Systems and methods for regulating the power output of multiple solar cell substrings

Abstract

A variant of a system for regulating the power output of multiple solar cell substrings includes: a set of solar cell substrings and a power regulator. The power regulator includes: a power source; an adder; a modulation signal generator; a demodulator; and an integrator. The power source is configured to receive an input voltage from the set of solar cell substrings. The adder is configured to modify the voltage gain of the input voltage at the power source. The modulation signal generator is coupled to the adder and configured to generate an oscillating power signal at the power source. The demodulator is configured to demodulate the oscillating power signal output from the power source. The integrator is coupled to the demodulator and the adder; and is configured to define a voltage gain step size at the power source based on the DC signal component output from the demodulator.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 326,121, filed March 31, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates generally to the field of solar power systems, and more specifically to a novel and practical system for regulating the power output of multiple solar substrings in a solar power system. Brief description of the attached diagram

[0005] Figure 1A and Figure 1B It is a schematic representation of the system;

[0006] Figure 2 It is a schematic representation of a variant of the system;

[0007] Figure 3 It is a schematic representation of a variant of the system;

[0008] Figure 4 It is a schematic representation of a variant of the system; and

[0009] Figure 5 It is a schematic representation of a variant of the system.

[0010] Implementation Example Description

[0011] The following description of embodiments of the present invention is not intended to limit the invention to these embodiments, but rather to enable those skilled in the art to make and use the invention. The variations, configurations, implementations, example implementations, and examples described herein are optional and not limited to them. The invention described herein can include any and all combinations of these variations, configurations, implementations, example implementations, and examples.

[0012] 1. System

[0013] like Figure 1A and Figure 1B As shown, the system 100 for regulating the power output of multiple substrings includes: a first set of solar cell substrings 110; a first power regulator 119; and a controller 160.

[0014] The first power regulator 119 includes: a first power supply 120; a first adder 128; a first modulation signal generator 122; a first demodulator 124; and a first integrator 126. The first power supply 120 is coupled to a first set of solar cell sub-strings 110 and configured to receive a first input voltage generated by the first set of solar cell sub-strings 110. The first adder 128 is coupled to gain control of the first power supply 120 and configured to modify the voltage gain of the first input voltage. The first modulation signal generator 122 is coupled to the first adder 128 and configured to modulate the voltage gain of the first input voltage. The first demodulator 124 is coupled to the first modulation signal generator 122 and the first power supply 120 and configured to demodulate a voltage signal output from the first power supply 120. The first integrator 126 is coupled to the first demodulator 124 and the first adder 128 and configured to define a voltage gain step for the first input voltage.

[0015] The controller 160 is configured to, during a first power cycle, trigger a first modulation signal generator 122 to modulate the voltage gain of the first input voltage with a first modulation signal having a first phase and a first frequency, thereby inducing a first oscillating power signal output from the first power supply 120; and generate a first demodulated signal at the first demodulator 124 based on the first oscillating power signal and the first modulation signal.

[0016] The controller 160 is also configured to, during the first power cycle, interpret a first voltage power point condition of the first input voltage based on the first demodulated signal; and modify the voltage gain of the first power supply 120 by a first voltage gain step size based on the first power point condition and in response to the first input voltage deviating from the maximum power point voltage of the first set of solar cell sub-strings 110.

[0017] In a variant of system 100, such as Figure 2As shown, a system 100 for regulating the power output of multiple substrings includes: a first set of solar cell substrings 110, a first power regulator 119, a second power regulator 139, and a controller 160. The first set of solar cell substrings 110 includes: a first subset of the solar cell substrings 110 connected to the first power regulator 119; and a second subset of the solar cell substrings 110 connected in series with the first subset and connected to the second power regulator 139. The first power regulator 119 includes: a first power supply 120 (e.g., a switch-mode power supply), a first modulation signal generator 122, a first adder 128, a first demodulator 124, and a first integrator 126. The first power supply 120 is connected to the first subset of the solar cell substrings 110 and is configured to receive a first input voltage generated by the first set of solar cell substrings 110. The first adder 128 is connected to the gain control of the first power supply 120 and is configured to modify the voltage gain of the first input voltage at the first power supply 120. A first modulation signal generator 122 is connected to a first adder 128 and configured to modulate the voltage gain of a first input voltage received at a first power supply 120. A first demodulator 124 is connected to the first modulation signal generator 122 and the first power supply 120. A first integrator 126 is connected to the first demodulator 124 and the first adder 128 and configured to define a first voltage gain step size for the first input voltage at the first power supply 120. A second power regulator 139 includes a second power supply 140, a second modulation signal generator 142, a second adder 148, a second demodulator 144, and a second integrator 146. The second power supply 140 is connected to a second subset of solar cell sub-strings 110 and configured to receive the first input voltage generated by the first set of solar cell sub-strings 110. The second adder 148 is connected to gain control of the second power supply 140 and configured to modify the voltage gain of the first input voltage at the second power supply 140. A second modulation signal generator 142 is connected to a second adder 148 and is configured to modulate the voltage gain of a first input voltage received at a second power supply 140. A second demodulator 144 is connected to the second modulation signal generator 142 and the first power supply 120. A second integrator 146 is connected to the second demodulator 144 and the second adder 148 and is configured to define a second voltage gain step size for the first input voltage at the second power supply 140.Then, during the first power cycle, the controller 160 can: trigger a first modulation signal generator 122 to modulate the voltage gain of the first input voltage with a first modulation signal (e.g., a sine wave, gold code, spread spectrum communication signal) having a first phase and a first frequency, thereby generating a first oscillating power signal from the first power supply 120; and trigger a second modulation signal generator 142 to modulate the voltage gain of the first input voltage with a second modulation signal having a second phase and a second frequency, the second modulation signal being different from the first modulation signal. Additionally, the controller 160 can: generate a first demodulated signal from the first demodulator 124 based on the first oscillating power signal and the first modulation signal from the first power supply 120; generate a second demodulated signal from the second demodulator 144 based on the first oscillating power signal and the second modulation signal from the first power supply 120; interpret a first voltage power point condition of the first input voltage based on the first demodulated signal; and interpret a second voltage power point condition of the first input voltage based on the second demodulated signal. Furthermore, in response to a first input voltage deviating from the maximum power point voltage, the controller 160 may: adjust the voltage gain of the first input voltage at the first power source 120 by a first voltage gain step size based on a first voltage power point condition; and adjust the voltage gain of the first input voltage at the second power source 140 by a second voltage gain step size based on a second voltage power point condition, wherein the first power source 120 and the second power source 140 cooperate to output maximum power from the first set of solar cell sub-strings 110.

