WO2003075113A1

WO2003075113A1 - Power generating system

Info

Publication number: WO2003075113A1
Application number: PCT/JP2002/001975
Authority: WO
Inventors: Josuke Nakata
Original assignee: Josuke Nakata
Priority date: 2002-03-04
Filing date: 2002-03-04
Publication date: 2003-09-12
Also published as: AU2002234951A1; TW563286B

Abstract

A power generating system (1) comprising a power generator (2) generating DC power, and an inverter circuit (3) for converting DC power into AC power, wherein the power generator (2) comprises a plurality of power generating modules (21-28) each comprising a plurality of power generating units (30). A plurality of first switch means (S11-17) connect/separate the positive electrodes (62) of the plurality of power generating modules (21-28) with/from a positive bus (6), a plurality of second switch means (S11-17) connect/separate the positive electrodes (62) of the plurality of power generating modules (21-28) with/from the negative electrodes (60) of the power generating modules (21-27) contiguous to the one side, a plurality of third switch means (S1-7) connect/separate the negative electrodes (60) of the plurality of power generating modules (21-27) with/from a negative bus (7), and the DC output voltage can be increased/decreased stepwise by switching the switch means (S1-S7, S11-17).

Description

Specification

Power generation system technical field

The present invention relates to a power generation system that generates AC power from DC power generated by a solar cell, a fuel cell, or the like via an inverter circuit, and is characterized by a switching mechanism that switches the voltage of DC power in multiple stages. . Background art

Recently, the cost of producing solar cells for solar power generation systems has been gradually reduced, and Zola power generation systems are becoming popular in many homes.The majority of Zola power generation systems are commercial single-phase AC power supplied to homes. It is a system linkage type system linked to the system. The solar cell of the home solar power generation system has an output of several kW, and several ten power generation modules are connected in series and parallel. In the above-mentioned system-linked Zora power generation system, it is necessary to convert DC power into AC power suitable for a single-phase AC system via an inverter circuit.

The known solar power generation system shown in Fig. 17 is a general system-coupling system that controls the inverter circuit by the PWM method.A plurality of power generation modules connected in series are connected in parallel. A control device 102 for switching and controlling the solar cell 100, the inverting circuit 101, and the inverting circuit 101 is provided. The control device 102 includes a voltage detector 103 for detecting a reference voltage of the AC system, an amplifier 104 for amplifying the detected voltage, a triangular wave generator 105, a PWM control unit 106, and the like. As shown in FIG. 17, the PWM control unit 106 controls the switch elements of the inverter circuit 101 based on the sine wave 107 of the command voltage based on the reference voltage and the carrier wave 108 generated by the triangular wave generator 105. Then, a square-wave AC voltage 109 as shown in Fig. 18 is generated, and the square-wave AC voltage 109 is smoothed by a filter circuit, converted into a sine-wave AC power, and output to the AC system. . In the above-mentioned technology for controlling the inverter circuit using the PWM method, the output of the solar cell is intermittently converted into AC power, so only about 90% of the output of the solar cell can be used. There's a problem. Moreover, since harmonic components related to the switching frequency of the switching elements of the inverter circuit and the impedance of the AC system are generated, it is necessary to provide a filter means for absorbing the harmonic components and a means for removing electromagnetic interference. No. In addition, since the number of times of switching accompanied by a large voltage change is large, there is also a problem that a loss in a power device such as a switching element of an inverter circuit increases.

On the other hand, a battery switching type solar power generation system has been proposed in which the output voltage is switched in multiple stages by switching the number of solar cells from which outputs are taken out of a plurality of solar cells. In this power generation system, as shown in FIG. 19, for example, four sets of solar cells 110 capable of generating DC power of 10 V, 20 V, 40 V, and 80 V are provided, and switches S i, S ₂ , by switching on only switch S i out of S ₃ and S ₄ , the DC power of 10 V is output, and by appropriately combining the switches that switch on, the DC power voltage is reduced by 10 V units. Can be increased or decreased step by step, and can be switched to 20 V, 30 V,..., 140 V, 15 OV. The DC power is converted into AC power as shown in FIGS. 20 (A) and (B) by the inverter circuit 111 and output to the AC system. In the case of this battery switching type solar power generation system, generation of harmonics and electromagnetic interference is improved as compared with the power generation system of FIG. 17 described above. However, the use of the output of the four solar cells is only for a very short period during which the peak voltage is generated, and one or more solar cells are in an idle state during most of the period. There is a problem that the rate becomes extremely low.

