Aircraft Solid State Power Controller With Isolated Gate Driver Protection
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Solution Overview
Problem
Existing aircraft solid state power controllers face challenges in controlling electric power supply with an electric control signal that is galvanically isolated from the power source, particularly in preventing damage from overvoltages and negative voltages exceeding the specifications of the isolated gate driver.
Innovation Solution
The aircraft solid state power controller employs a solid state switch, an isolated gate driver, and a voltage regulator to manage control signals with additional voltage references, using a galvanically isolated gate driver and a power supply switching circuit to prevent overvoltage damage, along with delay circuits for safe and reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the isolated gate driver is used to control the solid state switch with a control signal having an additional voltage reference, then the galvanic isolation between control signal and power source is achieved, but the gate driver may be damaged by overvoltages and negative voltages exceeding its specifications
Solution Approach 1:
A voltage regulator is introduced as an intermediary component between the power supply line and the isolated gate driver. This regulator mediates the voltage levels, ensuring that the gate driver receives only voltages within its safe operating range while maintaining the control signal's ability to properly switch the solid state switch. The regulator acts as a protective buffer that isolates the gate driver from harmful voltage excursions.
Solution Approach 2:
The voltage regulator provides beforehand cushioning by pre-limiting the voltage range supplied to the isolated gate driver before any overvoltage or negative voltage conditions can occur. This preventive measure ensures that even if the power supply line experiences voltage spikes or reverse polarity, the gate driver is already protected by the regulator's voltage clamping function, preventing damage before it can occur.
2Adaptability or versatility
If the control signal is applied as an additional voltage on top of the power supply voltage, then the control flexibility is improved, but the voltage regulator is required to limit the gate driver supply voltage
Solution Approach 1:
The voltage regulator serves as a necessary intermediary that enables the flexible control signal architecture without compromising system safety. By placing the regulator in the voltage supply path to the gate driver, the system maintains control signal flexibility (the ability to apply additional voltage references) while the regulator handles the complexity of voltage limitation, thus distributing the complexity burden to a dedicated protection component rather than requiring complex control logic.
Data Source
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AI summary
An aircraft solid state power controller (8) for controlling the supply of electric power to an electric load (6) in an aircraft (1), wherein the electric load (6) is electrically connected between an output terminal (14) of the aircraft solid state power controller (8) and a ground potential (GND) comprises: a solid state switch (10) arranged between and electrically connected to a power supply line (12) and the output terminal (14) of the aircraft solid state power controller (8) for selectively supplying or interrupting supply of electric power having a first voltage (U1), which is measured between the power supply line (12) and the ground potential (GND), to the electric load (6) in response to a control signal, which is provided at a control terminal (46) of the aircraft solid state power controller (8); wherein the control signal has a second voltage (U2) with reference to the power supply line (12) and the second voltage (U2) is applied as an additional voltage on top of the first voltage (U1) with respect to the ground potential (GND); and an isolated gate driver (18), comprising an input side (18a) and an output side (18b). The output side (18b) is galvanically isolated from the input side (18a). The isolated gate driver (18) is configured for receiving the control signal on its input side (18a), and for supplying a drive signal to the solid state switch (10) on its output side (18b) upon receiving the control signal on its input side (18a). A reference potential of the output side (18b) of the isolated gate driver (18) is electrically coupled to the output terminal (14) of the aircraft solid state power controller (8). A gate driver supply voltage (UG) for driving the output side (18b) of the isolated gate driver (18) is supplied to the output side (18b) of the isolated gate driver (18) with respect to the reference potential.