JP6305861B2 - Power transmission equipment - Google Patents

Description

  The present invention relates to a power transmission device capable of supplying power generated by a DC power source such as a solar power generation device to a commercial power source such as a house and consuming it in a house or the like.

  2. Description of the Related Art Conventionally, there has been proposed an apparatus for transmitting power from a DC power source such as a solar power generation device to a commercial power system connected to an AC power source in phase with the voltage of the AC power source (Patent Document 1). This device converts the magnitude of the voltage of the DC power supply to the magnitude of the voltage required to transmit power to the commercial power system, and controls the AC switch composed of a transistor bridge in synchronization with the voltage of the AC power supply. The AC current is made to flow backwards in phase with the AC power supply.

  In such a device, for example, as shown in FIG. 6, a DC-DC converter 51 using an insulating transformer is used to convert the voltage of the input DC power supply 50. The DC-DC converter 51 has a closed state in which the current of the DC power supply 50 is caused to flow to the primary side of the insulating transformer by a switching element 52 such as a transistor, and energy accumulated in the closed state is released, so that the insulating transformer Switch to the open state in which current flows to the secondary side.

Japanese Patent No. 3478338

  When this apparatus is connected to the commercial power system 53, the current is reversely flowed in phase with the sine wave voltage of the system. In order to increase the power factor of this device, it is preferable that the current waveform to be reversely flowed is a sine wave similar to the system voltage.

  FIG. 7 is a diagram illustrating a waveform of a current flowing backward in the commercial power system. According to the figure, the pulse width of the switch open / close signal near the apex 54a of the sine wave 54 is insufficient and the waveform is distorted. In order to increase the pulse width, for example, the time constant of the CR integration circuit may be increased to delay the rise of the pulse. However, since the discharge is also delayed, the improvement in the power factor of the apparatus could not be sufficiently handled.

  An object of the present invention is to provide a power transmission device capable of reducing the distortion of a current waveform and improving the power factor of the device while ensuring a necessary pulse width.

The power transmission device of the present invention is a power transmission device that is connected between an AC wiring system 2 connected to an AC power source 3 and a DC power source 1 and transmits power from the DC power source 1 to the AC wiring system 2.
AC power supply voltage signal generating means 10 connected to the AC wiring system 2 and detecting the polarity and magnitude of the voltage in the AC wiring system 2 to generate an AC power supply voltage signal;
In accordance with the change in polarity and magnitude of the voltage detected by the AC power supply voltage signal generation means 10, the connection between the DC power supply 1 and the AC wiring system 2 is repeatedly opened and closed, and the DC power output from the DC power supply 1. Power conversion means 7 for converting the power into AC power;
A DC voltage conversion unit 6 that includes an insulating transformer that insulates the input side and the output side, converts the DC voltage of the DC power supply 1 and applies it to the power conversion means 7;
A switching element 11 for switching between a closed state in which the DC voltage of the DC power source 1 is applied to the input side of the DC voltage converter 6 and an open state in which the DC voltage is not applied;
Switch opening / closing signal generating means 12 for generating a switch opening / closing signal for opening / closing the switching element 11;
The switch opening / closing signal generating means 12
A control signal generator 14 for generating a control signal composed of a predetermined pulse signal;
A delay signal generating means 15 for generating a delay signal in which the rising edge of the control signal is delayed when the control signal is input;
When the delay signal generated by the delay signal generating means 15 has a value corresponding to the magnitude of the voltage of the AC power supply voltage signal 10, the control signal is caused to fall so that the control signal becomes the switch open / close signal. Width determining means 16;
The delay signal generation unit 15 includes a delay signal delay unit 15b that further delays the rising of the delay signal according to the magnitude of the voltage of the AC power supply voltage signal generated by the AC power supply voltage signal generation unit 10. And
As the AC power source 3, for example, a commercial power source with an AC voltage of 100V is applied.
As the DC power source 1, for example, a solar power generation device or a battery is applied.
The predetermined pulse signal is determined by the magnitude of the voltage generated by the AC power supply voltage signal generation means 10, for example, the amplitude.

