JPH0764658A - Power conversion system - Google Patents

Abstract

PURPOSE:To operate an energy converting means with high efficiency while keeping the voltage of a DC part at an approximately constant level in a power conversion system which restores the remaining power to a commercial power supply out of the power that is generated by the energy converting means and privately consumed. CONSTITUTION:The voltmeters and the ammeters (3, 4, 10, 11, 14 and 15) are placed between an energy converting means 121 and a DC/DC converter 12, between a DC load 120 and a bidirectional converter 13, and between a commercial power supply 1 and the converter 13 respectively. The time ratio of the converter 12 is changed by a system control circuit 18 based on the result of comparison carried out between the output signals of the voltmeter and the ammeter provided between the means 121 and the converter 12 and the output signals of the voltmeter and the ammeter placed between the load 120 and the converter 13. Then the power is regenerated and run at the converter 13 based on the time ratio set by the circuit 18. Thus the means 121 can be operated at the maximum output point and also the voltage applied to the load 120 can be controlled approximately at a constant level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed power generation system for supplying self-consumed power with electric power obtained from energy conversion means such as a solar cell and a thermoelectric element, and regenerating the surplus power to a commercial power supply system. The present invention relates to a power conversion system of a distributed power generation system that is suitable for always maintaining the conversion means in the maximum output state.

[0002]

2. Description of the Related Art As a conventional technique for supplying electric power generated by a solar cell or the like installed on the roof of a home to household electrical equipment and regenerating surplus power to a commercial power source, the electric power described in Japanese Patent Laid-Open No. 62-221014 There is a converter. This prior art is shown in FIG. In this conventional technique, the output of the solar cell 141 is supplied to an inverter (DC load) 143 through the diode 140 to be converted into AC power, and the load 14 such as household electrical equipment
5 is operating. Then, the surplus power is regenerated to the commercial power supply 131 side through the voltage doubler rectifier circuit 137a.

[0003]

SUMMARY OF THE INVENTION The above-mentioned prior art is related to the magnitude relationship between the operating voltage determined by the characteristics of the solar cell and the load characteristics of the inverter, which is a DC load, and the maximum voltage of the voltage doubler circuit. There is a problem in that the solar cell may not be able to take out sufficient electric power depending on the weather conditions, the operating conditions of the power generation system, etc. without considering the solar radiation dependency and temperature dependency of the maximum output point of the battery.

FIG. 3 shows the output characteristics, load characteristics, and
It is a figure which shows the operating point determined from the characteristic and DC load of a solar cell, and the maximum output point of a solar cell. FIG. 3 shows a case where the voltage at the operating point is lower than the maximum voltage Vcom of the voltage doubler rectifier circuit. In this case, if the power of the solar cell can be regenerated to the commercial power source side, the voltage at the operating point can be lowered, and the solar cell can be operated at the maximum output point. However, since the voltage at the operating point is on the lower voltage side than the maximum voltage Vcom of the voltage doubler rectifier circuit, power regeneration cannot be performed and the operating point cannot be lowered. Therefore, as shown in FIG. 3, although the electric power (maximum output) that the solar cell can generate is much larger than the power consumption of the load, the electric power actually supplied by the solar cell is Only power consumption.

In this case, by increasing the number of solar cells, the voltage at the maximum output point of the solar cells is raised above the maximum voltage Vcom of the voltage doubler rectifier circuit, and the power of the solar cells is regenerated to the commercial power source side. The solar cell can operate at the maximum output point. FIG. 4A is an example showing that. By increasing the number of solar cells, the operating point determined by the characteristics of the solar cells and the load characteristics becomes operating point 1. When electric power is regenerated from this state to the commercial power source side, the operating point of the solar cell moves from the operating point 1 to the operating point 2 and the operating point of the DC load moves from the operating point 1 to the operating point 3. In this state, the output of the solar cell is supplied to both the DC load and the commercial power source, as shown in FIG.

Generally, in any of the following cases (a) and (b), the power generated by the solar cell can be regenerated or power-driven to the commercial power source side, and the solar cell can be operated at its maximum output point. Becomes (A) When the maximum output of the solar cell is greater than the power consumption of the DC load, and the maximum output point of the solar cell and the DC load operating point are higher than the maximum voltage of the voltage doubler rectifier circuit, (b) the maximum output of the solar cell Is smaller than the power consumption of the DC load, and the maximum output point of the solar cell and the DC load operating point are smaller than the maximum voltage of the voltage doubler rectifier circuit.

FIGS. 5 (a) and 5 (b) show the above (a),
It is a figure which shows that a solar cell can be operated at the maximum output point in the case of (b). In the above case (a), as shown in FIG. 5 (a), in the load characteristics in the figure (in this case, the same as the description of FIG. 4 (a)), the operating point 1 (voltage V1). When the amount of regenerated electric power from the solar cell operating in (1) to the commercial power source side is increased, the operating point moves and the voltage becomes V2, and the solar cell can be operated at the maximum output point. On the contrary, when the solar cell is operating with the voltage V3 as the operating point, the voltage at the operating point can be moved to V2 by reducing the regenerative electric energy, and the solar cell is similarly operated at the maximum output point. It becomes possible.

In the case of the above (b), as shown in FIG. 5 (b), the load characteristic in the figure shows the power running power amount from the commercial power source operating at the operating point (voltage V1) to the load. When reduced, the operating point moves to voltage V2, allowing the solar cell to operate at its maximum output point. On the contrary, when the power running power to the load is increased while the solar cell is operating at the operating point of voltage V3, the operating point moves to voltage V2,
It is possible to operate the solar cell at its maximum output point.

However, it is difficult to always keep the operating state in (a) or (b). For example, even if the state of (a) is kept at room temperature, the maximum output point of the solar cell largely moves to the low voltage side with the temperature as shown in FIG. 6, and thus, as in the case of FIG. Although solar cells have the ability to generate sufficient surplus power, there may be a problem in that they cannot be extracted.

Therefore, as a suboptimal measure, it is possible to increase the number of solar cells in series. But even in this case,
As shown in FIG. 7, when the amount of solar radiation decreases, the solar cell may not be able to cover the power consumption of the DC load. Also,
When the amount of solar radiation fluctuates, the operating point of the DC load becomes the operating point 2
(Or, the maximum output point: when the operating point moves to the maximum output point after power regeneration) and the operating point 1 are reciprocated. This means that, for example, when the motor is used as a DC load, the voltage applied to the motor fluctuates greatly due to fluctuations in the amount of solar radiation, and stable operation cannot be performed. Further, since the maximum output point of the solar cell is located at a high voltage, it becomes necessary to operate the solar cell at the maximum output point without applying an extra burden to the equipment inside and around the solar air conditioner.

These problems are the same when the thermoelectric element is used as the energy converting means, the thermoelectric element cannot be operated at the maximum output point, and the voltage applied to the DC load changes greatly. I have a problem.

There is a possibility that this problem can be solved by using a DC-DC converter. The DC-DC converter can change the voltage value and the current value on the output side while keeping the output power almost constant by changing the input signal (duty ratio), so the maximum output point of the solar cell, thermoelectric element, etc. The operating points of the DC load and the DC load can be set to the above state (a) or (b). However, the characteristics of the energy conversion means such as solar cells and thermoelectric elements used by the user are various, and in order to keep the operating point in an optimum state, the characteristic data of the energy conversion means to be used should be set in the system. Must be set in the control circuit. Furthermore, the temperature of the energy converting means used, the amount of solar radiation, etc. must be measured and the measurement result must be input to the system control circuit, which imposes a heavy burden on the user.

Since a system that imposes a heavy burden on the user cannot be expected to spread, it is necessary to make the energy converting means always operable at the maximum output simply by connecting the energy converting means to the solar air conditioner. When a DC-DC converter is used in a solar air conditioner, a high voltage higher than the output voltage of the energy converting means may be output from the DC-DC converter and applied to the inverter.
Even if such a situation occurs, it is necessary to have a system configuration that does not cause trouble. Furthermore, even if an abnormality occurs, it is necessary to ensure that the system is switched to the safe side.
Furthermore, it is desirable that the user can easily understand the operation status of the power generation system from the viewpoint of safety measures or from the viewpoint of promoting energy saving.

A first object of the present invention is to provide a power conversion system capable of keeping the energy converting means in the maximum output state regardless of the characteristics of the energy converting means used or the environment of use.

A second object of the present invention is to provide a power conversion system in which the input voltage of the DC load does not deviate from the set range.

A third object of the present invention is to provide a power conversion system in which malfunction of system control is unlikely to occur.

A fourth object of the present invention is to provide a power conversion system which can surely switch the system to the safe side even when the power conversion system malfunctions and can easily monitor the operating condition of the system. That is.

