Grid Synchronizer With Remote Sensor Feedback
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Solution Overview
Problem
Existing systems face challenges in rapidly removing gate charge from power switching devices while minimizing power loss, leading to shoot-through issues and reduced system reliability, and in synchronizing inverter outputs with the AC grid mains despite line impedance variations.
Innovation Solution
A grid synchronizer system that uses a controller with a receiver to communicate grid data from a remote sensor to an inverter, allowing it to synchronize its AC output with the AC grid mains, and a driver circuit with a low-value resistor and zener diode to rapidly remove gate charge from semiconductor switching devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If small ohmic resistors are used to rapidly remove gate charge, then gate charge removal speed is improved, but power loss in the resistors increases and system reliability decreases
Solution Approach 1:
The patent introduces a capacitor as an intermediary energy storage element between the power supply and the gate resistor. The capacitor stores energy during the non-switching period and releases it during the switching transition, enabling rapid gate charge removal without requiring continuous high power dissipation in the resistor. This mediator component allows the system to achieve fast switching speeds while significantly reducing average power loss.
Solution Approach 2:
The patent implements periodic charging and discharging of the capacitor in synchronization with the switching cycle. During each switching period, the capacitor is charged from the power supply and then discharged through the gate resistor to remove gate charge rapidly. This periodic action concentrates the energy dissipation into brief intervals rather than continuous loss, improving overall system efficiency while maintaining fast switching capability.
2Adaptability or versatility
If inverters are connected remotely to the AC grid, then installation flexibility is improved, but phase shifted line voltage occurs due to line impedance
Solution Approach 1:
The patent incorporates a feedback mechanism where the inverter controller continuously monitors the output voltage phase and current, and adjusts the switching timing to compensate for phase shifts caused by line impedance. The controller uses feedback signals from voltage and current sensors to detect phase deviations and dynamically adjusts the inverter output to maintain proper synchronization with the grid, enabling reliable remote installation despite line impedance variations.
Solution Approach 2:
The patent dynamically changes operating parameters including switching frequency, pulse width modulation (PWM) duty cycle, and switching timing based on detected line conditions. By adjusting these parameters in response to measured phase shifts and line impedance, the system maintains accurate phase synchronization even when connected remotely to the grid through long cables or complex distribution networks.
Data Source
AI summary
The invention relates to a grid synchroniser for connecting an AC output of a power converter to the AC grid mains. In one aspect the invention provides a grid synchroniser comprising an inverter controller to control an AC output of the inverter, the controller including a receiver to receive grid data from a grid sensor location remote from said inverter. In another aspect we describe techniques for rapid removal of charge from a control terminal of a power switching device such as a MOSFET, IGBT or Thyristor using a particular driver circuit.