JPS61120221A - Tracking device for maximum supply power of solar battery array - Google Patents

Abstract

PURPOSE:To stabilize the supply of maximum electric power to a load by controlling a power converting circuit after discriminating the coincidence or dissidence between the polarity code of secular change's share of the output electric power of a solar battery array, and the corresponding code of the output voltage. CONSTITUTION:A load 2 is connected to a solar battery array 1 via a power converting circuit 3. The voltage V and the current I of an output voltage detecting print Pv and an output current detecting part Pi of the array 2 are supplied to a power change detecting circuit 7 consisting of a multiplier 4, a sample holding circuit 5 and a divider 6. Then the control is carried out so that the maximum supply power is secured for the circuit 3 via a control circuit 8. Here a logical circuit 9 is connected to the divider 6 together with addition of a voltage change detecting circuit 10. A polarity code comparing/ deciding circuit 13 is formed with the circuit 9 and the circuit 8. Then the circuit 13 discriminates the polarity between the voltage and power change signals SV and SP, and the voltage increase/decrease signals are outputted with the coincidence/discordance comparison signal St.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a maximum supply power tracking device that can perform tracking control to maximize the power supplied to a load from a solar cell array. This invention relates to an improvement that enables tracking control to follow the external term change even when an external term change such as a change in the amount of incident light occurs.

<Prior art> A solar cell array converts solar energy into electric energy, but since its output power changes depending on the output voltage and output current, it is simply In this configuration, the loss due to impedance mismatch between the power supply and the load is too large to perform effective energy conversion.

Therefore, conventionally, a maximum supply power tracking device has been installed between the solar cell array and the load, which operates so that the output power of the solar cell array is always at the maximum even if the output voltage or output current changes. It was customary to insert

Figure yJ3 shows a conventional maximum supply power tracking device.
In Figure 0, which was disclosed at the National Conference 1104 of the Institute of Electrical Engineers of Japan in 1981, a power conversion circuit 3 is connected to a solar cell array 1, and a load 2 is connected to the solar cell array 1. The current detectors Pi inserted into the output voltage detection part P and the output current detection part of the solar pond array 1 are respectively connected to a multiplier 4.
A sample and hold circuit 5 and a divider 6 are connected subsequent to the sample and hold circuit 5. Here, the multiplier 4, sample hold circuit 5, and divider 6 constitute a power change detection circuit 7, and a control circuit 8 following the divider 6 is connected to the power conversion circuit 3.

L2. In the configuration 1 multiplier 4, solar array 1
The output voltage P is calculated in response to the output voltage V and the output current, and the sample and hold circuit 5 samples the output power P. The output power increment ΔP at each sampling point is sequentially calculated by the divider 6 as the time-dependent change ΔP/Δt with respect to the minute time Δt, and the calculation result is output to the control circuit 8 as the power change signal Sp. be done. This control circuit 8 responds to the power change signal Sp 4
In answer 1-, when the temporal change ΔP/Δt has a positive polarity sign, a voltage control signal Scu representing a command to increase the output voltage V of the solar cell array 1 (hereinafter referred to as voltage increase command) is output. Conversely, when the temporal change ΔP/Δt has a negative polarity sign, a command is issued to decrease the output voltage V of the solar t* array 1 (hereinafter referred to as a voltage reduction command).
It outputs a voltage control signal Scd representing . As a result, the power conversion circuit 3 responds to both type pressure control signals Scu and Scd to control the power supplied to the load 2 by the solar cell array 1 in the lightning region where the time variation ΔP/Δt becomes zero. This is to realize tracking control that drives the operating point of the solar cell array 1 to the region where the maximum The polarity sign of P/Δt alternates at each sampling time so that the operating point remains substantially near the operating point for maximum power supply.

However, in the conventional maximum supply power tracking device, the direction of change in the output voltage, which is a controlled variable, is always in the increasing direction, and the range of change is from the output voltage force to the characteristic curve (p-
V curve) is based on the premise that the range is approximately equal to the voltage that provides the maximum power supply, so if for some reason the output voltage is controlled in a decreasing direction, or the output voltage exceeds the maximum power supply. If the voltage increases significantly beyond the voltage required for the solar cell array 1, it will cause operational problems. In the case where an external term change occurs temporarily, even though the operating point of the solar cell array 1 has not reached the operating point for the maximum supply power on the characteristic curve, the temporal change △P
The polarity sign of /Δt may change from positive to negative. In that case, at the time of sampling, the power conversion circuit 3 receives a voltage reduction command, and then at the next sampling time, the output power P further decreases.
t remains at a negative polarity sign, and the power conversion circuit 3 continues to receive voltage reduction commands.

