JPS6237717A - Controller for photovoltaic power generation - Google Patents

Abstract

PURPOSE:To attain the control of a load pattern with high efficiency by using a maximum power controller with controls a DC converter for supply of the maximum power and a discharge control circuit which delivers the open/close commands of an accumulator. CONSTITUTION:The electric power generated by a solar cell 1 is branched through a blocking diode 7 and a DC/DC converter 2. The branching circuit at one side is supplied to a load 5 through a DC/DC converter 4. While the branching circuit at the other side is supplied to an accumulator 3 via a blocking diode 8. A contactor 9 functions to lead the electric power of the accumulator 3 to the converter 4. Here the converter 2 is controlled by a maximum power control circuit 10 and the contactor 9 is controlled by a discharge control circuit 11. The circuit 10 controls a point where the product of the output current and the voltage of the cell 1 is maximum. Furthermore, the circuit 11 decides that the electric power of the cell 1 is smaller than the electric power needed for the load 5 at a certain time point and delivers a command for application of the contactor 9 by a command given from the circuit 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a solar power generation control device that utilizes electric power that can be extracted from solar cells.

1. Technical background of the invention and its problems] As a method of utilizing gonergy in a photovoltaic power generation system, there are 9 examples from solar cells (hereinafter referred to as PV cells) 1. 6M15 force-tg)
It can be roughly divided into two methods: a method of transmitting electricity directly (in the case of grid connection) and a method of temporarily storing it in energy storage equipment such as storage batteries.

Although the technology for maximizing the use of power from PV cells has been established in each usage method, we are still at the stage of searching for an operating method for a system that combines the two.

For example, the power generated from the Pv cell is Do/D.

The converter stabilizes the storage battery and at the same time D
A method is proposed to stabilize the voltage again using an O/DO converter, convert it to the voltage required by the load, and supply it. On the other hand, when there is no power supply from the PV cell (such as at night), the power from the storage battery is converted to DC! /Do converter, power can be supplied to the load.

However, the disadvantage of this method is that the power from the PV cells must pass through two Do/Do converters before being supplied to the load, reducing system efficiency.

In another method, high efficiency can be achieved in that the power from the PV cell can be supplied to the load via only the DC/Do converter. In this case, the storage battery is charged with power from the PV cell through a bidirectional (i.e., current flows in both directions) Do/Do converter.
or discharge control. However, even in this system, when using the power from the storage battery, the bidirectional D
Since it passes through a C/DC converter and a Do/DC converter, there is also a difficulty in achieving high efficiency. Especially considering that a Pv cell can supply power for 7 to 8 hours, it is 16 to 17 hours a day to supply power via two Do/Do converters with low efficiency. The disadvantage was that it was long.

[Purpose of the invention]

The object of the invention is to compensate for the aforementioned drawbacks and provide a highly efficient system.

[Summary of the invention]

The present invention relates to a Do/Do converter that is connected to a DC circuit of a solar cell to control DC voltage, and a Do/Do converter that is connected to a DC circuit of a solar cell to control DC voltage.
A current transformer 4 that is branched from the O converter output circuit and measures the charging/discharging current of the storage battery, and a blocking diode that is connected in series with this current transformer and prevents the direct current from the storage battery from flowing back to the DC/DC converter. and a parallel circuit of contactors that bypass this blocking diode, a current transformer that is connected to another branch circuit from the DC/Do converter output circuit and measures the current to the load, and is connected in series to this current transformer. Other DC to be done! /Do converter, a maximum power control circuit that inputs the DC current signal of the current transformer and outputs a control signal to the DC/Do converter, and a maximum power control circuit that receives the control signal from the maximum power control circuit and compares it with the load pattern. This is a solar power generation control device consisting of a discharge control circuit that outputs contactor closing/release commands.

[Embodiments of the invention]

Next, the present invention will be explained in detail. FIG. 1 shows a solar power generation control device consisting of the following components.

(a) PV cell 1 that converts sunlight into energy (b) PV cell 10 output/output circuit Eight blocking diodes are connected to conduct DC current in one direction (c)
Do/DC converter 24 that is connected in series to the blocking diode 7 and performs DC-DC conversion DC-CT 13 (e) that is connected in series to the output DC circuits of the DC/DC converter 2 and measures the DC current Do/Do converter 4 connected in series to perform DC-DC conversion (g) DC-CT 12 connected branching from the connection circuit of DC/DC converter 2 and DC-CT 13
Blocking diode 8 connected in series to Do-CT12 and conducting DC in one direction Example Contactor 9 connected in parallel with blocking diode 8 (January Contactor 9 and) Locking diode 8
A storage battery 3 that is connected in series to a parallel circuit and receives DC power 3 ■! Add the measurement it of DC-OT 12.13,
A maximum power control circuit 10 that controls the DO/Do converter 2 to supply maximum power ←0 A discharge control circuit 11 that outputs an opening/closing command to the contactor 9 in response to a discharge command from the maximum power control circuit IO. That is, in FIG. The power generated by PV cell 1 is transferred to blocking diode 7, DC! /Do converter 2. One branch circuit is supplied with a load 56 through a Do/Do converter 4, and the other branch circuit is supplied with a storage battery 3 through a blocking diode 8. The contactor 9 is for bypassing the blocking diode 8 and guiding the power of the storage battery 3 to the DO/I°C converter 4 when the power of the storage battery 3 is required. Here, the DO/DO converter 2 is the maximum power control circuit 1.
0, and the contactor 9 is controlled by the discharge control circuit 11.

