JP2012085447A - Ac-dc converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AC-DC converter which simplifies a circuit configuration while allowing the use of a plurality of kinds of input power sources.SOLUTION: When an effective value of an input voltage Vin is high, a relay circuit Ryl sets a winding ratio RN of a transformer Tc to a low value, thereby lowering an induced electromotive force and an output voltage Vout generated by the induced electromotive force. On the other hand, when the effective value of the input voltage Vin is low, the relay circuit Ryl switches the winding ratio RN of the transformer Tc to a high value, thereby raising the induced electromotive force and the output voltage Vout generated by the induced electromotive force. That is, the output voltage Vout when the effective value of the input voltage Vin is high, and the output voltage Vout when the effective value of the input voltage Vin is low are controlled by operation of the relay circuit Ryl so as to reduce a difference between the output voltages.

Description

  The present invention relates to an AC-DC converter, and is particularly suitable for use as an in-vehicle charging device mounted on an electric vehicle or the like.

In recent years, with the advance of technology relating to battery capacity, commercialization of a battery that can withstand high power and long-term use has been promoted. In response, for example, in the automobile industry, by using such a battery product, long-distance traveling using an electric motor is realized. As a result of this development, HEV (Hybrid Electric Vehicle) and EV (Electric
Vehicle) has been commercialized.

  An EV (Electric Vehicle) is provided with an electric motor for traveling, an in-vehicle battery, an in-vehicle charging device, and a power supply connector. When the commercial power plug or the quick charging plug is connected to the power supply connector, the in-vehicle charging device converts the input power and controls the supplied power for charging the in-vehicle battery. And in an in-vehicle battery, electric power will be supplied from the vehicle-mounted charging device of the front | former stage, and charging will be performed.

  On the other hand, even in HEVs (Hybrid Electric Vehicles), products that are equipped with a charging system similar to EVs and charge on-vehicle batteries from commercial power or the like have been commercialized. Such a HEV (Hybrid Electric Vehicle) further includes a power system by an internal combustion engine. When driving power is obtained from an electric motor, the electric energy of the vehicle-mounted battery is consumed, and when driving power is obtained from the internal combustion engine, fossil fuel is used. By using the thermal energy generated by the vehicle and taking advantage of the advantages of both of these drive systems, low fuel consumption driving is realized.

  Hereinafter, a system that connects commercial power to a vehicle body and charges an in-vehicle battery, such as the above-described EV (Electric Vehicle) or HEV (Hybrid Electric Vehicle), will be referred to as a plug-in charging system. A vehicle equipped with the plug-in charging system is referred to as a plug-in electric vehicle.

  Japanese Patent Laid-Open No. 11-356043 (Patent Document 1) introduces a switching power supply device having a circuit configuration similar to the above-described charging device. As shown in FIG. 13, the switching power supply BCS0 includes an AC connector tin connected to a single-phase AC power supply ACm, a single-phase diode bridge Dbr0 that rectifies a single-phase AC voltage, and a single-stage diode bridge Dbr0. A smoothing capacitor C1 to be connected, a transformer Tc provided with an intermediate tap ts on the primary coil side, and a switch circuit Rc connected to the intermediate tap ts and the first end point ta of the transformer Tc for switching a power supply path (claims) Switching circuit in the range), a drive circuit Dr that includes the switching element T5 connected to the second end point tb, and that varies the primary current flowing through the primary coil L1, and a smoothing circuit that smoothes the induced electromotive force in the secondary coil T2. Voltage determination for switching the switch circuit Rc based on Sf and the detection signal Svin of the input voltage Vin And road CNTR, composed of a control circuit CNTd for controlling the drive circuit based on the detection signal Sv output voltage Vout.

  The switching power supply device BCS0 has a so-called capacitor input type circuit configuration in which a smoothing capacitor C1 is provided immediately after the single-phase diode bridge Drb0. When the single-phase AC power supply ACm is connected, the switching power supply BCS0 converts the single-phase AC voltage to the full-wave rectified wave Vd by the single-phase diode bridge Dbr0 (see FIG. 14a), and the subsequent smoothing circuit C1. A stable input voltage Vin is obtained by accumulating charges in (see FIG. 14b). This input voltage Vin is applied to the primary coil L1 of the transformer Tc via the switch circuit Rc.

  When driven by the control circuit CNTd, the drive circuit Dr intermittently generates a primary current that flows through the primary coil L1. At this time, since the magnetic flux of the iron core fluctuates according to the fluctuation of the primary current, the secondary coil L2 generates an induced electromotive force according to the fluctuation. The induced electromotive force is generated in response to energization or interruption of the primary current, and its waveform is set to an alternating current or oscillation state.

  The smoothing circuit Sf includes diode bridges D1 to D4, a reactor L3, a smoothing capacitor C2, and a diode D5. The smoothing circuit Sf performs full-wave rectification of the induced electromotive force in the oscillation state, and then converts it into DC state power. The output voltage Vout output from the smoothing circuit Sf is recognized by the control circuit CNTd, and the control circuit CNTd controls the operation of the drive circuit Dr, so that the voltage value of the output voltage Vout is appropriately adjusted. Will be.

  In addition, when the power supplied to the AC connector tin is different, the switching power supply device BCS0 according to Patent Document 1 controls the switch circuit Rc to function as follows so that no difference occurs between the output voltages Vout.

  For example, when a commercial power supply (AC100 [V]) is connected to the AC connector tin, the voltage determination circuit CNTr recognizes the input voltage Vin via a detection circuit (not shown) and AC100 [V] is applied. A signal Sr indicating that the data is present is output. At this time, the switch circuit Rc conducts the switch to the terminal ta based on the signal Sr. Therefore, in the primary coil L1, the primary current flows in the section from the terminal ta to the terminal tb. When AC100 [V] is rectified, the input voltage Vin is 140 [V].