According to this configuration, the AC power supply voltage signal generation means 10 connected to the AC wiring system 2 detects the polarity and magnitude of the voltage in the AC wiring system 2. The power conversion means 7 adjusts the polarity and magnitude of the voltage to the sine wave voltage of the AC wiring system 2, so that the connection between the DC power supply 1 and the AC wiring system 2 is made according to the detected polarity and magnitude of the voltage. Repeat opening and closing.
The DC voltage converter 6 converts the DC voltage of the DC power supply 1 into a voltage and applies it to the power converter 7. The DC voltage conversion unit 6 is in a closed state in which the DC voltage of the DC power source 1 is applied to the input side of the insulation transformer by the switching element 11, and the energy accumulated in this closed state is released, and a current is output to the output side of the insulation transformer. Switch to open state. The switch opening / closing signal generating means 12 generates a switch opening / closing signal for opening / closing the switching element 11.

  The control signal generator 14 in the switch opening / closing signal generator 12 generates a control signal composed of a predetermined pulse signal. The rise time of the control signal is determined by, for example, the frequency of the control signal (for example, about several tens of kHz to several hundreds of kHz) set sufficiently higher than the frequency of the AC power supply 3 (for example, 50 Hz or 60 Hz). . The delay signal generation means 15 receives the generated delay signal and generates a delay signal in which the rise of the control signal is delayed. The delayed signal whose rise is delayed refers to a signal in which the output voltage gradually increases from zero as time passes after the control signal is input.

  The pulse width determining means 16 determines that the delay signal is a value corresponding to the magnitude of the voltage of the AC power supply voltage signal (this corresponding value is a value proportional to the magnitude of the AC power supply voltage. Then, it is determined and adjusted while observing the current waveform to be reversely flowed to the control circuit). Then, the control signal falls and the control signal becomes the switch open / close signal.

  The delay signal delay unit 15b in the delay signal generation unit 15 further delays the rise of the delay signal in accordance with the voltage level of the AC power supply voltage signal generated by the AC power supply voltage signal generation unit 10. For example, the charging current of the capacitive element 20 of the CR integration circuit is reduced, the discharge current of the capacitive element 20 is increased, and the rise of the delay signal is delayed and the fall is accelerated. As a result, a sufficient pulse width of the switch opening / closing signal can be secured, and a sine wave current with less sine wave distortion can be flowed. Therefore, the power factor of the device can be increased.

  The AC power supply voltage signal may be generated by being insulated from the AC power supply 3 using an insulating transformer. In this case, the insulation transformer can insulate between the primary coil and the secondary coil to prevent primary noise from being directly conducted to the secondary side, and safety can be improved.

The delay signal generation means 15 may include an integration circuit 15a that generates a delay signal in which the rising of the input control signal is delayed. In this case, the delay signal can be easily and reliably generated by the integrating circuit 15a.
The integration circuit 15a may be a circuit in which a first resistance element 19 and a capacitance element 20 are connected in series (CR integration circuit). When a voltage is applied to the input side of the CR integration circuit, electric charge is accumulated in the capacitive element 20 that is a capacitor. The charge accumulated in the capacitor element 20 can be released by the first resistance element 19. As the electric charge accumulates in the capacitive element 20, the current flowing into the capacitive element 20 is reduced, thereby generating a delayed signal in which the rise of the control signal is delayed.

The delay signal delay unit 15b includes a second resistance element 23 and a rectifier that make the charging current of the capacitive element 20 smaller than a first threshold and the discharging current of the capacitive element 20 larger than a second threshold. The element 24 may be included.
The first and second threshold values are determined based on results of experiments, simulations, and the like, for example.