By the way, recently, the development of a fuel cell type power generation system is also progressing, and it is estimated that it will gradually be put into practical use as a household power generation system in the near future.

The fuel cell is configured such that a large number of unit cells are provided in a stacked state, and the large number of unit cells are connected in series to output DC power. Each unit battery generates DC power of about 0.6 to 0.7 V, so this power generation system is linked to a single-phase AC system for home use, and the DC power generated by the power generation system is To the AC system This technique has the same problems as those of the Zora power generation system. Disclosure of the invention

A power generation system according to the present invention is a power generation system including: a power generation device that generates DC power; and an inverter circuit that converts DC power generated by the power generation device into AC power. Each of the power generation modules has a plurality of power generation units or a plurality of power generation modules each including a plurality of power generation units, and a positive / negative bus connected to an input side of the inverter circuit, and each of the plurality of power generation modules. A plurality of first switch means that can be separated and a plurality of separable second switch means that connect the positive electrode of each of the plurality of power generation modules to the negative electrode of an adjacent power generation module on one side And a plurality of third switch means capable of connecting and separating each negative electrode of the plurality of power generation modules to the negative bus.

When all the first switch means are turned on, all the second switch means are turned off, and all the third switch means are turned on, all the power generation modules are connected in parallel to the positive and negative buses, and the DC output voltage is changed. Is the minimum voltage Vmin.

A plurality of power generation modules are divided into a plurality of groups, and a plurality of power generation modules of each group are connected in series by a plurality of second switch means, and are connected in parallel to positive and negative buses by first and third switch means. can do. If the number of power generation modules connected in series is two, the DC output voltage will be 2 Vmin, and if the number of power generation modules connected in series is four, the DC output voltage will be 4 Vmin. In this way, the DC output voltage output from the power generator can be increased or decreased stepwise.

Moreover, the DC output voltage can be switched stepwise only by switching the first, second, and third switch means as described above while effectively utilizing the outputs of all the power generation modules. The idle of the power generation module does not occur, and the utilization rate of the power generation module can be sufficiently increased.

Even if a plurality of first, second, and third switch means are switched, the voltage change at the time of switching the switch means is small. Noise and harmonics are less likely to occur. Therefore, the structure of the accompanying electric circuit can be simplified, for example, by reducing the filter capacitance for absorbing noise and harmonics and for measures against electromagnetic interference. The frequency of switching of the plurality of first, second, and third switch means is also less than the frequency of switching of the switching elements of the inverter circuit of the PWM system, and the plurality of first, second, and third switches are switched. As a means, a small switching element can be applied, and the switching loss is reduced.

Here, when the power generation module is a solar cell power generation module, the connection pattern of the plurality of first, second, and third switch means is changed according to a decrease in the output voltage of the power generation module, such as in cloudy weather, morning, or evening. In addition, the voltage of the DC power output from the power generator can be adjusted, so that there is no need to provide a boost chopper, and the system has high versatility and flexibility. When the output voltage is increased stepwise, the output current decreases stepwise, and when the output voltage is decreased stepwise, the output current increases stepwise so that the first and second output currents gradually increase. Since the third switch means can be switched, it is possible to control the power generator to operate at the maximum power point. The above is the operation and effect of the power generation system of the present invention.

Here, preferably, the following various configurations may be adopted.

(a) The plurality of first, second, and third switch means are respectively constituted by semiconductor switching elements, and by controlling the switching of the plurality of first, second, and third switch means, A control device for switching the output voltage stepwise is provided.

