PV MPPT Control With Adaptive Voltage Steps for High-Capacitance Panels
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Solution Overview
Problem
Existing Maximum Power Point Tracking (MPPT) methods, such as Perturb and Observe (P&O), face challenges in efficiently tracking the Maximum Power Point (MPP) of photovoltaic panels, especially those with high output capacitance like perovskite panels, due to varying capacitance with MPPT frequency and voltage steps.
Innovation Solution
The proposed solution involves determining MPPT timesteps based on different MPPT frequencies, where each frequency is associated with a corresponding voltage step. This approach allows for dynamic voltage steps, where the error current remains constant across all voltage steps and timesteps, enabling efficient MPP tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a fixed MPPT frequency and voltage step are used, then the system is simple to operate, but the response speed to MPP changes is slow and accuracy deteriorates for high capacitance panels
Solution Approach 1:
The patent implements dynamic voltage steps that vary based on the measured capacitance of the photovoltaic panel. The system adjusts the voltage step size and MPPT frequency in real-time according to the panel's capacitance characteristics, transitioning from fixed-parameter MPPT to adaptive dynamic MPPT. This resolves the contradiction by making the system responsive to changing conditions while maintaining operational simplicity through automated adaptation.
Solution Approach 2:
The system changes key parameters (voltage step size, MPPT frequency, and dwell time) based on the measured capacitance value. By dynamically adjusting these parameters according to the specific panel characteristics, the system achieves both fast response speed and high accuracy without requiring complex manual configuration, thereby resolving the contradiction between speed and complexity.
2Speed
If large voltage steps are used to achieve fast response, then the response speed improves, but the error between actual and measured power increases
Solution Approach 1:
The patent employs dynamic voltage steps that are automatically adjusted based on the measured capacitance. For high capacitance panels, the system uses smaller voltage steps with corresponding dwell times to maintain measurement accuracy, while for low capacitance panels, larger steps can be used for faster response. This dynamic adaptation resolves the contradiction by optimizing the voltage step size for each specific operating condition.
Solution Approach 2:
The system changes the voltage step size parameter based on the measured capacitance characteristics. By establishing a relationship between capacitance value and optimal voltage step size, the system achieves both fast response and high measurement accuracy simultaneously, resolving the contradiction between speed and precision.
3Measurement precision
If small voltage steps are used to maintain accuracy, then measurement precision improves, but the response speed to MPP changes deteriorates
Solution Approach 1:
The patent implements a dynamic MPPT system that automatically adjusts the voltage step size based on the measured capacitance. For panels with low capacitance, the system uses larger voltage steps to achieve fast response, while for high capacitance panels, it uses smaller steps to maintain accuracy. This dynamic parameter adjustment resolves the contradiction by optimizing performance for each specific condition.
Solution Approach 2:
The system changes the voltage step parameter according to the measured capacitance characteristics, establishing an optimal operating point for each panel type. This parameter adaptation enables the system to achieve both high measurement accuracy and fast response speed by selecting the appropriate voltage step size for the specific panel capacitance, resolving the contradiction between precision and speed.
4Speed
If MPPT frequency is increased to improve response speed, then the response time decreases, but the capacitance variation effects worsen for high capacitance panels
Solution Approach 1:
The patent implements a dynamic system that adjusts the MPPT frequency based on the measured capacitance. For high capacitance panels, the system automatically reduces the MPPT frequency to minimize capacitance variation effects, while for low capacitance panels, it can operate at higher frequencies for faster response. This dynamic frequency adjustment resolves the contradiction by optimizing the operating frequency for each specific panel type.
Solution Approach 2:
The system changes the MPPT frequency parameter according to the measured capacitance characteristics. By establishing an optimal frequency-c capacitance relationship, the system achieves both fast response time and high tracking reliability simultaneously, resolving the contradiction between speed and reliability through adaptive parameter selection.
5Measurement precision
If a single dwell time is used for all voltage steps, then the system is simple to control, but the MPPT accuracy deteriorates for high capacitance panels
Solution Approach 1:
The patent implements a dynamic control system that automatically adjusts the dwell time based on the measured capacitance and the selected voltage step size. The system calculates the appropriate dwell time to allow the panel voltage to stabilize before measurement, ensuring accurate MPPT tracking without requiring complex manual configuration. This dynamic adjustment resolves the contradiction by optimizing the dwell time for each operating condition while maintaining simple automated control.
Solution Approach 2:
The system changes the dwell time parameter according to the measured capacitance and operating conditions. By establishing optimal dwell time values for different capacitance ranges and voltage step sizes, the system achieves high MPPT tracking accuracy through automated parameter adaptation, resolving the contradiction between precision and control complexity.
Data Source
AI summary
The MPPT methods described herein use different MPPT timesteps with corresponding voltage steps. The voltage step may applied based on the MPPT timestep or vice versa. According to one example, a power difference between the output power level of the photovoltaic panel is determined and a previous output power level. For each MPPT frequency, the voltage of the photovoltaic panel by a voltage step corresponding to the MPPT frequency is modified based on the power difference. According to another example, a voltage step which corresponds to the power difference is determined. A timestep corresponding to the voltage step is determined and the voltage of the photovoltaic panel is modified by the voltage step for the duration of the timestep.