  On the other hand, when the in-vehicle battery (DC14 [V]) is connected to the AC connector tin, the voltage determination circuit CNTr outputs a signal Sr indicating that DC14 [V] is applied. At this time, the switch circuit Rc conducts the switch to the intermediate tap ts based on the signal Sr. The intermediate tap ts sets a section through which the primary current flows between ts and tb, and the number of turns of the primary coil L1 in the sections ts to tb is about 1/10 of the number of turns of the primary coil in the sections ta to tb. Is set to

  Therefore, since the winding ratio RN2 (secondary winding N2 / primary winding N1) when DC14 [V] is input is about 10 times the winding ratio RN1 at AC 100 [V], the switching power supply device The output voltage Vout output from the BCS0 is controlled to be substantially the same value or the same state regardless of the power of DC14 [V] or AC100 [V].

  Such a switching power supply device can be applied to the plug-in type electric vehicle charging device described above. In this case, the in-vehicle charging apparatus can set the winding ratio RN of the transformer Tc as appropriate even if different power is supplied to the power supply connector of the vehicle body. Without giving, the vehicle-mounted battery Bm can be suitably charged.

Japanese Patent Laid-Open No. 11-356043

  However, in the technique according to Patent Document 1, as shown in FIG. 14C, a current Iin flowing through the smoothing capacitor C1 is instantaneously generated in the vicinity of the peak value in the full-wave rectified wave Vd. Such an input current Iin is a cause of the generation of harmonics, which causes a problem of destabilizing the operation of the electrical equipment connected to the AC power source Acm.

  In addition, such a capacitor-input type power conversion circuit causes a reduction in power factor due to the input current Iin. For this reason, the power conversion circuit is required to have a circuit design that increases the input current Iin so as to compensate for the power factor decrease in order to output desired power. Therefore, a diode, a switching element, an electrolytic capacitor used as the smoothing capacitor C2, and other circuit elements must be selected from elements having a high rated current, resulting in an increase in size and cost of the circuit device. Occurs.

Furthermore, when such a power conversion circuit is used as a vehicle-mounted charging device, there is a concern that it may adversely affect the surrounding vehicle-mounted electrical equipment according to the generation of harmonics. In particular, ECU (Elctric Control) sensing the power supply from the AC connector
Unit), etc., the damage caused by the adverse effects can be enormous.

  For this reason, in order to avoid the harmful effects caused by the harmonics, a power conversion circuit intended to improve the power factor has been proposed. FIG. 15 shows an example thereof. Specifically, a power factor correction circuit PFC is additionally configured between the single-phase diode bridge Dbr and the smoothing capacitor C1. In addition, a control microcomputer CNTp for controlling the switching element Tp in the power factor correction circuit PFC is added. According to such a power conversion circuit, when the energization current of the switching element Tp is appropriately controlled, an input current Iin similar to the input voltage (full wave rectified wave) is generated, so that the power factor is improved. The adverse effects on the surrounding electrical equipment are improved within a certain range. However, in such a power conversion circuit, since the power factor correction circuit PFC must be additionally configured, the circuit becomes complicated, resulting in an increase in size and cost of the apparatus.

  Further, the smoothing capacitor C1 is always provided in any of the power conversion circuits of FIGS. Since the smoothing capacitor C1 has a capacitance set according to the magnitude of the input voltage, an electrolytic capacitor having a large element size is generally used. Therefore, in an in-vehicle charging device, it is necessary to select an electrolytic capacitor that can withstand use in the order of several hundred volts. If an electrolytic capacitor that satisfies this requirement is used, the element size will increase, Extremely difficult.

  In addition, recent automobiles are manufactured and sold in multiple countries. In this case, the smoothing capacitor C1 (electrolytic capacitor) must be selected according to the country A where the voltage value of the commercial power source is high among the countries A to C where the use of the plug-in electric vehicle is planned. Therefore, as for a certain plug-in type electric vehicle, there is a problem that a charging device having a specification corresponding to the country A must be mounted even though it is not used in the country A where the voltage value of the commercial power supply is large. Arise.

  In view of the above problems, an object of the present invention is to provide an AC-DC converter that enables the use of a plurality of types of input power supplies and realizes a simplified circuit configuration.

  In order to solve the above problems, the first invention adopts the following AC-DC converter configuration. That is, a multi-phase diode bridge that rectifies a multi-phase AC voltage, a primary coil having three or more different contact points, and a secondary coil that generates an induced electromotive force according to fluctuations in the primary current flowing in the primary coil And a drive circuit that includes a first switching element that intermittently controls energization or interruption of the primary current, and that varies the current value of the primary current according to the operation of the first switching element. A switching circuit that is connected to a plurality of contact points among the three or more contact points and selectively switches the energization section in which the primary current flows through the primary coil by selectively energizing any of the plurality of contact points; And a smoothing circuit for smoothing the induced electromotive force.

In the second invention, the following AC-DC converter configuration may be used. That is, a multi-phase diode bridge that rectifies a multi-phase AC voltage, a primary coil having three or more different contact points, and a secondary coil that generates an induced electromotive force according to fluctuations in the primary current flowing in the primary coil Including a transformer, a switching circuit having a second switching element provided corresponding to a plurality of contact points among the three or more contact points, and a smoothing circuit for smoothing the induced electromotive force,
The switching circuit switches the energization section of the primary current by selectively driving any of the second switching elements, and the switching element that is selectively driven among the second switching elements. The energization or interruption of the primary current shall be controlled intermittently.

  Preferably, with respect to these inventions, the switching circuit sets the current-carrying section longer when the first multiphase AC voltage having a high effective value is input, and the second multiphase AC voltage having a low effective value is input. In such a scene, the energization section is set to be short.

  More preferably, the effective value of the first multiphase AC voltage is set to V1 rms, the effective value of the second multiphase AC voltage is set to V2 rms, and is set for the first multiphase AC voltage by the switching circuit. The number of turns of the primary coil wound in the first current-carrying section is N1a, and the switching circuit is wound in the second current-carrying section set for the second multiphase AC voltage. When the number of turns of the primary coil is N1s, these values satisfy the relationship of V1rms / N1a = V2rms / N1s.