  In this case, at the rise of the control signal, for example, a part of the charging current of the capacitive element 20 that flows through the first resistive element 19 flows into the second resistive element 23, whereby the second resistive element 23 and the rectifying element Compared with the case where 24 is not provided, the charging current of the capacitive element 20 becomes smaller and the rise of the control signal is delayed. At the falling edge of the control signal, for example, the discharge current of the capacitive element 20 flows through the first and second resistive elements 19 and 23, so that the capacitive element is more than when there is no second resistive element 23 and rectifying element 24. The discharge current of 20 becomes large and the fall of the control signal becomes quick. As a result, the power factor of the apparatus can be improved by reducing distortion of the current waveform while ensuring the necessary pulse width.

The power transmission device of the present invention is a power transmission device that is connected between an AC wiring system connected to an AC power source and a DC power source, and transmits power from the DC power source to the AC wiring system. AC power supply voltage signal generating means connected to generate an AC power supply voltage signal by detecting the polarity and magnitude of the voltage in the AC wiring system, and the polarity and magnitude of the voltage detected by the AC power supply voltage signal generating means In accordance with the change in power, the DC power source and the AC wiring system are repeatedly opened and closed to convert the DC power output from the DC power source into AC power, and the insulating transformer that insulates the input side from the output side. A DC voltage converter that converts the DC voltage of the DC power supply and applies it to the power conversion means, and a DC voltage of the DC power supply on the input side of the DC voltage converter Comprising a switching element to switch to the open state of not applying the closed state of pressure, and a switch-off signal generating means for generating a switch-off signal for opening and closing the switching element.
The switch opening / closing signal generating means includes a control signal generating section for generating a control signal composed of a predetermined pulse signal, and a delay signal generating means for generating a delay signal in which the control signal is input and the rise of the control signal is delayed. And when the delay signal generated by the delay signal generating means has a value corresponding to the magnitude of the voltage of the AC power supply voltage signal, the control signal is caused to fall and the control signal becomes the switch open / close signal. Width determining means. The delay signal generation unit includes a delay signal delay unit that further delays the rising of the delay signal according to the voltage level of the AC power supply voltage signal generated by the AC power supply voltage signal generation unit.
For this reason, it is possible to reduce the distortion of the current waveform and improve the power factor of the apparatus while ensuring the necessary pulse width.

1 is a circuit diagram of a power transmission device according to an embodiment of the present invention. It is a block diagram which expands and shows the principal part of the power transmission device. It is a circuit diagram which shows the principal part structures, such as a delay signal production | generation means in the power transmission apparatus. It is a figure explaining the state which compares the magnitude | size of a delay signal and the voltage of an alternating current power supply voltage signal, and produces | generates a switch opening / closing signal by the power transmission apparatus. It is a figure which shows the state which reduced the distortion of the current waveform of the sine wave current with the power transmission apparatus. It is a circuit diagram of the conventional power transmission apparatus. It is a figure which shows the waveform of the electric current which is flowing backward into the conventional commercial power system.

A power transmission apparatus according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a circuit diagram of the power transmission device. This power transmission device transmits power from a DC power source 1 to an AC wiring system 2 serving as an indoor wiring. This power transmission device can be consumed in a house by supplying power generated by a DC power source 1 such as a solar power generator to an AC wiring system 2 such as in a house connected to an AC commercial power source. It is.

  The power transmission device is connected between the AC wiring system 2 connected to the AC power source 3 and the DC power source 1. The AC wiring system 2 is connected to a single-layer AC power supply 3 via a distribution board 4 such as a house. The voltage in the wiring on the indoor side of the distribution board 4 in the house or the like actually fluctuates depending on the usage state of the connected electrical equipment, but in a general home, there are some voltage fluctuations and voltage waveform fluctuations. And frequency fluctuations do not affect the operation of electrical equipment. Therefore, there is no problem even if the DC power generated by the DC power source 1 is converted into AC power by a DC voltage conversion unit, power conversion means, or the like having a simple configuration and consumed in a house.

