherein the first and second voltage adjusting circuits operate in accordance with the detected voltages. The rectifier of description.   The power supply circuit operates the first voltage adjustment circuit when the first MOSFET is in an off state based on the drive signal output from the first drive control circuit, and the first MOSFET 4. The rectifier according to claim 3, wherein the second voltage regulator circuit is operated in an ON state. 5.   The first and second voltage adjusting circuits operate using the voltage between the two terminals as an input voltage, and include means for detecting the input voltage, and the first and second voltage adjusting circuits are provided according to the detected voltage. The rectifier according to claim 3, wherein the voltage adjustment circuit is operated alternately.   The reference voltage includes a voltage value obtained by subtracting an on-voltage between the drain and source of the first MOSFET from a forward voltage of the diode, and a drain voltage between the drain and source of the first MOSFET to a forward voltage of the diode. The rectifier according to claim 4, wherein the rectifier is set between a voltage value obtained by adding an on-voltage.   The rectifier according to claim 4, further comprising a sensor that detects a temperature of the diode, wherein the reference voltage is adjusted according to the detected temperature.   5. The rectifier according to claim 4, wherein a hysteresis width is provided in the reference voltage, and the reference voltage is changed between when the first MOSFET is turned on and when the first MOSFET is turned on. . One or both of one or a plurality of second MOSFETs connected in series to the first MOSFET and one or a plurality of third MOSFETs connected in parallel to the first MOSFET are connected between the two terminals. An on-voltage adjusting circuit,
A second drive control circuit for outputting a drive signal to the gate electrodes of the second and third MOSFETs in the on-voltage adjusting circuit using the control voltage from the power supply circuit;
The second drive control circuit includes: an anode of the diode that is detected by the detection circuit of a combination of MOSFETs to be turned on from the first MOSFET and the second and third MOSFETs in the on-voltage adjusting circuit; 5. The rectifier according to claim 4, wherein the drive signal is output by selecting so as to reduce an on-resistance between the two terminals in accordance with a potential.   The second drive control circuit outputs a signal for limiting the drive signal of the first MOSFET to the first drive control circuit in accordance with the anode potential of the diode detected by the detection circuit. The rectifier according to claim 15.   17. The rectifier according to claim 15, wherein a shunt resistor is connected in parallel with the second MOSFET.   The rectifier according to claim 15 or 16, further comprising a diode between the two terminals, the anode being connected to the anode terminal and the cathode being connected to the cathode terminal. An abnormal cutoff MOSFET having a drain electrode connected to the anode terminal and a source electrode connected to the source electrode of the first MOSFET, and a gate electrode of the abnormal cutoff MOSFET using the control voltage from the power supply circuit And a third drive control circuit for outputting a drive signal to
5. The rectifier according to claim 4, wherein the third drive control circuit detects a current-voltage abnormality and turns off the abnormal-time cutoff MOSFET to cut off a current between the two terminals. 6.   A diode is provided between the anode terminal and the power supply circuit, and a positive voltage applied between the two terminals is charged to the power supply circuit via the diode when the abnormal-time cutoff MOSFET is in an OFF state. The rectifier according to claim 19.   The third drive control circuit detects a current-voltage abnormality by comparing with a set reference value, and the rectifier includes means for setting and changing the reference value from the outside. Item 20. The rectifier according to Item 19.   The third drive control circuit detects an overcurrent which is the current voltage abnormality based on an anode potential of the diode detected by the detection circuit. The rectifier described in 1.   The rectification according to any one of claims 19 to 21, wherein the third drive control circuit includes means for receiving an external signal, and detects the current voltage abnormality based on the received external signal. apparatus.   The rectifier according to any one of claims 19 to 21, further comprising means for notifying the outside of the abnormality when the abnormal-time cutoff MOSFET is in an off state.   The third drive control circuit provides a predetermined transition period when controlling the abnormal cutoff MOSFET to switch the conduction / cutoff state of the current between the two terminals, and gradually changes the current value between the two terminals. The rectifying device according to any one of claims 19 to 21, wherein the rectifying device is changed.   A current limiting circuit that limits the current between the two terminals only during the predetermined transition period is provided, and the third drive control circuit gradually changes the current supply rate of the abnormal-time cutoff MOSFET during the predetermined transition period. 26. The rectifier according to claim 25, wherein the current value between the two terminals is gradually changed.   The third drive control circuit gradually changes the current value between the two terminals by gradually changing the voltage of the drive signal to the abnormal-time cutoff MOSFET during the predetermined transition period. 26. A rectifier according to claim 25, characterized in that: In a solar power generation system that generates power using one or more solar panels,
Each of the above solar panels
A plurality of photovoltaic cells connected in series;
A rectifier connected in parallel to each of the photovoltaic power generation cells, with the external terminal as two terminals of an anode terminal and a cathode terminal,
Each of the above rectifiers is
A first MOSFET connected between the two terminals with the source electrode on the anode terminal side;
A power supply circuit that generates and outputs a predetermined control voltage from the voltage applied between the two terminals;
A first drive control circuit that outputs a drive signal to the gate electrode of the first MOSFET using a control voltage from the power supply circuit;
A current limiting resistor connected to the output of the power supply circuit; and a detection circuit for detecting an anode potential of the diode, having a diode having an anode connected to the current limiting resistor and a cathode connected to the cathode terminal. Prepared,
The first drive control circuit detects an abnormality of the connected photovoltaic power generation cell from the anode potential of the diode detected by the detection circuit, turns on the first MOSFET, and the rectifier A photovoltaic power generation system characterized in that the photovoltaic power generation cell is bypassed.

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