Solid-State Transformer for Bidirectional HV to LV Power Conversion
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Solution Overview
Problem
Conventional power conversion systems from medium or high voltage networks to low voltage DC applications are bulky, consume many resources, and only allow unidirectional power flow, necessitating multiple devices for different voltage/current ratings.
Innovation Solution
A power conversion system comprising a high voltage switchgear, a solid-state transformer, and a low voltage switchgear, enabling bidirectional power flow through modules that convert HV AC to HV DC and LV DC, allowing flexible power transfer between HV and LV networks and applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional power transformer is used for HV/MV AC to LV DC conversion, then galvanic insulation and voltage conversion are achieved, but the system occupies large space, consumes significant raw materials, has high weight, and creates power losses
Solution Approach 1:
The patent replaces the conventional mechanical/power transformer with a solid-state transformer consisting of power electronic converters. This substitution eliminates the need for heavy magnetic cores and windings while achieving the same voltage conversion and galvanic insulation functions through electronic switching and isolation techniques.
Solution Approach 2:
The invention changes the operating parameters by using high-frequency switching in the solid-state transformer compared to the low-frequency operation of conventional transformers. This parameter change enables smaller component sizes, reduced weight, and lower material consumption while maintaining the required insulation and conversion capabilities.
2Power
If a conventional power transformer is used for HV/MV AC to LV DC conversion, then voltage conversion is achieved, but the system occupies large space and consumes significant raw materials
Solution Approach 1:
The patent replaces the conventional mechanical/power transformer with a solid-state transformer consisting of power electronic converters. This substitution eliminates the need for heavy magnetic cores and windings while achieving the same voltage conversion and galvanic insulation functions through electronic switching and isolation techniques.
Solution Approach 2:
The invention changes the operating parameters by using high-frequency switching in the solid-state transformer compared to the low-frequency operation of conventional transformers. This parameter change enables smaller component sizes, reduced weight, and lower material consumption while maintaining the required insulation and conversion capabilities.
3Device complexity
If conventional unidirectional power flow configuration is used, then simple system layout is achieved, but power flow is enabled only in one direction requiring multiple devices for different applications
Solution Approach 1:
The patent implements a bidirectional solid-state transformer that can operate in multiple modes: converting HV AC to LV DC, LV DC to HV AC, and enabling bidirectional power flow. This multi-functional device replaces the need for separate unidirectional converters for different applications, reducing the total number of devices while increasing versatility.
Solution Approach 2:
The invention introduces dynamic controllability to the power conversion system, allowing the power flow direction to be changed on-demand. The solid-state transformer can dynamically switch between different operating modes (HV AC to LV DC, LV DC to HV AC, charging, discharging) based on system requirements, unlike static conventional transformers.
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
The system minimizes footprint, enables efficient bi-directional power flow, and simplifies the integration of renewables into HV/MV distribution networks, reducing material usage and operational complexity.
Implementation Method 1
The first module is configured to convert a high voltage alternating current (HV AC) signal into a high voltage direct current (HV DC) signal
Data Source
AI summary
A power conversion system includes a high voltage (HV) switchgear; a solid-state transformer; and a low voltage (LV) switchgear. The HV switchgear connects to and disconnects from a HV network. The HV switchgear connects to an input of the solid-state transformer, which comprises first and second modules. The first module converts an HV alternating current (AC) signal into a HV DC signal, and the first module converts an HV DC signal into an HV AC signal. The second module converts an HV DC signal into at least one LV DC signal, and the second module converts at least one LV DC signal into an HV DC signal. The LV switchgear connects to an output of the solid-state transformer. The LV switchgear connects to a plurality of applications or devices and disconnects from the plurality of applications or devices.