JP2000312484A - Solar power generating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar power generating device, which can suppress cost increase and enlargement of a reactor used. SOLUTION: A solar power generating device, which inputs a DC voltage from a solar battery, boosts the voltage by means of a booster section, and generates AC power to a system by converting the boosted DV voltage into an AC output by means of a converter section, is housed in a case 1. The reactor 6 for boosting used for the booster section is arranged on the top side, namely, the downstream side of a reactor 7 for filter used for the converter section.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic power generator for generating AC power based on DC power from a solar cell or the like.

[0002]

2. Description of the Related Art A photovoltaic power generator is disclosed in Japanese Unexamined Patent Publication No.
As described in No. 16, the voltage of the solar cell is boosted and stabilized by the next-stage DC-DC converter, and further converted into a sine-wave AC current by the next-stage DC-AC inverter and output. . For this DC-DC converter, a step-up chopper method described in JP-A-10-23686 is generally used because of its simple circuit configuration.

FIG. 7 shows the circuit configuration. Solar cell PV
1 is connected to an input capacitor C1 at both ends, and a series circuit of a boost reactor L1 and a switch element Q1 is connected to both ends of the input capacitor C1. The anode of the diode D1 is connected to one end of the switch element Q1 to which the boost reactor L1 is connected, and the other end of the switch element Q1 is connected to the diode D1.
The output capacitor C2 is connected between the cathodes. Here, the boost chopper circuit 10 is configured by the boost reactor L1, the switch element Q1, the diode D1, the input capacitor C1, and the output capacitor C2.

In this step-up chopper circuit 10, the switching element Q1 is periodically turned on and off, and the electric energy stored in the step-up reactor L1 when the switching element Q1 is turned on is added to the solar cell PV1 when the switching element Q1 is turned off and output. Supply to capacitor C2. At this time, the output voltage of the boost chopper circuit 10 is adjusted by changing the on / off time ratio of the switch element Q1.

[0005] Further, the DC-AC inverter described above has
A bridge configuration in which four switch elements are combined as described in Japanese Patent Application Laid-Open No. 10-207559 is shown in FIG. The output capacitor C shown in FIG.
2, a series circuit of switch elements Q2 and Q4 and a series circuit of switch elements Q3 and Q5 are connected in parallel. The connection point between the switching elements Q2 and Q4 and the switching element Q
3, a filter reactor L2, an output filter capacitor C3, and a filter reactor L3 between the connection points of Q3 and Q5.
Is connected to the output filter capacitor C3.
Are connected to the system U1 at both ends. At this time, a switching circuit 11 is configured by the switch elements Q2 to Q5, and an output filter 12 is configured by the filter reactors L2 and L3 and the output filter capacitor C3.

Here, the above-mentioned switch elements Q2 to Q5
Of these, the diagonal switch elements Q2 and Q5 and the switch elements Q3 and Q4 respectively perform on / off operations at the same time, the switch elements Q2 and Q4 connected in series perform inversion operations with each other, and the switch elements Q3 and Q5 also The inversion operation is performed mutually.

Here, when the on / off time ratio of the switching elements Q2 to Q5 is 1: 1, the output current becomes zero. By changing the on / off time ratio, the current value and the current direction of the output current are changed. Can be. At this time, when the on / off time ratio is changed to a sinusoidal ratio, a sinusoidal output current is output due to the smoothing effect of the filter reactors L2 and L3.

[0008]

By the way, a DC voltage from a DC power source such as the solar cell PV1 is input and the AC power is output to the system, comprising the above-described boost chopper circuit 10, switching circuit 11, and output filter 12. In a general photovoltaic power generation device, a portion that generates a main loss during operation of the device includes switch elements Q1 to Q5 and a boost reactor L.
1 and filter reactors L2 and L3.

Among them, the switch elements Q1 to Q5 have a certain degree of freedom in that the shape and size of the attached heat sink for reducing the temperature rise due to the loss can be selected to some extent in accordance with the equipment shape of the photovoltaic power generator. On the other hand, the step-up reactor L1, the filter reactors L2, L3
Since the shape is almost uniquely determined by the output power, the switching frequency, and the temperature rise, it lacks the degree of freedom such as thinning in accordance with the shape of the device, and the boosting reactor L1 and the filter reactor L2 in the device are not provided. L
The arrangement of 3 is restricted, and is often installed in a two-story structure in the vertical direction of the device.