  As the AC power source 3, for example, a commercial power source with an AC voltage of 100V is applied. As the DC power source 1, for example, a battery of a solar power generation device, other batteries, or the like (for example, a battery of an electric vehicle connected to a distribution board such as a house) is applied. A load facility 5 is connected to the AC wiring system 2. The DC power generated by the DC power source 1 is converted into AC power as will be described later, and this AC power is supplied to the load facility 5.

  The power transmission apparatus includes a DC voltage converter 6, a rectifier circuit 8, a power converter 7, an AC voltage converter 9, an AC power supply voltage signal generator 10, a switching element 11, and a switch open / close signal generator 12. And a plug 22. This power transmission device can consume the power generated by the DC power source 1 in a house or the like only by inserting the plug 22 connected to the output side of the power conversion means 7 into the outlet 21 in the AC wiring system 2. The outlet 21 may be an arbitrary outlet in the AC wiring system 2.

  In this example, the DC voltage converter 6 is an insulating flyback converter including a first insulating transformer that insulates the input side and the output side. The primary coil 6 a of the DC voltage converter 6 and the switching element 11 are connected in series to a terminal of the DC power supply 1. The DC voltage conversion unit 6 converts, for example, the DC voltage of the DC power supply 1 into a boosted DC voltage, and applies it to the power conversion means 7 described later via the rectifier circuit 8. The voltage of the electric power generated by the solar power generation device is about DC35V, but the DC voltage converter 6 boosts the DC voltage of about DC35V to about DC100V.

  In this DC voltage conversion unit 6, when the DC voltage of the DC power source 1 is applied to the primary coil 6a (input side) by the switching element 11, the current flows through the primary coil 6a and is generated. The core is magnetized by the magnetic flux. When the switching element 11 is opened (off), the energy accumulated in the core is released, and a current flows through the secondary coil 6b (output side). In this DC voltage conversion unit 6, a reverse magnetic field is applied with a reverse magnetic field, and the switching element 11 is turned on and off as described above, thereby generating an induced electromotive force in the third quadrant. Therefore, the secondary coil voltage can be greatly changed with respect to the change of the primary coil voltage.

  The power conversion means 7 repeatedly opens and closes the connection between the DC power supply 1 and the AC wiring system 2 to convert the DC power output from the DC power supply 1 into AC power. The power conversion means 7 includes a bridge 7a including a plurality of switching elements 13 and a bridge controller 7b that controls the bridge 7a. Between the connection between the bridge 7 a and the AC wiring system 2, an AC voltage conversion unit 9 including a second insulating transformer that insulates the input side and the output side is connected.

  In the AC voltage converter 9, the AC voltage from the AC wiring system 2 is transformed according to the turn ratio of the primary coil 9a and the secondary coil 9b. The AC voltage output from the AC voltage conversion unit 9 is generated by being insulated from the AC power source 3 using a second insulating transformer. The AC power supply voltage signal generation means 10 detects the polarity and magnitude of the AC voltage transformed by the AC voltage converter 9, and generates a full-wave rectified AC power supply voltage signal (commercial power system voltage signal). The bridge control unit 7b converts the DC power into AC power by performing control to repeatedly open and close the plurality of switching elements 13 in accordance with the polarity and magnitude of the voltage detected by the AC power supply voltage signal generation means 10.

  FIG. 2 is an enlarged block diagram illustrating a main part of the power transmission apparatus. The switch opening / closing signal generating means 12 is connected between the AC power supply voltage signal generating means 10 and the switching element 11. The switch open / close signal generating means 12 is a means for generating a switch open / close signal for opening and closing the switching element 11, and includes a control signal generating unit 14, a delay signal generating means 15, and a pulse width determining means 16. The control signal generation unit 14 generates a control signal composed of a predetermined pulse signal. The rise time of the control signal is determined by, for example, a frequency (for example, about several tens of kHz to several hundreds of kHz) set higher than the frequency (for example, 50 Hz or 60 Hz) of the AC power supply 3 (FIG. 1).