Or<1. Once △P/△t turns negative in the operating region at the intermediate stage leading to the maximum power supply, the operating point moves toward the origin (P=O, V=O point) on the characteristic curve. As a result, the power control for maximizing the power supply to the load 2 is often temporarily disabled.

Furthermore, for example, if the operating point of the solar array 1 moves beyond the operating point for maximum power supply by a large vA (usually greater than or equal to the amount of movement of the operating point corresponding to the voltage control amount at each sampling point) Then, at the certain point of pulling 7, the polarity sign of the temporal change ΔP7/Δt in the output power becomes negative, and in response, the control circuit 8 outputs a voltage reduction command to return the operating point. At the time of sampling, the polarity sign of the change △P/△t changes to positive, and in response, the control circuit outputs a voltage increase command, and the alternation of voltage increase/decrease commands causes the operating point to stagnate. However, it sometimes failed to reach the operating point for maximum power supply.

In this way, in the conventional maximum supply power tracking device, the movement of the operating point on the characteristic curve (PV curve) is always limited to the increasing direction of voltage (V), and the operating point for the maximum supply power is Based on the premise that the voltage control signals Scu and Scd do not significantly exceed the change in output power P over time △P/△t
Since the solar cell array 1 is controlled only by the polarity sign of , there is a drawback that tracking control becomes malfunctioning if the solar cell array 1 undergoes an external term change or the like.

Purpose of the present invention In view of the problem of control malfunction due to changes in the outer term of the solar cell array in the Ohsumi battery array maximum supply power tracking device based on the above-mentioned prior art, it is an object of the present invention to By comparing the polarity sign of the change in output voltage (or output current) over time, one mounting point is removed.

It is an object of the present invention to provide an excellent maximum power supply tracking device capable of controlling the drive to the operating range for the maximum power supply even if there is a change in the external term.

<#V formation> The configuration of the first invention according to the above object is to compare the polarity sign of the temporal change in the output power of the solar cell array and the polarity sign of the temporal change in the output voltage, and determine whether the polarity is When the signs match, a voltage control signal representing a voltage increase command is output to the power conversion circuit, and when the polarity signs do not match, a voltage control signal representing a voltage decrease command is output to the power conversion circuit. This is a summary.

Furthermore, the configuration of the invention of wII2 that follows the E layout is as follows.

The gist of this invention is to use a change in output current over time instead of a change in output voltage over time in the configuration of the invention of wiIll.

<Example> Next, an example of the present invention will be described based on FIGS. 1 and 2. Components that are the same as those in the prior art are given the same reference numerals and redundant explanations will be omitted.

In FIG. 1, a logic circuit 9 is connected to the divider 6 of the power change detection circuit 7, and a voltage change detection circuit 107 is further connected to this logic circuit 9. On the other hand, the voltage change detection circuit 10 includes a sample and hold circuit 12 and a divider 11 that follows this and is connected to the logic circuit 9, and the sample and hold circuit 12 is the output voltage detection portion of the solar cell array l. The logic circuit 9 connected to the P signal constitutes a polarity code comparison and determination circuit 13 together with the control circuit 8 that follows it, and this circuit 13
is the voltage control signal supply section 14 together with the rain detection circuit 7.10.
It consists of

In the above 4I configuration, the output voltage V of the solar cell array 1 is sampled by the sample hold circuit 12, and the output voltage change ΔV at each sampling time is supplied to the subsequent divider 11, where it The amount of change ΔV/Δt is calculated sequentially. The voltage change signal Sma representing the time change ΔV/Δt is obtained by the voltage change detection circuit 7 through signal processing similar to that in the configuration shown in FIG. It is supplied to the logic circuit 9 together with a power change signal Sp representing P/Δt. In this logic circuit 9, from the power change signal sp and the voltage change signal Sma, one time change △P/△t, △V
/Δt is detected, and it is determined (by an exclusive OR gate, etc.) whether the polarity codes match or do not match. When a comparison signal Si representing this determination result is supplied to the control circuit 8, the control circuit 8 outputs a voltage control signal Scu representing a voltage increase command when there is a "match".
However, when there is a mismatch J, a voltage control signal Scd representing a voltage decrease signal is output. The characteristic surface @(p
-v song 11) draws a locus that bulges upward on a plane between the vertical axis representing the output power P and the horizontal axis representing the output power V.