[0018]

The first object of the present invention is to convert the AC power from the energy converting means, the DC-DC converter, and the commercial power supply into the DC power, and to convert the DC power into the AC power. A bidirectional converter having a function of
A DC load, and an output side of the energy conversion means and a DC-
In a power conversion system in which an input side of a DC converter is connected and an output side of a DC-DC converter is connected to a DC section and a DC load of a bidirectional converter, a DC-DC
A first ammeter is provided between the converter and the DC load or the bidirectional converter, a second ammeter is provided between the DC load and the bidirectional converter, and between the DC-DC converter and the DC load or the bidirectional converter, or A voltmeter is provided in the DC section between the DC load and the bidirectional converter, and
DC- based on the detection signals of the ammeter, the second ammeter and the voltmeter
This is achieved by providing a duty ratio setting means for changing the duty ratio of the DC converter and a control means for causing the bidirectional converter to regenerate or power the power under the duty ratio set by the duty ratio setting means. (Claim 1).

The first object is also to provide at least a first voltmeter and a first ammeter between the energy converting means and the DC-DC converter, and to connect between the DC load and the bidirectional converter. When a second voltmeter and a second ammeter are provided in the DC part and the duty ratio of the DC-DC converter is changed based on the detection signals of the first ammeter, the second ammeter, the first voltmeter and the second voltmeter. This is achieved by providing a ratio setting means and a control means for causing the bidirectional converter to regenerate or power-run electric power based on the duty ratio set by the duty ratio setting means (claim 2).

The first object is also to provide a first voltmeter and a first ammeter between the commercial power supply and the bidirectional converter,
A second ammeter is provided between the AC load other than the bidirectional converter and the commercial power source, a second voltmeter and a third ammeter are provided between the DC load and the bidirectional converter, and a first ammeter,
Time ratio setting means for changing the time ratio of the DC-DC converter based on the detection signals of the second ammeter, the third ammeter, the first voltmeter, and the second voltmeter, and the time set by the time ratio setting means. This is achieved by providing the bidirectional converter with control means for regenerating or powering the electric power based on the ratio (claim 3).

The first object of the present invention is also that in any one of claims 1 to 3, a solar cell or a thermoelectric element is used as the energy converting means, and when the solar cell is the energy converting means, it is used as a DC load for the compressor. This is achieved by using an inverter for driving the motor of (4).

The above-mentioned first object is, in any one of claims 1 to 3, that a CuK type or Sepic type converter is used as the DC-DC converter and has a size proportional to the duty ratio. The signal and the signal from the triangular wave generation circuit are sent to the comparison circuit, and the output signal of this comparison circuit is set to DC-DC.
This is achieved by providing a circuit for sending to the semiconductor switching element of the converter (Claim 5).

The first object is also to provide the control means connected to the bidirectional converter according to any one of claims 1 to 3, the energy conversion means and the DC-DC converter.
A first multiplication circuit that receives detection signals from a voltmeter and an ammeter provided between the first and second differential circuits and a positive / negative sign of the output of the first differentiator circuit. First to judge
A positive / negative determination circuit and a second for differentiating the detection signal of the voltmeter
A differentiating circuit; a second positive / negative judging circuit for judging whether the output of the second differentiating circuit is positive or negative; an exclusive OR circuit for taking an exclusive OR of both outputs of the first and second positive / negative judging circuits; An integrating circuit for integrating the output of the logical OR circuit, a first error amplifying circuit for amplifying an error between the output of the integrating circuit and the detection signal of the voltmeter, a commercial power supply and a bidirectional converter. Error between the detection signal of the voltmeter and the second multiplication circuit for inputting the error amplification circuit, and the detection signal of the ammeter provided between the commercial power source and the bidirectional converter and the output signal of the second multiplication circuit Is achieved with the second error amplification circuit for amplifying

The first object is also to obtain the point at which the output of the DC-DC converter becomes maximum when the DC-DC converter is operated under a set duty ratio. In this state, (a) if the output power or output current of the DC-DC converter is equal to or higher than the input power or input current of the DC load, is the duty ratio maintained when the voltage of the DC part exceeds the set voltage value? If the output current or output power of the DC-DC converter is less than the input current or input power of the DC load, or if the voltage of the DC part is less than the set voltage value, This is achieved by providing a duty ratio control means for holding or raising the duty ratio and for lowering the duty ratio otherwise.

The first object is also to obtain the point at which the output of the energy converting means becomes maximum when the DC-DC converter is operated under a set duty ratio. In this state, (a) when the value obtained by multiplying the output of the energy converting means by the correction coefficient is equal to or more than the input of the DC load, and when the voltage of the DC part is higher than the set voltage value, the duty ratio is held or lowered or If the value obtained by multiplying the output of the energy conversion means by the correction coefficient is smaller than the input of the DC load, the duty is maintained when the voltage of the DC part is smaller than the set voltage value. It is achieved by providing a duty ratio control means for raising the duty or otherwise lowering the duty (claim 8).

The first object is also to obtain the point at which the output of the energy converting means becomes maximum when the DC-DC converter is operated at a set duty ratio in claim 3. In this state, the power value flowing into the bidirectional converter is calculated from the detected values of the voltmeter and ammeter between the commercial power source and the bidirectional converter, and the detected value of the ammeter connected to the AC load. From the value obtained by multiplying the value by the correction coefficient or the current value obtained by dividing this value by the voltage value at the DC part, and the electric power or current flowing into the DC load, the energy conversion means passes through the DC-DC converter. The power or current flowing into the DC part by (a) If this value is greater than the input power or input current of the DC load,
When the voltage of the DC part is higher than the set voltage value, the duty ratio is maintained or lowered, and otherwise the duty ratio is increased. (B) If this value is smaller than the input power or input current of the DC load, the DC part When the voltage is lower than the set voltage value, the duty ratio is maintained or increased, and in other cases, the duty ratio control means for lowering the duty ratio is provided (claim 9).

The above-mentioned second object is, in claim 1, D
The point where the output of the DC-DC converter is maximized is found in the state where the C-DC converter is operated under the set duty ratio, and in this state, (a) the output power of the DC-DC converter or When the output current is equal to or higher than the input power of the DC load or the input current, the duty ratio is decreased when the voltage of the DC part is higher than the set upper limit voltage value, and the duty ratio is increased otherwise (b) of the DC-DC converter. When the output current or output power is smaller than the input current or input power of the DC load, the duty ratio is increased when the voltage of the DC part is less than the set lower limit voltage value, and the duty ratio is controlled to decrease the duty ratio otherwise. This is achieved by providing a control means (Claim 10).

The second object is also to obtain the point at which the output of the energy converting means becomes maximum when the DC-DC converter is operated under a set duty ratio. In this state, (a) when the value obtained by multiplying the output of the energy converting means by the correction coefficient is equal to or more than the input of the DC load, the duty ratio is decreased when the voltage of the DC portion is higher than the set upper limit voltage value, and other than that, (B) If the value obtained by multiplying the output of the energy conversion means by the correction coefficient is smaller than the input of the DC load, increase the duty ratio when the voltage of the DC part is smaller than the set lower limit voltage value. Other than the above, it is achieved by providing a duty ratio control means for lowering the duty ratio (claim 11).

The second object is also to obtain the point at which the output of the energy converting means becomes maximum when the DC-DC converter is operated under a set duty ratio. In this state, the power value flowing into the bidirectional converter is calculated from the detected values of the voltmeter and ammeter between the commercial power source and the bidirectional converter, and the detected value of the ammeter connected to the AC load. From the value obtained by multiplying the value by the correction coefficient or the current value obtained by dividing this value by the voltage value at the DC part, and the electric power or current flowing into the DC load, the energy conversion means passes through the DC-DC converter. The power or current flowing into the DC part by (a) If this value is greater than the input power or input current of the DC load,
When the voltage of the DC part is higher than the set upper limit voltage value, the duty ratio is decreased, and otherwise the duty ratio is increased. (B) When this value is smaller than the input power or input current of the DC load, the voltage of the DC part Is smaller than the set lower limit voltage value, the duty ratio is increased, and in other cases, the duty ratio is reduced to provide the duty ratio control means (claim 12).

The second object is also achieved by using the efficiency of the DC-DC converter or the efficiency of the bidirectional converter as the correction coefficient in claims 8 to 12 (claims 14 and 15). .

A third object is to provide a switching circuit between the first error amplification circuit and the second multiplication circuit, and to operate the switching circuit in response to an external control signal. This is achieved by adopting a configuration in which a predetermined signal is input to one input of the multiplication circuit (claim 1
6).