In the case where a relationship is assumed in which the effective value of the first multiphase AC voltage is approximately twice the effective value of the second multiphase AC voltage,
The primary coil of the transformer includes a first end point connected to a contact point at one end, a second end point connected to a contact point at the other end, and a winding from the first end point to the second end point. It is good also as having a center tap connected with the contact location which divides a line equally.

  All the above-described inventions are preferably mounted on a plug-in electric vehicle capable of inputting commercial power and used as a vehicle-mounted charging device that charges a vehicle-mounted battery based on the commercial power. At this time, the commercial power is preferably supplied from a three-phase AC power source.

  The AC-DC converter according to the present invention obtains electric power from a three-phase AC power supply, smoothes the input voltage by full-wave rectifying each phase voltage, and allows the smoothing capacitor on the input side to be omitted. Thus, the advantage of simplifying the circuit configuration and reducing the cost of the apparatus is utilized.

  Such a smoothing action is realized by a one-converter type power conversion circuit, and a function for switching the winding ratio of the transformer in accordance with the value of the input voltage is added. As a result, the AC-DC converter that can be used for input power of different values adopts a one-converter circuit, thereby eliminating harmonics without using a power factor correction circuit, and Both effects of simplifying the circuit configuration are exhibited. In addition, the AC-DC converter contributes to downsizing and cost reduction of the device by simplifying the circuit configuration.

  In particular, even if the AC-DC converter is an in-vehicle charging device, the plug-in electric vehicle on which the device is to be mounted has multiple countries, and the commercial power supply value in each country is different. As described above, in the in-vehicle charging device according to the present invention, the smoothing capacitor on the input side is omitted, so that the physique of the device is not affected by the voltage value (input value) of the commercial power supply. Can be designed freely. In addition, in such an in-vehicle charging apparatus, since the generation of harmonics is eliminated, stable operation of the in-vehicle electrical equipment / ECU and the like mounted on the plug-in type electric vehicle is ensured.

The figure which shows the circuit structure of the vehicle-mounted charging device which concerns on embodiment. The time chart which shows the waveform after a three-phase alternating current voltage and its full wave rectification. The figure which shows the structural example of an input voltage detection circuit. The figure which shows the other circuit structure of the vehicle-mounted charging device which concerns on embodiment. The figure which shows the structural example of a smoothing circuit. The figure which shows the structural example of a smoothing circuit. The figure which shows the structural example of a switching circuit. The figure which shows the structural example of a switching circuit. The figure which shows the structural example of a switching circuit. The figure which shows operation | movement with the switching circuit and transformer which concern on an Example. The figure which shows operation | movement with the switching circuit and transformer which concern on an Example. The figure which shows the relationship between the input voltage and output voltage which concern on an Example. The figure which shows the circuit structure of the vehicle-mounted charging device which concerns on a prior art example. The time chart which shows the input voltage and input current in a prior art example. The figure which shows the structure of the vehicle-mounted charging device which concerns on another prior art example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the AC-DC converter BCS1 according to the present embodiment uses a one-converter type power conversion circuit as follows. Specifically, it comprises a multiphase diode bridge Dbr, a drive circuit Dr, a switching circuit Rc, a transformer Tc, a smoothing circuit Sf, a voltage detection circuit INSv, a current detection circuit INSi, and a signal processing device CNT1. The AC-DC converter is a charging device mounted on a plug-in vehicle in the present embodiment, and is hereinafter referred to as an in-vehicle charging device BCS1. In addition, the in-vehicle charging device BCS1 is provided with an input connector tin and an output terminal tout, a power plug for applying a three-phase commercial power supply ACt is connected to the input connector tin, and an in-vehicle charging terminal BCS1 is connected to the output terminal tiout. Battery Bm is connected.

  The commercial power supply ACt differs from the prior art in that a three-phase AC power supply (r phase / s phase / t phase) is used. Such a three-phase commercial power supply ACt is supplied with AC200 [V] and AC400 [V] in the case of Japan, and supplied with AC380 [V] and AC400 [V] in the case of Europe. Even if it exists, each electric power company sets the voltage value (polyphase alternating voltage) variously. These voltage values indicate effective values.

  The input connector tin is formed with terminals corresponding to a plurality of types of plug shapes so that the above-described plurality of types of commercial power (three-phase AC power) are applied. In addition to this, the input connector tin may be provided with a separate connector for a quick charge plug.

  As shown in the figure, the output terminal tout is provided on the rear side of the in-vehicle charging device BCS1 and wired so that the output voltage Vout of the smoothing circuit Sf is applied. The output terminal tout is further wired so that the power supply line is connected to the rear stage portion and the output voltage Vout is applied to the in-vehicle battery Bm via the power supply line. Hereinafter, in the in-vehicle charging apparatus, the direction in which the in-vehicle battery Bm is connected may be referred to as an output side, and the direction in which the commercial power ACt is connected may be referred to as an input side.

  The in-vehicle battery Bm includes a plurality of battery cells such as lithium ion batteries disposed in the battery module, and generates a DC voltage of about 400 [V] as a whole. The power output from the in-vehicle battery Bm is distributed to a main inverter device that generates three-phase AC power from the battery power, and a DC-DC converter that supplies power to the in-vehicle electrical equipment and the sub-battery (about DC 12 [V]). Is done. In the inverter circuit, the DC power of the in-vehicle battery Bm is converted into three-phase AC power, and the three-phase AC power is supplied to the drive motor (three-phase synchronous motor, three-phase induction motor, etc.). At this time, the drive motor generates torque in accordance with the input electric power and transmits the torque to the drive wheels, thereby appropriately controlling the static motion of the vehicle or the vehicle speed.

  The multiphase diode bridge Dbr is wired in a bridge shape by the diodes Da to Df, and the arm corresponding to each phase voltage (r phase voltage / s phase voltage / t phase voltage) is formed by these configurations. In this arm, when the three-phase AC voltage Vact is applied (see FIG. 2a), the phase voltage (Vr / Vs / Vt) corresponding to each phase is full-wave rectified (see FIG. 2b). Therefore, since the multiphase diode bridge Drb sequentially outputs the full-wave rectified phase voltages (Vr / Vs / Vt), the output voltage Vin appearing thereby is a certain range as shown in FIG. It will only fluctuate at ΔV, and will receive a smoothing action.

