JP5716682B2 - DC power supply - Google Patents

Description

  The present invention relates to a DC power supply apparatus that rectifies an AC output of a magnet generator driven by an engine and supplies electric power to a DC load.

  As a DC power supply device that rectifies the output of a magnet generator driven by an engine and supplies a charging current to a battery, the one disclosed in Patent Document 1 is known. As shown in FIG. 6, in the DC power supply shown in Patent Document 1, an AC output of a magnet generator 1 driven by an engine is applied between AC input terminals 2u ′ to 2w ′, and the positive side And a bridge-type control rectifier circuit 2 'connected to the battery 3 between the DC output terminals 2a' and 2b 'on the negative electrode side and a controller 4' for controlling the control rectifier circuit 2 '.

  A control rectifier circuit used in a direct current power supply device to which the present invention is directed is a switch having a switch element in which each upper side of a bridge is configured by a thyristor and capable of on / off control, and a feedback diode connected in reverse parallel to the switch element. It consists of a bridge-type rectifier circuit in which each lower side of the bridge is constituted by elements. In this control rectifier circuit, a full-wave rectifier circuit is constituted by a thyristor constituting the upper side of the bridge and a feedback diode provided in a switch element constituting the lower side of the bridge.

  In the control rectifier circuit 2 'shown in FIG. 6, the upper side of the bridge is constituted by thyristors 201u' to 201w 'having cathodes connected in common. Further, N-channel MOSFETs 202u ′ to 202w ′ whose sources are connected in common constitute a switch element constituting the lower side of the bridge, and the drains of the MOSFETs 202u ′ to 202w ′ are connected to the anodes of the thyristors 201u ′ to 201w ′. Yes. In this example, parasitic diodes Dpu ′ to Dpw ′ existing between the respective drains and sources of the MOSFETs 202u ′ to 202w ′ are used as feedback diodes. Then, AC input terminals 2u ′ to 2w ′ are derived from the drains of the MOSFETs 202u ′ to 202w ′, and are connected to the positive side from the common connection point of the cathodes of the thyristors 201u ′ to 201w ′ and the common connection point of the sources of the MOSFETs 202u ′ to 202w ′. The DC output terminals 2a 'and 2b' on the negative electrode side are led out.

  The controller 4 ′ shown in the figure includes battery charge control means for controlling the thyristors 201 u ′ to 201 w ′ and MOSFETs 202 u ′ to 202 w ′ of the control rectifier circuit 2 ′ so that the battery 3 can be charged properly. When it is necessary to boost the output voltage of the magnet generator 1 in order to obtain an output necessary for charging the battery 3, all MOSFETs 202u 'to 202w are provided with a trigger signal applied to each thyristor of the control rectifier circuit 2. And a step-up control means for controlling to turn on and off at the same time.

  In FIG. 6, a MOSFET is used as a switch element constituting the lower side of the bridge of the control rectifier circuit. However, the bridge is formed by another switch element such as an IGBT and a feedback diode connected in reverse parallel to the switch element. It is also possible to configure a switch element that constitutes each lower side.

JP 2005-198426 A

  In the DC power supply device shown in FIG. 6, in order to boost the voltage induced in the power generation coil of the magnet generator 1, all the thyristors 201u ′ to 201w ′ of the control rectifier circuit 2 ′ are given trigger signals. In the case where the boost control means for performing the boost control for simultaneously turning on and off the MOSFETs 202u ′ to 202w ′ is provided, when the MOSFETs 202u ′ to 202w ′ are turned from the ON state to the OFF state during the boost control, the MOSFET 202u ′ for the following reason. A surge voltage is generated between each drain and source of 202w '.

  When the MOSFETs 202u ′ to 202w ′ are turned from the on state to the off state, the energy stored in the power generation coil of the magnet generator during the period in which these MOSFETs are in the on state is released to the control rectifier circuit 2 ′. If this energy is released instantaneously, no surge voltage is generated at both ends of each MOSFET. In practice, however, there is a conduction delay in the thyristor, and the wiring portion in the thyristor and in the control rectifier circuit. Since the rise of the current is delayed due to the inductance present in the MOSFET, energy is not released in time, and a surge voltage appears between the drain and source of each MOSFET. FIG. 8 shows the voltage VDS appearing between the drain and source of the MOSFET and the current Ith flowing through the thyristor when the MOSFET is turned off. After the MOSFET is turned off from the on state at time t1, there is a time delay Δt until the current Ith flows after the thyristor is turned on, so that a surge voltage Vsu is generated between the drain and source of the MOSFET immediately after time t1. To do. If this surge voltage exceeds the breakdown voltage of the MOSFET, the MOSFET may be destroyed.

  In order to cope with the above problem, it is conceivable to use elements having a high withstand voltage as the MOSFETs 202u ′ to 202w ′. However, since a MOSFET with a high breakdown voltage has a high resistance between the drain and the source, when a MOSFET with a high breakdown voltage is used, a loss occurs between the drain and the source of the MOSFET, resulting in a problem that charging efficiency is lowered. Moreover, since it is unavoidable that the heat generation from the MOSFET increases, there is a problem that it is necessary to limit the output, or it is necessary to attach a large heat dissipation device to the MOSFET, and the device becomes large. .

  In order to protect the MOSFET from the surge voltage generated when the MOSFETs 202u ′ to 202w ′ are turned from the on state to the off state, as shown in FIG. 7, a CR type comprising a series circuit of a snubber resistor Rs and a snubber capacitor Cs. It is also conceivable to connect a snubber circuit in parallel between the drain and source of each MOSFET. When such a CR type snubber circuit is provided, the energy released from the magnet generator can be absorbed by the snubber circuit and consumed by the resistor Rs, so that the occurrence of a surge voltage at both ends of the MOSFET is suppressed. be able to. However, when a CR type snubber circuit is provided, a large loss is generated in the snubber resistor Rs, and the switching speed of the MOSFET is reduced to increase the switching loss of the MOSFET. The problem arises that a device is required and the apparatus becomes larger.