(b) The plurality of power generation modules are divided into a plurality of groups, and the plurality of power generation modules of each group are connected in series by the plurality of second switch means by the control device. It is configured to be connectable in parallel to the positive and negative buses.

(c) The inverter circuit includes a plurality of semiconductor switching elements, and the semiconductor switching elements are controlled by the control device.

(d) voltage detection means for detecting a voltage of an AC power system receiving power supply from the power generation system; and the control device detects first, second, and third switch means based on a detection signal of the voltage detection means. And controlling a plurality of semiconductor switching elements of the impeller circuit. (f) The plurality of power generation units of the power generation module are arranged in a matrix of a plurality of columns and a plurality of rows, and are connected in parallel and in series.

(g) Each of the power generation units is a solar cell formed by forming a pn junction on a granular semiconductor.

(h) The power generation device is configured by a fuel cell in which a plurality of unit cells are stacked, and each of the power generation units is configured by the unit cell. BRIEF DESCRIPTION OF THE FIGURES

1 is a configuration diagram of the power generation system, FIG. 2 is a cross-sectional view of the power generation unit, FIG. 3 is a cross-sectional view of the power generation unit, FIG. 4 is a cross-sectional view of the power generation unit, and FIG. FIG. 6 is a transistor circuit diagram showing a configuration of switches S11 to S17, and FIG. 7 is a block diagram of a control device of the power generation system. 8 is an explanatory diagram of an operation of the power generation system in the power generation mode Ml, FIG. 9 is an operation explanatory diagram of the power generation system in the power generation mode M2, and FIG. 10 is a diagram in the power generation mode M4. Fig. 11 is a diagram illustrating the operation of the power generation system. Fig. 11 is a diagram illustrating the operation of the power generation system in the power generation mode M8. Fig. 12 is a diagram illustrating the voltage waveform of the DC power output from the power generation system of Fig. 1 and the single-phase AC. FIG. 13 is a diagram of voltage waveforms of a power system, and FIG. 13 shows a power generation system according to a modified embodiment. FIG. 14 is a circuit diagram of the power generation module, FIG. 15 is an explanatory diagram of the power generation mode and output voltage in the power generation system of FIG. 13, and FIG. 16 is a diagram of FIG. Fig. 17 is a configuration diagram of a power generation system provided with two sets of power generation systems of Fig. 3, Fig. 17 is an explanatory diagram of output voltage in the power generation system of Fig. 16, and Fig. 18 is a diagram of DC power output from the power generation system. It is a figure of a voltage waveform and a voltage waveform of a single phase alternating current system.

Fig. 19 to Fig. 22 show the prior art, Fig. 19 shows the overall configuration of the PWM type power generation system, and Fig. 20 shows the command voltage sine wave, carrier wave and square wave AC in the PWM system. Fig. 21 is the overall configuration diagram of the battery switching type power generation system, and Fig. 22 (A) is a diagram of the voltage waveform generated in the power generation system of Fig. 19; Figure 22 (B) shows the current waveform generated in the power generation system of 闵 19. FIG. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the power generation system of the present invention will be described. As shown in FIGS. 1 to 7, the power generation system 1 includes a power generation device 2 that generates DC power, and a DC power generated by the power generation device 2 that is converted into AC power to form a single-phase AC system. Controls the inverter circuit 3 to be output, the switching mechanism S m for switching the DC power voltage of the power generator 2 in multiple stages, and the switching mechanism S m and the switching elements 51 to 54 of the evening circuit 3 And a voltage detector 5 that detects the voltage of the single-phase AC system and inputs the voltage to the control device 4. For convenience of explanation, the power generation device 2 in the present embodiment has eight power generation modules 21 to 28 arranged in one row in the same power generation direction, and each power generation module 21 to 28 has two rows. It has 10 power generation units 30 arranged in a matrix of 5 rows and connected in parallel and in series.

Each of the power generation units 30 is composed of any one of the three types of granular solar cells 30 A to 30 C shown in FIGS. 2 to 4, for example. It can generate DC of 5 to 0.6 V.