The third object is, in any one of claims 7 to 9, that the set voltage value is proportional to the detected value of a voltmeter provided between the commercial power source and the bidirectional converter. Achieved by giving a value multiplied by a constant (claim 1
7).

The fourth object is to claim 1 to claim 3.
In any of the above, a contactor is provided between the commercial power source and the bidirectional converter, and if an AC overcurrent, an AC overvoltage, or an AC undervoltage occurs, it is provided between the commercial power source and the bidirectional converter. By the logical sum of the system cutoff signal from the control means for detecting the measurement value of the voltmeter and the independent system overcurrent, alternating current overvoltage, alternating current undervoltage, and the system shutdown signal from the circuit for judging the frequency abnormality, This can be achieved by activating a contactor provided between the bidirectional converter and the commercial power source to cut off the commercial power source (claim 18).

A fourth object of the present invention is that, in any one of the first to third aspects, the regenerative mode is obtained from the respective measured values of the voltmeter and the ammeter provided between the commercial power source and the bidirectional converter. Whether the mode is powering mode or not, and at least one of regenerative power or cumulative regenerative power is calculated from the voltage signal or current signal, and the result or the value obtained by multiplying the unit price of the power is displayed. Is achieved (claim 19).

The fourth object is also achieved by the power conversion system according to claim 19 comprising an outdoor unit and an indoor unit, and the display function being provided in the indoor unit (claim 20).

[0036]

According to the invention of claim 1, the output of the energy converting means via the DC-DC converter can be calculated from the voltmeter and the ammeter provided on the output side of the DC-DC converter.
The input of the DC load can be calculated from the voltmeter and ammeter provided between the DC load and the bidirectional converter. From these comparisons, it is possible to judge whether the duty ratio of the DC-DC converter is increased or decreased. As an example, FIG. 8 shows how the operating points of the solar cell, which is the energy converting means, and the DC load change from the state of operating point 1 by increasing the duty ratio. At the operating point 1, the output of the solar cell is equal to the power consumption of the DC load, and the operating point is smaller than the maximum output voltage Vcom of the bidirectional converter (rectifier circuit). This state is
It does not meet the condition already described, that is, the condition that maximum output point tracking is possible.

Next, when the duty ratio is increased by the increment A, the operating point 1 moves according to the arrow in the figure, and the operating point voltage becomes Vco.
It becomes m or more. Next, when the electric power is regenerated by the bidirectional converter, the operating point of the solar cell moves from the operating point 2 to the operating point 3 and the duty ratio is further increased by A while regenerating the electric power.
Then, the operating point of the solar cell moves to operating point 4. Then, if the amount of regenerated electric power is adjusted, the operating point of the solar cell can be moved to the operating point 5 (maximum output point). That is, the duty ratio control of the DC-DC converter,
By controlling the power regeneration and power running of the bidirectional converter, the solar cell can be operated at the maximum output point.

According to the invention of claim 2, the output of the energy converting means can be calculated from the voltmeter and the ammeter provided between the energy converting means and the DC-DC converter, and the output between the DC load and the bidirectional converter can be calculated. The input of the DC load can be calculated from the provided voltmeter and ammeter. From these comparisons, claim 1
Similarly to the invention described in (1), it is possible to determine whether the duty ratio of the DC-DC converter increases or decreases. That is, the output of the DC-DC converter can be calculated from the output of the energy converting means. on the other hand,
The power consumption of the DC load can be seen from the voltmeter and ammeter provided in the DC section. Here, when the output of the DC-DC converter and the power consumption of the DC load are the same and the voltage is Vcom or less, the solar power is increased by the control for increasing the duty ratio and the powering / regeneration control of the power as described in FIG. It is possible to operate the battery at its maximum power point.

According to the invention of claim 3, the input from the commercial power source can be calculated from the detection signals of the voltmeter and the ammeter between the commercial power source and the bidirectional converter. On the other hand, the power consumption of the AC load can be known from the ammeter connected to the AC load other than the bidirectional converter and the detection signal of the voltmeter. Therefore, if the power consumption of the AC load is reduced from the input from the commercial power source, and the power consumption of the DC load is further reduced, the energy conversion means outputs D
The power supplied to the DC part via the C-DC converter is known. Therefore, the solar cell can be operated at its maximum output point by performing the same control as in the invention of claim 1 or claim 2 based on the comparison between this power and the power consumption of the DC load.

The above is an example of using a solar cell as the energy converting means, but an example of using a thermoelectric element as the energy converting means will be described. Unlike the solar cell, the output voltage-current characteristic of the thermoelectric element is almost linear. However, also in this case, the operating point can be moved to the maximum output point as in the case of the solar cell. FIG. 9 shows this state, and the operating point of the thermoelectric element moves from the operating point 1 to the maximum output point according to the arrow in the figure.

In the case of the fifth aspect of the present invention, since the DC-DC converter of the Cuk type or the Sepic type is used, when a signal proportional to the duty ratio is input to the converter, the output of the energy converting means. It is possible to step up or step down while maintaining electric power. Therefore, according to the principle described in the invention of claim 1, when the bidirectional converter is operated, the solar cell can be brought to the maximum output state.

In the case of the invention of claim 6, electric power is obtained from the voltage and current signals of the solar cell, and the signal is processed by a differentiating circuit, a positive / negative judging circuit, etc. Can be calculated. When a signal obtained by multiplying the difference between this voltage and the current voltage by a sine wave is sent to the drive circuit, the bidirectional converter regenerates or powers the power in the direction that should be incremented, and the solar cell is set to the maximum output state. can do.

The inventions of claims 7 to 9 will be described with reference to FIG. First, when the solar cell that is the energy converting means has the output characteristic of, the operating point of the solar cell and the DC load is the operating point 1. At this time, the input of the DC load and the output of the solar cell are equal, and the voltage between the bidirectional converter and the DC load is lower than the set voltage (maximum voltage of the bidirectional converter). The output of the solar cell rises to, and the operating point moves from operating point 2 to operating point 3. At the operating point 3, the voltage between the bidirectional converter and the DC load is higher than the set voltage (the maximum voltage of the bidirectional converter). Here, if you keep the duty ratio,
The operating point moves from the operating point 3 to the maximum output point 3.

FIG. 11A shows the movement of the operating point when the output of the energy converting means is less than the input power of the DC load. In the initial state, the operating point of the energy converting means is the operating point. In 1. In this case, since the output of the energy conversion means is smaller than the input of the DC load and the voltage between the bidirectional converter and the DC load is equal to the set voltage (the maximum voltage of the bidirectional converter), the duty ratio is After that, the operating point moves to the operating point 2, and the solar cell can be operated at the maximum output point.

Further, an RO having this control program built-in
If M is a constituent element, the control signal from this ROM is
The solar cell can be operated at the maximum output point by sending it to the C-DC converter and the bidirectional converter.

In the case of the inventions of claims 7, 8 and 9, FIG.
As shown in (b), operating point (solar cell maximum output point)
Moves to the Vcom side, and the control for decreasing the duty ratio works until it falls below Vcom, so that the operating point of the solar cell is finally positioned on Vcom. That is, the voltage applied to the DC load has a substantially constant value. Further, if the ROM containing the control program is used as a constituent element, the voltage applied to the DC load can be made substantially constant by sending a control signal from this ROM to the DC-DC converter and the bidirectional converter.

In the case of the condition (a) of the tenth, eleventh and twelfth aspects of the invention, as shown in FIG. 12 (a), the characteristic of the energy converting means in the initial state is that the duty ratio is changed. Changes to. In this case, when the operating point 3 reaches Vmax, control for lowering the duty ratio works, so the operating point does not exceed Vmax.

On the other hand, also in the case of the condition (b) of the invention of claims 10, 11, and 12, as shown in FIG. 12 (b), the characteristics of the energy converting means in the state of (4) change the duty ratio. It changes to. If, operating point 3
Has reached Vmin, the control for increasing the duty ratio works, and the operating point does not fall below Vmin. Also in this case, if a ROM containing a control program is used as a constituent element, the control signal from this ROM is converted into a DC-DC converter.
And the bidirectional converter, the input voltage of the DC load can be prevented from exceeding the upper limit value and the lower limit value.

By using the correction coefficient as in the fourteenth and fifteenth aspects of the present invention, the input from the energy converting means to the DC portion can be accurately evaluated, and the energy converting means is held or set at the maximum output state. It is possible to prevent the upper and lower limits from being exceeded.

In the case of the sixteenth aspect of the invention, if the predetermined signal is set to 0 V, for example, the multiplication circuit outputs a signal of 0 V, that is, no change. Therefore, the control for changing the duty ratio and the control for tracking the maximum output point of the solar cell can be separated in time series, and there is no malfunction due to the interference between the two.