  The DC power supply device shown in FIG. 6 also reverses the thyristors 201u ′ to 201w ′ due to the voltage induced in the power generation coil of the magnet generator when the MOSFETs 202u ′ to 202w ′ change from the off state to the on state during boost control. A voltage is applied. Therefore, a reverse current flows through each thyristor due to a delay in the recovery of the thyristor, which causes a large loss in each thyristor and a large amount of heat generation or a decrease in charging efficiency. In order to avoid such a problem, it is conceivable to slow down the switching time of the MOSFET. However, if the switching time of the MOSFET is slowed down, the switching loss generated in the MOSFET increases, so that the charging efficiency decreases or occurs in the MOSFET. Problems such as increased heat generation occur.

  A problem similar to the above also occurs when each lower side of the bridge of the control rectifier circuit 2 is configured by a switch element including a switch element other than a MOSFET and a feedback diode connected in antiparallel to the switch element.

  An object of the present invention is to provide a control in which each upper side of a bridge is configured by thyristors, and each lower side of the bridge is configured by a switch element including a switch element that can be controlled on and off and a feedback diode connected in reverse parallel to the switch element. In a DC power supply device that rectifies the output of a magnet generator by a rectifier circuit and supplies power to a load, the output voltage of the magnet generator is changed by turning on and off the switch element of the switch element that forms the lower side of the bridge of the control rectifier circuit. When boost control is performed to boost the voltage, a high surge voltage is applied to the switch elements that make up each lower side of the control rectifier circuit without reducing charging efficiency, increasing heat generation, or limiting the output. Is to protect the switch element.

  Another object of the present invention is to prevent an increase in loss generated in a thyristor due to a reverse current flowing through the thyristor constituting each upper side of the control rectifier circuit in the above-described DC power supply device when performing step-up control. is there.

  The present invention has an AC input terminal to which an AC output of a magnet generator driven by an engine is input and a DC output terminal on a positive electrode side and a negative electrode side to which a load is connected, and is input to the AC input terminal The present invention is directed to a DC power supply device including a bridge-type control rectifier circuit that rectifies an AC voltage and outputs it between DC output terminals, and a controller that controls the control rectifier circuit. Here, in the control rectifier circuit, each upper side of the bridge is constituted by a thyristor, and each lower side of the bridge is formed by a switch element having a switch element that can be controlled on and off and a feedback diode connected in reverse parallel to the switch element. Thus, a full-wave rectifier circuit is configured by a thyristor that configures the upper side of the bridge and a feedback diode of a switch element that configures the lower side. Further, the controller needs to boost the output voltage of the magnet generator in order to supply power to the load, and output control means for controlling the output of the control rectifier circuit so as to properly supply power to the load. Boost control means for controlling the switch elements of all the switch elements to be simultaneously turned on and off in a state where a trigger signal is given to each thyristor of the control rectifier circuit.

  In the present invention, a snubber diode with a cathode facing the thyristor side constituting each upper side is inserted between the thyristor constituting each upper side of the bridge of the control rectifier circuit and the switch element constituting the lower side, and each A snubber capacitor is connected between the cathode of the snubber diode and the DC output terminal on the negative side of the control rectifier circuit. The snubber diode and the snubber capacitor constitute a snubber circuit that absorbs a surge voltage generated when the switch element is turned from the on state to the off state.

  If the snubber circuit is configured as described above, the energy released from the magnet generator when the switch element of the switch element constituting the lower side of the bridge of the control rectifier circuit is switched from the on state to the off state during boost control. Is instantaneously absorbed by the snubber capacitor through the snubber diode, so that a surge voltage can be prevented from being generated across the switch element. At this time, the snubber capacitor is charged to a high voltage, but a snubber diode in the opposite direction to the voltage at both ends of the snubber capacitor is interposed between the snubber capacitor and the switch element of the control rectifier circuit. No voltage across the capacitor is applied to the switch element. The charge accumulated in the snubber capacitor is turned on after the lapse of a certain delay time after the switch element of the switch element constituting the lower side of the bridge of the control rectifier circuit is turned off. Sometimes it is discharged to the battery side through the thyristor.

  According to the present invention, since it is not necessary to increase the withstand voltage of the switch element constituting the lower side of the bridge of the control rectifier circuit, it becomes easy to select a switch element having a low internal resistance, which occurs in the switch element. Loss can be reduced. Therefore, it is possible to reduce the heat generated in the switch element, eliminate the need to attach a large radiator to the switch element, and prevent the apparatus from becoming large. In addition, since no power is consumed in the snubber circuit as in the case of using a CR type snubber circuit, the loss generated in the control rectifier circuit can be reduced, and the charging efficiency is increased. Can do.

  In a preferred embodiment of the present invention, the output control means provides a trigger signal to each thyristor of the control rectifier circuit when supplying power to the load, and includes a switch element of a switch element in which a forward voltage is applied to the feedback diode. The control rectifier circuit is configured to perform the synchronous rectification operation in the on state.

  In the present invention, an element having a low withstand voltage can be used as the switch element of the switch element constituting the lower side of the bridge of the control rectifier circuit. Therefore, the on-state resistance of the switch element is smaller than the internal resistance of the feedback diode. Elements can be easily selected. Therefore, as described above, when the switching element of the switching element in which the forward voltage is applied to the feedback diode is turned on and the control rectifier circuit performs the synchronous rectification operation, the thyristor on the upper side of the control rectifier circuit and the Compared with the case where the output of the magnet generator is rectified through a rectifier circuit including a feedback diode, the rectification operation can be performed with low loss.

  The switch element constituting the lower side of the bridge of the control rectifier circuit includes an IGBT (insulated gate bipolar transistor) and a feedback diode connected in reverse parallel between the collector and emitter of the IGBT, and a MOSFET (field effect transistor). ) Can be used. When a MOSFET is used as a switch element constituting the lower side of the bridge of the control rectifier circuit, a parasitic diode formed between the drain and source of the MOSFET can be used as a feedback diode.