  Considering a case where a single-phase AC voltage of AC 200 [V] is applied, the output voltage in the case of a single phase is 282 [V] to 0 [V] because each rectified wave has a phase difference π. ] In the range of]. However, by adopting a balanced three-phase AC power supply as in this embodiment, the output voltage Vin has an effect that the fluctuation range falls within the range of 282 [V] to 245 [V]. That is, by changing the input power source from single phase to three phases, the fluctuation range of the output voltage Vin is suppressed to about 13%. In this embodiment, a three-phase AC power source is used as an input power source. However, the present invention is not limited to this, and the smoothing action described here becomes more remarkable by using a multi-phase power source.

  In this embodiment, since the one-converter type power conversion circuit is employed, the input side smoothing circuit used in the capacitor input method is omitted. Therefore, the device itself can be miniaturized and the generation of higher harmonics can be eliminated.

  The in-vehicle charging device BCS1 is provided with a voltage detection circuit (not shown) that detects the input voltage Vin. As shown in FIG. 2A, the voltage detection circuit may be a voltage dividing resistor composed of resistors Rm and Rn, and may output a detection signal Svin related to the input voltage Vin from the voltage dividing point. Further, as shown in FIG. 2B, a sensor circuit SCN2 is provided between the input connector tin and the multiphase diode bridge Dbr, and detection signals Svin (r), Svin (s), Svin (t) may be output. Note that the circuit for detecting the input voltage Vin is merely shown as an example in the drawing, and a currently known technique can be used as appropriate.

  The transformer Tc includes an iron core, and a primary coil L1 and a secondary coil L2 are wound around the iron core. Among these, the primary coil L1 according to the present embodiment includes an end point ta, an intermediate tap ts, and an end point tb. The intermediate tap ts is a terminal electrically connected to a contact point in the middle of the wire of the primary coil L1, and determines the winding N of the end point ta to the intermediate tap ts or the end point tb to the intermediate tap ts. To do. In addition, the end point ta and the end point tb are electrically connected to contact points at each end of the primary coil L1. On the other hand, as the secondary coil L2, in the case of the present embodiment, a normal coil that does not include an intermediate tap is used. In such a transformer Tc, when the primary current flowing through the primary coil L1 varies, the magnetic flux penetrating the iron core varies. At this time, in the secondary coil L2, an induced electromotive force is generated according to a change in magnetic flux. As described above, since the voltage applied from the drive circuit Dr is in an AC state, the polarity of the primary current and the induced electromotive force also changes with time.

  Here, the number of turns from the section ta to ts in the primary coil L1 is N1a, the number of turns (total number of turns) in all sections ta to tb in the primary coil is N1b, and the total number of turns in the secondary coil L2 is N2. At this time, when the primary current flows only in the section ta to ts, the winding ratio RNa of the transformer Tc is expressed by RNa = N2 / N1a. On the other hand, when the primary current flows in all the sections ta to tb, the winding ratio RN2 at this time is expressed by RN2 = N2 / N1b.

  The switching circuit Rc includes an input terminal, a first output terminal, a second output terminal, and switch means. In the present embodiment, the input terminal is connected to one arm of the drive circuit Dr, the first output terminal is connected to the end point ta of the primary coil L1, and the second output terminal is the intermediate tap ts of the primary coil L1. Connected to. Then, the switching circuit Rc selects either the first output terminal or the second output terminal by the switch means, and conducts the selected output terminal to the input terminal, thereby supplying power. Switch routes.

  In the switching circuit Rc, one output terminal is connected to the end point ta and the other output terminal is connected to the intermediate tap ts. Therefore, when the power supply route is changed by the switch means, the primary current in the primary coil L1 is changed. The energization section is switched to any one of the sections ta to ts or the sections ta to tb. That is, the switching circuit Rc plays a role of appropriately switching the energization section of the primary current by switching the output terminal to be conducted to the input terminal. The switch means provided in the switching circuit Rc can be variously modified, and specific examples thereof will be described in detail later.

  The drive circuit Dr used in the present embodiment employs a full bridge circuit composed of power transistors T1 to T4 (first switching elements in the claims). The drive circuit Dr is connected to the multiphase diode bridge Dbr via the power supply lines on both sides. The contacts of the power transistors T1 and T2 are connected to the input terminal of the switching circuit Rc, and the contacts of the power transistors T3 and T4 are connected to the end point tb of the transformer Tc. In addition, each of the transistors T1 to T4 has a gate connected to the signal processing device CNT1, and each transistor is ON / OFF controlled by a drive signal Sd output from the signal processing device CNT1. Therefore, when the drive circuit Dr receives the drive signal Sd from the signal processing device CNT1, each power transistor is driven at a predetermined duty ratio, and intermittent voltage is applied between the switching circuit Rc and the end point tb. Let

  Since this intermittently generated voltage is applied to the primary coil L1 via the switching circuit Rc, in the energizing section of the primary coil L1 selected by the switching circuit Rc, the primary current is generated at a high frequency in that section. Energization or interruption is repeated. That is, when the power transistors T1 to T4 are driven, the current value of the primary current varies according to this operation. Therefore, in the transformer Tc, the current value of the primary current fluctuates by such intermittent control, thereby generating the induced electromotive force V2.

  As shown in FIG. 1, a shunt resistor Rk may be provided at the end of the full bridge circuit, and the signal processor CNT1 may monitor the current value Sk of the drive circuit Dr. In this case, abnormal operation of the power transistors T1 to T4 can be detected.

  1 employs a full bridge circuit, the drive circuit Dr is not limited to such a configuration. For example, as shown in FIG. 4, the drive circuit Dr may be configured by a single power transistor T5 (first switching element in claims). The power transistor T5 in the figure is inserted between the end point tb and the multiphase diode bridge circuit Dbr, and is repeatedly energized / interrupted in accordance with the drive signal Sd received from the signal processing device CNT1, thereby the primary coil. A primary current is generated in L1. The drive circuit Dr may be connected to the end point ta. In this case, the switching circuit Rc has an input terminal connected to the power supply line on the other side, and each of the output terminals is connected to the intermediate tap ts and the end point tb.