In the seventeenth aspect of the present invention, the current set voltage, that is, the maximum output voltage of the bidirectional converter can be detected. In general, the maximum output voltage depends on the commercial voltage, so without detecting that the commercial voltage fluctuates,
Judgment of the magnitude relationship between the voltage of the DC part and the set voltage may result in an erroneous judgment. However, in the present invention, since the maximum output voltage of the bidirectional converter can be accurately determined from the voltage of the commercial power supply at the present time, malfunction in system control can be avoided.

In the case of the eighteenth aspect of the present invention, the system is cut off by the logical sum of the system cutoff signal from the system control circuit and the system cutoff signal of the circuit for judging abnormality, which is independent of the system cutoff signal. In this case, the system can be surely switched to the safe side.

According to the nineteenth aspect of the invention, since the regenerative power or the regenerative power is displayed at a position where the user can easily notice it, the user can detect the abnormality of the system at an early stage.

According to the twentieth aspect of the invention, since the indoor unit that the user sees daily has a display function, the operating state of the system can be easily monitored.

[0055]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a basic configuration diagram of a power conversion system according to an embodiment of the present invention. In the power conversion system according to the present embodiment, the output from the commercial power supply 1 is passed through the reactor 2, the voltmeter 3, the ammeter 4, and the AC load 5 to the input end (the commercial power supply side) of the bidirectional converter 13. Connected to. The bidirectional converter 13 is composed of a plurality of diodes 6 and a semiconductor switching element 7. The diode 6 full-wave rectifies the AC voltage of the commercial power supply 1 with a smoothing capacitor 8 and the AC voltage is input to the input terminal. When operated, it operates as a DC voltage source.
The output of the energy converting means 121 is the voltmeter 10 and the ammeter 1.
1 to the input terminal of the DC-DC converter 12. The output end of the DC-DC converter 12 is connected in parallel to the output end (DC load side) of the bidirectional converter 13, and the voltmeter 14 detects the voltage at this output end. Output of bidirectional converter 13 and output of energy conversion means 121 (output of DC-DC converter 12)
Is a DC load 1 via a smoothing capacitor 8 and an ammeter 15.
Connected to 20.

The system control circuit 18 includes an AC voltage VAC and an AC current IAC detected by the voltmeter 3 and the ammeter 4.
And the output voltage VS and output current IS of the energy conversion means 121 detected by the voltmeter 10 and the ammeter 11, and the voltmeter 1
4, the voltage VD of the DC portion and the current ID of the DC portion detected by the ammeter 15 are input. System control circuit 18
Outputs a control signal sig1 to the bidirectional converter control circuit 19, and the bidirectional converter control circuit 19 alternately turns on and off each semiconductor switching element 7 in the bidirectional converter 13 based on this control signal. Output a control signal. The system control circuit 18 further outputs a control signal sig2 to the DC-DC converter 12, and the energy conversion means 12
Change the output of 1.

Next, the control method of the system will be described with reference to the flowchart of FIG. In FIG. 13, DR
The system control circuit 18 is the DC-DC converter 12
To the control signal, that is, the duty ratio, A is the increment of the control signal, S is a sign flag that gives the sign of the proportional constant K, P
L is the power consumed by the DC load 120, PS is the output of the energy conversion means 121, VD is the voltage of the DC section, and Vcom is the power running mode.
Is the maximum output voltage at the drive.

First, as an initial setting, the minimum value is substituted for the duty ratio DR. Next, the output PS of the energy conversion means 121 is calculated from the detected voltage VS and the detected current IS. At this time, in order to determine the maximum output power, several outputs PS of the energy conversion means 121 are obtained, and the maximum point among them is PS.

Next, this PS and the detection voltage VD of the DC part,
The power consumption PL of the DC load 120 obtained from the detected current ID is compared, and the output PS of the energy conversion means 121 is the DC load 1
If the power consumption is 20 or more, the code flag S is substituted with "1", and under other conditions, the code flag S is substituted with "-1". After that, the proportional multiplier K is multiplied by the value of the sign flag S, and the result is substituted into the increment A.

Next, the sign flag S is "1" and the voltage VD of the DC portion is the maximum output voltage Vcom in the powering mode.
Whether or not it is greater than the sign flag S is "-1"
And the voltage VD of the DC part is smaller than the maximum output voltage Vcom in the powering mode. If the result of the judgment is affirmative, the process returns to the process of obtaining PS. When the determination result is negative, the increment A is added to the duty ratio DR, and the result is substituted for the duty ratio DR again. Then, after holding for a certain period of time, the process returns to the process for obtaining PS.

By repeating the above processing, the energy converting means can be operated at the maximum output point.

FIG. 14 is a block diagram of an embodiment in which the solar cell 9 is used as the energy converting means and the inverter 16 which drives the motor 17 for the compressor is used as the DC load. The rotation speed of the motor for the compressor is controlled by turning on and off the respective transistors forming the inverter 16 and adjusting the output voltage and frequency of the inverter.

The manner in which the operating point of the solar cell 9 moves by this rotation speed control will be described with reference to FIG. Here, the black circles in FIG. 8 represent operating points of the solar cell 9, and the star marks represent the maximum output point of the solar cell 9. Now, it is assumed that the signal of duty ratio DR0 is input from the system control circuit 18 to the DC-DC converter, and the solar cell 9 and the load 16 are operating at the operating point 1. In this state, as described above, since PL≤PS, "1" is assigned to the code flag S and the condition of VD> Vcom is not satisfied, so the duty ratio DR is increased by the increment A, and the system control circuit outputs DR0 + A. Signal is input to the DC-DC converter.

At this time, when the duty ratio changes and the output of the solar cell 9 changes, the operating point of the solar cell 9 moves from the operating point 1 to the operating point 2 according to the load characteristics. However, since the state of the operating point 2 is in the regenerative mode, the operating point of the solar cell 9 immediately moves to the intersection with Vcom and operates at that point (operating point 3). In the comparison judgment of PL and PS at this operating point, PL≤PS and still the condition of VD> Vcom is not satisfied, so the duty ratio DR is increased by the increment A. As a result, the signal DR0 + 2A is input from the system control circuit 18 to the DC-DC converter.

Since this state is in the regenerative mode, if the maximum output point of the solar cell is smaller than Vcom, the operating point of the solar cell moves only to the intersection (operating point 4) with Vcom. However, as shown in FIG. 8, when the maximum output point is higher than Vcom, the operating point moves to the maximum output point of the solar cell, that is, operating point 5 in FIG.

FIG. 15 is a block diagram of a power conversion system according to another embodiment of the present invention. In this embodiment, the motor 122 is used as the DC load, and the solar cell can be operated at the maximum output point by performing the same control as in the case of FIG.

FIG. 16 is a block diagram of a power conversion system according to still another embodiment of the present invention. This embodiment is shown in FIG.
The voltmeter 10 for detecting the output of the solar cell and the ammeter 11 shown in FIG. 2 are omitted, and an ammeter 21 for detecting the current of the AC load is provided.

In this embodiment, the input of the inverter 16 obtained from the detected value VD of the voltmeter 14 and the detected value ID of the ammeter 15 and the voltmeter 3 and the current provided between the commercial power source 1 and the bidirectional converter 13 are used. The power consumption or power generation amount of the solar air conditioner is obtained from the detected values VAC and IAC of the total 21, and the power consumption of the AC load 5 obtained from VAC and IACL is subtracted to obtain the power that enters the DC part or the power that exits from it. The output of the solar cell 9 is calculated by calculating and subtracting the input of the inverter from this electric power. As a result, FIG.
The control shown in can be executed, and the solar cell can be operated at the maximum output point.

FIG. 17 is a block diagram of an embodiment using a thermoelectric element as the energy converting means. Also in this case, FIG.
By performing the control shown in FIG. 9, the thermoelectric element can be operated at the maximum output point as shown in FIG.

FIG. 18 is a diagram for explaining the operation of the Cuk type DC-DC converter. In FIG. 18, a solar cell is assumed as the input side DC power source. A switch circuit 34 including a semiconductor switching element 32 and a diode 33 is connected in parallel to the output end of the solar cell 30 via a reactor 31. The output of the switch circuit 34 is connected to a load 39 via a capacitor 35, a diode 36, a reactor 37, and a capacitor 38.

The semiconductor switching element 32 is on / off controlled by a control signal sent from the system control circuit 18. This control signal is a square wave signal output from the comparison circuit 41, and is a wave obtained by multiplying the duty ratio DR read from the ROM 42 and the constant amplitude wave from the constant voltage source 43 in the multiplication circuit 40. Is compared with the triangular wave output from the triangular wave generating circuit in the comparison circuit 14, and is obtained. FIG. 19 shows the configuration of the multiplication circuit, and FIG. 20 shows the configuration of the comparison circuit.

