KR100269090B1 - Peak power tracker - Google Patents

Abstract

PURPOSE: A maximal power tracing system with simple structure is provided to use mainly as a power system of a small sized satellite and to use in a solar light power generation system in case of ground electric power technology. CONSTITUTION: A voltage tracing unit(60) traces relative change of operating voltage of a solar battery plate while a current tracing unit traces relative change of actuating current. A multi-vibrator(80) outputs a control signal for tracing a maximal power point with receiving a result of the current tracing unit. A signal fed to an integrator, that is an output Q of the multi-vibrator is changed, then a switch control signal of a regulator that is output from the integrator is changed. A switch of the regulator is continuously turned on and off to control output of a solar array for finding a maximal power point. As the maximal power point is traced without injecting disturbance or calculating digital conversion, constitution of hardware is simplified and power dissipation rate is lower.

Description

Max power tracker

The present invention relates to a maximum power tracker, mainly used as a power system of a small satellite in the satellite technology field, and relates to a maximum power tracker used in the maximum power tracking system used in the solar power generation system in the ground power technology. .

In the maximum power tracking system as described above, the maximum power tracker may use an analog method and a digital method. Both methods are configured based on Equation 1 below.

V / I = dV / dI

Equation 1 is a formula indicating that the same impedance and the static impedance.

The maximum power tracking method implemented by the above-described formula and generally used now finds the maximum power point while repeatedly comparing the product of the solar panel current and voltage many times.

The maximum power tracking method in the conventional maximum power tracker implemented to use the above-described method, by forcibly injecting repetitive disturbance to the current and voltage of the solar panel, the variation of the output power by the change of the operating point is the same Tracking will track the maximum power point.

However, the conventional maximum power tracker using the above-described method has a problem that the variation of the sensed current voltage signal is small while the analog voltage method has a wide dynamic range because the current voltage sensing unit is sensitive to noise. The complex configuration of the regulator voltage input and output and current sensing leads to increased hardware mass, footprint and cost.

In addition, in the digital method, the analog value of the sensed current voltage is converted into digital, the converted sense current voltage value is stored in the memory, and the microprocessor calculates the sensed current voltage value and transmits the control variable to the memory. The maximum power point is tracked by converting the digital control variables transmitted to the memory to analog. As described above, the current voltage sensing information is digitally calculated to calculate the analog / digital conversion module, the calculation and memory module, and the like. In addition, a complicated configuration such as a digital / analog conversion module and an accessory circuit is required, which causes problems such as increased weight, cost, and power consumption, and slow operation of the entire system.

The present invention aims to more simply configure the maximum power tracker in view of the above problems.

In order to achieve the above object, the present invention is based on the maximum power point when the dynamic impedance and the constant impedance of the solar panel are the same, so that the relative change of the operating voltage and the operating current of the solar panel are equal to the maximum power point. Recognizing that the relative change in the operating voltage of the solar panel and the relative change in the operating current is configured to track the point.

That is, the system is implemented by Equation 2 below.

dI / I = dV / V

Equation 2 is a modification of Equation 1, the maximum power tracker of the present invention implemented by Equation 2 as described above, the relative change of the operating voltage and the relative change of the operating current of the solar panel through continuous vibration Find the maximum power point by tracking the point at which is equal.

The maximum power tracker of the present invention which tracks the relative change of the operating voltage of the solar panel and the relative change of the operating current as described above includes a voltage tracker for tracking the relative change of the operating voltage of the solar panel, and And a multivibrator for outputting a control voltage for tracking the maximum power point as a result of the voltage tracker and the current tracker.

1 is a schematic diagram of a typical maximum power tracking system,

2 is a circuit diagram of a maximum power tracker of the present invention;

3 is a signal waveform diagram showing a current voltage characteristic curve of a solar array;

4 is an input / output signal waveform diagram of a comparator in the maximum power tracker of the present invention;

5 is a timing diagram showing timing of input / output signals of a multivibrator in the maximum power tracker of the present invention;

6 is a signal waveform diagram showing changes in output voltage and current of a solar array;

7 is a signal waveform diagram showing an input signal conversion rate of a multivibrator according to a change in output voltage and current of a solar array;

8 is a signal waveform diagram illustrating an example of a maximum power tracking process of the present invention.

