Parallel Inverter Power Control Systems with Master-Slave Coordination
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Solution Overview
Problem
Conventional solar energy generation systems with on-site energy storage face complexity in managing power flow between various components, leading to inefficient operation and potential under-utilization, especially when multiple PV strings and energy storage devices are involved.
Innovation Solution
The implementation of a power control system with multiple inverter power control systems (PCS) configured in parallel, where one PCS acts as a master to manage the operation of others, allowing for coordinated power transfer between DC sources, energy storage devices, and the AC grid or back-up loads, and including a central AC disconnect to prevent overloading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple inverter power control systems are used to manage power flow between multiple PV strings and energy storage devices, then the functionality and versatility of the energy generation system are improved, but the device complexity increases
Solution Approach 1:
The system divides the power control function into multiple independent inverter PCS units, each capable of managing specific PV strings or energy storage devices. This segmentation allows the system to handle complex power flow scenarios while maintaining manageable individual control units with standardized interfaces.
Solution Approach 2:
Each inverter PCS is designed as a multi-functional unit that can perform multiple operations including converting DC to AC power, managing energy storage charging/discharging, and coordinating with other PCS units. This universal design reduces overall system complexity by using standardized components rather than specialized dedicated units.
2Productivity
If multiple inverter power control systems operate independently to manage power flow, then the power management capability is improved, but the risk of conflicting power flow and system instability increases
Solution Approach 1:
The master inverter PCS continuously monitors the operational status of all slave PCS units and receives feedback signals about power flow conditions. Based on this feedback, the master PCS dynamically adjusts the operating parameters of slave units to prevent conflicting power flows and maintain system stability during various operational scenarios.
Solution Approach 2:
The master inverter PCS acts as an intermediary coordinator between multiple slave PCS units, the PV arrays, and the grid connection. It mediates power flow decisions by receiving commands from one PCS and distributing coordinated control signals to other PCS units, ensuring that all units operate in a harmonized manner without conflicts.
3Ease of operation
If one inverter PCS manages the operation of other PCS units, then the ease of operation is improved, but the device complexity of the master PCS increases
Solution Approach 1:
The master inverter PCS combines multiple control functions into a single centralized unit, including monitoring of all slave PCS units, coordination of power flow paths, management of energy storage devices, and grid synchronization. This consolidation provides ease of operation through a single point of control while the internal architecture manages the complexity through modular functional blocks.
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 enhances the functionality and versatility of solar energy generation systems by ensuring efficient power management, reducing the risk of component damage, and maximizing energy utilization across multiple PV strings and energy storage devices.
Implementation Method 1
a DC to AC inverter stage configured to receive the DC power input
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A power control system includes a first inverter power control system and a second inverter power control system coupled in a parallel configuration with the first inverter power control system. Both first and second inverter power control systems may each include an input configured to receive direct current (DC) power; a DC to alternating current (AC) inverter stage configured to receive the DC power input; an anti-islanding relay coupled to the output of the DC/AC inverter stage; and a transition relay coupled to the anti-islanding relay. The transition relay may be configured to route an output of the inverter power control system between one or more onsite back-up loads and an AC grid. The first inverter power control system may be designated as a master that is configured to control the operation of the second inverter power control system designated as a slave.