Now, when a control signal is input to the semiconductor switching element 32 and the switch is turned off, the solar cell 3
The current generated from 0 charges the capacitor 35 via the reactor 31, and energy is stored in the capacitor 35. When the semiconductor switching element 32 is turned on in this state, the diode 33 is turned off, a current flows through the reactor 37, the capacitor 35 is discharged, and energy is discharged from the capacitor 35.

In this circuit,

[0074]

## EQU00001 ## V2 = (. Alpha./(1-.alpha.))V1 Here, the relationship of V1: input voltage V2: output voltage α: duty ratio is established.

Therefore, by controlling the operation (duty ratio) of the semiconductor switching element 32, various solar cell outputs can be given to the DC load, and the operating point of the DC load and the maximum output point of the solar cell are By the power running or regenerative operation of the bidirectional converter, it becomes possible to move the optimum operating point to a region where it can be tracked.

FIG. 21 is an explanatory diagram of the operation of the Sepic type DC-DC converter. Even if this DC-DC converter is used, the operating point of the DC load and the maximum output point of the solar cell can be moved to a region where the optimum operating point can be tracked by the power running or regenerative operation of the bidirectional converter, as described above. it can.

FIG. 22 is a block diagram of the main part of the system control circuit. The output current value IS and the output voltage value VS from the solar cell described in FIG. 14 are input to the system control circuit.
The multiplication circuit 50 calculates the output value PS of the solar cell from these values, and the PS value is input to the positive / negative determination circuit 52 after passing through the differentiation circuit 51. In addition, the voltage value VS is the differential circuit 5
3 is input to the positive / negative determination circuit 54. Each of the positive / negative determination circuits 52 and 54 uses the input value as a reference value (0 in this example).
V), and outputs a signal indicating the comparison result, that is, whether the input value is positive or negative. The outputs of the positive / negative determination circuits 52 and 54 are the gate 5
The exclusive OR is taken at 5, and then integrated by the integrating circuit 56. 23 is used as the differentiating circuit, FIG. 24 is used as the integrating circuit, and the circuit shown in FIG. 25 is used as the error amplifying circuit.

The output signal VOPT of the integrating circuit 56 and the voltage value VS
Are input to the error amplification circuit 57. This amplifier circuit 57
And the AC voltage value VAC are input to the multiplication circuit 59, and the output of the multiplication circuit 59 and the AC current IAC are input to the error amplification circuit 60. The output of the amplifier circuit 60 becomes the above-mentioned control signal sig1 and operates the bidirectional converter control circuit.

FIG. 26 is a block diagram of a bidirectional converter control circuit. The bidirectional converter control circuit according to this embodiment includes triangular wave generation circuits 82 and 83 for generating triangular waves having a phase difference of 180 degrees, control signals sig1 from the system control circuit shown in FIG. 22, and each triangular wave generation circuit. Comparing with the triangular wave signals from 82 and 83, it is composed of comparing circuits 84 and 85, and inverting circuits 86 and 86 for inverting the output of each comparing circuit. The outputs of each comparing circuit 84 and 85 are both branched into two. ,
Each inverting circuit 86 is connected to one of them.

Next, an example of the operation of the system control circuit in the powering mode will be described with reference to FIGS. Here, the waveform A in FIGS. 28 and 29 is a triangular wave output from the two triangular wave generating circuits shown in FIG. I1-I
Reference numeral 3 is a control signal sig1 from the system control circuit. Waveforms B to E are voltage signals applied to the semiconductor switching elements in the bidirectional converter shown in FIG.
4 outputs B, C, of the bidirectional converter control circuit 6
D, E). The voltage signals B to E shown in FIG. 28 are voltage signals generated by the control signal I2, and the voltage signals B to E shown in FIG. 29 are voltage signals generated by the control signal I3. Although there is a delay time in the actual circuit operation,
Here, for convenience of explanation, the description will be made assuming that the delay time is zero.

In FIG. 27, it is assumed that the system control circuit outputs the control signal I1 (see FIGS. 28 and 29) and the solar cell is operating at the position of the black circle. When the operating point is moved in the direction in this state, the amplitude of the control signal is increased as I1 → I2. As a result, the control signal I
The result of comparison between 2 and the triangular wave A is the waveforms B to E in FIG. 28, and the semiconductor switching elements in the bidirectional converter are turned on and off in response to the waveforms B to E, respectively. The electric power rectified by the bidirectional converter by the voltage signals B to E is higher than the electric power generated by the control signal I1.
As shown in FIG. 27, the voltage of the DC part increases. As a result, the operating point of the solar cell moves in the direction of. Similarly, in order to move the operating point in the direction of, it suffices to give a signal I3 having a smaller amplitude than the control signal I1 shown in FIG.

In this way, the operating point of the solar cell can be moved to the maximum output point by adjusting the control signal sent from the system control circuit to the bidirectional converter control circuit.

FIG. 30 is a block diagram of a power conversion system according to another embodiment of the present invention. In this embodiment, the control algorithm shown in FIG. 13 is provided in the form of ROM as a part of the system control circuit. Also in this embodiment, the maximum output point tracking of the solar cell is possible.

FIG. 31 shows a modification of the algorithm shown in FIG. 13. When the process shifts to the process of comparing VD and Vcom to obtain the maximum point of PS, a process of setting the duty ratio DR to DR-A is added. It is a thing. By adding this processing, the maximum output point of the solar cell is changed to Vco as shown in FIG. 11 (b).
It can be moved near m. Therefore, according to this embodiment, there is an effect that the voltage applied to the DC load can be kept substantially constant.

FIG. 32 is a flow chart showing another embodiment of the control algorithm. Energy conversion means 12
The output PS of 1 is compared with the electric power PL consumed by the DC load 120 obtained from the voltage VD and the current ID of the DC portion which is the input signal, and the output PS of the energy converting means 121 is the DC load 120.
If the power consumption is equal to or higher than the power consumption PL of, the code flag S is substituted with "1", and under the other conditions, "-1" is substituted with the code flag S. After that, the proportional multiplier K is multiplied by the sign flag S and substituted for the increment A.

Condition of branching process which comes after the process of multiplying the increment A by the sign flag S and substituting the result into the increment A again (1) The sign flag S is "1" and the voltage VD of the DC part is set. When it is greater than the upper limit voltage value Vmax, or (2) the sign flag S is -1 and the voltage VD of the DC portion is less than the set lower limit voltage value Vmin, the processing of DR = DR-A is performed, The process returns to the process of obtaining the maximum value of PS. Under other conditions, the increment A is added to the duty ratio DR, and the result is again added to the duty ratio DR.
To the next process. By repeating this process, it is possible to prevent the voltage applied to the load from exceeding the upper limit or the lower limit.

FIG. 33 is a block diagram of a power conversion system having the control algorithm shown in FIG. 32 in the form of ROM as a part of the system control circuit. Also in this example,
There is an effect that the voltage applied to the DC load can be prevented from exceeding the upper limit or the lower limit.

FIG. 34 is a flow chart showing a control method using the algorithms shown in FIG. 31 and FIG. 32 at the same time. At the same time when the solar cell is tracked at the maximum output point, the voltage applied to the DC load has an upper limit value and an upper limit value. It can be controlled so that it does not exceed the lower limit. FIG. 35 is a diagram showing this state. The operating point of the solar cell and the DC load is the maximum output point of the solar cell, and the voltage applied to the DC load is substantially constant (Vcom).

In FIG. 36, when calculating the output of the solar cell, the electric power generated by the solar cell and flowing into the DC portion through the DC-DC converter (subscript "P" is referred to as "effective output"). FIG. 6 is a configuration diagram of an embodiment in which is calculated by substituting the efficiency of the DC-DC converter as a correction coefficient.
In the case of this embodiment, the formula for calculating the correction coefficient η (VS, IS) is written in the ROM, and this value is used to find the electric power PS supplied by the energy converting means. According to this method, it is possible to accurately compare the magnitude relationship between PS and the power consumption PL of the load.

Similarly, FIG. 37 is a block diagram of an embodiment for calculating by substituting the electric power flowing into the DC portion (subscripted to P as "effective output") as a correction coefficient.
The correction coefficient η is the voltage VD and current VD of the DC part, the voltage VAC of the commercial power supply, and the current IAC flowing into the bidirectional converter.
-Determine using IACL. Also in this embodiment, since the magnitude relationship between PS and the power consumption PL of the DC load can be compared accurately, no malfunction occurs.