<Description of Symbols for Main Parts of Drawings>

1: current voltage detector 2: regulator

3: additional circuit part 4: comparator

5: integrator 6: maximum power tracker

60: voltage tracking unit 70: current tracking unit

80: multivibrator 61: voltage divider 1

62: Follow voltage 1 63: Sample-hold circuit 1

64: Comparator 1 65: Switch 1

66 capacitor 1 71 current voltage converter

72: Boltage Divider 2 73: Boltage Follow 2

74: sample-hold circuit 2 75: comparator 2

76: switch 2 77: capacitor 2

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the general configuration of the maximum power tracking system includes a current voltage detector 1 that receives a signal output from a solar array, which is a power source, and detects and outputs a voltage and a current value, and the current. The maximum power tracker 6 which receives the voltage and current value detected by the voltage detector 1 and outputs a control signal for tracking the maximum power point, and integrates and outputs the signal output from the maximum power tracker 6. The integrator 5 and the comparator 4 which compares the signal output from the integrator 5 with a reference signal and outputs the resulting signal as a control signal, and the switch is turned on by the comparison result of the comparator 4. Including a regulator (2) to be turned on / off to change the voltage and current value of the solar array (Charlar ARRAY), and an additional circuit unit (3) consisting of a charger / discharger / battery, etc. to assist the role of the regulator (2) It is sex.

FIG. 2 is a detailed circuit diagram of the maximum power tracker 6 according to the present invention. The voltage tracker 60 tracks the relative change in the operating voltage of the solar panel, and the relative change in the operating current of the solar panel. The current tracker 70 and a multivibrator 80 that receives the results of the voltage tracker 60 and the current tracker 70 and outputs a control signal for tracking the maximum power point.

The voltage tracker 60 receives the voltage divider 1 61 which drops the input voltage level to a desired voltage, and the voltage follower 1 which receives and outputs the voltage generated by the voltage divider 1 61. And a sample-hold circuit 1 (63) for receiving and holding or outputting the output voltage of the voltage follower 1 (62), and a signal and initial input applied from the sample-hold circuit 1 (63). And a comparator 1 64 for comparing the signal V _SA and controlling the reset terminal R of the multivibrator 80 as a result.

단자의 출력값에 의해 온/오프가 제어되는 스위치1(65)와, 볼테이지 팔로우1(62)에서 인가된 전압을 홀드하고 있는 캐패시터1(66)로 이루어진다.In the above, the sample-hold circuit 1 (63) of the multi-vibrator 80

A switch 1 (65) whose on / off is controlled by the output value of the terminal, and a capacitor (1) 66 holding the voltage applied from the voltage follower (62).

The current tracking unit 70 is a current voltage converter 71 for converting an input current signal into a voltage signal, and a voltage divider 2 for dropping the voltage level output from the current voltage converter 71 to a desired voltage level. 72, a voltage follower 273 that receives and outputs the voltage generated by the voltage divider 2 72, and an output voltage of the voltage follower 273 is held and output. The sample-hold circuit 2 74 and the signal applied from the sample-hold circuit 2 74 and the initial input signal I _SA are compared, and as a result, the trigger terminal T of the multivibrator 80. It comprises a comparator 2 (75) for controlling the.

In the above-described sample-hold circuit 2 (74) is a switch 2 (76) that is controlled on / off by a signal applied from the Q terminal of the multi-vibrator 80, and the voltage applied from the voltage follow 2 (73) It consists of the holding capacitor 2 (77).

The current voltage power characteristic curve of the solar array shows the signal waveform as shown in FIG.

In addition, the output signal for the input signal of each comparator (64, 75) is as shown in Figure 4, when the + terminal input is lower than the input of the-terminal, the low is output, the + terminal input is lower than the-terminal input High outputs high.

의 출력이 하이가 되며, 비교기2(75)의 출력이 하이가 되는 순간 트리거 단자가 셋트되면 Q의 출력이 하이가 되고

의 출력이 로우가 된다.As shown in FIG. 5, the input / output signal waveforms of the multivibrator 80 with respect to the output signals of the comparators 64 and 75 are Q when the reset terminal is set at the instant when the output of the comparator 1 64 becomes high. The output goes low

The output of Q becomes high when the trigger terminal is set at the moment when the output of comparator 2 (75) becomes high.