  The smoothing circuit Sf is connected to the secondary coil L2 of the transformer Tc, smoothes the induced electromotive force V2 output from the secondary coil, and applies the output voltage Vout converted to the DC state to the output terminal Vout at the subsequent stage. .

  FIG. 5 shows a configuration example of the smoothing circuit Sf. For example, the smoothing circuit Sf shown in FIG. 5A includes diodes Dp and Dq, a reactor L3, and a smoothing capacitor C2. The anodes of the diodes Dp and Dq are each connected to the end point of the secondary coil L2. Moreover, both the diodes Dp and Dq are connected to each other on the cathode side, and their contact points are connected to the input side of the reactor L3. The reactor L3 is wired so as to be inserted into the power supply line. The smoothing capacitor C2 is connected in parallel to the secondary coil L2 after the reactor L3. Such a smoothing capacitor C2 is required to output a voltage of the order of several hundred volts, but generally an electrolytic capacitor or the like is used.

  Further, a smoothing circuit Sf as shown in FIG. In this case, a center tap is provided on the secondary coil L2. Then, the cathodes of the diodes Dp and Dq are respectively connected to the end points of the secondary coil L2, and the anodes of the diodes Dp and Dq are connected to each other. This contact is connected to the cathode side of the smoothing capacitor C2. Moreover, the anode side of the smoothing capacitor C2 is connected to the center tap of the secondary coil L2 via the reactor L3.

  In both of these smoothing circuits Sf, when an induced electromotive force V2 in an alternating state whose polarity changes rapidly is applied, the electric charge generated in response thereto is accumulated in the smoothing capacitor C2 to generate a force flow power. However, since such a smoothing circuit is already a well-known technique, description of operations and the like will be omitted.

  FIG. 6 shows another configuration example of the smoothing circuit. The smoothing circuit Sf in FIG. 6A includes diodes Dh to Dk, power transistors Tj and Tk, a reactor L3, and a smoothing circuit C2. The diodes Dh to Dk are wired in a bridge shape, and are connected to power transistors Tj and Tk as illustrated. In the smoothing circuit Sf, the current flowing to the smoothing capacitor C2 is limited by controlling the power transistors Tj and Tk. Even in the drive circuit Dr described above, the output voltage Vout can be adjusted to a desired value by adjusting the drive duty of the power transistor. However, by adding such a function to the smoothing circuit Sf, the output voltage Vout can be adjusted more accurately. For example, the output voltage Vout may be adjusted by setting the drive duty on the drive circuit Dr side to a fixed value and controlling the drive duty on the smoothing circuit Sf side.

  In the smoothing circuit Sf of FIG. 6B, the above-described diode bridges Dh to Dk are replaced with power transistors Th to Tk. In general, since the voltage drop at the transistor can be suppressed lower than the voltage drop at the diode, the output efficiency can be improved in such a configuration. It should be noted that the smoothing circuit Sf introduced here is merely an example, and other well-known techniques at the present time can be appropriately adopted.

  The voltage detection circuit INSv includes, for example, voltage dividing resistors R1 and R2, and outputs a detection signal Sv related to the output voltage Vout from the voltage dividing point of this circuit.

  The current detection circuit INSi is composed of, for example, a shunt resistor R3 and an operational amplifier AMP, and outputs a detection signal Si that is proportional to the current value detected by the shunt resistor R3.

  As shown in FIG. 1, the signal processing device CNT1 includes a first control circuit CNTd and a second control circuit CNTr. The signal processing device CNT1 includes a CPU, a memory circuit, an AD conversion circuit, and other circuits necessary for generating and outputting a predetermined signal. The signal processing device CNT1 does not ask the circuit configuration such as whether it is one-chip or the number of CPUs. The signal processing device CNT1 receives Svin indicating the input voltage Vin, a detection signal Sv indicating the output voltage Vout, and a detection signal Si indicating the value of the current flowing through the secondary power line in the charging device. Then, the first control circuit CNTd defines the drive duty of the power transistors T1 to T4 based on the detection signal Si and the detection signal Sv, and outputs a drive signal corresponding to this. The control circuit CNTd appropriately sets a mode so that the output power of the charging device becomes a constant voltage or a constant current, and thereby controls the output voltage Vout or the output current of the charging device.

  On the other hand, the second control circuit CNTr outputs a switching signal Sr based on the value of the input voltage Vin. More specifically, when Svin indicating the input voltage Vin is higher than a predetermined threshold, a signal indicating that the input voltage Vin is high (hereinafter referred to as a switching signal Sra) is output. On the other hand, when Svin indicating the input voltage Vin is lower than a predetermined threshold, a signal indicating that the input voltage Vin is low (hereinafter referred to as a switching signal Srb) is output.

  FIG. 7A shows a relay circuit Ryl that is an embodiment of the switching circuit Rc. The relay circuit Ryl is provided with an input terminal te, a first output terminal t1, and a second output terminal t2, and includes switch means including a switch mechanism SW and a solenoid coil Co. The switch mechanism includes a driven terminal and operates according to the polarity of the solenoid coil Co. When the switching signal Sra is input, the solenoid coil Co applies a repulsive force to the driven terminal and makes the input terminal te and the first output terminal t1 conductive. Further, when the switching signal Srb is input, the driven terminal is drawn and the input terminal te and the second output terminal t2 are brought into conduction.

  Therefore, when a multiphase AC power source that is higher than the threshold value is connected to the charging device BCS1, the relay circuit Ryl receives the switching signal Sra from the signal processing device CNT1, thereby connecting the input terminal te and the first output terminal ta. Conduct. In this case, the applied voltage from the drive circuit Dr is applied to the energization sections ta to tb, and the relay circuit Ryl sets a long energization section for passing the primary current.