FIG. 38 is a block diagram of another embodiment of the system control circuit. The switching circuit 58 between the error amplification circuit 57 and the multiplication circuit 59 in the figure switches the switch according to the control signal output from the ROM 61 in the system control circuit and sends a signal of "0" to the multiplication circuit 59. as a result,
A signal of 0V is sent from the multiplication circuit 59 to the error amplification circuit 60,
The current AC current IAC is output from the error amplification circuit 60. The bidirectional converter control circuit continues this operation while the control signal is sent from the ROM 61 to the switching circuit 58.

FIG. 39 is a graph showing how the system control circuit is controlled. For example, in the case of a solar air conditioner, the duty ratio DR is kept constant for a while after starting up, and the control for obtaining the maximum value of the output PS of the solar cell is performed. Next, when the maximum value of the output PS of the solar cell is determined at time T1, the control for detecting the maximum value of the output PS of the solar cell is stopped for a while from time T1, the duty ratio is changed, and the solar cell is changed. The control is performed to obtain the maximum value of the output PS of the. At this time, the switch circuit is activated by the signal from the system control circuit, and the current control command IC outputs the 0 signal. Then, at time T2, when the maximum value of the output PS of the solar cell is determined,
The duty ratio DR is kept constant and control is performed to find the maximum value of the output PS of the solar cell. By repeating such an operation, the solar cell can be operated at an operating point where the output of the solar cell can be maximally utilized. The circuit shown in FIG. 26 is used as the drive circuit. In the present embodiment, the control of the duty ratio and the maximum output control of the solar cell are separately performed in time series, so that both controls do not interfere with each other, and there is no erroneous judgment.

FIG. 40 is a block diagram of a power conversion system according to still another embodiment of the present invention. In this embodiment, Vcom is set by a value obtained by multiplying the commercial power supply VAC by a proportional constant, and even if the voltage of the commercial power supply fluctuates, it is possible to accurately determine whether the power running or the regenerative mode is set. There is.

FIG. 41 is a block diagram of a solar air conditioner system in which a protection device is provided in the solar air conditioner. In the solar air conditioner described above, a contactor 91, an insulating transformer 92, and a contactor 93 are provided between the commercial power source 91 and the input part of the bidirectional converter 95, and the solar cell 94 and the DC-DC converter are provided. A contactor 96 is provided between the input parts of 102. The contactor 91 detects the information of the detectors 97 to 99 for detecting AC overvoltage, AC undervoltage, and frequency abnormality, and the contactor 93 detects AC overcurrent. The contactor 96 operates on the basis of the information of the detector 100 which detects the DC ground fault.

The contactor 91 prevents the poor quality alternating current from flowing into the commercial system when the solar air conditioner is operating in the regenerative mode and the electric power generated by the solar cell is flowing backward to the commercial system. It is for doing. The contactor 93 prevents an AC overcurrent from flowing into the bidirectional converter during operation in the power running mode, and prevents the contactor 93 from being destroyed in the regenerative mode. This is to prevent the device from being destroyed. The contactor 96 is provided to prevent electric shock when a person touches the solar cell panel because the output of the solar cell leaks to the outside.

In the present embodiment, the system cutoff signal of the protection circuit is operated independently of the system cutoff signal of the detector itself, using the signal of the control device of the solar air conditioner. That is, the protection circuit side and the system control side are double-checked to further enhance safety.

FIG. 42 is a block diagram of an embodiment in which a miniaturized protection device is incorporated in an outdoor unit of a solar air conditioner to save space. If you are required to install an external protective device, or if you already have an external protective device installed, you can use the outdoor unit built-in type protective device of this embodiment to perform a double-check and make it more secure. The nature is enhanced.

FIG. 43 is a block diagram of a power conversion system according to another embodiment of the present invention. In this embodiment, when the current operation mode is detected from the voltmeter and the ammeter provided between the commercial power source and the bidirectional converter and the power is reversely flowed to the commercial system, the display which is easily noticed by the user is displayed. The device 124 is adapted to indicate the use or generation of electric power. According to this embodiment, there is an effect that the operation status of the system can be easily monitored.

FIG. 44 is an external view of a solar air conditioner to which an example of the present invention is applied. For example, the AC voltage V in FIG.
AC and AC current IAC are input to the system control circuit 112 to calculate electric power, and a timer circuit and an electric charge per 1 kW / h are given to the system control circuit 112 as information to calculate the electric charge. For example, as the display mode, the power purchase fee per day, the power purchase fee per month, and the like can be displayed on the display panel 111. With this configuration, not only can you know the electricity bill that is causing the power generated by the solar cell to flow backward to the commercial grid, but the display value will change when a portion of the solar cell panel is damaged, so the solar cell panel will be damaged early. Can be sensed.

FIG. 45 is a block diagram of a power conversion system according to another embodiment of the present invention. In the embodiment shown in FIG. 1, the measuring device 1 measures the voltage and current on the input side of the energy converting means 121.
In the present embodiment, DC is measured, while 0 and 11 are measured.
-The only difference is that the output side current of the DC converter 12 is detected. The present embodiment has the same effects as the embodiment of FIG. 1 even if such a detection method is adopted.

[0101]

According to the present invention, the energy conversion means can be maintained at the maximum output state regardless of the characteristics of the energy conversion means or the operating environment, and the input voltage of the DC load can be controlled almost unchanged.

Further, according to the present invention, malfunction of the system is unlikely to occur, and even if an abnormality occurs in the system, the system can be switched to the safe side. Moreover, the user can easily monitor the system.

[0103]

[Brief description of drawings]

FIG. 1 is a basic configuration block diagram of the present invention.

FIG. 2 is a configuration block diagram of a known example.

FIG. 3 is a diagram showing operating points of a solar cell and a DC load.

FIG. 4A is a diagram showing operating points of a different number of solar cells and a DC load. (B) is a figure which shows the electric power of a solar cell.

FIG. 5 is a diagram illustrating movement of operating points.

FIG. 6 is a diagram showing temperature dependence of solar cell characteristics.

FIG. 7 is a diagram showing operating points of a solar cell and a DC load.

FIG. 8 is a diagram showing operating points of a solar cell and a DC load.

FIG. 9 is a diagram showing operating points of a thermoelectric element and a DC load.

FIG. 10 is a diagram showing operating points of an energy conversion unit and a DC load.

FIG. 11 is a diagram showing operating points of the energy converting means and the DC load.

FIG. 12 (a) is a diagram showing operating points of the energy converting means and the DC load. (B) is a figure which shows the operating point of an energy conversion means and a DC load.

FIG. 13 is a flowchart illustrating a method for controlling the system of the present invention.

FIG. 14 is a configuration block diagram of a solar air conditioner according to the present invention.

FIG. 15 is a configuration diagram of an embodiment using a motor as a DC load.

FIG. 16 is a block diagram of a solar air conditioner according to the present invention.

FIG. 17 is a structural block diagram of the present invention using a thermoelectric element.

FIG. 18 is a block wiring diagram showing an operation of a DC-DC converter (Cuk type).

FIG. 19 is a circuit diagram showing an example of a multiplication circuit.

FIG. 20 is a circuit diagram showing an example of a comparison circuit.

FIG. 21 is a block wiring diagram of a DC-DC converter (Sepic type).

FIG. 22 is a configuration block diagram showing a part of a system control circuit.

FIG. 23 is a circuit diagram showing an example of a differentiating circuit.

FIG. 24 is a circuit diagram showing an example of an integrating circuit.

FIG. 25 is a circuit diagram showing an example of an error amplifier circuit.

FIG. 26 is a block wiring diagram showing a bidirectional converter control circuit.

FIG. 27 is an explanatory diagram showing the operation of the system control circuit.

FIG. 28 is an explanatory diagram showing the operation of the system control circuit.

FIG. 29 is an explanatory diagram showing the operation of the system control circuit.

FIG. 30 is a block diagram showing a system configuration of the present invention.

FIG. 31 is a flowchart showing a control method of the system of the present invention.

FIG. 32 is a flowchart showing a control method of the system of the present invention.

FIG. 33 is a block diagram showing a system configuration of the present invention.

FIG. 34 is a flowchart showing a method for controlling the system of the present invention.

FIG. 35 is a diagram showing operating points of the energy converting means and the DC load.

FIG. 36 is a block diagram showing a system configuration of the present invention.

FIG. 37 is a block diagram showing the system configuration of the present invention.

FIG. 38 is a configuration block diagram of a system control circuit.

FIG. 39 is a diagram showing a state of system control.

FIG. 40 is a block diagram showing a system configuration of the present invention.

FIG. 41 is a configuration block diagram of a solar air conditioner provided with a protection circuit.

FIG. 42 is a schematic view of a solar air conditioner (outdoor unit) of the present invention.

FIG. 43 is a system configuration diagram of a system using a thermoelectric element.

