JP6350818B2 - Non-contact power transmission device - Google Patents

Description

  The present invention relates to a switching power supply, and more particularly to a contactless power transmission device.

  As an example of a conventional non-contact power transmission apparatus, there is a method provided by Japanese Patent Publication No. 2007-312585. One of the circuit diagrams shown as the embodiment is shown in FIG.

  In FIG. 8, 111 is an AC power source, 112 and 113 are MOSFETs constituting a bidirectional switch circuit, 114 and 115 are MOSFETs constituting another bidirectional switch circuit, and 116 is for turning on and off four MOSFETs in a predetermined sequence. This is an oscillation control circuit. Reference numerals 117, 118, 119, and 120 denote insulating buffers for sending signals to gates having different potentials. 121 and 122 transmit electromagnetic energy by a power transmission coil and a power reception coil. Reference numeral 123 denotes a rectifying / smoothing circuit which converts it into a DC voltage. A constant voltage circuit 124 supplies a stable DC voltage to the load 125.

  Since the transmission between the power transmission coil 121 and the power reception coil 122 is one-way, the output voltage of the rectifying and smoothing circuit 123 varies depending on the current flowing through the load. Therefore, although a constant voltage circuit is required, the input voltage range which the constant voltage circuit 124 bears is wide because of the large change width.

  The present invention provides a non-contact power transmission device in which a rectifying / smoothing circuit on a power receiving side has a function of stabilizing a DC voltage, and thus there is no need to add a constant voltage circuit corresponding to a wide input voltage range on the power receiving side. The purpose is that.

  The invention according to claim 1 is an AC power supply, a first capacitor, a series circuit composed of first and second bidirectional switch circuits connected in parallel to the AC power supply, and a first circuit connected in parallel to the AC power supply. An oscillation control circuit for alternately turning on / off a series circuit composed of 3 and a fourth bidirectional switch circuit, a set of first and fourth bidirectional switch circuits, and a set of second and third bidirectional switch circuits A series circuit including a power transmission coil and a power transmission capacitor connected between a connection point of the first and second bidirectional switch circuits and a connection point of the third and fourth bidirectional switch circuits, and the power transmission coil and the power transmission Connected between one terminal of the first circuit and the first circuit of the series circuit consisting of the receiving coil and the receiving capacitor that are electromagnetically coupled to the series circuit consisting of the capacitor, and the series circuit consisting of the receiving coil and the receiving capacitor Was A first diode, a second diode connected between the other terminal of the series circuit consisting of the receiving coil and the receiving capacitor and the other terminal of the first capacitor, a series circuit consisting of the receiving coil and the receiving capacitor, A connection point of the first diode, a third diode connected between the connection point of the second diode and the first capacitor, a series circuit composed of the receiving coil and the receiving capacitor, and a connection point of the second diode In a non-contact power transmission device including a fourth diode connected between a connection point of one diode and a first capacitor, a fifth switching element is connected in parallel to the first diode, and the second diode The sixth switch element is connected in parallel to the third diode, the seventh switch element is connected in parallel to the third diode, and the eighth switch element is connected in parallel to the fourth diode. When the output voltage of the AC power supply is a positive half wave, the fifth and sixth switch elements are turned on and off in synchronization with the first and fourth bidirectional switch circuit sets. The seventh and eighth switch element sets are turned on / off in synchronization with the on / off of the second and third bidirectional switch circuit sets, and the output voltage of the AC power supply is between the negative half-waves. Synchronizes with the on / off of the first and fourth bidirectional switch circuit sets to turn on / off the seventh and eighth switch element sets, and the second and third bidirectional switch circuit sets. A synchronous drive circuit for turning on / off the set of the fifth and sixth switch elements in synchronization with on / off is added.

  According to a second aspect of the present invention, each of the first to fourth bidirectional switch circuits is composed of two MOSFETs connected in series in opposite directions, and a positive half wave and a negative half wave of the voltage of the AC power supply. Of an oscillation control circuit for turning on / off the two signals output from the AC phase identification circuit and the first to fourth bidirectional switch circuits. The signals are synthesized by an OR circuit to form four types of signals, which are applied to predetermined gates of MOSFETs constituting the first to fourth bidirectional switch circuits.

  In the third aspect of the invention, the third bidirectional switch circuit is replaced with a second capacitor, and the fourth bidirectional switch circuit is replaced with a third capacitor.

  According to a fourth aspect of the present invention, the parallel circuit composed of the fourth diode and the eighth switch element is replaced with the fourth capacitor, and the parallel circuit composed of the second diode and the sixth switch element is replaced with the fifth capacitor. Replaced.