  When a multiphase AC power source lower than the threshold value is connected to the charging device BCS1, the relay circuit Ryl receives the switching signal Srb from the signal processing device CNT1, thereby causing the input terminal te and the second output terminal ts to be connected. Conduct. In this case, the applied voltage from the drive circuit Dr is applied to the energization intervals ts to tb, and the relay circuit Ryl sets the energization interval for flowing the primary current to be short.

  When such control is performed, the relay circuit Ryl causes the winding ratio RN of the transformer Tc to be set to a low value when the effective value of the input voltage Vin is high, and the induced electromotive force and the output voltage Vout generated thereby. Reduce. On the other hand, when the effective value of the input voltage Vout is low, the winding ratio RN of the transformer Tc is switched to a high value to increase the induced electromotive force and the output voltage Vout generated thereby. That is, the output voltage Vout when the effective value of the input voltage Vin is high and the output voltage Vout when it is low are controlled so that the difference between the voltage values is reduced by the operation of the relay circuit Ryl.

  In the present embodiment, two types of commercial power sources are connected to the in-vehicle charging device BCS1, and when one of the commercial power sources ACt1 is connected, the voltage at this time (first multiphase AC voltage) ) Is assumed to be V1rms. When the other commercial power supply ACt2 is connected, the effective value of the voltage (second multiphase AC voltage) at this time is V2rms. However, effective value V1rms> effective value V2rms.

  The energization sections ta to tb (all sections) in the primary coil L1 are sections set when the commercial power source ACt1 is connected, and the number of turns in the section is N1a. The energization sections ts to tb (partial sections) in the primary coil L1 are sections that are set when the commercial power source ACt2 is connected, and the number of turns in the section is N1s.

  In the primary coil L1 according to the present embodiment, the contact point with the intermediate tap ts is set so that the intermediate tap ts satisfies the relationship of V1rms / N1a = V2rms / N1s. Therefore, the induced electromotive force V2 (1) when the commercial power supply ACt1 is connected is expressed as V2 (1) = (N2 / N1a) · V1rms, where N2 is the number of turns of the secondary coil L2. On the other hand, the induced electromotive force V2 (2) when the commercial power source ACt2 is connected is expressed as V2 (1) = (N2 / N1s) · V2rms. Therefore, the induced electromotive force in both cases has a relationship of “V1 rms / N1a = V2 rms / N1s”, and both have the same voltage value. However, the output voltage Vout from the smoothing circuit Sf outputs the same voltage value regardless of whether the commercial power source ACt1 or the commercial power source ACt2 is connected.

  Therefore, regardless of whether the commercial power source ACt1 or the commercial power source ACt2 is connected, the in-vehicle battery Bm in the subsequent stage is charged with the same voltage value regardless of the connected power source. Therefore, according to such a charging device, detailed control at the time of charging, for example, control regarding overcharge protection is effective.

  As described above, the in-vehicle charging device BCS1 according to the present embodiment obtains electric power from the three-phase AC power supply, and applies a smoothing action to the input voltage by full-wave rectifying each phase voltage, thereby smoothing the input side. The advantage is that the capacitor can be omitted, thereby simplifying the circuit configuration and reducing the cost of the device.

  Such a smoothing action is realized by a one-converter type power conversion circuit, and a function of switching the winding ratio RN of the transformer Tc according to the value of the input voltage is added. As a result, the in-vehicle charging device BCS1 that can be used for different values of the input power supply adopts a one-converter circuit, thereby eliminating the harmonics without using the power factor correction circuit, and Both effects of simplifying the circuit configuration are exhibited. In addition, the AC-DC converter contributes to downsizing and cost reduction of the device by simplifying the circuit configuration.

  In addition, in such an in-vehicle charging apparatus, since the generation of harmonics is eliminated, stable operation of the in-vehicle electrical equipment / ECU and the like mounted on the plug-in type electric vehicle is ensured.

  Note that the relay circuit Ryl is not limited to the above-described aspect of the wiring method. For example, as shown in FIG. 7B, the input terminal te is connected to the other power supply line of the drive circuit Dr, the first output terminal t1 is connected to the intermediate tap, and the second output terminal t2 is connected to the end point tb. You may connect to. Even if the relay circuit Ryl is controlled to be switched in such a manner, the same effect as described above can be obtained.

  FIG. 8A shows a further modification of the switching circuit. The switching circuit Sc1 is constituted by two thyristors (second switching element in claims), and the anode sides of both thyristors are connected to the input terminal te. One cathode side is connected to the first output terminal t1, and the other cathode side is connected to the second output terminal t2. Then, drive signals Sr1 and Sr2 are sent to each gate from the signal processing device CNT1. The switching circuit Sc1 sets the energization section in the primary coil L1 to all sections ta to tb by energizing the thyristor connected to the first output terminal t1. On the other hand, by setting the thyristor connected to the second output terminal t2 in the energized state, the energized section is set to the section from ts to tb. That is, the switching circuit Sc1 shown in the figure selects the thyristor to be energized, thereby changing the power supply route and performing the energization section setting operation.

  Since the drive signals Sr1 and Sr2 here cannot self-extinguish the thyristor, it is necessary to give both an energization command (ignition) and a cut-off command (extinction) to the gate. Note that these thyristors can be replaced with switching elements capable of self-extinguishing. Such a switching element is preferably a power transistor such as IGBT or MOFET. It goes without saying that such power transistors can be used not only for the switching elements here but also for all the switching elements described in this specification.

  FIG. 8B shows a further modification of the switching circuit. The switching circuit Sc2 is configured by two switching elements Ty and Tz (second switching element in the claims), and the switching element Ty is connected to the output terminal t1, and the energization section is divided into sections ta to ts (one It is responsible for the function set in the section). Further, the switching element Tz is connected to the output terminal t2 and has a function of setting the energization section to sections ta to tb (all sections).