  The delay signal generation means 15 generates a delay signal in which the control signal is input and the rise of the control signal is delayed. The delay signal generation unit 15 includes an integration circuit 15a and a delay signal delay unit 15b. As shown in FIG. 3, the integration circuit 15a is a so-called CR integration circuit in which a first resistance element 19 and a capacitance element 20 are connected in series. When the voltage Vi is applied to the input side of the integrating circuit 15a, electric charge is accumulated in the capacitive element 20 which is a capacitor. As the electric charge accumulates in the capacitive element 20, the current flowing into the capacitive element 20 is reduced, thereby generating a delayed signal in which the rise of the control signal is delayed. The electric charge accumulated in the capacitive element 20 can be released by the first resistance element 19 and a second resistance element 23 described later.

The delay signal delay unit 15b further delays the rise of the delay signal according to the voltage level of the AC power supply voltage signal generated by the AC power supply voltage signal generation means 10. The delay signal delay unit 15b includes a second resistance element 23 and a rectifying element 24 connected in series. The second resistance element 23 and the rectifying element 24 are connected between the first resistance element 19 and the capacitive element 20 in the integrating circuit 15 a and across the AC power supply voltage signal generating means 10. The AC power supply voltage signal (commercial power system voltage signal * 2) from the second resistance element 23 and the rectifying element 24 to the AC power supply voltage signal generation means 10 is transmitted from the AC power supply voltage signal generation means 10 to the control signal generation unit 14 (FIG. This is an inversion of the AC power supply voltage signal (commercial power system voltage signal * 1) leading to 2).
Since the commercial power system voltage signal * 2 inverts the commercial power system voltage signal * 1, the phase is shifted by 180 °. The amplitude is determined by adjustment.
The commercial power system voltage signal * 1 is a waveform obtained by full-wave rectification of a sine wave. Since the commercial power system voltage signal * 2 is inverted, the commercial power system voltage signal * 2 has a waveform obtained by full-wave rectification on the negative side. Accordingly, as the commercial power system voltage signal * 1 is higher (value is positive), the value of the commercial power system voltage signal * 2 is smaller (value is negative). Therefore, the higher the commercial power system voltage signal * 1 is, the larger the current drawn by the delay signal delay unit is, and the delay time can be increased.

  At the rise of the control signal, a part of the charging current of the capacitive element 20 flowing through the first resistive element 19 flows to the second resistive element 23, so that the second resistive element 23 and the rectifying element 24 are absent. As a result, the charging current of the capacitive element 20 becomes smaller and the rise of the control signal is delayed. At the falling edge of the control signal, the discharge current of the capacitive element 20 flows through the first and second resistive elements 19 and 23, so that the capacitive element 20 can be obtained more than when the second resistive element 23 and the rectifying element 24 are not provided. Discharge current increases and the fall of the control signal becomes faster.

  As shown in FIG. 2, the pulse width determining unit 16 causes the control signal to fall when the delay signal generated by the delay signal generating unit 15 has a value corresponding to the magnitude of the voltage of the AC power supply voltage signal. The control signal is a switch open / close signal. The pulse width determining means 16 performs PWM control to reduce the pulse width when the voltage of the AC power supply voltage signal is low, and to increase the pulse width when the voltage of the AC power supply voltage signal is high, so that the AC power supply 3 (FIG. A current having a magnitude corresponding to the voltage of 1) is reversed.

The pulse width determination unit 16 includes a comparison unit 17 and a processing unit 18.
FIG. 4 is a diagram illustrating a state in which a switch open / close signal is generated by comparing the delay signal and the voltage level of the AC power supply voltage signal by the power transmission device. As shown in FIGS. 2 and 4, the comparison unit 17 compares the delay signal generated by the delay signal delay unit 15 b with the voltage level of the AC power supply voltage signal. When the comparison unit 17 determines that the delay signal is larger than the voltage of the AC power supply voltage signal, the processing unit 18 causes the control signal to fall and use the control signal as a switch open / close signal.

