JP2016025817A - Power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission device capable of stabilizing a circuit operation by suppressing the influence of a switching noise.SOLUTION: A power transmission device is connected between an AC wiring system connected to an AC power source and a DC power source, and transmits an electric power to the AC wiring system from the DC power source. The power transmission device constructs: an AC power source voltage signal forming means 10; electric power converting means; a DC voltage converting part; a switching element 11; and a switch opening/closing signal generating means 12. The switch opening/closing signal generating means 12 includes: a control signal generating part 14 generating a control signal formed by a pulse signal; and a pulse width determination part 15 generating delay signal that rising of the control signal is delay due to an input of the control signal, and setting the control signal as the switch opening/closing signal by falling the control signal when the delay signal becomes a value corresponding to the voltage of AC power source voltage signal.SELECTED DRAWING: Figure 2

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. 5, 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. Therefore, as shown in FIG. 6, PWM control is performed to change the time width t <b> 1 for turning on the switching element connected to the primary side of the insulation transformer in accordance with the system voltage.

  This PWM control is preferably performed using the voltage of the AC power supply on the device output side and the current flowing through the primary side of the isolation transformer. In order to obtain a current signal flowing through the isolation transformer, a shunt resistor 54 connected in series to the transformer is used as shown in FIG. A current signal can be obtained from the voltage across the shunt resistor 54. In consideration of efficiency, it is necessary to make this resistance value as small as possible, but in this case, the current signal becomes small. When PWM control is performed using this current signal, the circuit operation may become unstable due to the influence of switching noise of the switching element 52.

  An object of the present invention is to provide a power transmission device that is less susceptible to switching noise and stabilizes circuit operation.

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;
When the control signal is input, a delay signal in which the rise of the control signal is delayed is generated, and when the delay signal becomes a value corresponding to the magnitude of the voltage of the AC power supply voltage signal, the control signal is caused to fall. A pulse width determination unit 15 using the control signal as the switch open / close signal;
It is characterized by having.
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 power supply 3. 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 source 1 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 pulse width determination unit 15 reduces the pulse width when the voltage of the AC power supply voltage signal is low, and increases the pulse width when the voltage of the AC power supply voltage signal is high. For example, a current having a magnitude corresponding to a high value is reversely flowed. The pulse width determination unit 15 receives the generated control signal and generates a delayed 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 unit 15 determines that the delay signal corresponds 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, the control signal is made to fall and the control signal is used as the switch open / close signal.

  Since the delay signal is generated in this way and the switch signal is generated by comparing this delay signal with the AC power supply voltage signal, the effect of switching noise is greater than that obtained from the current signal from the voltage across the shunt resistor as in the prior art. The circuit operation can be stabilized because it is difficult to receive. In the prior art, in order to reduce the loss at the shunt resistor, it is necessary to reduce the resistance value of the shunt resistor. For this reason, since the value of the primary current signal of the insulating transformer becomes small, it is easily affected by the switching noise of the switching element, and the circuit operation may become unstable. Such a problem is solved by the above configuration.

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 pulse width determination unit 15 may include an integration circuit 16 that generates a delayed signal in which the rising edge of the input control signal is delayed. In this case, the delay signal can be generated easily and reliably by the integrating circuit, which can contribute to the stabilization of the circuit operation.
The integration circuit 16 may be a circuit in which a 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 electric charge accumulated in the capacitive element 20 can be released by resistance. 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 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 generates a control signal generating unit that generates a control signal composed of a predetermined pulse signal, and generates a delay signal in which the control signal is input and the rising edge of the control signal is delayed. Has a pulse width determining unit that causes the control signal to fall when the value corresponding to the magnitude of the voltage of the AC power supply voltage signal falls and uses the control signal as the switch open / close signal. For this reason, it becomes difficult to be affected by the switching noise, and the circuit operation can be stabilized.

1 is a circuit diagram of a power transmission device according to an embodiment of the present invention. It is a figure which expands and shows the principal part of the power transmission device. It is a circuit diagram which shows the principal part structure of the pulse width determination part of the power transmission device. 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 circuit diagram of the conventional power transmission apparatus. It is a figure explaining the state which determines the pulse width of the switch opening / closing signal of a switching element by comparing the commercial power supply voltage signal and the primary side current signal of an insulation transformer with the power transmission device.

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 a power transmission device according to this embodiment. 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-phase AC power source 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 a house or the like actually fluctuates according to the use state of the connected electrical equipment, but in a general home, some voltage fluctuations and frequency fluctuations are electric. Does not affect the operation of the device. 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 solar power generation panel, 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, and AC power obtained by converting DC power generated by the DC power supply 1 by the DC voltage conversion unit 6, the power conversion means 7, and the like 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 to generate 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 an AC power supply 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 view showing a main part of the power transmission device. 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 and a pulse width determining unit 15. 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 pulse width determination unit 15 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. 1). ) Reverse the flow of the current with the voltage matching the voltage. The pulse width determination unit 15 includes a delay circuit 16, a comparison unit 17, and a processing unit 18. The delay circuit 16 receives the control signal and generates a delay signal in which the rise of the control signal is delayed.

  As shown in FIG. 3, the delay circuit 16 includes a CR integration circuit in which a resistance element 19 and a capacitance element 20 are connected in series. When the voltage Vi is applied to the input side of the CR integration circuit, electric charge is accumulated in the capacitive element 20 which is a capacitor. The electric charge accumulated in the capacitive element 20 can be released by resistance. 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.

  FIG. 4 is a diagram illustrating a state in which a switch opening / closing 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 FIG. 2 and FIG. 4, the rise time of the delay signal is determined by a set frequency (for example, about several tens kHz to several hundreds kHz). The comparison unit 17 compares the delay signal generated by the delay circuit 16 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.

In this way, the delay signal and the AC power supply voltage signal are compared to create the switch open / close signal, so that the circuit operation is less affected by switching noise than the current signal obtained from the voltage across the shunt resistor as in the past. Can be stabilized.
As shown in FIG. 1, the DC power generated by the DC power source 1 can be converted into AC power by the DC voltage conversion unit 6 or the power conversion means 7 and supplied to the load facility 5 and consumed in the house. Therefore, for example, the electricity bill charged by the electric power company or the like can be reduced. Since the DC voltage conversion unit 6 and the power conversion unit 7 can be configured simply, the cost of the power transmission device can be reduced.

  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 ... Pulse width determination unit 16 ... Delay circuit 19 ... Resistance element 20 ... Capacitance element

Claims (4)

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 a 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;
When the control signal is input, a delay signal in which the rise of the control signal is delayed is generated, and when the delay signal becomes a value corresponding to the magnitude of the voltage of the AC power supply voltage signal, the control signal is caused to fall. A pulse width determining unit using the control signal as the switch open / close signal;
A power transmission device comprising:   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 pulse width determination unit includes an integration circuit that generates a delay signal in which a rising edge of the input control signal is delayed.   The power transmission device according to claim 3, wherein the integration circuit includes a resistance element and a capacitance element connected in series.

Images