  In the invention according to claim 5, a PWM circuit for controlling the width of a pulse generated by the synchronous drive circuit is added to stabilize the voltage of the first capacitor.

  In the invention according to claim 6, the series circuit composed of the power receiving coil and the power receiving capacitor is replaced with a parallel circuit composed of the power receiving coil and the power receiving capacitor.

  Since the non-contact power transmission device of the present invention can generate a stable DC voltage without a constant voltage circuit on the power receiving side, the efficiency is improved, the space inside the device on the power receiving side is vacant, and the cost is reduced.

  By appropriately controlling the pulse width generated by the synchronous drive circuit on the power receiving side, the waveform of the AC current supplied from the AC power supply on the power transmission side can be made similar to the waveform of the AC voltage, thereby improving the power factor. be able to.

  The best mode for carrying out the invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram showing an embodiment of the present invention.
In the figure, 1 is an AC power source, 3 to 6 are bidirectional switch circuits, 11 is an oscillation control circuit, 12 is a power transmission coil, 13 is a power transmission capacitor, 14 is a power reception coil, 15 is a power reception capacitor, 16 to 19 are diodes, 20 to 20 Reference numeral 23 is a switch element, 24 is a synchronous drive circuit, and 101 to 108 are insulating buffers.
The oscillation control circuit 11 outputs a signal Lo from the two output terminals M and N when M is Hi and M is Lo when N is Hi. M and N do not output a Hi signal at the same time, but may output a Lo signal at the same time. Both M and N call the Lo period the dead time.

  When M is Hi, the bidirectional switch circuits 3 and 6 are turned on, and an AC voltage is applied to both ends of the series circuit of the power transmission coil 12 and the power transmission capacitor 13 in the same direction. Subsequently, when N becomes Hi, the bidirectional switch circuits 4 and 5 become conductive, and an AC voltage is applied to the opposite ends of the series circuit of the power transmission coil 12 and the power transmission capacitor 13 in the opposite direction.

  If the operation of the synchronous drive circuit 24 is stopped, the diodes 16 to 19 rectify and charge the first capacitor 2. If a load is connected to the first capacitor 2, DC power is supplied to the load. When the load is no load or light load, the voltage of the first capacitor 2 increases depending on the resonance condition between power transmission and reception, and cannot be controlled.

  The operation of the synchronous drive circuit 24 will be described with reference to FIG. FIG. 7 shows a waveform diagram of the circuit of FIG. 1, wherein (a) shows the waveform of each part during the positive half wave of the AC voltage and (b) shows the waveform of each part during the half wave of the AC voltage negative. From the top, the gate voltage of the first and fourth bidirectional switch circuits 3 and 6, the gate voltage of the second and third bidirectional switch circuits 4 and 5, the voltage across the series circuit of the receiving coil 14 and the receiving capacitor 15, The waveforms of the gate voltages of the fifth and sixth switch elements 20 and 21 and the gate voltages of the seventh and eighth switch elements 22 and 23 are shown. Ton1 and Td1 are the pulse width and dead time set in the oscillation control circuit 11, and Ton2 and Td2 are the pulse width and delay time set by the synchronous drive circuit 11.

  Although the voltage of the series circuit of the power receiving coil 14 and the power receiving capacitor 15 changes when any one of the first to fourth bidirectional switch circuits on the power transmission side is switched from the on state to the off state, FIG. Then, when the second and third bidirectional switch circuits are switched off, they are switched from negative to positive. In FIG. 7B, the second and third bidirectional switch circuits are switched from positive to negative when switched off.

  In FIG. 7A, when the voltage across the series circuit of the power receiving coil 14 and the power receiving capacitor 15 changes from negative to positive, the synchronous drive circuit 24 generates a pulse with a width Td2 delayed by Ton2, and outputs the fifth and sixth pulses. The gates of the switch elements 20 and 21 are driven. When the voltage across the series circuit of the power receiving coil 14 and the power receiving capacitor 15 changes from positive to negative, a pulse with a width delayed by Td2 is generated to drive the gates of the seventh and eighth switch elements 18 and 19. If the synchronous drive circuit 24 outputs a pulse in this way, the on / off of the bidirectional switch circuit on the power transmission side and the switch element on the power reception side are synchronized. In FIG. 7, Td2 is set to the same value as Td1, and Ton2 is set to a value smaller than Ton1.