[0018] exist Figure 4 and Figure 5 In one variation of the depicted exemplary embodiment, system 100 may include a solar panel 170, which includes a set of solar cell sub-strings 110 and defines a front and a back side. System 100 may also include: a housing structure 172 disposed on the back side of the solar panel 170; and a rod structure extending outward from a side end of the housing and coupled to the solar panel 170. Housing structure 172 may include: a first power regulator 119; and a controller 160 coupled to the first power regulator 119. In the foregoing exemplary embodiment, each of the first power regulator 119 and the controller 160 is enclosed within housing structure 172.

[0019] 2. Application

[0020] Typically, system 100 can operate as a power controller 160, configured to connect to and balance the power output from a set of solar cell substrings 110, which may experience uneven irradiation and thus uneven power output throughout operation. For system 100 to continuously output maximum power, the set of solar cell substrings 110 must output a maximum power point voltage to achieve the maximum power from system 100. However, during operation of system 100, several factors (e.g., age of the solar cell substrings, foreign objects covering the solar cell substrings, weather conditions, etc.) can cause uneven irradiation of the set of solar cell substrings 110, which in turn causes the output voltage of the set of solar cell substrings 110 to deviate from the maximum power point voltage. Therefore, system 100 can then continuously adjust the voltage output from the set of solar cell substrings 110 toward the maximum power point voltage (i.e., modify the gain of the voltage) to enable system 100 to output maximum power regardless of the irradiation conditions of the set of solar cell substrings 110.

[0021] During operation, system 100 can output an oscillating power signal from first power supply 120 to explain how the voltage gain of the modified input voltage adjusts the power output of system 100. For example, system 100 may include: a first set of solar cell sub-strings 110 configured to output a first input voltage under a first irradiation condition; a first power supply 120 connected to the first set of solar cell sub-strings 110 and configured to receive the first input voltage output from the first set of solar cell sub-strings 110; a first modulation signal generator 122 connected to the gain control of the first power supply 120 and configured to oscillate the voltage gain of the first power supply 120; and a first demodulator 124 connected to the first modulation signal generator 122 and the first power supply 120. Then, during the first power cycle, system 100 can: trigger a first modulation signal generator 122 to modulate the voltage gain of the first power supply 120 with a first modulation signal to induce a first oscillating power signal output from the first power supply 120; apply a first demodulator 124 to the first oscillating power signal output from the first power supply 120 to generate a first demodulated signal; and interpret the voltage power point condition of the first input voltage deviating from the maximum power point voltage based on the first demodulated signal. Therefore, system 100 can interpret the voltage power point condition to explain whether the first input voltage is below or above the maximum power point voltage.

[0022] Furthermore, during operation, system 100 can then adjust the voltage input signal toward the maximum power point voltage (thereby adjusting the power output) based on the voltage power point condition interpreted from the first demodulated signal, in order to achieve the maximum power output of system 100. For example, system 100 may include: a first integrator 126 connected to the first demodulator 124; and a first adder 128 connected to the first modulation signal generator 122 and the first power supply 120. Then, during a first power cycle, system 100 can: integrate the first demodulated signal to define a first voltage gain step size tending toward the maximum power output voltage of system 100; and modify the first input voltage based on the first voltage gain step size to adjust the first input voltage toward the maximum power point voltage. Therefore, system 100 can perform multiple power cycles to continuously adjust the first input voltage toward the maximum power point voltage to ensure continuous maximum power output during operation of system 100.

[0023] 3. Power Regulator

[0024] Typically, system 100 may include: a first power supply 120 (e.g., a switch-mode power supply) connected to a first set of solar cell substrings 110 and configured to receive a first input voltage output by the first set of solar cell substrings 110; and a first modulation signal generator 122 connected to the gain control of the first power supply 120 and configured to modulate the voltage gain of the first input voltage received at the first power supply 120.

[0025] During operation of system 100, the first set of solar cell sub-strings 110 generates a voltage, which is then fed to the input of the first power supply 120 to define the input voltage of system 100. System 100 can then adjust the voltage gain of the input voltage received at the first power supply 120 to adjust the power output to the load connected to the first power supply 120. Additionally, system 100 can generate a power signal based on the voltage and current output from the first power supply 120. System 100 can trigger a first modulation signal generator 122 to generate a first modulation signal having a first phase and a first frequency, which adjusts the gain control of the first power supply 120 to modify the input voltage at the first power supply 120. Therefore, during operation of system 100, the gain control of the first power supply 120 remains consistent with the first phase and first frequency of the first modulation signal (i.e., the voltage gain increases when the amplitude of the modulation signal increases, and decreases when the amplitude of the modulation signal decreases). System 100 can then generate a power signal based on the output voltage from the first power supply 120 being modified by the first modulation signal. During operation of system 100, the power signal output from the first power supply 120 will fluctuate (i.e., the amplitude increases and decreases) as the gain control of the first power supply 120 is adjusted by the first modulation signal. System 100 can then use the fluctuating power signal output from the first power supply 120 to explain the deviation of the power output to the load from the maximum power output of system 100.

[0026] In a variant of system 100, the power signal output from the first power supply 120 can be filtered by a bandpass filter 130 to eliminate unwanted noise generated from the first power supply 120. The bandpass filter 130 can be defined as: a high-pass cutoff frequency greater than a first frequency of the first modulation signal; and a low-pass cutoff frequency configured to block the DC component of the power signal.

[0027] Typically, system 100 may also include a first demodulator 124 connected to a first modulation signal generator 122 and a first power supply 120, and configured to generate a first demodulated signal. System 100 may input a power signal output from the first power supply 120 and a first modulation signal output from the first modulation signal generator 122 to the first demodulator 124, and then output a demodulated signal based on the power signal and the first modulation signal.

