EV Inverter Non-Overlap Control With Single-Channel Feedback
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Solution Overview
Problem
Inverters used in electric vehicles face issues with overlapping turn-on events of opposing phase switches, which can damage the inverter, and the dead time between switching events leads to inefficiencies.
Innovation Solution
A closed-loop non-overlap enforcement architecture is implemented using a single galvanic channel for command and feedback signals, ensuring that an on-state phase switch is off before allowing the complementary off-state phase switch to turn on, thereby preventing shoot-through conditions and reducing dead time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dead time is increased between switching events, then overlapping turn-on events are prevented, but inverter efficiency deteriorates
Solution Approach 1:
The patent implements a closed-loop feedback mechanism where the actual switch state is sensed and fed back to the control logic. The non-overlap enforcement circuit monitors the real-time state of phase switches and dynamically adjusts the timing of complementary switch activation, replacing fixed dead-time delays with adaptive feedback-controlled timing that prevents shoot-through while minimizing unnecessary dead time.
Solution Approach 2:
The system transitions from static fixed dead-time intervals to dynamic non-overlap enforcement that adapts to actual switch behavior. The control circuit continuously adjusts the timing based on real-time switch state feedback, allowing the dead time to vary dynamically rather than remaining fixed, thereby optimizing both safety and efficiency under different operating conditions.
2Reliability
If multiple galvanic channels are used for command and feedback signals, then signal integrity is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines command and feedback signal transmission into a single galvanic channel by implementing bidirectional communication protocols. The same physical channel carries both control commands from the low-voltage side to the high-voltage side and status feedback from the high-voltage side to the low-voltage side, eliminating the need for separate dedicated channels for each direction and reducing overall system complexity.
Solution Approach 2:
The single galvanic channel is designed to serve multiple functions: transmitting turn-on commands, transmitting turn-off commands, and carrying feedback signals about switch states. This multi-functional channel replaces what would traditionally require multiple specialized channels, reducing component count while maintaining full bidirectional communication capability.
Data Source
AI summary
A system includes: an inverter configured to convert DC power from a battery to AC power to drive a motor, wherein the inverter includes: a galvanic interface configured to separate a high voltage area from a low voltage area, the galvanic interface including a command channel and a message channel; a low voltage controller in the low voltage area, the low voltage controller configured to receive a PWM signal from a PWM controller; and a high voltage controller in the high voltage area, the high voltage controller configured to receive a control signal from the low voltage controller using the command channel of the galvanic interface, and send a switch state signal to the low voltage controller using the command channel of the galvanic interface, wherein the low voltage controller is configured to control the control signal based on the PWM signal and the switch state signal.