The zora cell 3 OA in FIG. 2 is composed of a spherical semiconductor 31 composed of an n-type syringe with a diameter of about 1.5 to 3.0 mm, a p-type diffusion layer 32, a pn junction 33, a silicon oxide insulating film 34, It comprises a positive electrode 35 and a negative electrode 36 which face each other across the center of the spherical semiconductor 31. This type of solar cell 3OA is described in WO98 / 15983 filed by the present applicant. The zora cell 30 B in FIG. 3 includes a spherical semiconductor 37 made of a P-type syringe having the same size as described above, an n-type diffusion layer 38, a ∑11 junction 39, a silicon oxide insulating film 40, and a sphere. The positive electrode 41 and the negative electrode 42 oppose each other with the center of the semiconductor 37 interposed therebetween.To facilitate identification of the positive electrode 41 and the negative electrode 42, the negative electrode is formed on a flat surface formed at the bottom of the spherical semiconductor 37. 42 are provided. The solar cell 30 C shown in FIG. 4 is a columnar semiconductor 43 made of a p-type syringe having a diameter of about 1.5 to 3.0 mm, an n-type diffusion layer 44, 1 junction 45, p ⁺ diffusion layer 4 6, silicon oxide And a positive electrode 48 and a negative electrode 49 provided at both ends.

However, the above-mentioned solar cells 30 A to 30 C are merely examples, and various types of power generation modules having a function of generating DC power of about 5 to 10 V (for example, A single panel-shaped solar cell or a solar cell or a fuel cell that is a collection of multiple small panel-shaped solar cells can be applied. The power generation unit 30 includes, for example, various power generation units or power generation units or power generation function units that generate DC power of a relatively low voltage (for example, one panel-shaped solar cell / a plurality of small panels). One or more power generation units and power generation function units included in a solar cell that is assembled into a panel by grouping solar cells, one or more single cells of a fuel cell, or one or more batteries such as dry cells and storage batteries) It is also possible to apply

The inverter circuit 3 is composed of, for example, four switching elements 5:! To 54, which are composed of n-channel IGBTs, connected in a bridge form, and each of the switching elements 51 to 54 has a freewheeling diode 55 to 54. 5 and 8 are also connected. These four switching elements 51 to 54 are controlled by a control signal from the control device 4. The switching elements 51, 54 and the switching elements 53, 52 are paired and alternately turned on to output AC to a single-phase AC system. Next, the switching mechanism will be described.

The input side of the inverter circuit 3 is connected to a positive bus 6 and a negative bus 7. The switching mechanism S m is provided between the power generator 2 and the inverter circuit 3, and switches the output voltage of the DC power generated by the power generator 2 and output to the inverter circuit 3 in eight stages. An arbitrary number of modules 21 to 28 are connected in series, and each of the series-connected power generation module groups can be connected to the inverter circuit 3 in parallel. The switching mechanism Sm has a plurality of switches S1 to S7 and S11 to S17. The switches S1 to S7 are switches that can be switched between a state in which the negative electrode 60 of each of the seven power generation modules 21 to 27 is connected to the negative bus 7 and a state in which the negative electrode 60 is separated. Each of the switches S1 to S7 is composed of, for example, an npn-type bipolar transistor 61 that is turned on and off by a control device 4, as shown in FIG. Each of the switches S11 to S17 has seven power generation modules 22 to 28. Each of the positive electrodes 62 has a function of selectively connecting to the positive bus 6 with the negative electrodes 62 of one of the power generation modules 21 to 27 adjacent to the positive electrode 62 side. Each of the switches S11 to S17 is composed of, for example, two npn-type bipolar transistors 63 and 64 that are turned on and off by the control device 4, as shown in FIG. The positive electrode 62 can be connected and separated to the negative electrode 61 of the adjacent power generation module, and the positive electrode 62 can be connected and separated to the positive bus 6 by the other bipolar transistor 64. Then, when the transistor 63 is on, the transistor 64 is off, and when the transistor 64 is on, the transistor 63 is off.