  As shown in the waveform of FIG. 7, when the phase of the AC voltage changes from positive to negative, the set on the power receiving side is switched to the set on on the power transmission side.

  Since the bidirectional switch circuit that is turned on on the power transmission side and the switch element that is connected in parallel with the diode that is conducting at that time are turned on in synchronization, the voltage of the first capacitor 2 can be increased. For example, the energy is regenerated from the power receiving side to the power transmitting side.

FIG. 2 is a circuit diagram showing an embodiment of the second aspect of the present invention.
Components common to those in FIG. 1 are the same as those in FIG. In the figure, reference numeral 25 denotes an AC phase identification circuit. If the voltage of the AC power supply 1 is positive, the terminal P is Hi, the terminal S is Lo, and if it is negative, the terminal P is Lo and the terminal S is Hi.

  The output signal of the AC phase identification circuit and the output signal of the oscillation control circuit 11 are combined into four types of signals by the OR circuits 26 to 29 and supplied to the gates of the MOSFETs constituting the bidirectional switch circuits 3 to 6. If a Hi signal is output from the terminal P of the AC phase circuit, the MOSFETs 3b, 4b, 5b, and 6b are turned on regardless of the signal of the oscillation control circuit 11. If a Hi signal is output from the terminal S, the MOSFETs 3a, 4a, 5a and 6a are turned on regardless of the signal of the oscillation control circuit 11.

  When the terminals M and N of the oscillation control circuit 11 are both Lo, that is, when the dead time is reached, any of the MOSFETs in which the energy accumulated in the series circuit of the power transmission coil 12 and the power transmission capacitor 13 is on And is regenerated to the AC power supply 1 through a parasitic diode of a MOSFET connected in series with the MOSFET.

  The mechanism regenerated on the power transmission side when the voltage of the first capacitor 2 is high is the same as that in FIG.

FIG. 3 is a circuit diagram showing an embodiment of the third aspect of the present invention. Components common to those in FIG. 2 are the same as those in FIG. In the figure, a second capacitor 31 and a third capacitor 32 divide the voltage of the AC power supply 1 into two equal parts. Since both capacitors are selected to be larger than the capacity of the power transmission capacitor 13, they do not affect the resonance period of the circuit.
The circuit configuration of FIG. 2 is called a full bridge, whereas the circuit configuration of FIG. 3 is called a half bridge.

  FIG. 4 is a circuit diagram showing an embodiment of the invention as set forth in claim 4. Components common to those in FIG. 2 are the same as those in FIG. In the figure, the capacitor 33 is charged when the first diode 16 is turned on, and the capacitor 34 is charged when the third diode 18 is turned on. The first capacitor 2 is charged with the combined voltage of both capacitors.

  FIG. 5 is a circuit diagram showing an embodiment of the invention as set forth in claim 5. Components common to those in FIG. 2 are the same as those in FIG. In the figure, reference numeral 30 denotes a PWM circuit, which widens the pulse generated by the synchronous drive circuit 24 when the voltage of the first capacitor 2 exceeds the reference voltage. If the ON period of the switch element 20 and the switch element 22 becomes longer, the electric power returning from the power receiving side to the power transmission side increases and the voltage of the first capacitor 2 decreases. Thereby, the stability of the voltage of the first capacitor 2 is increased.

  FIG. 6 is a circuit diagram showing an embodiment of the invention as set forth in claim 6. Components common to those in FIG. 2 are the same as those in FIG. In the figure, the power receiving capacitor 15 on the power receiving side is connected to the power receiving coil 14 in parallel.

  In FIG. 1 to FIG. 6, MOSFETs are selected as the fifth to eighth switch elements, so that the first to fourth diodes can be omitted by substituting the parasitic diodes of the MOSFETs.

Industrial applicability

  It is possible to provide a new means for stabilizing the voltage applied to the load, which is one of the problems of the conventional non-contact power transmission apparatus. In addition, since the power factor is improved by the rectifier circuit that receives the transmitted energy by directly switching the alternating current, it is not necessary to insert a power factor improving circuit on both the power transmission side and the power receiving side, thereby reducing the cost. it can. The space on the power receiving side can also be reduced.

It is a circuit diagram which shows one Example of this invention. It is a circuit diagram which shows one Example of this invention. It is a circuit diagram which shows one Example of this invention. It is a circuit diagram which shows one Example of this invention. It is a circuit diagram which shows one Example of this invention. It is a circuit diagram which shows one Example of this invention. It is a wave form diagram of the circuit diagram of FIG. It is a circuit diagram which shows an example of a conventional system.