  Therefore, the switching circuit Sc2 also selectively drives either the switching element Ty or Tz to switch the energization section of the primary current. Further, in the switching circuit Sc2 in the figure, control for intermittently energizing or interrupting the primary current is performed for the selected switching element. The operation of the switching element is realized by the drive signal Sr1 or Sr2 sent from the signal processing device CNT1 as a high frequency pulse. When the switching element Ty is selected as the driving target, the driving signal Sr1 is input from the signal processing device CNT1, and the switching element Ty generates an intermittent primary current for the energization sections ta to ts. In addition, when the switching element Tz is selected as the driving target, the driving signal Sr2 is input, and the switching element Tz generates an intermittent primary current for the energization sections ta to tb.

  That is, the switching circuit Sc2 is a circuit having an original function of switching the energization path and a function of driving the transformer Tc such as the drive circuit Dr described above. For this reason, the vehicle-mounted charging device BCS having the switching circuit Sc2 does not require a separate drive circuit, and thus the circuit configuration is greatly simplified.

  FIG. 9A shows a further modification of the switching circuit. The switching circuit Rc3 includes a plurality of switching means Sw1 to Sw4, and is provided with one input terminal te and a plurality of output terminals t1 to t4. Among these, the switch means Sw1 is inserted between the input terminal te and the output terminal t1, the switch means Sw2 is inserted between the input terminal te and the output terminal t2, and the same wiring is also applied to the other switching means. Is given. The switching circuit Rc3 can switch the power conduction path to a plurality of types (te to t1, te to t2, te to t3, te to t4) according to the drive signals Sr1 to Sr4.

  The primary coil L1 of the transformer Tc is provided with intermediate taps ts1 to ts3, and generally includes five contact points. The primary coil L1 in FIG. 1 has an end point ta connected to the first output terminal t1, an intermediate tap ts1 connected to the second output terminal t2, an intermediate tap ts2 connected to the third output terminal t3, The tap ts3 is connected to the fourth output terminal t4, and the end point tb is connected to the drive circuit dr.

  In the in-vehicle charging device BCS in FIG. 6, since the power supply route can be selected from a plurality of routes by the switching circuit Rc3, it is possible to set a plurality of primary current energization sections according to the number of power supply routes. Become. Therefore, the in-vehicle charging device BCS having such a configuration is not limited to two types, and even if more types of commercial power sources are planned to be used, the number of turns set by the intermediate taps ts1 to ts3 is input. If it corresponds to the effective value of the power supply, it becomes possible to control the output voltage Vout from the charging device to have the same value, and it is possible to charge the vehicle-mounted battery suitably.

  FIG. 9B shows a further modification of the switching circuit. The switching circuit Rc4 is provided with a plurality of input terminals t1 to t4, and switch means Sw1 to Sw4 are connected to each of the input terminals. The switch means Sw1 to Sw4 are appropriately connected to the intermediate taps ts1 to ts3 and the end point tb of the primary coil L1 via the input terminals t1 to t4.

  The in-vehicle charging device BCS having such a configuration can charge the in-vehicle battery in each scene where three or more different input power sources are used, as in FIG. 9A. In addition, the switching circuit Rc4 in FIG. 9B simplifies the circuit configuration of the on-vehicle charging device BCS because the switching circuit Rc4 has a function of setting the primary current supply section and a function of driving the transformer Tc. obtain.

  Note that the switch means Sw1 to Sw4 shown here may be a mechanical device such as a relay circuit as described above, or may use a semiconductor element such as a power transistor. In addition, as described with reference to FIGS. 7A and 7B, these switching circuits are expected to be appropriately changed in connection positions and wiring.

  Hereinafter, a usage example of the in-vehicle charging device BCS1 will be specifically described. In this embodiment, it is assumed that the plug-in electric vehicle is planned to be used in either Japan or Europe. The plug-in electric vehicle charging device BCS1 is supplied with commercial power by a three-phase AC200 [V] when used in Japan, and by three-phase AC400 [V] when used in Europe. Shall be supplied.

  In the present embodiment, the center coil tg of the primary coil L1 of the transformer Tc is connected to a contact point that equally divides the number of turns of the coil. Further, the contact point on one end side of the primary coil L1 is electrically connected to the end point ta (first end point), and the contact point on the other end side is connected to the end point tb (second end point). The transformer Tc is switched to either the winding ratio RN of 100% or 50% in accordance with the switching operation of the relay circuit Ryl.

  First, when a plug-in electric vehicle is used in Europe, a commercial power plug of AC 400 [V] is connected to the input connector tin of the in-vehicle charging device BCS1 (see FIG. 10). In this case, as shown in FIG. 12 (a1), the applied voltage of the commercial power supply ACt1 is smoothed by the bridge circuit Drb to obtain the input voltage Vin. In this case, the input voltage Vin varies within a range of about 564 [V] to 490 [V]. Hereinafter, the effective value of the input voltage Vin in FIG.

  In this case, the signal processing device CNT1 drives the drive circuit Dr in a predetermined mode, recognizes the input voltage Vin related to AC400 [V], and switches the energization path of the relay circuit Ryl toward the output terminal t1. Accordingly, in the primary coil L1, the energization section is set to all sections ta to tb, and thereby the winding ratio RN is set to 50% in the transformer Tc. Then, the in-vehicle charging device BCS1 outputs a charging voltage (output voltage Vout) of 400 [V] from the output terminal tout according to the conditions of the DC voltage V1rms and the winding ratio RN = 50% (FIG. 12-a2). reference).

  On the other hand, when the plug-in electric vehicle is used in Japan, a commercial power plug of AC 200 [V] is connected to the input connector tin of the in-vehicle charging device BCS1 (see FIG. 11). In this case, as shown in FIG. 12 (b1), the applied voltage of the commercial power supply ACt2 is smoothed to the input voltage Vin that varies between about 282 [V] and 245 [V]. Hereinafter, the effective value of the input voltage Vin in FIG.

