Switching Power Source Controller for Magnetostrictive Noise Reduction
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Solution Overview
Problem
Switching power source apparatuses face issues with magnetostrictive noise generation due to varying load and input conditions, leading to inefficient operation and noise disturbances in consumer appliances and audio equipment.
Innovation Solution
The apparatus incorporates a controller with edge detectors, load testers, bottom detectors, and state testers to dynamically shift between pseudo resonant and bottom skip operations, delaying transitions and stabilizing switching operations to prevent sudden current changes and noise, using a series circuit with a transformer and switching element, and a current detector to manage the ON/OFF periods of the switching element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the switching frequency is increased under light load to improve response time, then the response speed is improved, but the switching loss increases and efficiency deteriorates
Solution Approach 1:
The patent implements dynamic switching frequency adjustment based on load conditions. The controller automatically increases switching frequency during light load periods for faster response, then decreases it during heavy load periods to reduce switching losses, optimizing both response speed and efficiency across different operating conditions
Solution Approach 2:
The patent changes the switching frequency parameter dynamically according to load conditions. By adjusting this key parameter based on real-time load detection, the system achieves fast response when needed while minimizing energy losses during sustained operation
2Speed
If the switching frequency is increased to improve transient response, then the response performance is improved, but magnetostrictive noise is generated
Solution Approach 1:
The patent employs periodic switching with frequency modulation. By using periodic action with variable frequency rather than fixed high frequency, the system achieves improved transient response while avoiding the continuous high-frequency operation that generates magnetostrictive noise
Solution Approach 2:
The system dynamically adjusts switching frequency based on transient conditions. During transient events, frequency increases temporarily to improve response, then returns to lower levels to eliminate noise, achieving both performance and noise reduction
3Loss of energy
If the bottom skip operation is implemented under light load to reduce switching loss, then the efficiency is improved, but the operation becomes unstable under varying load and input conditions
Solution Approach 1:
The patent incorporates feedback mechanisms that continuously monitor load and input conditions. This feedback enables the controller to determine when to apply bottom skip operation and when to switch to pseudo resonant operation, maintaining stability across varying conditions while preserving efficiency benefits
Solution Approach 2:
The system dynamically switches between bottom skip operation and pseudo resonant operation based on real-time conditions. This dynamic adaptation allows the system to maintain operational stability under varying load and input conditions while still achieving reduced switching losses through bottom skip when appropriate
4Reliability
If the pseudo resonant operation is used under heavy load to maintain continuous operation, then the reliability is improved, but the switching frequency increases causing noise
Solution Approach 1:
The patent changes operating parameters based on load conditions. Under heavy load, the system transitions to pseudo resonant operation with adjusted frequency and duty cycle parameters, maintaining reliable continuous operation while controlling noise through parameter optimization
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
This solution ensures stable switching operations and prevents magnetostrictive noise from the transformer even under varying load and input conditions, improving efficiency and reducing noise disturbances.
Implementation Method 1
a series circuit that includes a primary winding P of a transformer 2 and a switching element 3
Implementation Method 2
preventing magnetostrictive noise
Data Source
AI summary
A switching power source apparatus has a controller generating a drive signal that controls an ON/OFF period of a switching element 3. The controller includes a load tester for testing the switching power source apparatus when detecting an edge of the drive signal after the switching element is switched from ON to OFF, a bottom detector of the switching element during an OFF period thereof, a bottom skip state tester, and a bottom skip operation tester carrying out a pseudo resonant operation that turns on the switching element at a first minimum voltage point if the apparatus is in a heavy load state, and if the apparatus is in the light load state and if the bottom skip state has continued for a first predetermined time, shift the pseudo resonant operation to a bottom skip operation.