[0028] In one variant, the first demodulator 124 includes a multiplier circuit configured to apply a product operation to the power signal and the first modulated signal to generate a demodulated signal. In this variant, the system 100 may also include a first low-pass filter 132 connected to the first demodulator 124; defining a first cutoff frequency less than a first frequency of the first modulated signal; and configured to block the AC component of the first demodulated signal. The system 100 can then use the DC component output by the first low-pass filter 132 to interpret the voltage power point condition of the first input voltage. During operation of the system 100, when the first input voltage operates at the maximum power point voltage, the DC component of the demodulated signal output from the first demodulator 124 will be zero. Therefore, the system 100 can interpret the voltage power point condition of the first input voltage deviating from the maximum power point voltage in response to the observation of a non-zero DC component of the first demodulated signal output from the first demodulator 124.

[0029] Typically, system 100 may further include: a first integrator 126 connected to a first demodulator 124 and a first adder 128, and configured to define a voltage gain step size for a first input voltage at a first power supply 120 based on a first demodulated signal; and a first adder 128 connected to the first integrator 126 and gain control of the first power supply 120, and configured to adjust the first input voltage based on a voltage gain step size output by the first integrator 126.

[0030] During operation of system 100, the first integrator 126 can receive the demodulated signal output by the demodulator and apply integrator operation to the demodulated signal during power cycles. System 100 can then define a voltage gain step size (i.e., a voltage gain step size to increase the first input voltage in response to the first input voltage being lower than the maximum power point voltage, or a voltage gain step size to decrease the first input voltage in response to the first input voltage being higher than the maximum power point voltage) based on the demodulated signal of the first input voltage. System 100 can then apply the voltage gain step size defined by the first integrator 126 to the gain control of the first power supply 120 via the first adder 128 to adjust the first input voltage toward the maximum power point voltage. Therefore, during operation, system 100 can perform multiple power cycles to adjust the first input voltage until the maximum power point voltage is achieved and system 100 operates at maximum power output.

[0031] 3.1 Power Regulator: Increase Voltage Gain

[0032] In one implementation, when the first input voltage received at the first power supply 120 is lower than the maximum power point voltage, the system 100 can interpret the voltage power point condition of the first input voltage. During operation of the system 100 under this specific voltage condition, the oscillating power signal output from the first power supply 120 will reflect the first phase and first frequency of the first modulating signal (i.e., as the amplitude of the modulating signal increases, the amplitude of the power signal increases; and as the amplitude of the modulating signal decreases, the amplitude of the power signal decreases). Therefore, during operation of the system 100 under this specific voltage condition, the first demodulated signal output from the first demodulator 124 will always be a positive oscillating signal. In a variation, a low-pass filter 132 is applied to the positive oscillating signal received from the first demodulator 124 to block the AC component of the signal, thereby generating a positive DC signal component. In response to interpreting the positive DC signal component, the system 100 can then apply a positive voltage gain step to the gain control of the first power supply 120 to adjust the first input voltage upward toward the maximum power point voltage during the first power cycle. If system 100 interprets the adjusted input voltage as being below the maximum power point voltage after the first power cycle, system 100 can continue to apply positive voltage gain steps for subsequent power cycles until the maximum power point voltage is achieved.

[0033] For example, during a first power cycle, system 100 may: trigger a first modulation signal generator 122 to modulate the voltage gain of a first input voltage with a first modulation signal (e.g., a sine wave, gold code, spread spectrum communication signal) having a first phase and a first frequency, thereby generating a first oscillating power signal from a first power source 120; generate a first demodulated signal from a first demodulator 124 based on the product of the first oscillating power signal from the first power source 120 and the first modulation signal; apply a first low-pass filter to the first demodulated signal to isolate a first DC component of the first demodulated signal; interpret the first input voltage as being below the maximum power point voltage in response to detecting a positive value of the first DC component of the first demodulated signal; apply a first integrator 126 to the first DC component to define a voltage gain step increase for the first input voltage; and increase the voltage gain at the first power source 120 for the first input voltage toward the maximum power point voltage of the first set of solar cell strings by increasing the voltage gain step.

[0034] In another example, system 100 may: generate a first demodulated power signal based on the product of a first oscillating power signal from a first power source 120 and a first modulation signal; extract a DC component from the first demodulated power signal; and interpret a first input voltage lower than the maximum power point voltage in response to detecting a positive value of the first DC component of the first demodulated power signal. In this example, since the first oscillating power signal is proportional to the first modulation signal, the demodulated power signal includes an AC component and a positive DC component. Therefore, system 100 may then: apply a first integrator 126 to the positive DC component to define a positive voltage gain step for the first input voltage; and trigger a first adder 128 to apply a positive voltage gain step at the gain control of the first power source 120, thereby increasing the first input voltage toward the maximum power point voltage.

[0035] In the foregoing example, the first modulation signal generator 122 can be configured to output a first modulation signal defining a first sine wave, and is configured to generate an output of a first sinusoidal power signal from the first power supply 120, which is at a first phase and a first frequency. Therefore, the system 100 can then generate a first demodulated power signal based on the product of the first sinusoidal power signal from the first power supply 120 and the sine wave. In this example, the first demodulated power signal will include a DC component and an AC component according to the sine square identity. The system 100 can then isolate this DC component from the first demodulated power signal, for example, through a low-pass filter 132, to: interpret a first input voltage below the maximum power point voltage; and interpret a positive voltage gain step applied to the gain control of the first power supply 120.

[0036] 3.2 Power Regulator: Reduce Voltage Gain

[0037] In one implementation, when the first input voltage received at the first power supply 120 is higher than the maximum power point voltage, the system 100 can interpret the voltage power point condition of the first input voltage. During operation of the system 100 under this specific voltage condition, the oscillating power signal output from the first power supply 120 will reflect the first frequency of the first modulated signal. However, the oscillating power signal will not reflect the first phase of the first modulated signal (i.e., as the amplitude of the modulated signal increases, the amplitude of the power signal decreases; and as the amplitude of the modulated signal decreases, the amplitude of the power signal increases). Therefore, during operation of the system 100 under this specific voltage condition, the first demodulated signal output from the first demodulator 124 will always be a negative oscillating signal. In a variation, a low-pass filter 132 is applied to the negative oscillating signal received from the first demodulator 124 to block the AC component of the signal, thereby generating a negative DC signal component. In response to interpreting the negative DC signal component, the system 100 can then apply a negative voltage gain step to the gain control of the first power supply 120 to adjust the first input voltage downward toward the maximum power point voltage during the first power cycle. If system 100 interprets the adjusted input voltage as being higher than the maximum power point voltage after the first power cycle, then system 100 can continue to apply negative voltage gain steps for subsequent power cycles until the maximum power point voltage is achieved. Alternatively, if system 100 interprets the adjusted input voltage as being lower than the maximum power point voltage after the first power cycle, then system 100 can then apply positive voltage gain steps for subsequent power cycles until the maximum power point voltage is achieved.

