AFE Inverter Self-Sensing Voltage Vector Angle Detection
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Solution Overview
Problem
Existing Active Front End (AFE) control systems for AC grids rely on external voltage sensors to detect the angle of the grid voltage vector, which is costly and cumbersome, and do not allow for self-sensing capabilities, limiting their efficiency and flexibility.
Innovation Solution
A method for generating Pulse Width Modulation (PWM) signals for AFE inverters that estimates the grid voltage vector angle without physical voltage sensors by processing inverter terminal voltages and gate drive signals, enabling self-sensing and precise power factor control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external voltage sensors are used to detect the grid voltage vector angle, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The AFE inverter system performs self-sensing by using its own internal components (current sensors, switching state information, and terminal voltage measurements) to detect the grid voltage vector angle, eliminating the need for separate external voltage sensors. The controller utilizes readily available internal data to achieve the measurement function that would otherwise require additional hardware.
Solution Approach 2:
The existing current sensors and controller in the AFE inverter are made to serve multiple functions: they continue to perform current measurement for power control while also enabling grid voltage vector angle detection through self-sensing algorithms, thereby eliminating the need for dedicated voltage sensing hardware.
2Measurement precision
If external voltage sensors are used to detect the grid voltage vector angle, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The system uses its own internal measurement capabilities and switching state information to detect the grid voltage vector angle, making the system self-sufficient and eliminating the need for additional external voltage sensing components that would increase manufacturing cost.
Solution Approach 2:
Instead of using physical voltage sensors to directly measure grid voltage, the system creates a virtual representation of the grid voltage vector angle by processing current measurements and switching state data through mathematical algorithms, achieving the same functional result without additional hardware.
3Device complexity
If voltage sensors are eliminated for self-sensing, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent replaces the mechanical/electrical voltage sensing system with a computational approach using mathematical algorithms that process current measurements and switching state information to calculate the grid voltage vector angle, substituting physical sensing with signal processing.
Solution Approach 2:
The system uses terminal voltage measurements and current sensor data as intermediary variables to indirectly determine the grid voltage vector angle through mathematical relationships, rather than directly sensing the grid voltage with external sensors.
Data Source
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AI summary
A controller (100) may include a memory having computer-readable instructions stored therein; and a processor configured to execute the computer-readable instructions to generate Pulse Width Modulation (PWM) signals to control power switches of an Active Front End (AFE) inverter (500) based on at least a synthesized grid voltage vector angle at a terminal of an alternating current (AC) grid (400) without using physical voltage sensors at the terminal of the AC grid (400), and control the AFE inverter (500) to supply power to a load (700 or 800) based on the PWM signals.