The operation of the circuit shown in FIG. 1 will be explained in more detail with reference to FIGS. 2 and 3. Maximum power control circuit 10 is Pv cell 1
This is to maximize the use of the electric power of the PV cell 1, and controls the point where the product of the output current and voltage of the PV cell 1 becomes maximum.

Figure 2 shows the output characteristics of PV cell 1, and shows the amount of sunlight Q
This shows that the output voltage and current characteristics change depending on the output voltage and current characteristics.

- For example, in the song 11X-Y, the point showing the maximum power is point P1, and it moves on the curve P depending on the amount of sunlight. The maximum power control circuit 10 is a circuit that searches for a point Plt- on the curve X-Y, and is controlled by a voltage vI corresponding to the point P1. The current is inserted into the branch circuit DOOT 12
, 13, and the output voltage of the DC/DC converter 2 is used as the voltage.

FIG. 3 shows an example of the operating characteristics of the maximum power control circuit 10, and shows the relationship between the output voltage and output power of the DC/DC converter 2. In Figure 3, point A is Pv
The open circuit voltage of cell 1 is shown. The line segment A-B is located in a region where the output power of the PV cell 1 is small, so the output of the DC/DC converter does not become high. Line segment B-0 shows that the output voltage of PV cell 1 is sufficient, but all the power from PV cell 1 is transferred to load 5.
This is a region in which the output voltage of the DC/DC converter 2 is controlled to a constant value (point F in FIG. 3) and the storage battery 3 is not charged. That is, the value is the same as the floating charging mz pressure of the storage battery 3.

The line segment 0-D indicates that the power of PV cell 1 and p is a sufficient value,
Since the power supply capacity is greater than that required by the load 5, the output voltage of the DC/DC converter 2 is increased in order to store the excess power in the storage battery 5. DC/
The maximum output voltage of the DC converter 2 (point G in Figure 3) corresponds to the voltage of the uniform light determined by the storage battery 3.

As explained above, the range of the triangle ODH in FIG. 3 is the charging area of the storage battery 3.

In Figure 3, the point corresponds to the inverter output capacity, and point J is P
v is the maximum output power of cell l. MW is DC! - within the operating input voltage range of the DC converter 4.

Next, the discharge control circuit 11 will be explained.

The discharge control circuit 11 compares, for example, the output of the pattern generation circuit 11A that stores five load patterns in advance with the power of the maximum power control circuit 10 at that time, and determines the power required by the load 5 at a certain time Pv. It is determined that the force generated by the cell 1 is greater, and a command to close the contactor 9 is issued via the contactor control circuit 110. The power required by the load 5 at the time is P
When the power that can be generated by the V-cell 10 is also small, the discharge control circuit 11 opens the contactor 9, while the maximum power control circuit 10 increases the voltage (that is, controls on the line -E in FIG. 3). . Of course, the point I in FIG. 3 can be moved up and down on the vertical axis (by the control signal of the pattern generation circuit 11A). The maximum power control circuit 10 and the discharge control circuit 11 include circuits for carrying out the above explanation.

In FIG. 2, the blocking diode 8 is Do/D.

This is to prevent the output voltage of the converter 2 from falling within the range of the line segment A-B in FIG. Blocking diode 7 is contactor 9
This is to prevent the power of the storage battery 3 from flowing into the PV cell 1 through the Do/Do converter 2 when the switch is closed.

Oka, a solar power generation control device that uses a DO/Do converter as a Do/AO converter, or a solar cell and DC! /
A solar power generation control device characterized by using a blocking diode connected in series between the DO converter and preventing the power of the DC/Do converter from flowing back to the solar cell It goes without saying. By using these configurations, it is possible to provide a highly efficient system and at the same time configure a power supply/system depending on the load state.

〔Effect of the invention〕

As explained above, according to the present invention, a single solar generator equipped with electric energy storage means such as a storage battery,
Highly efficient load pattern control can be achieved. In particular, loads that require load pattern control include power consumption equipment such as B pumps and light/temperature control for artificial rearing of animals and plants. can be controlled.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a solar power generation control device showing one embodiment of the present invention, and Figs. 2 and 3 are for explaining Fig. 1. It's A diagram. 1H・PV cell 2H・DO/Do converter 3H・Storage battery 4H・DO/1)0 converter 5H・Load 7.8H・Blocking diode 9H・Contactor 10H・Maximum power control circuit 11H・Discharge control circuit 12.13 DC-OT Agent Patent attorney Nori Chika Ken Yudo Hirofumi Mitsumata 10 Most dog power control immediate circuit 7゛. I2τ To°. Figure 1 Snow pressure Figure 2

Claims (1)

[Claims] A solar power generation control device comprising the following components. (a) A solar cell that converts sunlight into electricity (b) A first backflow prevention device that is connected to the output circuit of this solar cell and conducts direct current in one direction (c) This first backflow prevention device Connected in series to the device and DC-
A first DC converter that converts DC current (D) A first DC measuring device that is connected in series to the output DC circuit of this first DC converter and measures DC current (E) A first DC measuring device that measures DC current. a second DC converter that is connected in series and performs DC-DC conversion; (f) a second DC measurement device that is branched from and connected to the connection circuit of the first DC converter and the first DC measurement device; (G) A second backflow blocking device that is connected in series to this second DC measuring device and conducts DC current in one direction (H) A switchgear that is connected in parallel with this second backflow blocking device (I) A storage battery (N) that is connected in series to the parallel circuit of the switchgear and the second backflow prevention device and stores DC power.The measured values of the first and second DC measurement devices are added together and the maximum power is supplied. a maximum power control circuit (1) for controlling the first DC converter; a discharge control circuit for outputting a switching command to the switching device according to a discharge command from the maximum power control circuit