[0038] For example, during a first power cycle, system 100 may: trigger a first modulation signal generator 122 to modulate the voltage gain of a first input voltage with a first modulation signal (e.g., a sine wave, gold code, spread spectrum communication signal) having a first phase and a first frequency, thereby generating a first oscillating power signal from a first power source 120; generate a first demodulated signal from a first demodulator 124 based on the product of the first oscillating power signal from the first power source 120 and the first modulation signal; apply a first low-pass filter to the first demodulated signal to isolate a first DC component of the first demodulated signal; interpret a first input voltage higher than the maximum power point voltage in response to detecting a negative value of the first DC component of the first demodulated signal; apply a first integrator 126 to the first DC component to define a voltage gain step size reduction for the first input voltage; and attenuate the voltage gain at the first power source 120 for the first input voltage toward the maximum power point voltage of the first set of solar cell strings by reducing the voltage gain step size.

[0039] In another example, system 100 may: generate a first demodulated power signal based on the product of a first oscillating power signal from a first power source 120 and a first modulation signal; extract a DC component from the first demodulated power signal; and interpret a first input voltage higher than the maximum power point voltage in response to detecting a negative value of the first DC component of the first demodulated power signal. In this example, since the first oscillating power signal is inversely proportional to the first modulation signal, the demodulated power signal includes an AC component and a negative DC component. Therefore, system 100 may then: apply a first integrator 126 to the negative DC component to define a negative voltage gain step size for the first input voltage; and trigger a first adder 128 to apply a negative voltage gain step size at the gain control of the first power source 120, thereby reducing the first input voltage toward the maximum power point voltage.

[0040] 3.3 Power Regulator: Maximum Power Point Voltage

[0041] In one implementation, when the first input voltage received at the first power supply 120 is at its maximum power point voltage, the system 100 can interpret the voltage power point condition of the first input voltage. During operation of the system 100 under this specific voltage condition, the oscillating power signal output from the first power supply 120 will not reflect the first phase or first frequency of the first modulation signal (i.e., the amplitude of the power signal decreases when the amplitude of the modulation signal increases, and the amplitude of the power signal decreases when the amplitude of the modulation signal decreases). Therefore, during operation of the system 100 under this specific voltage condition, the first demodulated signal output from the first demodulator 124 will always oscillate at a frequency greater than the first frequency of the first modulation signal. In a variant, a low-pass filter 132 defining a cutoff frequency less than the first frequency of the first modulation signal is applied to the oscillating signal received from the first demodulator 124 to block the AC component of the signal, thereby generating a zero DC signal component. In response to interpreting the zero DC signal component, the system 100 can then apply a zero (null) voltage gain step to the gain control of the first power supply 120 to maintain the first input voltage at its maximum power point voltage during the first power cycle. Alternatively, if system 100 interprets the first input voltage as being higher or lower than the maximum power point voltage after the first power cycle (e.g., system 100 experiences a change in the irradiation conditions of the solar cell sub-array 110), then system 100 may then apply voltage gain steps for subsequent power cycles until the maximum power point voltage is achieved.

[0042] For example, during a first power cycle, system 100 may: trigger a first modulation signal generator 122 to modulate the voltage gain of the first input voltage with a first modulation signal (e.g., a sine wave, gold code, spread spectrum communication signal) having a first phase and a first frequency, thereby generating a first oscillating power signal from the first power supply 120; generate a first demodulated signal from a first demodulator 124 based on the product of the first oscillating power signal from the first power supply 120 and the first modulation signal; apply a first low-pass filter to the first demodulated signal to isolate a first DC component of the first demodulated signal; interpret the first input voltage as matching the maximum power point voltage in response to detecting the absence of the first DC component in the first demodulated signal; apply a first integrator 126 to the first DC component to define a zero voltage gain step size for the first input voltage; and maintain the voltage gain at the first power supply 120 for the first input voltage to maintain the maximum power point voltage of the first set of solar cell strings.

[0043] In another example, system 100 may: generate a first demodulated power signal based on the product of a first oscillating power signal from first power supply 120 and a first modulation signal; and interpret the first input voltage as matching the maximum power point voltage in response to detecting the absence of a DC component in the first demodulated power signal. In this example, the oscillating power signal output from first power supply 120 will not reflect the first phase or first frequency of the first modulation signal, resulting in the absence of a DC component in the first demodulated power signal. Therefore, system 100 may then trigger first adder 128 to apply a zero-voltage gain step at the gain control of first power supply 120 in response to the matching of the first input voltage and the maximum power point voltage.

[0044] In the example above, since the maximum power point voltage is achieved for the output of the first power regulator 119, the gain control of the first power supply 120 does not require further adjustment. However, during the operation of system 100, environmental conditions (e.g., weather patterns) may cause uneven illumination across the set of solar cell substrings 110, which in turn affects the power output from the first power regulator 119. Therefore, system 100 can continue to perform power cycling at the power regulator to ensure that the voltage output remains at the maximum power point voltage. For example, in response to achieving the maximum power point voltage, system 100 can then initiate a low-power mode to reduce the number of power cycles performed at the power regulator. Subsequently, in response to identifying a deviation of the voltage output from the maximum power point voltage, system 100 can then terminate the low-power mode and initiate a series of power cycles until the maximum power point voltage is achieved from the set of solar cell substrings 110.

[0045] 4. Two-stage power regulator

[0046] In one implementation, such as Figure 2 As shown, system 100 includes: a first set of solar cell sub-strings 110, which includes a first subset of solar cell sub-strings 110 connected in series with a second subset of solar cell sub-strings 110; a first power regulator 119; and a second power regulator 139. In this embodiment, the first power regulator 119 is connected to the first subset of solar cell sub-strings 110 and configured to regulate a first voltage output from the first subset of solar cell sub-strings 110. Additionally, the second power regulator 139 is connected to the second subset of solar cell sub-strings 110 at the midpoint between the first subset and the second subset of solar cell sub-strings 110; and is configured to regulate a second voltage output from the second subset of solar cell sub-strings 110. System 100 can then adjust the first and second voltages to achieve the maximum power point voltage (and thus the maximum power output) of the first set of solar cell sub-strings 110.