The transistor 64 in the switches S11 to S17 corresponds to the first switch means, the transistor 63 in the switches S11 to S17 corresponds to the second switch means, and the transistor 61 in the switches S1 to S7 corresponds to the first switch means. This is equivalent to the third switch means. In addition, the npn-type bipolar transistors 61, 63, and 64 are merely examples, and any of these switching elements capable of on / off control may be applied. The switching elements 51 to 54 of the inverter circuit 3 are merely examples, and another switching element such as M0S FET may be applied.

Next, the control device 4 will be described.

As shown in FIG. 7, the control device 4 mainly includes a computer including a CPU 65, a ROM 66, and a RAM 67, and an input / output interface 68, and includes switches S1 to S7 and switches S11 to S17. Connected to input / output interface 68. A voltage detector 5 for detecting the AC voltage of the single-phase AC system is provided, and a detection signal of the voltage detector 5 is input to the control device 4. The ROM 66 of the control device 4 controls to switch the switches S1 to S7, the switches S11 to S17, and the switching elements 51 to 54 based on the detection signal from the voltage detector 5 as described later. The program is stored in advance.

The control device 4 controls the switches S1 to S7 and the switches S11 to S17 on and off based on the control program of the ROM 66, thereby switching the output voltage of the DC power of the power generation device 2 stepwise. Since the power generation voltage of each of the power generation modules 21 to 28 in this embodiment is about 1.0 to 1.2 V, as shown in FIG. 8, the state where the switches S1 to S7 and the switches S11 to S17 are switched (this is the power generation mode M 1 mode), when all the power generation modules 21 to 28 are connected in parallel to the positive and negative buses 6 and 7, power is generated by receiving sunlight. Power generator 2 outputs DC power of about 1.0 to 1.2 V . As shown in Fig. 9, switches S1 to S7 and switches S11 to S17 are switched, the eight power generation modules 21 to 28 are divided into two groups of two, and the two power generation modules of each group are connected in series. When the four power generation modules are connected in parallel to the positive and negative buses 6 and 7 in the connected state (this is referred to as the power generation mode M2), the power generator 2 outputs DC power of about 2.0 to 2.4 V. As shown in Fig. 10, switches S1 to S7 and switches S11 to S17 are switched, the eight power generation modules 21 to 28 are divided into two groups of four, and the four power generation modules of each group are connected in series. In the connected state (this is referred to as power generation mode M4), when the two power generation module groups are connected in parallel to the positive and negative buses 6, 7, the generator 2 outputs DC power of about 4.0 to 4.8 V. As shown in Fig. 11, switches S1 to S7 and switches S11 to S17 are switched, and eight power generation modules 21 to 28 are connected in series (this is referred to as power generation mode M8). 2 outputs DC power of about 8.0 to 9.6 V.

As shown in FIG. 12, the control device 4 switches S1 to S7 and S11 to S11 in accordance with the AC waveform 70 of the AC voltage of the single-phase AC system detected by the voltage detector 5. By switching S17 and controlling the switching of the switching elements 51 to 54, the AC power of the voltage waveform 71 that changes stepwise as shown by the solid line is output from the output terminals 8 and 9 of the impeller circuit 3 to the single-phase AC system. can do.

In this case, the times tl, t2, t3, and t4 shown in the figure are preset in the computer so as to match the frequency of the single-phase AC system, so that the switches S1 to S7 and the switches S11 to S11 are set. By switching S17, the output voltage can be switched stepwise. Then, when the voltage of the single-phase AC system switches from negative to positive, the switching elements 51 and 54 are turned on and the switching elements 53 and 52 are turned off, and the voltage of the single-phase AC system is switched from positive to negative. Sometimes, the switching elements 53 and 52 become conductive The switching elements 51 and 54 are switched off.

In the power generation system 1 described above, by switching the switches S 1 to S and S 11 to S 17 of the switching mechanism in various patterns, the DC output voltage output from the power generation system 1 is stepwisely changed. It can be increased or decreased.