Output goes low.

In the maximum power tracking system having the above configuration, the maximum power point is tracked by the control of the maximum power tracker 6.

That is, the switch of the regulator 2 changes the duty ratio of the turn-on and turn-off according to the output signal of the comparator 4 according to the tracking result of the maximum power tracker 6 to change the operating point of the solar panel. Move to maximum power point.

In the method of controlling the maximum power tracking system of the present invention for tracking the maximum power point, first, if the solar panel voltage is the maximum and the current is zero, V _OC -ΔV is input to the + terminal of the comparator 1 (64), but V _OC Since it is smaller, the output of comparator 1 64 goes low. However, after some time the initial reset signal resets the multivibrator 80 and pulls Q low until there is a trigger input.

In the above, V _OC represents a voltage in a state where current is zero.

On the contrary, if there is an initial trigger signal after a certain time after the initial reset signal in the state where the current detection voltage is 0, the Q of the multivibrator 80 turns high and the signal passes through the integrator 5 and the control signal. By switching to to drive the switch of the regulator (2) to increase the output current of the solar panel. If the current rise causes the output voltage to fall and becomes lower than the voltage stored in the sample-hold circuit 1 (63), the output of the comparator 1 (64) turns high and the reset signal is transmitted to the multivibrator (80) to repeat the operation. do.

Referring to the fourth operation and the fifth operation as described above in more detail as follows.

가 로우가 되어, 샘플-홀드 회로1(63)의 스위치1(65)는 오프 상태를 유지하고, 샘플-홀드 회로2(74)의 스위치2(76)는 온 상태를 유지한다. 이후 전압 추적부(60)에 인가되는 전압 레벨이 감소하면서 일정 시간이 경과하면, 비교기1(64)의 +단자에 인가되는 신호 레벨이 -단자에 인가되는 신호 레벨보다 높아지고, 비교기1(64)의 출력이 하이가 되어 초기 리셋 신호가 셋트되며, 멀티바이브레이터(80)의 출력 Q가 로우 상태로 전환되고

가 하이 상태로 전환된다. 멀티바이브레이터(80)의 출력 신호가 변화하면 샘플-홀드 회로1(63)의 스위치1(65) 상태는 온으로, 샘플-홀드 회로2(74)의 스위치2(76) 상태는 오프로 반전된다.When applied to the V _OC to the maximum power tracker (6) comparator 1 64 of the voltage tracking unit 60 - receives a V _OC -ΔV the V _OC to + terminal to the terminal. Comparator 1 (64) outputs a low value because the -terminal input is greater than the + terminal input, so that the output lasts for a predetermined time. While the output of comparator 1 64 remains low, the output Q of multivibrator 80 goes high.

Becomes low, switch 1 65 of sample-hold circuit 1 63 remains off, and switch 2 76 of sample-hold circuit 2 74 remains on. Thereafter, when a predetermined time elapses while the voltage level applied to the voltage tracking unit 60 decreases, the signal level applied to the + terminal of the comparator 1 64 becomes higher than the signal level applied to the-terminal, and the comparator 1 64 Of the output becomes high and the initial reset signal is set, the output Q of the multivibrator 80 is switched to the low state

Transitions to a high state. When the output signal of the multivibrator 80 changes, the switch 1 65 state of the sample-hold circuit 1 63 is turned on, and the switch 2 76 state of the sample-hold circuit 2 74 is turned off. .