  When the present invention is applied to a DC power supply device in which the upper side of the bridge of the control rectifier circuit is configured by a thyristor and the lower side is configured by a MOSFET, the thyristor and the control rectifier circuit of the upper side of the bridge of the control rectifier circuit A snubber diode with the cathode facing the thyristor is inserted between the MOSFETs constituting each lower side, and a snubber capacitor is connected between the cathode of each snubber diode and the DC output terminal on the negative side of the control rectifier circuit.

  In this case, the output control means supplies a trigger signal to each thyristor of the control rectifier circuit when supplying power to the load, and turns on the MOSFET in which the forward voltage is applied to the parasitic diode to turn on the control rectifier circuit. It is preferable that the synchronous rectification operation be performed.

  As the snubber diode, it is preferable to use a diode whose recovery time is shorter than the turn-off time of each thyristor constituting the upper side of the bridge of the control rectifier circuit.

  When the diode as described above is used as a snubber diode, the voltage induced in the generator coil of the magnet generator when the switch element of the switch element constituting the lower side of the control rectifier circuit is switched from the OFF state to the ON state during the boost control. When the reverse voltage is applied to the thyristor on the upper side of the control rectifier circuit, the time during which the reverse current flows through the thyristor can be shortened, so that the loss generated in the control rectifier circuit during boost control can be further reduced.

  In the present invention, a snubber diode having a cathode facing the thyristor side constituting each upper side is inserted between the thyristor constituting each upper side of the bridge of the control rectifier circuit and the switch element constituting the lower side. A snubber capacitor is connected between the cathode of the diode and the DC output terminal on the negative side of the control rectifier circuit, and the surge voltage generated when the switch element is turned from the on state to the off state by the snubber diode and the snubber capacitor. Since the snubber circuit is configured to absorb the energy released from the magnet generator when the switch element is switched from the on state to the off state during step-up control, the energy is instantaneously absorbed by the snubber capacitor through the snubber diode and is applied to both ends of the switch element. Generation of a surge voltage can be prevented.

  Therefore, according to the present invention, since it is not necessary to increase the withstand voltage of the switch element constituting the lower side of the bridge of the control rectifier circuit, a switch element having a low internal resistance is selected to reduce loss caused by the switch element. can do. As a result, it is possible to reduce the heat generated in the switch element and eliminate the need to attach a large radiator to the switch element, and thus prevent the apparatus from becoming large. In addition, according to the present invention, unlike the case where a CR type snubber circuit is used, no power is consumed in the snubber circuit, so that the loss generated in the control rectifier circuit can be reduced. The charging efficiency can be increased, and power can be supplied to the load using a smaller magnet generator than in the past.

  In the present invention, when power is supplied to the load, a trigger signal is given to each thyristor of the control rectifier circuit, and the switch element of the switch element in which the forward voltage is applied to the feedback diode is turned on to make the control rectifier circuit When the battery charge control means is configured to perform the synchronous rectification operation, the rectification operation can be performed with a low loss. This is in combination with the fact that the loss generated in the control rectification circuit and the snubber circuit can be reduced. Thus, the charging efficiency can be further increased.

  In the present invention, when a diode whose recovery time is shorter than the turn-off time of each thyristor constituting the upper side of the bridge of the control rectifier circuit is used as the snubber diode, the switch element constituting the lower side of the control rectifier circuit during the boost control When the reverse voltage is applied to the thyristor on the upper side of the control rectifier circuit due to the voltage induced in the generator coil of the magnet generator when the switch element is turned from the OFF state to the ON state, the time for the reverse current to flow through the thyristor is Since it can be shortened, the loss generated in the control rectifier circuit during the boost control can be further reduced, and the heat generation amount and the charging efficiency can be further reduced.

It is the circuit diagram which showed one Embodiment of this invention. It is the circuit diagram which showed other embodiment of this invention. It is the circuit diagram which showed the application example of the DC power supply device which concerns on this invention. In one Embodiment of this invention, it is the block diagram which showed schematically the structure of the apparatus containing the means comprised by a microprocessor. 6 is a flowchart showing an example of an algorithm of processing executed by a microprocessor to configure the DC power supply device shown in FIG. 5. It is the circuit diagram which showed the structure of the conventional DC power supply device. It is the circuit diagram which showed the structure of the snubber circuit used in order to protect MOSFET in the conventional DC power supply device. (A) and (B) schematically show the waveform of the surge voltage generated at both ends of the MOSFET constituting the lower side of the bridge of the control rectifier circuit and the waveform of the current flowing through the thyristor in the DC power supply device shown in FIG. FIG.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention. In this embodiment, the load is a battery, and the battery is charged with the output of a control rectifier circuit that rectifies the output of the magnet generator. . In FIG. 1, 1 is a magnet generator driven by an engine (not shown), 2 is a control rectifier circuit that rectifies the AC output obtained from the magnet generator 1, and 3 is charged with a charging current supplied from the control rectifier circuit 2. The battery 4 is a controller for controlling the control rectifier circuit 2.

  The magnet generator 1 is fixed by winding a three-phase power generation coils Lu, Lv, and Lw around an iron core having a magnet rotor attached to a crankshaft of an engine and a magnetic pole portion facing the magnetic pole of the magnet rotor. This is a known device including a child, and generates a three-phase AC voltage in synchronization with the rotation of the engine. The three-phase power generation coils Lu, Lv and Lw are star-connected.

  The control rectifier circuit 2 includes a thyristor 201u to 201w on the upper side of the bridge, and a bridge in which the lower side of the bridge is configured by a switch element including a switch element that can be controlled on and off and a feedback diode connected in reverse parallel to the switch element. It consists of a full-wave rectifier circuit. In this embodiment, the switch element constituting the lower side of the bridge is composed of N-channel type MOSFETs 202u to 202w, and parasitic diodes Dpu to Dpw formed between the drains and sources of the MOSFETs 202u to 202w are used as feedback diodes. .