FIG. 44 is a schematic view of a solar air conditioner (indoor unit) of the present invention.

FIG. 45 is a configuration diagram of a power conversion system according to another embodiment of the present invention.

[Explanation of symbols]

1,91 ... Commercial power supply, 2,31,37,65 ... Reactor, 3,
10, 14 ... Voltmeter, 4, 11, 15, 21 ... Ammeter, 5 ...
AC load, 6,33,36,66,79 ... Diode, 7,32
… Semiconductor switching element, 13,95… Bidirectional converter
, 8 ... smoothing capacitor, 9, 30, 94 ... solar cell, 1
2,102 ... DC-DC converter, 16 ... Inverter, 1
7 ... Motor for compressor, 18, 112 ... System control circuit, 1
9,87 ... Bidirectional converter control circuit, 34, 80 ... Switch circuit, 35, 38, 67, 71 ... Capacitor, 39 ... Load, 4
0,50,59 ... Multiplication circuit, 41 ... Comparison circuit, 51,53,81 ... Differentiation circuit, 52,54 ... Positive / negative determination circuit, 55 ... Exclusive OR circuit, 56
... Integrator circuit, 57,60 ... Error amplifier circuit, 58 ... Switching circuit, 61 ... ROM, 70 ... Resistance, 72 ... OP amplifier, 73 ... DC power supply, 74 ... FET, 75 ... GND, 76 ... AC power supply, 77 ...
Zener diode, 82,83 ... Triangular wave generation circuit, 84,85 ...
Comparing circuit, 86 ... Inversion circuit, 91, 93, 96 ... Contactor, insulating transformer ... 92, 97-101 ... Detector, 110 ... Indoor unit, 111 ... Display panel, 120 ... DC load, 121 ... Energy conversion means, 122 ... Motor, 123 ... Thermoelectric element, 124 ... Indoor unit, 125 ... ROM, 126
… Outdoor unit, 127… Protection circuit, 131… Commercial power supply, 132… Reactor, 133,134… Diode, 135,136… Capacitor,
137 ... Rectification means, 137 (a) ... Double voltage rectification circuit, 138, 139 ... Semiconductor switching element, 140 ... Backflow prevention diode, 141
… Solar cells, 142… DC voltage detectors, 143… Inverters,
144 ... Noise filter, 145 ... Motor, 146 ... Inverter
Control circuit, 147 ... Control means, 148 ... DC reference voltage, 149
… Error amplifier, 150… Voltage transformer, 151… Multiplier, 152…
Current transformer, 153 ... Hysteresis comparator, 154 ... Pulse shaping circuit, 155, 156 ... Isolation amplifier, 160
…switch.

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] September 24, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0071

[Correction method] Change

[Correction content]

The semiconductor switching element 32 is on / off controlled by a control signal sent from the system control circuit 18. This control signal is a square wave signal output from the comparison circuit 41, and is a wave obtained by multiplying the duty ratio DR read from the ROM 42 and the constant amplitude wave from the constant voltage source 43 in the multiplication circuit 40. Is compared with the triangular wave output from the triangular wave generating circuit in the comparison circuit 41 . FIG. 19 shows the configuration of the multiplication circuit, and FIG. 20 shows the configuration of the comparison circuit.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0094

[Correction method] Change

[Correction content]

FIG. 41 is a block diagram of a solar air conditioner system in which a protection device is provided in the solar air conditioner. In the solar air conditioner described above, a contactor 91, an insulating transformer 92, and a contactor 93 are provided between the commercial power source 90 and the input part of the bidirectional converter 95, and the solar cell 94 and the DC-DC converter are provided. A contactor 96 is provided between the input parts of 102. The contactor 91 detects the information of the detectors 97 to 99 for detecting AC overvoltage, AC undervoltage, and frequency abnormality, and the contactor 93 detects AC overcurrent. The contactor 96 operates on the basis of the information of the detector 100 which detects the DC ground fault.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of symbols] 1, 90 ... Commercial power supply, 2, 31, 37, 65 ... Reactor 3,
10, 14 ... Voltmeter, 4, 11, 15, 21 ... Ammeter, 5 ...
AC load, 6,33,36,66,79 ... Diode, 7,32
… Semiconductor switching element, 13,95… Bidirectional converter
, 8 ... smoothing capacitor, 9, 30, 94 ... solar cell, 1
2,102 ... DC-DC converter, 16 ... Inverter, 1
7 ... Motor for compressor, 18, 112 ... System control circuit, 1
9,87 ... Bidirectional converter control circuit, 34, 80 ... Switch circuit, 35, 38, 67, 71 ... Capacitor, 39 ... Load, 4
0,50,59 ... Multiplication circuit, 41 ... Comparison circuit, 51,53,81 ... Differentiation circuit, 52,54 ... Positive / negative determination circuit, 55 ... Exclusive OR circuit, 56
... Integrator circuit, 57,60 ... Error amplifier circuit, 58 ... Switching circuit, 61 ... ROM, 70 ... Resistance, 72 ... OP amplifier, 73 ... DC power supply, 74 ... FET, 75 ... GND, 76 ... AC power supply, 77 ...
Zener diode, 82,83 ... Triangular wave generation circuit, 84,85 ...
Comparing circuit, 86 ... Inversion circuit, 91, 93, 96 ... Contactor, insulating transformer ... 92, 97-101 ... Detector, 110 ... Indoor unit, 111 ... Display panel, 120 ... DC load, 121 ... Energy conversion means, 122 ... Motor, 123 ... Thermoelectric element, 124 ... Indoor unit, 125 ... ROM, 126
… Outdoor unit, 127… Protection circuit, 131… Commercial power supply, 132… Reactor, 133,134… Diode, 135,136… Capacitor,
137 ... Rectification means, 137 (a) ... Double voltage rectification circuit, 138, 139 ... Semiconductor switching element, 140 ... Backflow prevention diode, 141
… Solar cells, 142… DC voltage detectors, 143… Inverters,
144 ... Noise filter, 145 ... Motor, 146 ... Inverter
Control circuit, 147 ... Control means, 148 ... DC reference voltage, 149
… Error amplifier, 150… Voltage transformer, 151… Multiplier, 152…
Current transformer, 153 ... Hysteresis comparator, 154 ... Pulse shaping circuit, 155, 156 ... Isolation amplifier, 160
…switch.

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Correction target item name] Fig. 27

[Correction method] Change

[Correction content]

FIG. 27

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Kitayama 800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture Living Equipment Division, Hitachi, Ltd.

Claims (21)