Moreover, while effectively utilizing the outputs of all the power generation modules 21 to 28, as described above, only by switching the switches S1 to S and S11 to S17, the DC output voltage can be gradually increased. Can be switched. Therefore, the power generation modules 21 to 28 are not idled, and the utilization rate of the power generation modules 21 to 28 can be sufficiently increased. Since a parallel connection line is provided in the middle section of each power generation module 21 to 28, even if some of the power generation units are broken or power is not generated due to shade, current flows through the parallel connection lines as necessary. And output reliably.

Even if a plurality of switches S1 to S7 and S11 to S17 are switched, noise and harmonics are less likely to be generated because the voltage change when the switches are switched is small. Therefore, the structure of the accompanying electric circuit can be simplified, for example, by reducing the filter capacity for absorbing noise and harmonics and preventing electromagnetic interference. The switching frequency of the switches S1 to S7 and S11 to S17 is also lower than the switching frequency of the switching elements of the PWM inverter circuit, and the switches S1 to S7 and S1 As 1 to S 17, a small-sized switching element can be applied, and switching loss can be reduced.

Here, the switching pattern of the switches S1 to S7 and S11 to S17 is changed according to the decrease in the output voltage of the power generation modules 21 to 28 in cloudy weather, morning, evening, etc. Since the voltage can be adjusted, there is no need to provide a booster chopper, and the system is highly versatile and flexible. Also, the switches S1 to S7 and S7 are configured so that the output current decreases stepwise when the output voltage is increased stepwise, and the output current increases stepwise when the output voltage is decreased stepwise. Since the switching from 11 to S17 can be performed, it is possible to control the power generator 2 to operate at the maximum power point. In the power generation system 1 described above, the frequency of the power output from the inverter circuit 3 can be freely changed depending on the control of the control device 4, so that the versatility and flexibility are excellent. In the above description, the case where AC power is output by voltage control has been described as an example.However, AC power is output by current control by switching the switches S1 to S7 and S11 to S17. It can also be configured as follows.

In the above-described embodiment, the power generation device 1 having eight power generation modules 21 to 28 has been described as an example for easy understanding of the present invention. However, in the case of a power generation system that is connected to a commercial single-phase AC system at home, it must be configured to link to an AC system with an effective value of 100 V and a peak value of approximately 140 V. In addition, it is desirable to set the maximum output voltage of the power generation system to 200 V or more, considering that the output of the power generation system will decrease during cloudy weather, morning, and evening. An example of such a power generation system will be described with reference to FIGS.

The power generation system 1A shown in Fig. 13 has a panel structure assembled into one panel, and can be called a power generation panel.

This power generation system 1A includes a power generation device 2A composed of, for example, 48 power generation modules 21A to 25A arranged in the same power generation direction, and an inverter circuit 3 similar to the inverter circuit 3 described above. A, a positive bus 6 A and a negative bus 7 A on the input side of this circuit 3 A, and a switching mechanism S ma (this is a switch S 71 1 to S 74 and a switch S 81 to S 8 4), output terminals 8A and 9A, and a control device (not shown). The switching mechanism Sma is for obtaining the same function as the switching mechanism of the power generation system 1 shown in FIG. 1 of the embodiment, and the switches S71 to S74 include the power generation modules 21A to 2A. It switches between a state in which the 4 A negative electrode 6 OA is connected to the negative bus 7 A and a state in which the negative electrode 6 OA is separated, and is the same as the above-mentioned switches S 1 to S 7. The switches S81 to S84 are used to select the positive electrode 62A of the power generation module 22A to 25A to the negative electrode 6OA and the positive bus 6A of the power generation module 21 to 2448 adjacent to the positive electrode side. They are connected in a unified manner, and are the same as the switches S11 to S17.

Since the power generation modules 21A to 24A have the same structure, the power generation module Le 21A will be described. As shown in Fig. 14, the power generation module 21A is configured by arranging power generation units 3OA in a matrix of, for example, 10 rows and 100 columns, and connecting the power generation units 3OA in parallel and in series as shown. is there. Even when some of the power generation units 3OA are turned off due to shade or a failure, the power generation current flows through the parallel connection line, so the utilization rate of the power generation unit 30A is high, and Excellent durability.