  In the illustrated control rectifier circuit, the cathodes of the thyristors 201u to 202w are commonly connected, and the sources of the MOSFETs 202u to 202w are commonly connected. The positive DC output terminal 2a of the control rectifier circuit is derived from the common connection point of the cathodes of the thyristors 201u to 202w, and the negative DC output terminal 2b is derived from the common connection point of the sources of the MOSFETs 202u to 202w. In addition, snubber diodes Dsu to Dsw are inserted between the anodes of the thyristors 201u to 201w and the drains of the MOSFETs 201u to 201w, with the cathodes connected to the anodes of the thyristors 201u to 201w and the anodes connected to the drains of the MOSFETs 202u to 202w, respectively. Snubber capacitors Csu to Csw are connected between the respective cathodes of the snubber diodes Dsu to Dsw and the negative side DC output terminal 2b of the control rectifier circuit 2 (common connection point of the sources of the MOSFETs 202u to 202w). Three-phase AC input terminals 2u to 2w are derived from the connection points between the drains of the MOSFETs 202u to 202w and the anodes of the snubber diodes Dsu to Dsw, respectively. The three-phase AC input terminals 2u to 2w of the control rectifier circuit 2 are respectively connected to the three-phase output terminals of the magnet generator 1, and the positive and negative DC output terminals 2a and 2b of the control rectifier circuit 2 are respectively connected to batteries. 3 positive and negative terminals are connected.

  A reverse voltage is applied to the thyristors 201u to 201w on the upper side of the control rectifier circuit 2 by the voltage induced in the power generation coil of the magnet generator 1 when the MOSFET constituting the lower side of the control rectifier circuit 2 is switched from the off state to the on state during the boost control. In order to shorten the time during which a reverse current flows through the thyristors 201u to 201w when is applied, a diode whose recovery time is shorter than the turn-off time of the thyristors 201u to 201w is used as the snubber diodes Dsu to Dsw. In order to reduce the loss, it is preferable to use the snubber diodes Dsu to Dsw having a low voltage drop when ON (low internal resistance). Therefore, as the snubber diodes Dsu to Dsw, it is preferable to use a Schottky barrier diode with a short recovery time and a low voltage drop at the time of ON.

  In this embodiment, a parasitic diode between the drains and sources of the MOSFETs 202u to 202w is used as a feedback diode. However, if necessary, a feedback diode composed of a discrete diode is connected in parallel between the drains and sources of the MOSFETs 202u to 202w. It may be.

  The controller 4 includes a generator output voltage detection circuit that detects an output voltage of the magnet generator, a load voltage detection circuit that detects a terminal voltage of a load (battery 3), a memory such as a CPU, a ROM, and a RAM, and various interfaces. A rotation speed detecting means for detecting the rotation speed of the magnet generator, and supplying power to the load by executing a predetermined program stored in the ROM. Output control means for controlling the control rectifier circuit 2 to properly perform (to charge the battery 3 properly) and a voltage induced in the generator coil of the magnet generator 1 when the output voltage of the magnet generator 1 is low And boost control means for performing boost control for boosting. In this embodiment, the control rectifier circuit 2 and the controller 4 constitute a DC power supply device that rectifies the AC output of the magnet generator 1 and supplies power to the load (battery 3).

  Referring to FIG. 4, the configuration of the DC power supply device according to the present embodiment including a control rectifier circuit 2 and a controller 4 is shown together with a magnet generator 1 and a battery 3 as a load. In FIG. 4, 4A is a load voltage detection circuit that detects the voltage across the load (battery 3), 4B is a generator output voltage detection circuit that detects the interphase voltage between the two phases of the magnet generator 1, and 4C is the generator output. Waveform shaping circuit for shaping a half-wave waveform of one polarity of one-phase AC voltage detected by the voltage detection circuit 4B into a rectangular wave shape, 4D is a rotation speed detection means, 4E is an output control means, 4F is a boost control means Among these, the rotation speed detection means 4D, the output control means 4E, and the boost control means 4F are realized by the microprocessor executing a predetermined program.

  The load voltage detection circuit 4A is configured by, for example, a resistance voltage dividing circuit connected between the DC output terminals 2a and 2b of the control rectifier circuit 2. The generator output voltage detection circuit 4B is a circuit that detects the voltage between two of the three-phase output terminals of the magnet generator 1 through a transformer or the like.

  The waveform shaping circuit 4C is a circuit that shapes a half-wave waveform of one polarity of the AC voltage detected by the generator output voltage detection circuit 4B into a rectangular wave shape. This waveform shaping circuit is, for example, the generator output voltage detection circuit 4B. Turns on when the instantaneous value of the half wave of one polarity of the AC voltage detected exceeds the threshold level, and turns off when the instantaneous value of the one half wave falls below the threshold level. It can be configured by a switch circuit that enters a state.

  The rotational speed detecting means 4D is a means for detecting the rotational speed of the magnet generator, and this rotational speed detecting means detects the frequency or period of the AC voltage output from the magnet generator 1 to rotate the magnet generator 1. Detect speed. In the illustrated rotational speed detection means, the generator rotates by a fixed angle (an angle corresponding to one cycle of the AC voltage) α for the time from each rising edge to the next rising edge of the rectangular wave signal obtained from the waveform shaping circuit 4C. The rotation speed of the magnet generator is calculated from the measured time and the rotation angle α.

  The output control means 4E is configured to control the thyristor and MOSFET of the control rectifier circuit 2 in an appropriate manner so as to appropriately supply power to the load according to the type of load. In the present embodiment, since the load is a battery and the battery 3 is charged by the output of the control rectifier circuit 2, the output control means 4E causes the thyristors 201u to 201w of the control rectifier circuit 2 to properly charge the battery 3. The MOSFETs 202u to 202w are configured to be controlled. In the present embodiment, the output control means 4E is configured to perform the following controls (a) to (c).