  According to the power transmission apparatus described above, the integration circuit 15a in the delay signal generation unit 15 generates a delay signal whose rise of the control signal is delayed. Due to the delay signal delay unit 15b in the delay signal generation means 15, the rise of the control signal is further delayed and the fall of the control signal is accelerated. As a result, while ensuring the necessary pulse width, it is possible to reduce the distortion of the current waveform 25 and improve the power factor of the apparatus as shown in FIG.

  As shown in FIG. 1, since the DC power generated by the DC power source 1 can be converted into AC power, supplied to the load facility 5 and consumed in the house, for example, an electricity bill charged by a power company or the like Can be reduced. Since the DC voltage conversion unit 6 and the power conversion unit 7 can be easily configured, for example, the cost of the power transmission device can be reduced rather than using a power conditioner.

  As long as there is no problem in law, the power transmission device of the present invention can supply electric power generated by a DC power source to an AC commercial power source outside the house and ask an electric power company to purchase it.

DESCRIPTION OF SYMBOLS 1 ... DC power supply 2 ... AC wiring system 3 ... AC power supply 6 ... DC voltage conversion part 7 ... Power conversion means 10 ... AC power supply voltage signal generation means 11 ... Switching element 12 ... Switch opening / closing signal generation means 14 ... Control signal generation part 15 ... delay signal generation means 15a ... integration circuit 15b ... delay signal delay unit 16 ... pulse width determination means 19 ... first resistance element 20 ... capacitance element 23 ... second resistance element 24 ... rectifier element

Claims (5)

A power transmission device connected between an AC wiring system connected to an AC power source and a DC power source, and transmits power from the DC power source to the AC wiring system,
AC power supply voltage signal generating means connected to the AC wiring system and detecting the polarity and magnitude of the voltage in the AC wiring system to generate an AC power supply voltage signal;
According to the change in polarity and magnitude of the voltage detected by the AC power supply voltage signal generating means, the connection between the DC power supply and the AC wiring system is repeatedly opened and closed, and the DC power output from the DC power supply is changed to AC power. Power conversion means for converting;
A DC voltage conversion unit that includes an insulating transformer that insulates the input side and the output side, converts the DC voltage of the DC power supply to be applied to the power conversion unit, and
A switching element that switches between a closed state in which the DC voltage of the DC power supply is applied to the input side of the DC voltage converter and an open state in which the DC voltage is not applied
A switch opening / closing signal generating means for generating a switch opening / closing signal for opening / closing the switching element,
This switch open / close signal generating means
A control signal generator for generating a control signal composed of a predetermined pulse signal;
A delay signal generating means for generating a delay signal in which the rising edge of the control signal is delayed when the control signal is input;
When the delay signal generated by the delay signal generating means has a value corresponding to the voltage level of the AC power supply voltage signal, the control signal is caused to fall so that the control signal becomes the switch open / close signal. Means,
The delay signal generation unit includes a delay signal delay unit that further delays the rising edge of the delay signal according to the magnitude of the voltage of the AC power supply voltage signal generated by the AC power supply voltage signal generation unit. apparatus.   The power transmission apparatus according to claim 1, wherein the AC power supply voltage signal is generated by being insulated from the AC power supply using an insulating transformer.   3. The power transmission device according to claim 1, wherein the delay signal generation unit includes an integration circuit that generates a delay signal in which a rising edge of an input control signal is delayed.   4. The power transmission device according to claim 3, wherein the integration circuit includes a first resistance element and a capacitance element connected in series. 5.   5. The power transmission device according to claim 4, wherein the delay signal delay unit is configured to reduce a charging current of the capacitive element to be smaller than a first threshold value and to increase a discharging current of the capacitive element to be larger than a second threshold value. Power transmission device having a resistance element and a rectifying element.

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