Inverter Gate Driver Noise Reducer for Staggered Switching EMI Control
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Solution Overview
Problem
Existing power conversion apparatuses face challenges in improving electromagnetic interference (EMI) characteristics without increasing complexity or cost, particularly due to overlapping switching noise in power conversion systems for air conditioners.
Innovation Solution
A power conversion apparatus with a noise reducer circuit that uses resistor-capacitor (RC) filters to set different switching noise occurrence times for each phase, reducing EMI by dispersing noise peaks through staggered switching times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If switching frequency is changed or circuit configuration is modified to address EMI deterioration, then EMI characteristics improve, but device complexity and cost increase
Solution Approach 1:
The patent introduces a delay circuit that delays the switching signal before it reaches the gate driver, allowing the switching noise occurrence time to be controlled and staggered across different phases. This preliminary timing adjustment prevents noise overlap without requiring complex circuit reconfiguration or frequency changes, thus improving EMI characteristics while maintaining simple circuit architecture
Solution Approach 2:
The patent changes the timing parameter of the switching signal by introducing a controllable delay through the delay circuit. By adjusting the delay time, the switching noise occurrence times of different phases are staggered, preventing noise overlap. This parameter change approach improves EMI characteristics without modifying the fundamental circuit configuration or switching frequency
2Object-affected harmful factors
If switching frequency is changed or circuit configuration is modified to address EMI deterioration, then EMI characteristics improve, but cost increases
Solution Approach 1:
The delay circuit is integrated into the existing gate driver structure, adding only a simple timing delay function. This approach avoids the need for expensive EMI filters, shielding materials, or complex circuit redesigns, thereby improving EMI characteristics while maintaining cost-effectiveness and ease of manufacture
Solution Approach 2:
The delay circuit acts as an intermediary component between the control signal source and the gate driver, introducing a simple timing adjustment mechanism. This intermediary approach effectively staggers switching noise occurrence times without requiring expensive EMI suppression components or complex modifications to the power conversion circuitry
3Object-affected harmful factors
If noise reducer with RC filters is added to stagger switching noise occurrence times, then EMI characteristics improve, but device complexity increases
Solution Approach 1:
The delay circuit is integrated directly into the gate driver structure, combining the timing delay function with the existing gate drive circuitry. This integration approach minimizes additional complexity while effectively staggering switching noise occurrence times across different phases, preventing noise overlap without requiring separate noise reducer circuits
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively improves EMI characteristics by avoiding noise overlap and reducing switching noise, thereby enhancing the performance of power conversion systems without altering the switching frequency.
Implementation Method 1
A power conversion apparatus includes an inverter including a plurality of switching elements corresponding to three phases, a gate driver configured to drive the switching elements of the inverter, and a noise reducer connected to the gate driver and configured to set switching noise occurrence times caused by the switching elements in the respective phases to be different
Data Source
AI summary
A power conversion apparatus capable of improving an EMI characteristic and an air conditioner including the same are disclosed. The power conversion apparatus includes an inverter including a plurality of switching elements corresponding to three phases, a gate driver configured to drive the switching elements of the inverter, and a noise reducer connected to the gate driver and configured to set switching noise occurrence times caused by the switching elements in the respective phases to be different.