Voltage Level Multiplier Module for Multilevel Inverters
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Solution Overview
Problem
Multilevel inverters face challenges in increasing voltage levels without excessive components, complexity, and cost, as existing hybrid configurations require numerous DC power supplies and bulky capacitors, leading to increased size, cost, and decreased modularity.
Innovation Solution
A power converter circuit incorporating a multilevel inverter with an N-fold voltage level multiplier module that generates additional voltage levels by using series-connected circuit elements and switching pattern generators to control switches based on phase-shifted triangular carrier signals, reducing the number of components and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of output voltage levels is increased in conventional multilevel inverter topologies (NPC, CHB, FC), then the voltage levels are increased, but the number of components (DC-link capacitors, clamping diodes, flying capacitors, isolated DC power supplies) increases excessively
Solution Approach 1:
The inverter is divided into a base multilevel inverter unit and multiple voltage level multiplier modules. Each multiplier module is a standardized unit that can be independently designed and then cascaded in series to achieve the desired voltage levels, avoiding the need to redesign the entire inverter structure for each voltage level increase.
Solution Approach 2:
The voltage level multiplier modules are nested in series between the base inverter and the load. Each multiplier module takes the output from the previous stage and multiplies it, creating a hierarchical structure where the overall voltage multiplication factor is the product of individual module factors (e.g., 2-fold × 2-fold × 2-fold = 8-fold total multiplication).
2Quantity of substance
If the number of output voltage levels is increased in conventional multilevel inverter topologies, then the voltage levels are increased, but the size and cost of the converter increase due to more components
Solution Approach 1:
The invention changes the topological parameters of the inverter by introducing voltage level multiplier modules with specific switching patterns. By controlling the switching states of these modules, the effective voltage multiplication factor can be adjusted dynamically, allowing the same physical hardware to operate at different voltage levels without requiring additional components for each level.
3Quantity of substance
If the number of output voltage levels is increased in conventional multilevel inverter topologies, then the voltage levels are increased, but the control complexity increases due to DC-link capacitor voltage control and flying capacitor voltage balancing
Solution Approach 1:
The voltage level multiplier modules incorporate self-balancing mechanisms where the switching patterns automatically regulate the voltages across series-connected capacitors within each module. This self-service capability eliminates the need for complex external control systems to balance capacitor voltages, as the modules inherently maintain voltage equilibrium through their switching operation.
4Device complexity
If hybrid multilevel inverter configurations are used to increase voltage levels, then some component reduction is achieved, but numerous isolated DC power supplies with various voltages are required, decreasing modularity
Solution Approach 1:
The voltage level multiplier modules are designed as universal, standardized units that can be applied to any base multilevel inverter configuration. Each module performs the same function (voltage multiplication) and has the same structure, allowing them to be interchanged and cascaded in different combinations to achieve various voltage levels, thereby maintaining high modularity and adaptability.
Data Source
AI summary
Generalized circuit topology of voltage level multiplier modules (VLMMs) for use with multilevel inverters (MLIs) and power converter circuits comprising at least one VLMM and a MLI are described herein. The VLMM is configured to receive a first output voltage from the MLI having a first number of voltage levels and to generate a second output voltage having a second number of voltage levels. If the first number of voltage levels is M, and the VLMM is N-fold voltage level multiplier, then second number of voltage levels is M×N+1. Switching pattern generators for use with the VLMM and modulation methods for controlling switching elements of the VLMM are also described herein.