Adaptive Multi-Level Converter Control for Lower Switching Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Three-level converters, such as T-type converters, incur increased cost due to the need for low RDSON middle power switches, which are rated for half the full Vbus voltage, and conventional converters have high switching losses and electromagnetic interference (EMI).
Innovation Solution
An adaptive control mechanism for multi-level converters that allows operation as a two-level or three-level converter, or in a transitional mode, using lower-cost middle power switches with high RDSON and activating them briefly to generate zero voltage, reducing switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three-level converters use middle power switches with low RDSON to support high current drives, then the current handling capability is improved, but the cost increases
Solution Approach 1:
The converter dynamically switches between two-level and three-level operation modes based on load conditions. During light-load operation, the system operates as a two-level converter using only outer switches, eliminating the need for expensive low-RDSON middle switches. During heavy-load operation, the system transitions to three-level mode, activating middle switches only when necessary to handle high current demands. This dynamic operation resolves the contradiction by making middle switches optional rather than mandatory.
Solution Approach 2:
The invention changes the operational parameters of the converter by introducing a transitional mode with three distinct states: two-level mode, three-level mode, and a novel transitional mode where the switching connection point is held at zero voltage. This parameter change allows the system to adapt its configuration based on load requirements, enabling cost-effective operation at light loads while maintaining high current capability when needed.
2Power
If conventional converters operate at high power levels, then the power output is improved, but switching losses increase
Solution Approach 1:
The converter dynamically adapts its topology based on power level and load conditions. At light-load conditions, the system operates in two-level mode or transitional mode with reduced switching activity, minimizing switching losses. At heavy-load conditions requiring high power output, the system transitions to three-level mode which inherently reduces switching losses through its voltage distribution architecture. This dynamic adaptation resolves the contradiction between power output and switching losses.
Solution Approach 2:
The controller periodically monitors load conditions and transitions between operational modes accordingly. The system uses feedback signals to determine when to switch between two-level and three-level operation, optimizing the balance between power output and switching losses based on real-time operating conditions.
3Power
If conventional converters operate at high power levels, then the power output is improved, but electromagnetic interference increases
Solution Approach 1:
The converter dynamically selects its operational mode to minimize electromagnetic interference while maintaining required power output. The transitional mode with zero-voltage holding at the switching connection point reduces voltage transitions and associated EMI. The system adapts its switching strategy based on load conditions, using softer switching characteristics during transitions to reduce electromagnetic radiation and conduction interference.
Solution Approach 2:
The invention converts the potential harm of voltage transitions during mode switching into a benefit by deliberately holding the switching connection point at zero voltage during transitional operation. This controlled zero-voltage state reduces voltage stress and minimizes electromagnetic interference, transforming what could be a disruptive transition into a beneficial EMI-reduction mechanism.
Data Source
AI summary
An apparatus includes a two-level converter circuit, a higher-level converter circuit (having switches), and a controller. The controller receives a feedback signal associated with the two-level/higher-level converter circuits and generates a control signal based on the feedback signal. The apparatus operates in one of three modes (first/second/third modes) based on the control signal. In the first mode, the apparatus operates as a two-level converter to generate a two-level output voltage from an input voltage. In a second mode, the apparatus operates as a higher-level converter to increase a number of levels to more than two-levels for the output voltage. In a third mode, the apparatus transitions between the first/second modes where the apparatus operates as the two-level converter and where the switches of the higher-level converter circuit are activated for a period of time to generate a zero voltage at a switching connection point of the apparatus.