(A) When the charge state of the battery is detected from the battery voltage detected by the load voltage detection circuit 4A and it is detected that the battery 3 is not fully charged, the control rectifier circuit 2 is subjected to synchronous rectification operation. In order to perform this, a trigger signal is given to the thyristors 201u to 201w of the control rectifier circuit 2, and among the MOSFETs 202u to 202w, a MOSFET in which a forward voltage is applied to a parasitic diode existing between the drain and source is turned on. The thyristors 201u to 201w and the MOSFETs 202u to 202w of the control rectifier circuit 2 are controlled.
(B) The rotation speed of the magnet generator 1 detected by the rotation speed detection means 4D is the set value in a state where it is detected that the charging of the battery 3 is completed from the battery voltage detected by the battery voltage detection circuit 4A. When all the MOSFETs are stopped for the time required to turn off each thyristor and stop supplying the trigger signal to each thyristor to commutate each thyristor of the control rectifier circuit 2 The thyristor and the MOSFET of the control rectifier circuit 2 are controlled so that is turned on (short-circuits between the output terminals of the magnet generator).
(C) When it is detected that the charging of the battery 3 is completed, it is detected that the rotational speed of the magnet generator 1 is equal to or higher than the set value, or the charging of the battery 3 is completed. When it is detected that the output voltage of the magnet generator 1 is equal to or higher than the set value in a state in which the thyristor is operated, the thyristor and the MOSFET of the control rectifier circuit 2 are controlled to turn on all the MOSFETs .

  As described above (a), when the MOSFETs 202u to 202w are controlled when supplying power to the load and the control rectifier circuit performs the synchronous rectification operation, the thyristors 201u to 201w and the parasitic diodes Dpu to Dpw of the MOSFETs 202u to 202w Compared with the case where the rectified output of the magnet generator is supplied to the load (battery) through the full-wave rectifier circuit constituted by In order to obtain this effect, as the MOSFETs 202u to 202w, elements whose resistance values between the respective drains and sources are sufficiently smaller than the resistance values between the anodes and the cathodes of the parasitic diodes Dpu to Dpw are used.

  In the control rectifier circuit 2, when the MOSFETs 202u to 2020w constituting the lower side of the bridge are simultaneously turned on, the output of the magnet generator 2 is short-circuited between the drain and source of any MOSFET and the parasitic diode of any MOSFET. . For example, when the potential of the non-neutral point terminal of the U-phase power generation coil Lu of the magnet generator 1 is higher than the potential of the non-neutral point terminal of the V-phase power generation coil Lv, the power generation coil A short circuit between the drain and source of the Lu-MOSFET 202u, the parasitic diode Dpv of the MOSFET 202v, and the power generation coil Lv is formed, and the power generation coils Lu and Lv are short-circuited. Therefore, as shown in the above (b), when the charging of the battery is completed, if all the MOSFETs constituting the lower side of the bridge of the control rectifier circuit are turned on, the output of the magnet generator 2 is short-circuited and the control is performed. Since the voltage input to the rectifier circuit 2 can be reduced to zero, the currents flowing through the thyristors 201u to 201w can be quickly made equal to or lower than the holding current, and the thyristors 201u to 201w can be quickly commutated. it can.

  As shown in (c) above, when it is detected that the charging of the battery 3 is completed, when it is detected that the rotational speed of the magnet generator 1 is equal to or higher than the set value, all the MOSFETs are turned on. When controlled to be in a state, it is possible to increase the engine load and brake the engine rotation by short-circuiting between the output terminals of the magnet generator 1, thereby suppressing an increase in the rotation speed of the generator can do. Further, by short-circuiting the output of the magnet generator by turning on all the MOSFETs, the supply of power from the magnet generator 1 to the control rectifier circuit 2 can be stopped, and charging of the battery can be stopped. Can be prevented from being overcharged.

  Similarly, when it is detected that the charging of the battery 3 has been completed and the output voltage of the magnet generator 1 has exceeded the set value, all the MOSFETs are When the control is turned on, the output of the magnet generator is short-circuited to suppress an increase in the rotation speed of the generator, and the charging of the battery is stopped to prevent the battery from being overcharged. be able to.

  The boost control means 4F triggers each thyristor of the control rectifier circuit 2 when it is necessary to boost the output voltage of the magnet generator 1 in order to obtain the output required to charge the battery 3 from the magnet generator 1. In this state, the switch elements (MOSFETs 202u to 202w in this embodiment) of all the switch elements are controlled to be turned on / off simultaneously.

  The step-up control means 4F used in the present embodiment is used when the output voltage of the magnet generator 1 does not reach a voltage necessary for charging the battery 3 (this voltage is referred to as a specified voltage) or when the magnet generator 1 rotates. When the speed does not reach the rotational speed necessary for outputting the voltage necessary for charging the battery 3 from the generator 1 (this rotational speed is referred to as a prescribed rotational speed), the control rectifier circuit 2 In a state where a trigger signal is applied to the thyristors 201u to 201w, the thyristor and MOSFET of the control rectifier circuit 2 are controlled so that all the MOSFETs 202u to 202w are simultaneously turned on and off at a sufficiently high frequency.

  As described above, when all the MOSFETs 202u to 202w are simultaneously turned on and off at a sufficiently high frequency in a state where a trigger signal is applied to the thyristors 201u to 201w of the control rectifier circuit 2, the current flowing through the generator coil of the magnet generator is increased. Since the current flowing through the power generation coil can be changed at a large temporal change rate by being intermittent at the frequency, a boosted voltage can be induced in the power generation coil, and the magnet generator 1 can control the control rectifier circuit 2. Can be boosted. At this time, the control rectifier circuit 2 converts the alternating current output from the magnet generator 1 into a full-wave rectifier circuit composed of thyristors 201u to 201w to which a trigger signal is applied and parasitic diodes (feedback diodes) of the MOSFETs 202u to 202w. Is rectified and supplied to the battery 3.