  In this case, the signal processing device CNT1 drives the drive circuit Dr in a predetermined mode, recognizes the input voltage Vin related to AC200 [V], and switches the energization path of the relay circuit Ryl toward the output terminal t2. Accordingly, in the primary coil L1, the energizing section is set to a section (ts to tb) in which the winding is halved, whereby the winding ratio RN is set to 100% in the transformer Tc. The in-vehicle charging device BCS1 outputs a charging voltage (output voltage Vout) according to the conditions of the DC voltage V2rms and the winding ratio RN = 100%. The charging voltage is proportional to the effective value of the input voltage Vin and inversely proportional to the winding ratio RN, and the output voltage Vout is also controlled to 400 [V] (see FIG. 12-b2).

  Thus, when there is a possibility that the plug-in electric vehicle is used in both Europe and Japan, the plug-in electric vehicle is charged in any of these countries by providing the center tap Tg in the transformer Tc. It becomes possible.

  In addition, there are many electric power companies that supply three-phase AC power in various countries around the world. As in this embodiment, the in-vehicle charging device BCS1 with a three-phase rectifier bridge is very useful in each country. It becomes highly practical.

  Further, in the case of adopting a capacitor input type circuit configuration in the prior art, in order to design so that commercial power of both AC 400 [V] and AC 200 [V] can be input, smoothing of the input side is required. The capacitor had to be selected according to AC400 [V], leading to an increase in the size of the device and an increase in cost.

  On the other hand, according to the in-vehicle charging device BCS1 according to the present embodiment, the smoothing capacitor on the input side is omitted by adopting the one-converter circuit configuration. Therefore, even if it is designed to be able to input both AC400 [V] and AC200 [V] commercial power supplies, the physique of the device is not affected by the commercial power supply voltage value (input value). It becomes possible to design freely. That is, the in-vehicle charging apparatus according to the present embodiment can be downsized from the technical aspect, and the cost can be kept low. Further, since the smoothing capacitor on the input side is omitted, the harmonic problem is solved, and a complicated circuit configuration such as a power factor correction circuit or an active filter becomes unnecessary.

  Although the embodiment according to the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the technical idea described in the claims. It is. For example, in the on-vehicle charging device described above, the same charging voltage Vout is obtained for different input power sources by accurately determining the number of windings of the primary coil L1. However, even if the number of turns of the primary coil L1 is not strictly determined, the charging voltage Vout1 converted from one input power supply and the charging voltage Vout2 converted from the other input power supply are controlled to approach a predetermined range. It's enough. However, in such a case, complementary control by the drive circuit Dr or the like is required, so that in the in-vehicle charging device, both output voltages Vout1 and Vout2 are made coincident and charging control that is not affected by the type of commercial power supply Is realized.

  Moreover, in this specification, although the vehicle-mounted charging device has been described in detail as a representative example of the AC-DC converter, the AC-DC converter described in the claims is limited to the charging device. However, the present invention can be widely applied in various technical fields by appropriately changing the form.

  Finally, the gist of the present invention is to apply a switchable transformer to the one-converter system to solve the problem that the circuit configuration is complicated in the prior art, and to make such a simple configuration a harmonic or device. It is the place that leads to the solution of the problem of size etc. at once. In other words, the technical idea is not limited to the combination of the transformer and the one-converter circuit configuration used here, but is intended to exceed the assumptions of those skilled in the art.

BCS1, BCS2 On-vehicle charger (AC-DC converter)
Dbr polyphase diode bridge Tc transformer L1 primary coil L2 secondary coil Dr drive circuit T1 to T4, T5 first switching element Rc (Ryl, Sc1, Sc2) switching circuit Ty, Tz second switching element Sf smoothing circuit

Claims (7)

  A multi-phase diode bridge that rectifies a multi-phase AC voltage, a primary coil having three or more different contact points, and a secondary coil that generates an induced electromotive force in accordance with fluctuations in the primary current flowing through the primary coil. A drive circuit that has a first switching element that intermittently controls energization or interruption of the primary current, and that varies the current value of the primary current according to the operation of the first switching element, A switching circuit that is connected to a plurality of contact points out of three or more contact points and selectively switches energization of any one of the plurality of contact points, thereby switching an energization section in which the primary current flows through the primary coil; and An AC-DC converter comprising a smoothing circuit for smoothing an induced electromotive force. A multi-phase diode bridge that rectifies a multi-phase AC voltage, a primary coil having three or more different contact points, and a secondary coil that generates an induced electromotive force in accordance with fluctuations in the primary current flowing through the primary coil. A transformer, a switching circuit having a second switching element provided corresponding to a plurality of contact points among the three or more contact points, and a smoothing circuit for smoothing the induced electromotive force,
The switching circuit is
By selectively driving any one of the second switching elements, the energization section of the primary current is switched, and the primary current is applied to the switching elements that are selectively driven among the second switching elements. An AC-DC converter characterized by intermittently controlling interruption.   The switching circuit sets the energization section long in a scene where a first multiphase AC voltage having a high effective value is input, and the energization section in a scene where a second multiphase AC voltage having a low effective value is input. The AC-DC converter according to claim 1, wherein the AC-DC converter is set to be short. The effective value of the first multiphase AC voltage is V1rms, the effective value of the second multiphase AC voltage is V2rms, and the first multiphase AC voltage is set for the first multiphase AC voltage by the switching circuit. N1a is the number of turns of the primary coil wound in the current-carrying section, and the number of turns of the primary coil that is wound in the second current-carrying section set for the second multiphase AC voltage by the switching circuit. Is N1s,
The AC-DC converter according to claim 3, wherein these values satisfy a relationship of V1rms / N1a = V2rms / N1s. In a case where a relationship is assumed in which the effective value of the first multiphase AC voltage is approximately twice the effective value of the second multiphase AC voltage,
The primary coil of the transformer includes a first end point connected to a contact point at one end, a second end point connected to a contact point at the other end, and a winding from the first end point to the second end point. The AC-DC converter according to claim 3, further comprising a center tap that is electrically connected to a contact point that equally divides the line.   6. The AC according to claim 1, wherein the AC is mounted on a plug-in electric vehicle capable of inputting commercial power, and is used as a vehicle-mounted charging device that charges a vehicle-mounted battery based on the commercial power. DC converter.   The AC-DC converter according to claim 6, wherein the commercial power is supplied from a three-phase AC power source.

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