When the apparatus of the solar power generation device thus configured is mounted on a wall, the boosting reactor L1 and the filter reactors L2 and L3 both generate heat based on loss, and the upper reactor is actuated by convection of air. It is further heated by the lower reactor. For this reason,
It is necessary to increase the heat resistance rank of the wire type of the upper reactor and the Curie point of the core material, or to increase the shape of the reactor to suppress self-heating, but the problem is that the cost of the reactor itself is increased and the shape is enlarged. Will occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a photovoltaic power generator in which the cost of a reactor to be used and the size of the reactor are suppressed.

[0012]

In order to solve the above-mentioned problems, a first aspect of the present invention provides a booster for boosting a DC voltage from a DC power supply such as a solar cell, and a DC voltage boosted by the booster. And a converter for converting DC power into AC power according to the above, and in a photovoltaic power generation device that generates AC power based on sunlight, a filter that uses an arrangement position of a boosting reactor used for the booster for the converter. It is characterized by being located on the leeward side of the flow of the surrounding air with respect to the arrangement position of the reactor. Therefore, the other reactor is heated by the heat generated by the other reactor, which is the booster reactor that generates less heat, and raises the heat resistance rank of the wire type, the Curie point of the core material, and increases the shape of the reactor to self-heat. It is not necessary to control the amount, and it is possible to prevent an increase in cost and enlargement of the shape.

According to a second aspect of the present invention, in the first aspect of the invention, at least the shape of the boosting reactor on the side facing the filter reactor is substantially circular or streamlined. . Therefore, the air heated by the filter reactor flows smoothly without stagnating in the gaps between the reactors, and the effect of heating the leeward pressure boosting reactor can be reduced.

According to a third aspect of the present invention, in the first aspect of the present invention, at least the step-up reactor is disposed so as to be oblique with respect to the direction of flow of the surrounding air. Therefore, the air heated by the filter reactor flows smoothly without stagnating in the gaps between the reactors, and the effect of heating the leeward pressure boosting reactor can be reduced.

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, a sensor for detecting a temperature of the boosting reactor is provided, and a temperature rise of the filter reactor can be estimated. Features. Therefore,
The temperature rise can be estimated without providing a sensor for detecting the temperature of the filter reactor, and the cost can be reduced.

[0016]

Embodiments of the present invention will be described. FIG. 3 shows a circuit configuration of the photovoltaic power generator of the present invention,
FIGS. 1 and 2 show a state where the main components are mounted. FIG. 1 is a front view of a photovoltaic power generator installed on a wall as viewed from the front, and FIG. 2 is an exploded view of the photovoltaic power generator. 7 and 8 showing a conventional example in FIG.
The same reference numerals are given to the same components.

In FIG. 3, a photovoltaic power generation device 20 receives AC voltage supplied from a solar cell PV1 as a DC power supply and supplies AC power to a system U1 and has the following configuration. An input capacitor C1 is connected to the solar cell PV1 via a noise filter 22, and a voltage sensor SV1 is connected to both ends of the input capacitor C1. Further, a series circuit of a current sensor SI1, a step-up reactor L1 to which a temperature sensor TH1 is thermally coupled, and a switch element Q1 is connected to both ends of the input capacitor C1.
An anode of a diode D1 is connected to a connection point between the boosting reactor L1 and the switch element Q1.

The output capacitor C2 is connected between the side of the switching element Q1 not connected to the boosting reactor L1 and the cathode of the diode D1. Here, as in the prior art, the input capacitor C1, the boosting reactor L1,
Switch element Q1, diode D1, output capacitor C
2 constitutes a step-up chopper circuit 10 as a step-up unit. The boost chopper circuit 10 boosts the DC voltage from the solar cell PV1 in the same manner as described in the conventional example.

A voltage sensor SV2 is connected to both ends of the output capacitor C2.
2, Q4 and a series circuit of switch elements Q3, Q5 are connected in parallel. Then, the switching elements Q2, Q
The series circuit of the reactor L2 for the filter, the current sensor SI2, the capacitor C3 for the output filter, and the reactor L3 for the filter is connected between the connection point 4 and the connection point of the switch elements Q3 and Q5. Further, a system U1 is connected to both ends of the output filter capacitor C3 via a noise filter 22 and a disconnector 23. At this time, a switching circuit 11 is configured by the switching elements Q2 to Q5,
An output filter 12 is constituted by the filter reactors L2 and L3 and the output filter capacitor C3. Further, the switching unit 11 and the output filter 12 constitute a conversion unit.

A signal is inputted from the voltage sensor SV1, the current sensor SI1, the temperature sensor TH1, and the current sensor SI2, and a control circuit FB2 for outputting a control signal to the switching circuit 11, and an input signal from the voltage sensor SV2. And a control circuit FB1 that controls the switching element Q1 based on the power supply from the power supply circuit unit 21 connected to the input capacitor C1.