가 로우가 되어 샘플-홀드 회로1(63)의 스위치1(65)를 오프시키고 샘플-홀드 회로2(74)의 스위치2(76)를 온 시킨다.When V _OC is applied, a zero level signal is applied to the negative terminal and the positive terminal of comparator 2 75 of current tracking unit 70 to output a high signal. After that, when a certain time elapses while the current level applied to the current tracker 70 increases, the signal level applied to the + terminal of the comparator 2 75 becomes lower than the signal level applied to the-terminal, and the comparator 2 (75). As the output of is low, the initial reset signal of the multivibrator 80 is set. When the initial reset signal is set, the current level applied to the current tracker 70 decreases, and a signal applied to the negative terminal of the comparator 2 75 is applied to the + terminal held in the sample-hold circuit 2 74 after a predetermined time. Lower than the signal, comparator 2 (75) outputs a high signal to set the initial trigger signal. When the initial trigger signal is set, the output Q of the multivibrator 80 goes high

Goes low to turn off switch 1 (65) of sample-hold circuit 1 (63) and switch 2 (76) of sample-hold circuit 2 (74).

While the initial trigger signal is set so that the comparator 1 64 maintains the low state, the operation in the voltage tracker 60 is repeated, and the reset signal is set again after a predetermined time.

As described above, the maximum power point is tracked through an operation process in which the reset signal and the trigger signal are periodically set repeatedly. As shown in FIG. 6, the voltage and current levels change rapidly for a predetermined time after the initial V _OC voltage is applied. However, after a certain period of time, a stable state is entered and there is no significant change in current and voltage. That is, when it is in a stable state, it changes with a variation of ΔV and ΔI based on the maximum power point in FIG. 3.

As a result, the input signal conversion speed of the multivibrator 80 is as shown in FIG. 7, but the conversion speed of the input / output signal of the multivibrator 80 is slow for a predetermined time after the initial set signal is applied. When entering a stable state, the input signal conversion of the multivibrator 80 proceeds quickly.

8 is a diagram illustrating an embodiment of a process of tracking a maximum power point by repeating the operation.

When the signal applied to the integrator 5, that is, the output Q of the multivibrator 80 changes through the above process, the regulator changes while the switch control signal of the regulator 2 output from the integrator 5 changes accordingly. The switch in (2) is continuously turned on and off to control the output of the solar array to find the maximum power point.

As described above, the maximum power tracker 6 detects a change in the output signal of the solar array and controls the output of the solar array, thereby making it easier to track the maximum power point.

As described above, the present invention can track the maximum power point without forcibly injecting disturbance or performing a digital conversion operation, thereby simplifying hardware configuration, lowering power consumption, and improving the speed control performance by a simplified process. There is an effect it has.

Claims (5)

A voltage tracker 60 for tracking a relative change in the operating voltage of the solar panel, a current tracker 70 for tracking a relative change in the operating current of the solar panel, and the voltage tracker 60 and a current tracker ( And a multivibrator (80) for receiving a result of 70) and outputting a control signal for tracking the maximum power point. The voltage tracker 60 receives the voltage generated by the voltage divider 1 61 and the voltage divider 1 61 for dropping the input voltage level to a desired voltage. Is applied from the sample follow-up 1 62 and the sample-hold circuit 1 63 for receiving and holding or outputting the output voltage of the voltage follow 1 62 and the sample-hold circuit 1 63. And a comparator 1 (64) which compares the signal to the initial input signal (V _SA ) and controls the reset terminal (R) of the multivibrator (80) as a result. The multi-vibrator 80 of claim 2, wherein the sample-hold circuit 1 (63)

And a capacitor 1 (66) holding the voltage applied from the voltage follower (62) on and off controlled by the output value of the terminal. 2. The current tracking unit 70 according to claim 1, wherein the current tracking unit 70 drops a current voltage converter 71 for converting an input current signal into a voltage signal and a voltage level output from the current voltage converter 71 to a desired voltage level. Inputs the falling voltage divider 2 (72), the voltage follower 2 (73) which receives and outputs the voltage generated by the voltage divider 2 (72), and the output voltage of the voltage follower 2 (73). The sample-hold circuit 2 74 that receives and holds or outputs the signal, and the signal applied from the sample-hold circuit 2 74 and the initial input signal I _SA are compared, and as a result, the multivibrator 80 And a comparator 2 (75) for controlling the trigger terminal (T). 5. The sample-hold circuit 2 (74) according to claim 4, wherein the sample-hold circuit (2) includes a switch 2 (76) and a voltage follower (2) whose on / off is controlled by a signal applied from the Q terminal of the multivibrator (80). And a capacitor (2) holding the voltage applied from the maximum power tracker.

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