First, let's say that the operating point of the solar cell array l is 1.

When the operating point M1 is in the operating region in the process of increasing the output power P while gradually increasing the output voltage V while starting from the origin, the movement of the operating point in that direction in that region is as follows. The polarity sign of the temporal change △P/△t of the output power P and the polarity sign of the temporal change △V/△t of the output voltage V are both positive, and the two polarity signs "match," so , in response to the comparison signal Si representing "match", the control circuit 8 outputs a voltage control signal Scu representing a voltage increase command to the power conversion circuit 3, and the operating point is set at the highest point on the characteristic curve. Driven towards the operating point MO for the supplied power.

Then, when the operating point passes through the operating point MO for maximum supplied power and moves to the operating point M2 in the operating region where the output power P decreases as the output voltage V increases, in that direction in that region Regarding the movement of the operating point, the polarity sign of the temporal change △P/△t is negative and the temporal change △
Since the polarity sign of V/Δt is positive, both polarity signs are "inconsistent". In response to the comparison signal Si representing this "mismatch", the control circuit 8 outputs a voltage control signal Scd representing a voltage reduction command, and the operating point is returned to the operating point MO for maximum power supply.

If, for some reason, the operating point moves beyond the operating point MO for maximum supply power toward the origin and moves in a direction that gradually decreases the output voltage V, the output power P also decreases as the output voltage ■ decreases. When the operating point M4 in the operating region is reached,
For movement in this direction here, the bipolar sign is “
Therefore, the control circuit 8 outputs the voltage control signal Scu representing the voltage increase command, and the operating point is returned to the operating point MO for the maximum power supply.

Furthermore, the operating point reverses after passing the operating point MO for maximum supply power, and as the output voltage V decreases, the output power P
When we reach the operating point M3 in the operating region where increasing
Therefore, the voltage control signal Scd representing the voltage reduction command is output from the control circuit 8, and the operating point is returned to the operating point MO for the maximum power supply, as in the case of the operating point M2.

In the description of the above embodiment, the power conversion circuit 3 is controlled by voltage control signals Scu and Scd.

Although it is assumed that this function is realized, it may be more convenient to use current control depending on the circuit conditions, so in such a case, the configuration is such that a current control signal is supplied.

That is, the output 'cardiac current' is detected from the current detector Pi inserted in the output current detection part of the solar cell array 1, and this is sent to the sample and hold circuit 12' as shown by the broken line in FIG. The output current I is supplied and sampled here, and the time variation ΔI/ΔL of the output current I at the time of valley sampling is calculated by the divider 11'. Then, a current change signal Si representing a change over time △I/△t is outputted from the electric plate change detection circuit 10', which is composed of a sample hold circuit 12 and a divider 11', and is converted into a power change signal Si. Detection circuit 7
The signal is supplied to the polarity code comparison and determination circuit 13 together with the power change signal Sp from . In this way, the power change detection circuit 7
, a current control signal supply section 14' consisting of a current change detection circuit 10' and a polarity sign comparison/discrimination circuit 13 issues a current increase command when the polarity signs of each time-varying portion ΔP/Δt and ΔI/Δt match. A current control signal S cu representing
′ is output, and when the polarity signs are unmatched,
A current control signal S cd ' representing the current AIV command is output.

Other configurations and operations are the same as in the case of voltage control. In addition,
In the case of current control, in Fig. 1, the symbols representing circuits and signals specific to the circuit and signals (excluding the current change signal S1) are given a dash, and the characteristic curve (P-I curve 1) is It is indicated by a broken line in FIG.

As described above, according to the first invention, it is determined whether the polarity sign of the output power of the solar cell array changes over time and the polarity sign of the output voltage changes over time, and the polarity sign of the output voltage changes over time. Due to the configuration in which the power conversion circuit is configured to control the power converter circuit, the operating point on the characteristic curve (PV curve) may shift in the direction of gradual decrease in output voltage due to some reason such as a change in the external term for the solar cell array. However, since the operating point is always controlled to be in the operating region where the maximum power can be supplied, an excellent effect can be obtained in that the maximum power can be extremely stably supplied from the solar cell array to the load.