[0047] In this embodiment, system 100 includes a first set of solar cell sub-strings 110, which includes a first solar cell sub-string 112 and a second solar cell sub-string 114 arranged in series. System 100 also includes a first power regulator 119 coupled to a voltage output from the first solar cell sub-string 112. A second power regulator 139 is defined as: an output terminal coupled to the midpoint voltage between the first solar cell sub-string 112 and the second solar cell sub-string 114; and an input terminal coupled to the voltage output terminal of the first solar cell sub-string 112.

[0048] Furthermore, the second power regulator 139 includes: a second power supply 140; a second modulation signal generator 142; a second demodulator 144; and a second integrator 146. The second power supply 140 is configured to receive a first input voltage generated at a second solar cell sub-string in a solar cell sub-string. The second modulation signal generator 142 is coupled to the second power supply 140 for second gain control; generates a second modulation signal having a second phase and a second frequency (the second phase and second frequency differ from the first phase and first frequency of the first modulation signal); and is configured to generate a second oscillating power signal output from the second power supply 140. The second demodulator 144 is coupled to the second modulation signal generator 142 and the first power supply 120; and is configured to generate a second demodulated power signal based on the first oscillating power signal and the second modulation signal. The second integrator 146 is coupled to the second power supply 140 for second gain control and the second demodulator 144; and defines a second voltage gain step based on the second demodulated power signal to define the midpoint of the voltage.

[0049] Environmental conditions (e.g., weather patterns) can cause uneven illumination across the first solar cell sub-string 112 and the second solar cell sub-string 114. Therefore, in the aforementioned embodiment, system 100 can: modify the voltage output from the set of solar cell sub-strings 110; and modify the input voltage at the midpoint between the sets of solar cell sub-strings 110 to balance the voltage output across the sets of solar cell sub-strings 110. In this embodiment, as described above, system 100 can perform power cycling for the first power regulator 119 and the second power regulator 139 to modify gain control to achieve the maximum power point voltage from the set of solar cell sub-strings 110. When the maximum power point voltage is achieved, the midpoint voltage between the first solar cell sub-string 112 and the second solar cell sub-string 114 should match half of the total voltage output value from the set of solar cell sub-strings 110.

[0050] In this embodiment, it is desirable for system 100 to generate different and distinct modulation signals for the first power regulator 119 and the second power regulator 139 (e.g., modulation signals with different frequencies or modulation signals with different spread spectrum communication signals) in order to prevent interference between the power regulators.

[0051] In one example, a first modulation signal generator 122 outputs a first modulation signal defining a first sine wave and is configured to generate an output of a first sinusoidal power signal from a first power source 120. In this example, the first sinusoidal power signal includes a first phase and a first frequency of the first sine wave. Additionally, a second modulation signal generator 142 outputs a second modulation signal defining a second sine wave having a second frequency offset from the first frequency (e.g., 20 Hz); and is configured to generate an output of a second sinusoidal power signal from a second power source 140, at a second phase and a second frequency. Therefore, system 100 can perform a series of power cycles across the first power regulator 119 and the second power regulator 139 to achieve the maximum power point voltage from the set of solar cell substrings 110.

[0052] During operation, the system 100 may experience uneven illumination between a first subset and a second subset of the solar cell substrings 110. In one variation, a first voltage output from the first subset of the solar cell substrings 110 operates below the maximum power point voltage, while a second voltage output from the second subset of the solar cell substrings 110 operates above the maximum power point voltage. The system 100 can then: adjust the first voltage gain of the first power source 120 to increase the first voltage; and adjust the second voltage gain of the second power source 140 to decrease the second voltage, thereby achieving the maximum power point voltage of the first set of solar cell substrings 110.

[0053] For example, during a first power cycle, system 100 may: trigger a first modulation signal generator 122 to modulate a first voltage gain of a first voltage with a first modulation signal (e.g., a sine wave, gold code, or spread spectrum communication signal) having a first phase and a first frequency, thereby generating a first oscillating power signal from a first power supply 120; and trigger a second modulation signal generator 142 to modulate a second voltage gain of a second voltage with a second modulation signal (e.g., a sine wave, gold code, or spread spectrum communication signal) having a second phase and a second frequency, the second modulation signal being different from the first modulation signal. Additionally, during the first power cycle, system 100 may: generate a first demodulated signal from a first demodulator 124 based on the product of the first oscillating power signal from the first power supply 120 and the first modulation signal; generate a second demodulated signal from a second demodulator 144 based on the product of the first oscillating power signal from the first power supply 120 and the second modulation signal; apply a first low-pass filter to the first demodulated signal to isolate a first DC component of the first demodulated signal; and apply a second low-pass filter to the second demodulated signal to isolate a second DC component of the second demodulated signal. Furthermore, during the first power cycle, the system 100 can: interpret a first voltage as lower than the maximum power point voltage in response to detecting a positive value of a first DC component of a first demodulated signal; interpret a second voltage as higher than the maximum power point voltage in response to detecting a negative value of a second DC component of a second demodulated signal; increase the first voltage gain at the first power source 120 for the first voltage by increasing the voltage gain step size; and decrease the second voltage gain at the second power source 140 for the second voltage by decreasing the voltage gain step size, wherein the first voltage gain and the second voltage gain cooperate to achieve the maximum power point voltage of the first set of solar cell sub-strings 110.

[0054] 4.1 Maximum power point voltage deviation

[0055] In one embodiment, system 100 may: interpret the output voltage from the set of solar cell substrings 110 as a deviation from the maximum power point voltage; and interpret the midpoint voltage between the first solar cell substring 112 and the second solar cell substring 114 as a deviation from the maximum power point voltage. Therefore, as described above, system 100 may perform a power cycle to balance the voltage output across the set of solar cell substrings 110 to achieve the maximum power point voltage.

