Three-Stage Energy Storage Inverter for Split-Phase Bus Balance
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Solution Overview
Problem
In 120V/240V split-phase or single-phase power supply systems, existing energy storage inverters with T-type or I-type three-level topology solutions experience unbalanced positive and negative bus voltages when a single-phase half wave load is used, necessitating additional balance circuits that increase cost and space.
Innovation Solution
An energy storage inverter with a three-stage topology structure, including a DC-DC conversion circuit, a three-level Boost or Buck circuit, and a three-level inversion circuit, employs multiple operating modes to balance bus voltages by controlling power switch transistors, eliminating the need for additional hardware balance circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If T-type or I-type three-level topology solutions are adopted to improve AC output performance, then AC output performance is improved, but bus voltage balance deteriorates under single-phase half wave load
Solution Approach 1:
The inverter is divided into three independent stages: DC-DC conversion circuit, three-level Boost/Buck circuit, and three-level inversion circuit. Each stage can be independently controlled to perform specific functions, allowing the DC-DC stage to handle voltage conversion while the inversion stage handles AC output, thus maintaining bus balance without compromising AC output performance
Solution Approach 2:
The patent implements dynamic control by switching between multiple operating modes (Boost mode 1-4, Buck mode 1-4) based on real-time bus voltage conditions. The controller dynamically adjusts the operating mode of the DC-DC circuit to maintain positive and negative bus voltage balance while adapting to varying load conditions, thereby resolving the contradiction between performance and stability
2Reliability
If additional balance circuits are added to maintain bus voltage balance, then bus voltage balance is improved, but device complexity and cost increase
Solution Approach 1:
The DC-DC conversion circuit is designed to serve multiple functions: voltage conversion, bus balance maintenance, and energy management. By making the DC-DC circuit multi-functional, the patent eliminates the need for separate balance circuits, reducing device complexity while maintaining bus voltage balance under single-phase half wave load conditions
Solution Approach 2:
The system achieves self-balancing through intelligent control of the existing DC-DC conversion circuit. The controller automatically detects bus voltage imbalances and adjusts the operating mode accordingly, enabling the system to maintain balance without external intervention or additional dedicated balance hardware, thus simplifying the overall circuit structure
3Reliability
If additional balance circuits are added to maintain bus voltage balance, then bus voltage balance is improved, but device space requirements increase
Solution Approach 1:
The DC-DC conversion circuit is designed to serve multiple functions: voltage conversion, bus balance maintenance, and energy management. By making the DC-DC circuit multi-functional, the patent eliminates the need for separate balance circuits, reducing device complexity while maintaining bus voltage balance under single-phase half wave load conditions
Solution Approach 2:
The patent merges the bus balance function into the existing DC-DC conversion circuit by implementing multiple operating modes. This consolidation eliminates the need for separate balance circuits and their associated components (inductors, capacitors, switches), thereby reducing the overall space requirement while maintaining effective bus voltage balance
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
Effectively balances bus voltages without additional hardware, maintaining balanced operation during single-phase half wave loads, reducing costs and space requirements.
Implementation Method 1
a first stage of the energy storage inverter including a DC-DC conversion circuit, configured to convert a voltage of an energy storage battery into a DC voltage higher than the voltage of the energy storage battery
Implementation Method 2
the three-level Boost circuit includes a first inductor, a second inductor, a first power switch transistor, a second power switch transistor, a third power switch transistor, an fourth power switch transistor, a first capacitor and a second capacitor
Implementation Method 3
a drain electrode of the third power switch transistor is electrically connected to one terminal of the first capacitor; a source electrode of the fourth power switch transistor is electrically connected to one terminal of the second capacitor
Data Source
AI summary
The present disclosure provides an energy storage inverter, a bus balance method of the energy storage inverter, and a storage medium. The energy storage inverter includes a first stage of the energy storage inverter including a DC-DC conversion circuit, configured to convert a voltage of an energy storage battery into a DC voltage higher than the voltage of the energy storage battery; a second stage of the energy storage inverter including a three-level Boost circuit or a three-level Buck circuit configured to stabilize a bus voltage; and a third stage of the energy storage inverter including a three-level inversion circuit. The energy storage inverter includes a Boost operating mode 1, a Boost operating mode 2, a Boost operating mode 3, a Boost operating mode 4, a Buck operating mode 1, a Buck operating mode 2, a Buck operating mode 3 and a Buck operating mode 4.