Furthermore, according to the second invention, since the power conversion circuit can be controlled by current control, there is an advantage that the application conditions of the circuit that can achieve the same effects as the first invention can be expanded.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, @2
The figure shows a characteristic curve (P-
The graph showing the V curve, P-r[1hyJ), FIG. 3, is
FIG. 2 is a circuit diagram showing the configuration of a conventional maximum supply power tracking device. 1...Solar cell array 2...Load 3
...Power conversion circuit 4... Multiplier 5
...Sample hold circuit 6...Divider 7...Passenger force change detection circuit 8...Control circuit 9...Logic circuit 10 ...Voltage change detection circuit 10'...Current change detection circuit 11.11'.
...Divider 12.12' ...Sample and hold circuit 13.
. . . Polarity sign comparison and discrimination circuit 14 . . . Voltage control signal supply section 14' . . . Current control signal supply section Sp...
・Power change signal Si...Voltage change signal Si...Current change signal Si...Comparison signal

Claims (4)

[Claims] (1) A solar cell array 1, a load 2 that receives the output power from the solar cell array 1, and a voltage increase command or A power conversion means 3 for increasing or decreasing the output voltage from the solar cell array 1 to the load 2 to maximize the output power to the load in response to each of the voltage reduction commands; and for the power conversion means 3. and a voltage control signal supply section 14 that supplies voltage control signals Scu and Scd. The change detection means 7 and the change over time △V/ of the output voltage V from the solar cell array 1
The voltage change detection means 10 for detecting Δt compares the polarity sign of the output power change over time ΔP/Δt with the polarity sign of the output voltage change over time ΔV/Δt, and determines the difference between the two. When it is determined that they match, it outputs a voltage control signal Scu representing a voltage increase command, and when it is determined that they do not match, it outputs a voltage control signal Scd that represents a voltage decrease command. A maximum supply power tracking device for a solar cell array, characterized in that: (2) The power change detection means 7 is configured to detect a change in the power of the solar cell array 1.
Detecting the temporal change △P/△t of the output power P from
The detection result is output as a power change signal Sp, and the voltage change detection means 10 detects the time change ΔV/Δt of the output voltage V from the solar cell array 1, and converts the detection result into a voltage Further, the polarity sign comparing and determining means 13 outputs the power change signal Sp as a change signal Sv.
The polarity sign of the temporal change ΔP/Δt in the output power P represented by is compared with the polarity sign of the temporal change ΔV/Δt in the output voltage V represented by the voltage change signal Sv. A maximum power supply tracking device for a solar cell array according to claim 1. (3) A solar cell array 1, a load 2 receiving output power from the solar cell array 1, and a current increase command interposed between the solar cell array 1 and the load 2 and represented by current control signals Scu' and Scd'. or a power conversion means 3 that increases or decreases the output current from the solar cell array 1 to the load 2 to maximize the output power to the load in response to each of the current reduction commands; On the other hand, the current control signal Scu′Scd′
and a current control signal supply section 14' that supplies a current control signal supply section 14', the current control signal supply section 14' is a power change amount detection means that detects a time change amount ΔP/Δt of the output power P from the solar cell array 1. 7, and the change over time of the output current I from the solar cell array 1 △I
A current change detection means 10' for detecting /Δt compares the polarity sign of the output power change over time ΔP/Δt with the polarity sign of the output current change over time ΔI/Δt. , when it is determined that they match, it outputs a current control signal Scu' representing a current increase command, and when it is determined that they do not match, it outputs a current control signal Scd' that represents a current decrease command.
A maximum supply power tracking device for a solar cell array, comprising: a polarity sign comparison and determination means 13 that outputs a polarity code comparison and determination means 13 for outputting a polarity code comparison and determination means 13 for outputting a polarity code comparison and determination means 13 for outputting a polarity code comparison and determination means 13 for outputting a polarity code comparison and determination means 13 for outputting a polarity code comparison and determination means 13 for outputting a polarity sign comparison and determination means 13 for outputting a polarity sign comparison and determination means 13 for outputting a polarity sign comparison and determination means 13; (4) The power change detection means 7 is configured to detect a change in the power of the solar cell array 1.
Detecting the temporal change △P/△t of the output power P from
The detection result is output as a power change signal Sp, and the current change detection means 10' detects the time change ΔI/Δt of the output current I from the solar cell array 1, and outputs the detection result as a power change signal Sp. Output as a current change signal Si, and further,
The polarity sign comparing and determining means 13 compares the polarity sign of the temporal change ΔP/Δt of the output power P represented by the power change signal Sp and the output current I represented by the current change signal Si.
4. The maximum power supply tracking device for a solar cell array according to claim 3, wherein the tracking device compares the polarity sign of the temporal change ΔI/Δt.