[Claims] 1. An energy conversion means, a DC-DC converter, and a bidirectional converter having a function of converting AC power from a commercial power source into DC power and a function of converting DC power into AC power. A direct current load is provided, the output side of the energy conversion means and the input side of the DC-DC converter are connected, and the output side of the DC-DC converter and the bidirectional converter.
In a power conversion system in which a DC portion and a DC load of the DC power converter are connected, a first ammeter is provided between the DC-DC converter and the DC load or the bidirectional converter, and a second ammeter is provided between the DC load and the bidirectional converter. An ammeter is provided, and a voltmeter is provided in the DC portion between the DC-DC converter and the DC load or the bidirectional converter or between the DC load and the bidirectional converter, and the first ammeter, the second ammeter and the voltmeter are connected. A duty ratio setting means for changing the duty ratio of the DC-DC converter based on the detection signal, and a control means for causing the bidirectional converter to regenerate or power-run the power based on the duty ratio set by the duty ratio setting means are provided. A power conversion system characterized by that. 2. An energy conversion means, a DC-DC converter, and a bidirectional converter having a function of converting AC power from a commercial power source into DC power and a function of converting DC power into AC power. A direct current load is provided, the output side of the energy conversion means and the input side of the DC-DC converter are connected, and the output side of the DC-DC converter and the bidirectional converter.
In a power conversion system in which a DC part of a power supply and a DC load are connected, at least an energy conversion means and a DC-DC
A first voltmeter and a first ammeter are provided between the converter and a second voltmeter and a second ammeter are provided at the direct current portion between the direct current load and the bidirectional converter. DC- based on the detection signals of the second ammeter, the first voltmeter, and the second voltmeter
A duty ratio setting means for changing the duty ratio of the DC converter, and a control means for causing the bidirectional converter to regenerate or power the power based on the duty ratio set by the duty ratio setting means are provided. Power conversion system. 3. An energy conversion means, a DC-DC converter, and a bidirectional converter having a function of converting AC power from a commercial power source into DC power and a function of converting DC power into AC power. A direct current load is provided, the output side of the energy conversion means and the input side of the DC-DC converter are connected, and the output side of the DC-DC converter and the bidirectional converter.
In the power conversion system in which the DC part of the inverter and the DC load are connected, a first voltmeter and a first ammeter are provided between the commercial power supply and the bidirectional converter, and the AC load other than the bidirectional converter and the commercial power supply are connected. A second ammeter is provided between them, a second voltmeter and a third ammeter are provided between the DC load and the bidirectional converter, and a first ammeter, a second ammeter, a third ammeter,
DC-DC based on the detection signals of the first voltmeter and the second voltmeter
Electric power characterized by comprising duty ratio setting means for changing the duty ratio of the converter, and control means for causing the bidirectional converter to regenerate or power the power based on the duty ratio set by the duty ratio setting means. Conversion system. 4. The motor for a compressor according to claim 1, wherein a solar cell or a thermoelectric element is used as the energy conversion means, and when the solar cell is used as the energy conversion means, a DC load is driven. A power conversion system characterized by using an inverter that operates. 5. The CuK type or Sepic as the DC-DC converter according to claim 1.
Type converter, a signal having a magnitude proportional to the duty ratio and a signal from the triangular wave generating circuit are sent to the comparing circuit, and the output signal of the comparing circuit is sent to the semiconductor switching element of the DC-DC converter. A power conversion system having a circuit. 6. The voltmeter and the current according to claim 1, wherein the control means connected to the bidirectional converter is provided between the energy conversion means and the DC-DC converter. A first multiplying circuit that receives the detection signal of the meter, a first differentiating circuit that is connected to the first multiplying circuit, a first positive / negative determining circuit that determines whether the output of the first differentiating circuit is positive or negative, and the voltage Exclusive OR of a second differential circuit that differentiates the detection signal of the meter, a second positive / negative determination circuit that determines the positive / negative of the output of the second differential circuit, and both outputs of the first and second positive / negative determination circuits An exclusive OR circuit, an integration circuit that integrates the output of the exclusive OR circuit, a first error amplification circuit that amplifies an error between the output of the integration circuit and the detection signal of the voltmeter, and a commercial power supply Input the detection signal of the voltmeter installed between the bidirectional converters and the error amplifier circuit. And a second error amplification circuit for amplifying an error between the detection signal of the ammeter provided between the commercial power source and the bidirectional converter and the output signal of the second multiplication circuit. Power conversion system characterized by. 7. A point where the output of the DC-DC converter becomes maximum when the DC-DC converter is operated under a set duty ratio is obtained. In this state, (a) DC
-When the output power or output current of the DC converter is equal to or higher than the input power or input current of the DC load, the duty ratio is maintained or lowered when the voltage of the DC part is higher than the set voltage value, and the duty ratio is raised otherwise. (B) When the output current or output power of the DC-DC converter is smaller than the input current or input power of the DC load, when the voltage of the DC part becomes smaller than the set voltage value, the duty ratio is maintained or increased or The power conversion system according to claim 1, further comprising duty ratio control means for performing control to reduce the duty ratio. 8. A point where the output of the energy conversion means is maximized is obtained in a state where the DC-DC converter is operated under a set duty ratio, and in this state, (a) the energy conversion means When the value obtained by multiplying the output by the correction coefficient is equal to or greater than the input of the DC load, hold or reduce the duty ratio when the voltage of the DC part is higher than the set voltage value, or increase the duty ratio otherwise.
(b) When the value obtained by multiplying the output of the energy conversion means by the correction coefficient is smaller than the input of the DC load, the duty ratio is maintained or increased when the voltage of the DC portion is smaller than the set voltage value, or otherwise. The power conversion system according to claim 2, further comprising duty ratio control means for decreasing the ratio. 9. A point where the output of the energy conversion means is maximized in a state where the DC-DC converter is operated under a set duty ratio is obtained, and in this state, the commercial power source and the bidirectional converter are connected. Calculate the power value that flows into the bidirectional converter from the detected values of the voltmeter and ammeter between the two, and the detected value of the ammeter connected to the AC load, and multiply this power value by the correction coefficient or this value. Is divided by the voltage value in the DC portion and the electric power or current flowing into the DC load is compared to obtain the electric power or current flowing into the DC portion from the energy conversion means via the DC-DC converter ( a) When this value is equal to or higher than the input power or the input current of the DC load, the duty is maintained or lowered when the voltage of the DC part is higher than the set voltage value, and the duty is increased otherwise.
(B) When this value is smaller than the input power or input current of the DC load, the duty ratio is maintained or increased when the voltage of the DC portion is lower than the set voltage value, and the duty ratio is decreased otherwise. The power conversion system according to claim 3, further comprising means. 10. A point where the output of the DC-DC converter becomes maximum in a state where the DC-DC converter is operated under a set duty ratio is obtained, and in this state, (a) D
When the output power or output current of the C-DC converter is equal to or higher than the input power or input current of the DC load, the duty ratio is decreased when the voltage of the DC portion is higher than the set upper limit voltage value, and the duty ratio is increased otherwise. (b) When the output current or output power of the DC-DC converter is smaller than the input current or input power of the DC load, increase the duty ratio when the voltage of the DC part is less than the set lower limit voltage value, or otherwise. The power conversion system according to claim 1, further comprising duty ratio control means for controlling to lower the ratio. 11. A point where the output of the energy converting means is maximized in a state where the DC-DC converter is operated under a set duty ratio is obtained, and in this state, (a) the energy converting means When the value obtained by multiplying the output by the correction coefficient is equal to or higher than the input of the DC load, the duty ratio is decreased when the voltage of the DC portion is higher than the set upper limit voltage value, and the duty ratio is increased otherwise (b) the energy converting means. If the value obtained by multiplying the output of 1 by the correction coefficient is smaller than the input of the DC load, the duty ratio is increased when the voltage of the DC part is less than the set lower limit voltage value, and the duty ratio is decreased otherwise. The power conversion system according to claim 2, further comprising: 12. A point where the output of the energy conversion means is maximized in a state where the DC-DC converter is operated under a set duty ratio is obtained, and in this state, the commercial power source and the bidirectional converter are connected. Calculate the power value that flows into the bidirectional converter from the detected values of the voltmeter and ammeter between the two, and the detected value of the ammeter connected to the AC load, and multiply this power value by the correction coefficient or this value. Is divided by the voltage value in the DC portion and the electric power or current flowing into the DC load is compared to obtain the electric power or current flowing into the DC portion from the energy conversion means via the DC-DC converter ( a) When this value is equal to or higher than the input power or input current of the DC load, the duty ratio is decreased when the voltage of the DC portion is higher than the set upper limit voltage value, and the duty ratio is increased otherwise, and (b) this value is DC load on 4. A duty ratio control means for increasing the duty ratio when the voltage of the direct current portion is less than the set lower limit voltage value and lowering the duty ratio when the voltage of the DC portion is less than the set power voltage or the input current. The described power conversion system. 13. The power conversion system according to claim 7, wherein the duty ratio control means operates according to a control program stored in advance in the ROM. 14. The power conversion system according to claim 8, wherein the efficiency of the DC-DC converter is used as the correction coefficient. 15. The power conversion system according to claim 9, wherein the efficiency of the bidirectional converter is used as the correction coefficient. 16. The switching circuit according to claim 6, wherein a switching circuit is provided between the first error amplification circuit and the second multiplication circuit, and the switching circuit is operated by a control signal from the outside to operate one of the second multiplication circuits. A power conversion system having a configuration in which a predetermined signal is input to the input. 17. In any one of claims 7 to 9, the set voltage value is a value obtained by multiplying a detection value of a voltmeter provided between the commercial power source and the bidirectional converter by a proportional constant. A power conversion system characterized by giving. 18. A contactor is provided between the commercial power source and the bidirectional converter, and is provided between the commercial power source and the bidirectional converter when AC overcurrent, AC overvoltage, or AC undervoltage occurs. By the logical sum of the system cutoff signal from the control means for detecting the measurement value of the voltmeter and the independent system overcurrent, alternating current overvoltage, alternating current undervoltage, and the system shutdown signal from the circuit for judging the frequency abnormality, 18. The power conversion system according to claim 1, wherein a contactor provided between the bidirectional converter and the commercial power supply is operated to cut off the commercial power supply. 19. A regenerative mode or a power running mode is determined from the measured values of a voltmeter and an ammeter provided between a commercial power source and a bidirectional converter, and from the voltage signal and current signal, 19. A function for calculating at least one of regenerative power and cumulative regenerative power and displaying a result or a value obtained by multiplying the result by a power unit price, according to any one of claims 1 to 18. Power conversion system. 20. The power conversion system according to claim 19, wherein the power conversion system includes an outdoor unit and an indoor unit, and the display function is provided in the indoor unit. 21. A control ROM for a power conversion system, which stores a control program executed by the duty ratio control means according to any one of claims 7 to 12.