Solar Circulation Pump Duty-Cycle Control Under Variable Irradiation
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Solution Overview
Problem
Solar circulating pumps connected to photovoltaic panels face challenges in maintaining optimal operating efficiency due to varying solar irradiation conditions, leading to fluctuations in electrical power supply and potential unnecessary noise emissions during start-up when insufficient energy is available.
Innovation Solution
A control device that varies the commutation signal's switch-on to switch-off time ratio to maximize the speed of the electric motor, utilizing a control circuit and measuring device to optimize performance, and includes a buffer store for ensuring sufficient energy is available for start-up, along with an adjustment device to set a lower voltage limit for power throttling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the solar circulating pump operates directly with varying photovoltaic power supply, then the device complexity is reduced, but the operating efficiency and speed stability deteriorate due to fluctuations in solar irradiation conditions
Solution Approach 1:
The control device dynamically adjusts the commutation signal parameters (switch-on to switch-off time ratio) based on the available photovoltaic power, optimizing the motor speed and pump efficiency for varying solar irradiation conditions without requiring complex additional hardware
2Loss of time
If the pump attempts to start-up immediately upon initialization, then the response time is reduced, but unnecessary noise emissions occur when insufficient electrical energy is available
Solution Approach 1:
The control device performs a preliminary check of the buffer store energy level before initiating start-up sequences. This preliminary action prevents unnecessary start-up attempts and associated noise emissions when insufficient electrical energy is available, while still enabling rapid start-up when energy conditions are favorable
Solution Approach 2:
The control device continuously monitors the buffer store charge level and uses this feedback information to determine whether to proceed with start-up, thereby avoiding noise-generating start-up attempts when energy is insufficient while maintaining fast response when energy is available
3Device complexity
If the commutation signal ratio is fixed, then the device complexity is minimized, but the speed optimization under varying irradiation conditions is lost
Solution Approach 1:
The control device dynamically adjusts the commutation signal's switch-on to switch-off time ratio in response to varying photovoltaic power output, enabling the motor speed to be optimized for current irradiation conditions while using a relatively simple control circuit implementation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables continuous optimization of the solar circulating pump's performance under varying irradiation conditions, reduces unnecessary noise emissions, and ensures efficient operation by maximizing speed and power while adapting to different solar collector configurations.
Implementation Method 1
a solar circulating pump for connection to a photovoltaic panel device (20), with an electric motor (22) that is electronically commutated and has a control device (32) that can be used to provide a periodic commutation signal
Implementation Method 2
the control device is designed in such a way that the commutation signal is varied with regard to the ratio of switch-on time to switch-off time... the control objective for the controlled variable is to maximize the speed
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
In order to provide a solar circulation pump for connection to a photovoltaic panel device (20), with an electric motor (22) which is electronically commutated and has a control device (32) by which a periodic commutation signal can be provided, it is proposed that the control device (32) be designed such that the commutation signal is varied with respect to the ratio of on-time (44) to off-time (46).