[0056] For example, during a first power cycle, system 100 may: generate a first demodulated power signal based on the product of a first oscillating power signal from a first power source 120 and a first modulation signal; and extract a first DC component from the first demodulated power signal. In this example, due to environmental conditions (e.g., weather), the first solar cell sub-string 112 may output a voltage output lower than the maximum power point voltage. Therefore, system 100 may then: in response to detecting a positive value of the first DC component in the first demodulated power signal, interpret the first input voltage as being lower than the maximum power point voltage; and in response to interpreting the first input voltage as being lower than the maximum power point voltage, trigger a first adder 128 to apply a positive voltage gain step at the gain control of the first power source 120, thereby increasing the first input voltage toward the maximum power point voltage.

[0057] Then, system 100 can cycle (sequentially or synchronously) with the first power source to generate a second demodulated power signal based on the product of a first oscillating power signal and a second modulation signal from the first power source 120; and extract a second DC component from the second demodulated power signal. In this example, system 100 can then: in response to detecting a negative value of the second DC component in the second demodulated power signal, interpret that the first input voltage is higher than the maximum power point voltage; and in response to interpreting that the first input voltage is higher than the maximum power point voltage, trigger a second adder 148 to apply a negative voltage gain step at the second gain control of the second power source 140 to reduce the midpoint voltage.

[0058] Therefore, regardless of the environmental conditions (e.g., weather) that hinder the solar cell sub-string 110, the system 100 can modify the voltage output across multiple voltage points of the solar cell sub-string 110 to achieve the maximum power point voltage output from the solar cell sub-string 110.

[0059] 4.2 Achieving maximum power point voltage

[0060] In one implementation, system 100 may: interpret the output voltage from the set of solar cell substrings 110 as deviating from the maximum power point voltage; and interpret the midpoint voltage between the first solar cell substring 112 and the second solar cell substring 114 as matching the maximum power point voltage. Therefore, system 100 may perform the power cycling described above to modify the voltage output from the first solar cell substring 112 to achieve the maximum power point voltage.

[0061] For example, during a first power cycle, system 100 may: generate a first demodulated power signal based on the product of a first oscillating power signal from a first power source 120 and a first modulation signal; and extract a first DC component from the first demodulated power signal. In this example, system 100 may then: interpret a first input voltage higher than the maximum power point voltage in response to detecting a negative value of the first DC component in the first demodulated power signal; and trigger a first adder 128 to apply a negative voltage gain step at the gain control of the first power source 120 to decrease the first input voltage toward the maximum power point voltage in response to interpreting the first input voltage higher than the maximum power point voltage.

[0062] Then, system 100 can cycle (sequentially or synchronously) with the first power supply to generate a second demodulated power signal based on the product of a first oscillating power signal and a second modulation signal from the first power supply 120; and interpret the first input voltage as matching the maximum power point voltage in response to detecting the absence of a second DC component in the second demodulated power signal. Therefore, in response to the first input voltage matching the maximum power point voltage, system 100 can trigger a second adder 148 to apply a zero-voltage gain step at the second gain control of the second power supply 140.

[0063] Therefore, when the maximum power point voltage is achieved at the output voltage from the group of solar cell sub-strings 110, the system 100 can: maintain the maximum power point voltage at the first power regulator 119 and the second power regulator 139; and, in response to detecting a change deviating from the maximum power point voltage, initiate a power cycle as described above to balance the voltage output across the group of solar cell sub-strings 110.

[0064] 5. Three-stage power regulator

[0065] In one embodiment, system 100 includes a third power regulator 149 connected to the set of solar cell substrings 110 and configured to regulate the voltage output across three voltage points in the set of solar cell substrings 110. In this embodiment, the first set of solar cell substrings includes a first solar cell substring 112, a second solar cell string 114, and a third solar cell string 116 arranged in series with each other. The third power regulator 149 defines an output coupled to a second midpoint voltage between the second solar cell substring 114 and the third solar cell string 116; and an input coupled to the voltage output of the first solar cell string 112.

[0066] The third power regulator 149 includes: a third power supply 150; a third modulation signal generator 152; a third demodulator 154; and a third integrator 156. The third power supply 150 is configured to receive a first input voltage generated by the set of solar cell sub-strings 110. The third modulation signal generator 152 is coupled to the third power supply 150 for a third gain control; generates a third modulation signal having a third phase and a third frequency different from the second phase and second frequency of the second modulation signal; and is configured to generate a third oscillating power signal output from the third power supply 150. The third demodulator 154 is coupled to the third modulation signal generator 152 and the first power supply 120; and is configured to generate a third demodulated power signal based on the first oscillating power signal and the third modulation signal. The third integrator 156 is coupled to the third power supply 150 for the third gain control and the third demodulator 154; and defines a third voltage gain step based on the third demodulated power signal at the midpoint of the second voltage. Additionally or alternatively, system 100 may include a third adder 158, which is coupled to a third modulation signal generator 152 and a third integrator 156 and is configured to modify the third gain control of the third power supply 150.

[0067] Therefore, as described above, system 100 can perform power cycling (sequentially or synchronously) across the first power regulator 119, the second power regulator 139, and the third power regulator 149 to achieve the maximum power point voltage output from the set of solar cell substrings 110.

[0068] 6. Multi-stage power regulator

[0069] In one embodiment, system 100 may include: a set of solar cell substrings 110 defining a predefined (e.g., more than two) subset of solar cell substrings 110; and a set of power regulators configured to adjust the voltage gain at a set of voltage points for each subset of the solar cell substrings 110 in the set of solar cell substrings 110. During operation, system 100 may use the above-described structure and techniques to modify the gain control of a set of power supplies corresponding to each of the set of voltage points to achieve the maximum power point voltage (and thus maximum power output) of the set of solar cell substrings 110.

[0070] 7. Example: Rooftop solar panels

[0071] Typically, due to variations in solar irradiance, shading, and local reflectivity (hereinafter referred to as "irradiance"), a set of solar cell substrings 110 will exhibit uneven power output over time. The illumination profile of the solar cell substring array can also vary significantly depending on the geographical location and the installation orientation of the solar cell substrings. For example, a set of solar cell substrings can be installed on a flat roof, across multiple non-parallel surfaces of a sloping roof, on top of a vehicle, or in an open field. Therefore, the set of solar cell substrings 110 can be exposed to significantly different illumination profiles over time, and the solar cells within the set of solar cell substrings 110 can be subject to different levels of irradiance and shading, and thus can output significantly different power amplitudes at any given time. In another example, system 100 includes a solar panel 170: disposed on a roof; including the set of solar cell substrings 110; and defining a front and a back side. In this example, system 100 also includes a housing: disposed on the back side of the solar panel 170; and including a first power conditioner 119 and a controller 160 disposed within a cavity of the housing.

