Capacitor Discharge Control for Power Conversion Apparatus
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Solution Overview
Problem
Conventional power conversion apparatuses face power loss and inefficiency due to the use of bleeder resistors for discharging energy from capacitors during AC input power interruptions, which fails to meet energy-saving standards.
Innovation Solution
A power conversion apparatus with a discharge unit comprising switch elements and a control circuit that enables quick and low-power discharge of energy from capacitors when AC input power is interrupted, using a control chip to manage the discharge paths and minimize power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bleeder resistor is used to discharge energy from the X capacitor when AC input power is interrupted, then safety requirements are met (voltage drops to safe level within 1 second), but power loss increases and energy-saving performance deteriorates
Solution Approach 1:
The patent applies dynamics by making the discharge path controllable rather than fixed. Switch elements (MOSFETs or IGBTs) are used to dynamically enable or disable the discharge path based on the AC input power status. When AC power is present, the discharge path is disabled to avoid power loss. When AC power is interrupted, the discharge path is enabled to ensure safety. This dynamic control resolves the contradiction between maintaining safety and reducing energy loss.
Solution Approach 2:
The control circuit automatically detects AC input power interruption and autonomously activates the discharge path without requiring external intervention. The system monitors the AC input state and self-adjusts the discharge configuration, eliminating the need for manual switching or continuous external control while ensuring both safety and energy efficiency.
2Speed
If a bleeder resistor is connected in parallel to the X capacitor for continuous discharge capability, then discharge readiness is improved, but standby power consumption increases
Solution Approach 1:
The discharge function is activated periodically or event-driven rather than continuously. The control circuit monitors AC input power status and activates the discharge path only when needed (upon detecting power interruption). This periodic/event-driven operation eliminates continuous standby power consumption while maintaining discharge readiness when required.
Solution Approach 2:
The discharge path transitions from a static always-on configuration to a dynamic on-demand configuration. Switch elements controlled by the detection circuit enable the discharge path only when AC power interruption is detected, eliminating continuous power loss while maintaining rapid discharge capability when needed.
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 reduces power consumption and ensures safe voltage levels within 1 second during AC input power interruptions, optimizing EMI filtering and reducing inductor costs while adhering to energy-saving standards.
Implementation Method 1
a capacitor, an AC-to-DC conversion unit and a discharge unit. The capacitor is coupled to the input side
Data Source
AI summary
A power conversion apparatus is provided. The power conversion apparatus receives an AC input power by an input side and includes a capacitor, an AC-to-DC conversion unit and a discharge unit. The capacitor is connected with the input side. The AC-to-DC conversion unit is coupled to the input side, and configured to convert the AC input power after receiving the AC input power to generate a DC output power. The discharge unit is coupled to the capacitor and has at least two switch elements. The discharge unit enables the at least two switch elements when supply of the AC input power is interrupted, such that one of a first discharge path and a second discharge path formed by the at least two switch elements is taken to discharge or drain the energy stored in the capacitor.