Brief description of symbols

DESCRIPTION OF SYMBOLS 1 AC power supply 2 1st capacitor 3-6 1st-4th bidirectional switch circuit 11 Oscillation control circuit 12 Power transmission coil 13 Power transmission capacitor 14 Power reception coil 15 Power reception capacitor 16-19 First to fourth diodes 20-23 Fifth to eighth switch elements 24 Synchronous drive circuit 25 AC phase identification circuits 26 to 29 OR circuit 30 PWM circuits 31 to 34 Capacitors 101 to 108 Insulation buffer 111 AC power supply 112 to 115 MOSFET
116 Oscillation control circuits 117 to 120 Insulation buffer 121 Power transmission coil 122 Power reception coil 123 Rectification smoothing circuit 124 Constant voltage circuit 125 Load 126, 127 Capacitor

Claims (6)

  A series circuit composed of an AC power source, a first capacitor, and first and second bidirectional switch circuits connected in parallel to the AC power source, and third and fourth bidirectional switches connected in parallel to the AC power source An oscillation control circuit for alternately turning on and off a series circuit composed of a circuit, a set of the first and fourth bidirectional switch circuits, and a set of the second and third bidirectional switch circuits; From a series circuit including a power transmission coil and a power transmission capacitor connected between a connection point of the second bidirectional switch circuit and a connection point of the third and fourth bidirectional switch circuits, and from the power transmission coil and the power transmission capacitor A series circuit comprising a receiving coil and a receiving capacitor electromagnetically coupled to the series circuit comprising: one terminal of the series circuit comprising the receiving coil and the receiving capacitor; and one end of the first capacitor. And a second diode connected between the other terminal of the first capacitor and the other terminal of the first capacitor, and the receiving coil. A series circuit composed of a power receiving capacitor, a connection point of the first diode, a third diode connected between the connection point of the second diode and the first capacitor, the power receiving coil, and the power receiving capacitor. In a non-contact power transmission device comprising a fourth diode connected between a connection point of a circuit and the second diode and a connection point of the first diode and the first capacitor, the contactless power transmission device is parallel to the first diode. A fifth switch element is connected to the second diode, a sixth switch element is connected in parallel to the second diode, and a seventh switch element is connected to the third diode. And an eighth switch element is connected to the fourth diode. When the output voltage of the AC power source is a positive half-wave, the set of the first and fourth bidirectional switch circuits is turned on / off. The fifth and sixth switch element sets are turned on / off in synchronization with the off state, and the seventh and sixth switch elements are synchronized with the on / off state of the second and third bidirectional switch circuit sets. The switch element group of 8 is turned on / off, and the first and fourth bidirectional switch circuit groups are synchronized with the on / off state of the AC power supply during a negative half-wave output voltage. The set of the fifth and sixth switch elements is synchronized with the on / off of the set of the second and third bidirectional switch circuits by turning on and off the set of the seventh and eighth switch elements. Non-contact power transfer characterized by the addition of a synchronous drive circuit that turns on and off Feeding device.   Each of the first to fourth bidirectional switch circuits is composed of two MOSFETs connected in series in opposite directions, and is synchronized with the phases of the positive half wave and the negative half wave of the voltage of the AC power supply, respectively. An AC phase identification circuit that outputs two signals is added, and the two signals output by the AC phase identification circuit and the signal of the oscillation control circuit that turns on and off the first to fourth bidirectional switch circuits are ORed. 2. The non-contact power transmission apparatus according to claim 1, wherein four types of signals are synthesized by a circuit and applied to predetermined gates of MOSFETs constituting the first to fourth bidirectional switch circuits.   The non-contact power transmission apparatus according to claim 1 or 2, wherein the third bidirectional switch circuit is replaced with a second capacitor, and the fourth bidirectional switch circuit is replaced with a third capacitor.   The parallel circuit composed of the fourth diode and the eighth switch element is replaced with a fourth capacitor, and the parallel circuit composed of the second diode and the sixth switch element is replaced with a fifth capacitor. The non-contact power transmission device according to any one of claims 1 to 3.   5. The non-contact power transmission apparatus according to claim 1, further comprising: a PWM circuit that controls a width of a pulse generated by the synchronous drive circuit in order to stabilize the voltage of the first capacitor.   The non-contact power transmission device according to any one of claims 1 to 5, wherein a series circuit including the power receiving coil and the power receiving capacitor is replaced with a parallel circuit including the power receiving coil and the power receiving capacitor.

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