[0072] Therefore, system 100 may include a power regulator configured to regulate the output of the set of solar cell substrings (which may be nearly the same (e.g., all 300 watts) during certain daily time windings (e.g., midday) and very different (e.g., between 50 watts and 500 watts) at other times of the day (e.g., early afternoon)) and to combine the outputs of these solar cell substrings into a common higher voltage, higher current output.

[0073] For example, in a solar panel installation comprising multiple sets of solar cell strings arranged on different faces of a sloping roof, from sunrise to mid-morning (e.g., 5 a.m. to 10 a.m.), the east-facing solar cell strings receive the majority of the illumination, the south-facing solar cell strings receive some illumination, and the west-facing solar cell strings receive the least illumination (e.g., reflected illumination). Therefore, in this example, if these sets of solar cell strings were not connected and operated independently, then: the east-facing solar cell strings could generate a peak power of 200 watts with an average operating voltage of 1.12 volts during that morning period; the south-facing solar cell strings could generate an average power of 50 watts and a peak power of 200 watts with an average operating voltage of 1.09 volts during that morning period; and the west-facing solar cell strings could generate an average power of 5 watts and a peak power of 20 watts with an average operating voltage of 1.0 volts during that morning period.

[0074] In the aforementioned example, from midday to approximately 3 PM (e.g., from 10 AM to 3 PM), the east-facing solar sub-strings receive some illumination (e.g., from both reflected and direct light), the south-facing solar sub-strings receive the majority of the illumination, and the west-facing solar sub-strings receive some illumination. Therefore, if these groups of solar sub-strings are not connected and operate independently, the east-facing solar sub-strings can generate an average of 150 watts and a peak of 300 watts at an average operating voltage of 1.15 volts during this midday period; the south-facing solar sub-strings can generate an average of 300 watts and a peak of 350 watts at an average operating voltage of 1.2 volts during this midday period; and the west-facing solar sub-strings can generate an average of 150 watts and a peak of 300 watts at an average operating voltage of 1.15 volts during this midday period.

[0075] Furthermore, in this example, from approximately 3 PM to dusk (e.g., 3 PM to 8 PM), the east-facing solar sub-string receives minimal illumination (e.g., reflected illumination), the south-facing solar sub-string receives some illumination, and the west-facing solar sub-string receives the majority of illumination. Therefore, in this example: the east-facing solar sub-string can generate an average of 5 watts and a peak of 20 watts with an average operating voltage of 1.0 volt during this evening period; the south-facing solar sub-string can generate an average of 50 watts and a peak of 200 watts with an average operating voltage of 1.09 volts during this evening period; and the west-facing solar sub-string can generate a peak of 200 watts with an average operating voltage of 1.12 volts during this evening period.

[0076] Therefore, the effective operating voltage and power output of the east-facing, south-facing, and west-facing solar cell strings can vary significantly over time throughout the day and can differ significantly between solar cell strings (e.g., at any single moment, the difference between two solar cell strings can be as high as 200 watts and 0.2 volts). Furthermore, under uneven illumination, the differences in output power and current from these solar cell strings can significantly reduce the total power output of the series-connected group of solar cell strings 110. Therefore, system 100 can: include a set of power conditioners coupled to multiple groups of solar cell strings arranged on the roof; and perform power cycling as described above to achieve a uniform voltage output from the multiple groups of solar cell strings.

[0077] The systems and methods described herein can be embodied and / or implemented at least in part as a machine configured to receive a computer-readable medium storing computer-readable instructions. The instructions can be executed by a computer-executable component integrated with hardware / firmware / software components of an application, app, host, server, network, website, communication service, communication interface, user computer or mobile device, wristwatch, smartphone, or any suitable combination thereof. Other systems and methods of the embodiments can be embodied and / or implemented at least in part as a machine configured to receive a computer-readable medium storing computer-readable instructions. The instructions can be executed by a computer-executable component integrated with a computer-executable component integrated with devices and networks of the types described above. The computer-readable medium can be stored on any suitable computer-readable medium, such as RAM, ROM, flash memory, EEPROM, optical devices (CD or DVD), hard disk drives, floppy disk drives, or any suitable device. The computer-executable component can be a processor, but any suitable dedicated hardware device can (optionally or additionally) execute the instructions.

[0078] As will be appreciated by those skilled in the art from the foregoing detailed description and from the drawings and claims, modifications and variations may be made to the embodiments of the invention without departing from the scope of the invention as defined in the appended claims.

Claims

1. A system for regulating the power output of multiple solar cell substrings, comprising: A first power regulator, comprising: First power source: The first power source is coupled to a first set of solar cell substrings, the first set of solar cell substrings comprising a first subset of solar cell substrings and a second subset of solar cell substrings; and The first power source is configured to receive a first input voltage generated by the first set of solar cell substrings; A first adder, the first adder being coupled to a first gain control of the first power supply; First modulation signal generator: The first modulation signal generator is coupled to the first adder; and The first modulation signal generator is configured to supply a first modulation signal to the first adder to modulate a first voltage gain of the first power supply and induce the output of a first oscillating power signal from the first power supply; First demodulator: The first demodulator is coupled to the first modulation signal generator and the first power supply; and The first demodulator is configured to generate a first demodulated signal based on the first modulation signal and the first oscillation power signal; and First integrator: The first integrator is coupled to the first demodulator and the first adder; and The first integrator is configured to supply a first voltage gain step to the first adder based on the first demodulated signal output from the first demodulator, and the first adder is configured to drive the first input voltage to the maximum power point voltage; and A second power regulator, comprising: Second power source: The second power source is coupled to the first set of solar cell substrings; and The second power source is configured to receive the first input voltage generated by the first set of solar cell substrings; A second adder, the second adder being coupled to a second gain control of the second power supply; Second modulation signal generator: The second modulation signal generator is coupled to the second adder; and The second modulation signal generator is configured to supply a second modulation signal, different from the first modulation signal, to the second adder to modulate the second voltage gain of the second power supply and induce the output of a second oscillating power signal from the second power supply; Second demodulator: The second demodulator is coupled to the second modulation signal generator and the second power supply; and The second demodulator is configured to generate a second demodulated signal based on the second modulation signal and the second oscillation power signal; and Second integrator: The second integrator is coupled to the second demodulator and the second adder; and The second integrator is configured to supply a second voltage gain step to the second adder based on the second demodulated signal output from the second demodulator, and the second adder is configured to drive the midpoint voltage between the first subset of the solar cell substring and the second subset of the solar cell substring to half of the maximum power point voltage.