  If the boost control means 4F as described above is provided, the rotational speed of the magnet generator 1 is low, and a current necessary for charging the battery 1 cannot be flowed only by rectifying the output of the magnet generator 1. Even in the state, the battery can be charged. Even after the engine is started, the battery can be charged even when the rotational speed is not sufficiently increased.

  FIG. 5 shows a flowchart showing an example of a processing algorithm executed by the microprocessor provided in the controller 4 in order to constitute the battery charge control means 4E and the boost control means 4F in the present embodiment.

  The process of FIG. 5 is executed at regular timings. When this process is started, first, in step S101, a trigger signal is given to the thyristors (SCR) 201u to 201w of the control rectifier circuit 2, and a forward voltage is applied between the anodes and cathodes of the thyristors 201u to 201w. Allow the thyristor to conduct. Next, in step S102, a drive signal is given to the gate of the MOSFET in which the forward voltage is applied to the parasitic diode (feedback diode) among the MOSFETs 202u to 202w so that the control rectifier circuit 2 performs the synchronous rectification operation. Control to turn on the MOSFET is performed. Thereby, the alternating current output of the magnet generator 1 is synchronously rectified, and the rectified output is supplied to the battery 3 to charge the battery 3.

  Next, in step S103, the battery voltage detected by the battery voltage detection circuit 4A is compared with the determination voltage to determine whether or not the battery is fully charged. As a result, when it is determined that the battery is fully charged (battery voltage is equal to or higher than the determination value), the process proceeds to step S104, and whether or not the rotational speed N of the magnet generator 1 is equal to or higher than the set value Ns. Determine whether. As a result, when it is determined that the rotation speed is not equal to or higher than the set value (when charging of the battery is completed but the rotation speed of the generator is lower than the set value), the process proceeds to step S105 and the thyristor 201u or The trigger of 201w is stopped, and in step S106, all the MOSFETs 202u to 202w of the control rectifier circuit 2 are turned on for a certain period of time necessary to commutate the thyristors 201u to 201w. Thereby, the output of the magnet generator 1 is short-circuited for a certain time, and the thyristor in the on state is commutated. After executing step S106, this process is terminated.

  When it is determined in step S104 that the rotational speed N of the magnet generator 1 is equal to or higher than the set value Ns, the process proceeds to step S107, and all the MOSFETs 202u to 202w of the control rectifier circuit are turned on, and this process ends. By turning on all the MOSFETs 202u to 202w of the control rectifier circuit, the output of the magnet generator 1 is short-circuited, the engine rotation is braked, and an increase in the rotation speed of the magnet generator is suppressed. Further, by short-circuiting the output of the magnet generator 1, the supply of power from the magnet generator 1 to the control rectifier circuit 2 is stopped, the charging of the battery is stopped, and the battery is prevented from being overcharged. .

  When it is determined in step S103 that charging of the battery is not completed (battery voltage is less than the determination value), the process proceeds to step S108, and whether or not the rotation speed of the magnet generator is equal to or less than the specified rotation speed Ni. Determine. As a result, when it is determined that the rotation speed of the magnet generator is equal to or less than the specified rotation speed, the process proceeds to step S109, and trigger signals are given to all the thyristors (SCR) 201u to 201w of the control rectifier circuit 2, and the thyristor Among thyristors 201u to 201w, a thyristor to which a forward voltage is applied between the anode and cathode is allowed to conduct, and in step S110, all MOSFETs 202u to 202 of the control rectifier circuit 2 are turned on and off at a high frequency to This process is terminated after the operation for boosting the output voltage is performed.

  When it is determined in step S108 that the rotation speed N is not equal to or less than the specified rotation speed Ni (exceeds the specified rotation speed), the process proceeds to step S111, and whether or not the output voltage Vac of the magnet generator is equal to or less than the specified voltage Vi. Determine whether. If it is determined that the output voltage Vac of the magnet generator is equal to or less than the specified voltage Vi as a result of the determination, the process proceeds to step S109 to apply trigger signals to all thyristors of the control rectifier circuit 2 and turn on all thyristors. To be in a state. Next, in step S110, all the MOSFETs 202u to 202 are turned on / off at a high frequency so that the output voltage of the magnet generator 1 is boosted, and then this process ends. If it is determined in step S111 that the output voltage Vac of the magnet generator is not less than or equal to the specified voltage Vi, this process is terminated without doing anything thereafter.

  In the case of the algorithm shown in FIG. 5, the output control unit 4E is configured by steps S101 to S107, and the boost control unit 4F is configured by steps S103 and steps S108 to S110.

  In the above embodiment, when the boost control unit 4F performs the operation of boosting the output voltage of the magnet generator by turning on and off the MOSFETs 202u to 202w of the control rectifier circuit 2, the MOSFET is turned from the on state to the off state. Sometimes the energy released from the magnet generator 1 is instantaneously absorbed by the snubber capacitors Csu to Csw through the snubber diodes Dsu to Dsw, so that it is possible to prevent a surge voltage from being generated across the MOSFETs 202u to 202w. At this time, the snubber capacitors Csu to Csw are charged to a high voltage, but the snubber capacitors Csu to Csw and the MOSFET of the control rectifier circuit 2 have a snubber in the reverse direction with respect to the voltages at both ends of the snubber capacitors Csu to Csw. Since the diodes Dsu to Dsw are interposed, the voltage across the snubber capacitors Csu to Csw is not applied to the MOSFETs 202u to 202w. The charges accumulated in the snubber capacitors Csu to Csw are discharged to the battery 3 side through the respective thyristors when the corresponding thyristors 201u to 201w are turned on after the MOSFETs 202u to 202w are turned off.