Next, the solar power generator 20 shown in FIG.
Will be described. A DC voltage from a solar cell PV1 as a DC power supply is boosted by a boost chopper circuit 10, and the boosted DC voltage is subjected to switching control by a switching circuit 11 and a sine-wave AC output due to a smoothing effect of the filter reactors L2 and L3. And the AC power flows backward to the system U1 via the noise filter 22 and the de-parallelizer 23.

The control circuit FB1 adjusts the ON width of the pulse control signal applied to the switch element Q1 so that the output voltage from the boost chopper circuit 10 detected by the voltage sensor SV2 becomes a predetermined value. Further, the control circuit FB2 sets and sets the amplitude of the output AC current output via the switching circuit 11 so that the product of the voltage sensor SV1 and the current sensor SI1 becomes the maximum from the detected values of the voltage sensor SV1 and the current sensor SI1. Current feedback is performed based on the detection value of the current sensor SI2 so as to obtain a sine wave output of amplitude,
A pulse control signal having the calculated ON width is given to each of the switch elements Q2 to Q5.

Next, the structure of the photovoltaic power generator will be described with reference to FIGS. In FIG. 1 and FIG. 2, the photovoltaic power generation device has a switch element 3 inside a case 1 in which slits 1a are provided on upper and lower surfaces when mounted on a wall surface.
And a radiator plate 2 on which input / output terminals 4 for the solar cell PV1, the system U1, etc. are connected, and the device is mounted on a wall on the side of the radiator plate 2 (left side in FIG. 1). The boosting reactor 6 is arranged at the upper part (upper side in FIG. 1), and the filter reactor 7 is arranged at the lower part (lower side in FIG. 1).

At this time, switch element 3 corresponds to switch elements Q1 to Q5 in FIG. 3, and boost reactor 6 and filter reactor 7 correspond to boost reactor L1, filter reactors L2 and L3 in FIG. ing.

The input capacitor C1 and the output capacitor C2 for the booster circuit shown in FIG.
2. A circuit board 5 having an output filter capacitor C3 and a disconnector 23 for connecting and disconnecting to and from the system U1 is installed, and is connected to the switch element 3 and the input / output terminal 4.
A control board 9 on which a control microcomputer or the like is mounted is connected to the circuit board 5, and a part of the signal is connected to the switch element 3 via the gate drive circuit section 8. At this time, the control circuits FB1 and FB2 shown in FIG. 3 are mounted on the circuit board 5, the gate drive circuit unit 8, and the control board 9.

Here, the air around the boosting reactor 6 and the filter reactor 7 in FIG. 1 is heated by the heat generated by each reactor to become an ascending current, and as shown by an arrow in FIG. From the upper slit 1a.

The current waveform flowing through the step-up reactor 6 is a DC waveform shown in FIG. 4B, and the current waveform flowing through the filter reactor 7 is an AC waveform shown in FIG. Even if the currents are equivalent at the effective value level (I1), the current shown in FIG. 4B is caused to flow as a result of the periodic existence of a current portion larger than the effective value as shown in FIG. Generates more heat than the thing. This is because the relationship between the current flowing through the reactor and the temperature rise is as shown in FIG. 4 (c).
Increases exponentially.

Therefore, the filter reactor 7 generates more heat than the boost reactor 6, so that the boost reactor 6 is installed above the filter reactor 7, that is, leeward of the surrounding air flow. I have. As a result, the boosting reactor 6, which generates less heat, is heated by the above-described ascending airflow, and the temperature rise of both the boosting reactor 6 and the filter reactor 7 can be homogenized. In other words, since it is the pressure rising reactor 6 that generates less heat that is heated by the above-described ascending airflow, the heat resistance rank of the wire type and the Curie point of the core material are increased, and the shape of the reactor is increased. It is not necessary to suppress the amount of self-heating, and it is possible to prevent cost increase and enlargement of the shape.

Although natural convection has been described here,
When forced air cooling is performed by an air cooling fan, the same effect as described above can be obtained by installing the boosting reactor 6 on the leeward side of the air flowing from the air cooling fan.

FIG. 5 shows another example of the step-up reactor 6 and the filter reactor 7 described above. FIG.
FIG. 5A shows a boost reactor 6A and a filter reactor 7A as another example viewed from the front when the reactor 6A is arranged in the case 1 as shown in FIG. 1, and FIG. 5B shows the boost reactor 6A. The view from the side is shown.
In FIG. 5A, the boosting reactor 6A is arranged on the upper side, and the filter reactor 7A is arranged on the lower side. As shown by an arrow, an upward airflow flows from the bottom to the top.