2. The system according to claim 1, wherein: The first demodulator is configured to generate the first demodulated signal based on the product of the first oscillation power signal from the first power source and the first modulation signal; as well as The first integrator is configured to supply a positive voltage gain step to the first adder in response to the first input voltage dropping below the maximum power point voltage. The first adder is based on the positive DC component of the first demodulated signal; as well as The first adder is configured to increase the first voltage gain of the first power supply to drive the first input voltage toward the maximum power point voltage.

3. The system according to claim 2: in, The first modulation signal generator outputs a first modulation signal defining a first sine wave, and is configured to trigger the output of a first oscillating power signal defining a first sinusoidal power signal, the first sinusoidal power signal originating from the first power source and being at a first phase and a first frequency; and The first demodulator is configured to generate the first demodulated signal based on the product of the first sinusoidal power signal from the first power source and the sine wave, wherein the first demodulated signal includes a DC component and an AC component.

4. The system according to claim 1, wherein: The first demodulator is configured to generate the first demodulated signal based on the product of the first oscillation power signal from the first power source and the first modulation signal; and The first integrator is configured to supply a negative voltage gain step to the first adder in response to the first input voltage exceeding the maximum power point voltage. The first adder is based on the negative DC component of the first demodulated signal; and The first adder is configured to reduce the first voltage gain of the first power supply to drive the first input voltage toward the maximum power point voltage.

5. The system according to claim 1, wherein: The first demodulator is configured to generate the first demodulated signal based on the product of the first oscillation power signal from the first power source and the first modulation signal; as well as The first integrator is configured to supply a zero-voltage gain step to the first adder in response to the first input voltage approaching the maximum power point voltage. The first adder is based on the fact that the first demodulated signal has no DC component; and The first adder is configured to maintain the first input voltage at the maximum power point voltage.

6. The system according to claim 1, wherein: During the first power cycle of the first power regulator: The first demodulator is configured to generate the first demodulated signal based on the product of the first oscillation power signal from the first power source and the first modulation signal; as well as The first integrator is configured to supply a positive voltage gain step to the first adder in response to the first input voltage dropping below the maximum power point voltage. The first adder is based on the positive DC component of the first demodulated signal; as well as The first adder is configured to increase the first voltage gain of the first power supply to drive the first input voltage toward the maximum power point voltage; as well as Following the first power cycle, during the second power cycle of the second power regulator: The second demodulator is configured to: generate the second demodulated signal based on the product of the first oscillation power signal from the first power source and the second modulation signal; and The second integrator is configured to supply a negative voltage gain step to the second adder in response to the first input voltage exceeding the maximum power point voltage. The second adder is based on the negative DC component of the second demodulated signal; and The second adder is configured to reduce the second voltage gain of the second power supply to drive the midpoint voltage between the first subset of the solar cell substring and the second subset of the solar cell substring to half of the maximum power point voltage.

7. The system according to claim 1, wherein: During the first power cycle of the first power regulator: The first demodulator is configured to generate the first demodulated signal based on the product of the first oscillation power signal from the first power source and the first modulation signal; and The first integrator is configured to supply a negative voltage gain step to the first adder in response to the first input voltage exceeding the maximum power point voltage. The first adder is based on the negative DC component of the first demodulated signal; and The first adder is configured to reduce the first voltage gain of the first power supply to drive the first input voltage toward the maximum power point voltage; and Following the first power cycle, during the second power cycle of the second power source: The second demodulator is configured to: generate the second demodulated signal based on the product of the first oscillation power signal from the first power source and the second modulation signal; and The second integrator is configured to supply a positive voltage gain step to the second adder in response to the first input voltage dropping below the maximum power point voltage. The second adder is based on the positive DC component of the second demodulated signal; and The second adder is configured to increase the second voltage gain of the second power supply to drive the midpoint voltage between the first subset of the solar cell substring and the second subset of the solar cell substring to half of the maximum power point voltage.

8. The system according to claim 1: in, The first modulation signal generator outputs a first modulation signal defining a first sine wave, and is configured to trigger the output of a first oscillating power signal defining a first sinusoidal power signal, the first sinusoidal power signal originating from the first power source and being at a first phase and a first frequency; and Wherein, the second modulation signal generator: Output the second modulation signal, the second modulation signal defining a second sine wave having a second frequency offset by 20 Hz from the first frequency; and The output of the second oscillating power signal, which is configured to trigger a second sinusoidal power signal that is derived from the second power source and is in the second phase and at the second frequency, is configured to trigger the output of the second oscillating power signal that is defined as the second sinusoidal power signal.

9. The system according to claim 1, further comprising a low-pass filter: The low-pass filter is coupled to the input of the first integrator and the output of the first demodulator; The low-pass filter is defined with a low-pass cutoff frequency greater than a first frequency of the first modulation signal; and The low-pass filter is configured to deliver the DC component of the first demodulated signal output from the first demodulator to the first integrator.

10. The system according to claim 1: It also includes solar panels: The solar panel includes the first set of solar cell sub-strings; and The solar panel defines a front and a back; It also includes the casing: The housing is disposed on the back side of the solar panel; and The housing includes the first power regulator and controller disposed within the cavity of the housing.

11. The system according to claim 1, further comprising a bandpass filter: The bandpass filter is coupled to the output of the first power supply and the input of the first demodulator; The bandpass filter is defined as follows: A high-pass cutoff frequency, wherein the high-pass cutoff frequency is greater than a first frequency of the first modulation signal; and A low-pass cutoff frequency, said low-pass cutoff frequency being less than the first frequency of the first modulated signal, and configured to block the DC component of the first modulated signal; and The bandpass filter is configured to deliver the AC component of the first modulated signal to the first demodulator.

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