Note that the “matrix of 10 rows and 100 columns” is an example, and the number of rows is not limited to 10, and may be 100 rows or several hundred rows. The number of columns is not limited to 100, but may be several tens, several hundred, or several thousand.

It is also desirable to incorporate a diode for preventing backflow at the positive end of each row of the power generation module 21A.

The power generation unit 3OA itself is the same as the above-described power generation unit 30. Since the output voltage of each power generation unit 3OA is 0.5 to 0.6 V, the maximum output voltage of each of the power generation modules 21A to 25A (clear weather) The output at the time is, for example, 5.0 to 6.0 V. By appropriately switching between the plurality of negative switches S71 to S74 and the plurality of positive switches S81 to S84, the "power generation modes Ml, M2, ”And“ output voltage ”. Regarding technology for configuring a power generation module such as the power generation module 21A into a panel-like structure, a plurality of international applications filed by the present applicant (for example, PCT / JPOO / 073 60, PCT / JP01 / 06972, PCT / JP01 / 09234, PCT / JP01 / 11416).

It is possible to configure a power generation system composed of not only one power generation system 1 (power generation panel) described above but also a plurality of power generation panels. However, only one set of control devices is required. For example, as shown in FIG. 16, in the power generation system 1A, two power generation systems 1A (power generation panels) are provided, and the two power generation systems 1A are connected in series and in parallel. A switch mechanism for switching is also provided. This switch mechanism is composed of switches S65, S66 and the like. The switch S65 is capable of connecting and disconnecting the illustrated circuit, and is formed of, for example, an npn-type bipolar transistor, like the switches S1 to S7. Switch S 66 The switch can be switched between a state in which it is selectively connected to one of the contacts and a state in which it is not connected to any of the contacts. Like the switches S11 to S17, for example, two npn-type pipes are provided. It is composed of a polar transistor. With this switch mechanism, it is possible to switch between a state in which the two power generators 1A are connected in series and a state in which the two power generators 1A are connected in parallel. Then, the output terminals 8B and 9B of the power generating device composed of these two power generating devices 1A are connected to the AC system, and this power generating system is designed so that the output power is linked to the frequency and voltage of the AC system. It is controlled by the control device.

When two power generation panels are connected in parallel, the output voltage of this power generation system can be switched as shown in FIG. In a state where the power generation modes of the two power generation panels are shifted and connected in series, the output voltage of this power generation system can be switched as shown in the total output voltage of FIG.

However, by appropriately setting the power generation mode of both power generation panels while appropriately switching between a state in which the two power generation panels are connected in parallel and a state in which the two power generation panels are connected in series, the output voltage of the power generation equipment is 5 to 6 V , 10 ~ 12V, 15 ~ 18V, 30 ~ 36V, 40 ~ 48V, 60 ~ 92V, 80 ~ 96V, 120 ~ 144V, 200 ~ 240V, 240 ~ 288V, 360 ~ 432V, 480 ~ 576V This is also possible. However, the output voltages described above and the output voltages in FIGS. 15 and 17 show examples in the case where all the power generation units generate the maximum output. When the output voltage of the power generator decreases due to the decrease in the amount of sunlight, such as when it is cloudy, morning, or evening, the total output power shown in Fig. 17 may actually decrease by several to several tens of percent. become . With such a power generation system, as shown in Fig. 18, the AC power of AC voltage 70 of the AC voltage of the commercial It can be output to the AC system.

In this power generation system 1A, a plurality of semiconductor modules 21A to 25A, an inverter circuit 3A, and a plurality of switches S71 to 74 and S81 to S84 are integrated into one panel. In addition, if necessary, it is possible to adopt a structure in which an inverter circuit and multiple switches are incorporated in one semiconductor chip, so that the structure can be simplified as a whole and the manufacturing cost can be reduced. . In addition, since a plurality of power generation systems (power generation panels) can be combined in various forms to generate AC power having a desired frequency, a desired output voltage, or a desired output current, it is excellent in versatility and flexibility. .