  With the above configuration, it is not necessary to increase the withstand voltage of the MOSFETs 202u to 202w constituting the lower side of the bridge of the control rectifier circuit 2, so that it is easy to select a MOSFET having a low internal resistance. Therefore, it is possible to reduce the loss generated in the MOSFETs 202u to 202w, reduce the heat generated in the MOSFETs 202u to 202w, eliminate the need to attach a large heat sink to each MOSFET, and increase the size of the device. Can be prevented. Further, since no power is consumed in the snubber circuit as in the case where a CR type snubber circuit is used, the loss generated in the control rectifier circuit 2 can be reduced, and the charging efficiency is increased. be able to.

  Further, as in the above-described embodiment, when a diode whose recovery time is shorter than the turn-off time of each thyristor constituting the upper side of the bridge of the control rectifier circuit 2 is used as the snubber diodes Dsu to Dsw, the control rectifier circuit 2 The upper side of the control rectifier circuit 2 is configured by the voltage induced in the power generation coil of the magnet generator 1 when the switch element (MOSFET in the above example) that configures the lower side of the magnet generator is switched from the off state to the on state. When a reverse voltage is applied to the thyristor, the time during which the reverse current flows through the thyristor can be shortened, so that the loss generated in the control rectifier circuit during boost control can be further reduced. Further, if a diode having a low voltage drop when ON, such as a Schottky barrier diode, is used as the snubber diodes Dsu to Dsw, an increase in loss due to the provision of the snubber diodes Dsu to Dsw can be minimized.

  In the DC power supply device described above, the upper limit value of the output that can be taken out is necessary because it is necessary to suppress the temperature rise of each semiconductor element constituting the control rectifier circuit 2 below the upper limit value of the temperature allowed for each element. Determined. When a snubber diode is added to the upper side of the bridge of the control rectifier circuit as described above, heat is generated in the snubber diode. Generally, the upper limit value of the temperature allowed in the PN junction of the diode is the temperature allowed in the thyristor junction. Since the value is sufficiently higher than the upper limit value, the addition of the snubber diode on the upper side of the bridge does not cause the output of the DC power supply device to be limited.

  In the above embodiment, the MOSFET is used as the switch element constituting the lower side of the bridge of the control rectifier circuit. However, the switch element constituting the lower side of the bridge of the control rectifier circuit includes the switch element capable of on / off control and the switch A switch element having feedback diodes connected in antiparallel to both ends of the element may be used, and is not limited to the above example.

  Referring to FIG. 2, the switch element constituting the lower side of the bridge of the control rectifier circuit 2 includes a feedback diode Du connected in reverse parallel between the insulated gate bipolar transistors (IGBT) 203u to 203w and the collector emitters of these IGBTs. The example comprised by thru | or Dw is shown. In the example shown in FIG. 2, the cathode is connected to the anode of the thyristors 201u to 201w between the thyristors 201u to 201w constituting the upper side of the bridge of the control rectifier circuit 2 and the IGBTs 203u to 203w constituting the lower side of the bridge. Snubber diodes Dsu to Dsw, which are connected and have anodes connected to the collectors of IGBTs 203u to 203w, are inserted. The anodes of the thyristors S201u to 201w are commonly connected, and the emitters of the IGBTs 203u to 203w are commonly connected. From the common connection point of the cathodes of the thyristors S201u to 201w and the common connection point of the emitters of the IGBTs 203u to 203w, respectively. DC output terminals are derived. Three-phase AC input terminals 2u to 2w of the control rectifier circuit 2 are derived from the connection points between the collectors of the IGBTs 203u to 203w and the anodes of the snubber diodes Dsu to Dsw, respectively. The other configuration of the DC power supply device shown in FIG. 2 is the same as that shown in FIG.

  The present invention is not limited to the case where the load of the control rectifier circuit 2 is the battery 3 and the battery 3 is charged with the rectified output of the magnet generator 1 as in the above embodiment. The present invention can also be applied to a DC power supply device that rectifies the power by a control rectifier circuit and supplies power to an appropriate load. For example, as shown in FIG. 3, the present invention can also be applied to a DC power supply device that applies a DC power supply voltage to the inverter 5 using the inverter 5 as a load.

  In the inverter 5 shown in FIG. 3, the upper side of the bridge is constituted by P-channel type MOSFETs 501u to 501w whose sources are commonly connected, the drains are connected to the drains of the MOSFETs 501u to 501w, respectively, and the sources are commonly connected. A channel type MOSFET 502u to 502w is a well-known one that forms the lower side of the bridge. From the common connection point of the sources of the MOSFETs 501u to 501w and the common connection point of the sources of the MOSFETs 502u to 502w, the DC input terminals 5a on the positive side and the negative side respectively. 5b is derived. Three-phase AC output terminals 5u, 5v and 5w are derived from the connection points between the drains of the MOSFETs 501u, 501v and 501w and the drains of the MOSFETs 502u, 502v and 502w, respectively.

  A power supply capacitor Cs is connected between the DC output terminals 2a and 2b of the DC power supply device according to the present invention instead of the battery, and the voltage at both ends of the capacitor Cs is the DC input terminals on the positive side and the negative side of the inverter 5. Applied between 5a and 5b. A drive signal (a signal for turning on the MOSFET) is supplied from the inverter control circuit 6 to the gates of the MOSFETs 501u to 501w and 502u to 502w of the inverter 5.

  The inverter control circuit 6 converts the DC voltage across the power supply capacitor Cs connected between the output terminals of the DC power supply device into an AC voltage having a certain frequency and outputs the AC voltage from the AC output terminals 5u to 5w. 5 MOSFETs 501u to 501w and 502u to 502w are controlled on and off. Since the configuration of the inverter 5 is well known, a detailed description of its operation is omitted.

  In the embodiment shown in FIG. 3, the output control means of the controller 4 controls the control rectifier circuit 2 so that the control rectifier circuit 2 outputs a DC voltage required to keep the output voltage of the inverter 5 at a set value. To do. In the embodiment shown in FIG. 3, the configuration of the DC power supply device 1 is the same as that shown in FIG. 1.