The pressure-boosting reactor 6A has a substantially elliptical shape in which both ends 6a and 6b in the XY directions in which air flows are substantially circular when viewed from the front, and the core 6c has two cores. Parts 6d and 6e are provided, and coils 16d and 16e are wound around each of them.

The filter reactor 7A also has two ends 7 in the XY directions in which air flows when viewed from the front.
Each of the cores 7a and 7b has a substantially elliptical shape having a substantially circular shape. The core 7c has two core portions similarly to the core 6c, and the coils 17d and 17e are wound around the respective cores. ing.

Since the boosting reactor 6A and the filter reactor 7A have the above-described shapes, the air flow smoothly flows along the substantially circular ends 6a, 6b, 7a, 7b to reduce the temperature rise of each reactor. Can be suppressed. Also,
Both ends 6a and 6b of the boosting reactor 6A are made substantially circular, and both ends 7a and 6a of the filter reactor 7A are formed.
Since each of the reactors 7b has a substantially circular shape and each of the reactors has the same shape, it can be substituted and the manufacture thereof is facilitated.

In addition, the filter reactor 7A of the boosting reactor 6A provided especially on the upper side, that is, on the leeward side.
Since the end 6b on the side opposite to the upper surface is formed in a substantially circular shape so as to expand in the upward direction toward the air, the air heated by the lower filter reactor 7A stagnates in the gap between the reactors. Without this, it is possible to reduce the heating effect on the leeward pressure boosting reactor 6A without flowing smoothly.

In FIG. 5A, the ends 6a, 6b, 7a, 7b of each reactor are substantially circular. However, the same effect can be obtained even if the reactor has a streamline shape for smooth air flow. Can be

Next, still another example of the step-up reactor 6 and the filter reactor 7 is shown in FIG. FIG.
FIG. 6A shows a boost reactor 6B and a filter reactor 7B, which are still other examples, as viewed from the front when arranged on the case 1 and attached to a wall or the like in the same manner as in FIG. 1, and FIG. The view from the side of the boosting reactor 6B is shown. In FIG. 6A, the boosting reactor 6B is on the upper side, and the filter reactor 7 is on the lower side.
B is arranged, and ascending air flows from bottom to top as indicated by arrows.

The step-up reactor 6B has a substantially rectangular shape when viewed from the front, and its core 6h has two core portions 6i and 6j, and a coil 1
6i and 16j are wound. The substantially rectangular step-up reactor 6B is disposed so as to be oblique to the XY directions in which air flows.

The filter reactor 7B also has a substantially rectangular shape when viewed from the front, and has a core 7h.
Like the core 6h, is provided with two core portions and configured so that coils 17i and 17j are wound around each of them. Then, a substantially rectangular filter reactor 7 is provided.
B is disposed so as to be oblique to the XY directions in which air flows.

As shown in FIG. 6, the step-up reactor 6B and the filter reactor 7B have the X
Since they are arranged so as to be oblique to the Y direction,
The air flow spreads from the lower part to the upper part, so that the air flow is smooth, and the temperature rise of each reactor can be suppressed. In particular, if at least the boosting reactor 6B is oblique to the XY direction in which the air flows, the air heated by the lower filter reactor 7B flows smoothly without stagnation in the gap between the reactors, The effect of heating the boosting reactor 6B on the leeward side can be reduced.

Here, the operation according to the output value of the temperature sensor TH1 thermally coupled to the boosting reactor L1 described with reference to FIG. 3 will be described. When the output value of the temperature sensor TH1 exceeds a predetermined value, the step-up reactor L1
Alternatively, assuming that the filter reactors L2 and L3 are abnormally overheated, the control circuit FB2 turns off the operation of the switching circuit 11, stops the output power of the photovoltaic power generation device 20, and protects each reactor from overheating. As described above, the boost reactor L1 is the filter reactor L2, L
3, the boosting reactor L
1 includes the temperature rise due to the heat received from the filter reactors L2 and L3, the temperature sensor T
The temperature rise of the filter reactors L2 and L3 can be estimated from the output value of H1.

At this time, if the current value of boosting reactor L1 detected by current sensor SI1 is within a predetermined range, filter reactor L2,
It is determined that L3 is abnormally overheated, and if it is out of the specified range, it is determined that the boosting reactor L1 is abnormally overheated. Therefore, by detecting the temperature of the boosting reactor L1 and simultaneously monitoring the current and the like of the boosting reactor L1, the temperature rise of the filter reactors L2 and L3 can be estimated, and the temperatures of the filter reactors L2 and L3 are detected. There is no need to provide a sensor. Note that a plurality of the specified values and the specified ranges are set for each predetermined condition.