The explanations regarding Figs. 16 to 17 are based on the example of a power generation system equipped with two power generation panels (power generation systems). In practice, however, multiple power generation panels are provided and they are connected in parallel. While switching between the connected state and the series connected state, it is also possible to configure so as to output electric power adapted to the voltage or current of the commercial single-phase AC system supplied to the home or the like.

The power generation system shown in FIG. 13 and the power generation system shown in FIG. 16 can basically obtain the same operation and effect as the power generation system 1 described above, and thus the description thereof is omitted here. An example in which the embodiment is partially changed will be described.

(1) In the power generation systems 1 and 1A, the description of the filter, impedance, and the like provided in the circuit on the output side of the inverter circuit 3 has been omitted. However, in an actual power generation system, a filter may be used if necessary. A dance dance is provided. (2) The inverter circuits 3 and 3 A have been described as an example of generating single-phase AC.However, the DC power generated by the power generators 2 and 2 A is converted into three-phase AC by the inverter circuit. In some cases, the DC power generated by the power generator is converted into AC power corresponding to each phase of three-phase AC.

(3) The whole of the power generation system 1 may be formed in one plate or panel. In some cases, for example, as shown in FIG. 16, a plurality of sets of the power generation system shown in FIG. 13 are provided in a plate or panel shape.

(4) It is not necessary to manufacture each of the plurality of power generation modules 21 to 28 and 21A to 25A individually, but may be manufactured integrally as a whole. For example, the plurality of power generation modules in FIG. 13 may be apparently configured as one power generation module, and the electrical circuit may include a plurality of power generation modules as illustrated in FIG.

(5) The above-described power generation systems 1 and 1A have been described by way of example of a separately-excited power generation system linked to an external AC system, but are provided with a battery for storing generated power and a means for generating a reference AC voltage. The present invention can be applied to a self-excited power generation system equipped with

Four Of course you can.

Claims

The scope of the claims

1. In a power generation system including a power generation device that generates DC power, and an inverter circuit that converts DC power generated by the power generation device into AC power,

The power generation device includes a plurality of power generation modules, each including a plurality of power generation units or a plurality of power generation modules including a power generation unit,

Positive and negative buses connected to the input side of the inverter circuit;

A plurality of first switch means capable of connecting each positive electrode of the plurality of power generation modules to the positive bus

A plurality of second switch means capable of connecting and separating each positive electrode of the plurality of power generation modules to a negative electrode of an adjacent power generation module on one side;

A plurality of third switch means capable of connecting each negative electrode of the plurality of power generation modules to the negative bus

A power generation system comprising:

2. The plurality of first, second, and third switch means are each constituted by a semiconductor switching element, and by controlling switching of the plurality of first, second, and third switch means, 2. The power generation system according to claim 1, further comprising a control device that switches an output voltage of the power generation in a stepwise manner.

3. The plurality of power generation modules are divided into a plurality of groups, and the plurality of power generation modules of each group are connected in series by the plurality of second switch means by the control device.

3. The power generation system according to claim 2, characterized in that the power generation system is configured to be connectable in parallel to the positive and negative buses by first and third switch means.

4. The power generation system according to claim 2, wherein the inverter circuit includes a plurality of semiconductor switching elements, and the semiconductor switching elements are controlled by the control device.

5. Voltage detecting means for detecting a voltage of an AC power system receiving power supply from the power generation system is provided, and the control device is configured to perform first, second, and third switching based on a detection signal of the voltage detecting means. A plurality of semiconductor switching of said inverter circuit 4. The power generation system according to claim 3, wherein the element is controlled.

6. The power generation system according to claim 1, wherein the plurality of power generation units of the power generation module are arranged in a matrix of a plurality of columns and a plurality of rows and connected in parallel and in series.

7. The power generation system according to claim 1, wherein each of the power generation units is formed of a solar cell in which a pn junction is formed in a granular semiconductor.

8. The power generation system according to claim 1, wherein the power generation device is configured by a fuel cell in which a plurality of unit cells are stacked, and each of the power generation units includes the unit cell.