  In the example shown in FIG. 3, the output frequency changes at any time because it is driven by an engine whose rotational speed is not constant by the DC power supply device according to the present invention comprising the control rectifier circuit 2 and the controller 4 and the inverter 5. A power supply device is configured in which the AC output voltage of the magnet generator 1 is converted into a DC voltage and then converted into an AC voltage having a certain frequency by the inverter 5.

  As in the above embodiment, when supplying power to the load, a trigger signal is given to each thyristor of the control rectifier circuit 2, and the switch element of the switch element in which the forward voltage is applied to the feedback diode is turned on. If the output control means is configured to cause the control rectifier circuit 2 to perform the synchronous rectification operation, the switching element of the switch element constituting the lower side of the bridge of the control rectifier circuit has less loss when turned on than the feedback diode. Compared with the case where the output of the magnet generator is rectified by a full-wave rectifier circuit composed of a thyristor that forms the upper side of the bridge and a feedback diode of the switch element that forms the lower side of the bridge The rectifying operation can be performed with However, the present invention is not limited to the case where the output control means is configured to cause the control rectifier circuit to perform the synchronous rectification operation when supplying power to the load.

  For example, the output control means provided in the controller of the DC power supply device according to the present invention is a switch element that constitutes the lower side of the control rectifier circuit when supplying power to the load in a situation where it is not necessary to boost the output of the magnet generator The output of the magnet generator is rectified by a full-wave rectifier circuit composed of a thyristor that forms the upper side of the bridge of the control rectifier circuit and a feedback diode of the switch element that forms the lower side of the bridge. Thus, power may be supplied to the load.

  In the above embodiment, the magnet generator 1 is configured to output a three-phase AC voltage, but the present invention can also be applied to the case where a magnet generator that outputs a single-phase AC voltage is used. Of course you can.

  The DC power supply device according to the present invention can be widely used in applications that require conversion of AC output of a magnet generator driven by an engine into DC output. For example, it can be used as a battery charger for charging a battery mounted on a vehicle driven by an engine, or an alternating current output of a magnet generator driven by an engine whose rotational speed is not constant is converted into an alternating current output having a constant frequency. It can be used as a DC power supply unit of a power supply device (engine generator).

DESCRIPTION OF SYMBOLS 1 Magnet generator 2 Control rectifier circuit 2u-2w AC input terminal 2a, 2b DC output terminal 201u-201w Thyristor 202u-202w MOSFET
Dsu to Dsw Snubber diode Csu to Csw Snubber capacitor 3 Battery 4 Controller 4A Load voltage detection circuit 4B Generator output voltage detection circuit 4C Waveform shaping circuit 4E Output control means 4F Boost control means 5 Inverter 501u to 501w P channel type MOSFET
502u to 502w N-channel MOSFET

Claims (6)

An AC input terminal to which an AC output of a magnet generator driven by an engine is input and a DC output terminal on a positive electrode side and a negative electrode side to which a load is connected, and an AC voltage input to the AC input terminal A bridge-type control rectifier circuit that rectifies and outputs between the DC output terminals, and a controller that controls the control rectifier circuit. The control rectifier circuit is configured by thyristors on each upper side of the bridge, and is turned on and off. Each lower side of the bridge is configured by a switch element having a switch element that can be freely controlled and a feedback diode connected in reverse parallel to the switch element, and a thyristor that forms the upper side of the bridge and a feedback diode of the switch element that forms the lower side And a full-wave rectifier circuit, and the controller appropriately supplies power to the load. And an output control means for controlling the output of the control rectifier circuit to trigger the thyristor of the control rectifier circuit when the output voltage of the magnet generator needs to be boosted to supply power to the load. A step-up control means for controlling so as to simultaneously turn on and off the switch elements of all the switch elements in a state where a signal is applied,
A snubber diode having a cathode facing the thyristor side constituting each upper side is inserted between the thyristor constituting each upper side of the bridge of the control rectifier circuit and the switch element constituting the lower side, and the cathode of each snubber diode And a snubber capacitor connected between a negative output side DC output terminal of the control rectifier circuit.   The output control means applies a trigger signal to each thyristor of the control rectifier circuit when supplying power to the load, and turns on a switch element of a switch element in which a forward voltage is applied to a feedback diode. The DC power supply device according to claim 1, wherein the control rectifier circuit is configured to perform a synchronous rectification operation.   The DC power supply device according to claim 1, wherein the switch element of the switch element is an insulated gate bipolar transistor. An AC input terminal to which an AC output of a magnet generator driven by an engine is input and a DC output terminal on a positive electrode side and a negative electrode side to which a load is connected, and an AC voltage input to the AC input terminal A bridge-type control rectifier circuit that rectifies and outputs between the DC output terminals, and a controller that controls the control rectifier circuit. The control rectifier circuit includes a thyristor and a MOSFET on the upper side and the lower side of the bridge, respectively. A full-wave rectifier circuit comprising the thyristor and a parasitic diode between the drain and source of the MOSFET, and the controller outputs the control rectifier circuit so as to properly supply power to the load. And output control means for controlling the output of the magnet generator in order to supply power to the load The control in the state given a trigger signal to the thyristors of the rectifier circuit a DC power supply and a boost control means for controlling all of the switch elements of the switching element so as to simultaneously turned on and off,
A snubber diode with the cathode facing the thyristor is inserted between the thyristor constituting each upper side of the bridge of the control rectifier circuit and the MOSFET constituting the lower side, and the cathode of each snubber diode and the negative electrode of the control rectifier circuit A direct current power supply device, wherein a snubber capacitor is connected to the direct current output terminal on the side.   The output control means applies a trigger signal to each thyristor of the control rectifier circuit when power is supplied to the load, and turns on a MOSFET in which a forward voltage is applied to a parasitic diode to turn on the control rectifier circuit. The DC power supply device according to claim 4, wherein the DC power supply device is configured to cause a synchronous rectification operation to be performed.   6. The DC power supply device according to claim 1, wherein the snubber diode is a diode having a recovery time shorter than a turn-off time of each thyristor constituting the upper side of the bridge of the control rectifier circuit.

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