[0042]

As described above, according to the first aspect of the present invention, there is provided a booster for boosting a DC voltage from a DC power supply such as a solar cell, and converting the DC power by the DC voltage boosted by the booster into AC power. In the photovoltaic power generation device that includes a conversion unit for converting, and generates AC power based on sunlight, the arrangement position of the boosting reactor used in the boosting unit with respect to the arrangement position of the filter reactor used in the conversion unit. Therefore, because it is on the leeward side of the flow of the surrounding air, what is heated by the heat generated by the other reactor is the boosting reactor with the smaller heat generation, raising the heat resistance rank of the wire type and the Curie point of the core material, It is not necessary to suppress the amount of self-heating by increasing the shape of the reactor, and it is possible to prevent cost increases and enlargement of the shape.

According to a second aspect of the present invention, in the first aspect of the present invention, at least the shape of at least the boosting reactor on the side facing the filter reactor is substantially circular or streamlined. The heated air flows smoothly without stagnation in the gap between the reactors, and the effect of heating the leeward pressure boosting reactor can be reduced.

According to the third aspect of the present invention, in the first aspect of the present invention, at least the step-up reactor is disposed so as to be oblique to the flow direction of the surrounding air, so that the reactor is heated by the filter reactor. The obtained air flows smoothly without stagnation in the gap between the reactors, and the effect of heating the leeward pressure boosting reactor can be reduced.

According to a fourth aspect of the present invention, in the first to third aspects of the present invention, a sensor for detecting the temperature of the boosting reactor is provided, and the temperature rise of the filter reactor can be estimated. The temperature rise can be estimated without providing a sensor for detecting the temperature of the reactor, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view showing the structure of a solar power generation device according to the present invention.

FIG. 2 is an exploded view showing the structure of the photovoltaic power generator of the present invention.

FIG. 3 is a circuit diagram showing a configuration of a photovoltaic power generator of the present invention.

FIGS. 4A and 4B are waveform diagrams showing current waveforms of each reactor used in the photovoltaic power generator of the present invention, and FIG.
FIG. 3 is a relationship diagram showing a relationship between a current value flowing through a reactor and a temperature thereof.

5A and 5B are diagrams showing another structure of each reactor used in the solar power generation device of the present invention, wherein FIG. 5A is a front view, and FIG.
Is a side view.

FIG. 6 is a diagram showing still another structure of each reactor used in the solar power generation device of the present invention, wherein (a) is a front view,
(B) is a side view.

FIG. 7 is a circuit diagram showing a configuration of a boost chopper circuit used in a conventional solar power generation device.

FIG. 8 is a circuit diagram showing a configuration of an inverter circuit used in a conventional solar power generation device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 case 1 a slit 2 heat sink 3 switch element 4 input / output terminal 5 circuit board 6 boosting reactor 7 filter reactor 8 gate drive circuit section 9 control board 21 power supply circuit section 22 noise filter C1 input capacitor C2 output capacitor C3 output filter Capacitors

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisami Usui 1048 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. (72) Inventor Akira Yoshitake 1048 Kadoma Kadoma, Kadoma City, Osaka Matsushita Electric Works (72) Inventor Shinichiro Okamoto 1048 Kadoma Kadoma, Kadoma-shi, Osaka Pref. Matsushita Electric Works, Ltd. (72) Inventor Tadayoshi Mukai 1048 Kadoma Kadoma, Kadoma-shi, Osaka Pref. AA08 BB07 CA01 CB05 CC09 CC12 DC02 DC05 DC08 HA03 HA05 5H420 CC03 CC10 DD03 DD10 EA10 EA34 EA39 EA45 EA47 EB04 EB19 EB39 FF03 FF04 FF14 FF24 FF25 KK06 LL07

Claims (4)

[Claims] A booster for boosting a DC voltage from a DC power supply such as a solar cell; and a converter for converting DC power by the DC voltage boosted by the booster into AC power. In the photovoltaic power generation device that generates AC power, the arrangement position of the boosting reactor used in the boosting unit is set to the leeward side of the flow of the surrounding air with respect to the arrangement position of the filter reactor used in the conversion unit. A solar power generation device characterized by the above-mentioned. 2. The photovoltaic power generation device according to claim 1, wherein at least a shape of the step-up reactor facing the filter reactor is substantially circular or streamlined. 3. The photovoltaic power generator according to claim 1, wherein at least the step-up reactor is disposed so as to be oblique to a flow direction of the surrounding air. 4. The photovoltaic power generator according to claim 1, further comprising a sensor for detecting a temperature of the step-up reactor, which is capable of estimating a temperature rise of the filter reactor. .