Switchable Filter Capacitor Circuit for Low-Standby Power
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Solution Overview
Problem
Household devices experience increased standby energy consumption due to the continuous operation of filter capacitors, which consume energy even when the device is in standby mode.
Innovation Solution
A switching arrangement that includes a control unit to decouple the filter capacitor from the supply voltage during standby mode, and temporarily links it to an electrical load to limit the charging current when the device is activated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filter capacitor is continuously connected to the supply voltage to ensure proper filtering, then the filtering function is maintained, but the standby energy consumption increases
Solution Approach 1:
The patent applies the dynamics principle by making the filter capacitor switchable between connected and disconnected states. The capacitor is dynamically controlled based on operational mode: connected during normal operation for filtering, and disconnected during standby to reduce energy consumption. This is achieved through switching elements (transistors or relays) that control the connection state of the capacitor to the supply voltage.
Solution Approach 2:
The patent implements periodic action by repeatedly connecting and disconnecting the filter capacitor based on the appliance's operational state. The capacitor is connected periodically when the appliance is in normal operation and disconnected periodically during standby mode. This periodic switching allows the system to maintain filtering functionality when needed while minimizing energy consumption during idle periods.
2Use of energy by stationary object
If the filter capacitor is disconnected from the supply voltage during standby mode to reduce energy consumption, then standby energy consumption is reduced, but the capacitor requires charging current limitation upon reconnection
Solution Approach 1:
The patent merges the switching control of the filter capacitor with the existing control of the electrical load. The same control unit that manages the load switching also controls the capacitor connection, and the same switching elements are used for both purposes. This integration reduces the need for separate control circuits and simplifies the overall system architecture while still achieving energy savings.
Solution Approach 2:
The patent introduces an intermediary resistor that limits the charging current when the capacitor is reconnected to the supply voltage. This resistor acts as a mediator between the high-voltage supply and the capacitor, preventing excessive inrush current. The resistor is typically switched in series with the capacitor during reconnection and can be bypassed or removed after the capacitor is charged, balancing current limitation needs with energy efficiency.
3Use of energy by stationary object
If the filter capacitor is disconnected during standby mode, then energy consumption is reduced, but voltage peaks from the supply network may affect the electrical load
Solution Approach 1:
The patent applies preliminary action by ensuring the filter capacitor is reconnected and charged before the electrical load is activated after standby mode. The control sequence is designed to first connect the capacitor to the supply voltage, allow it to charge (with current limitation via resistor), and only then enable the electrical load. This preliminary charging action ensures the capacitor is ready to filter voltage peaks when the load becomes operational, preventing harmful voltage fluctuations from affecting the load.
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 effectively reduces the standby energy consumption of household devices by minimizing the energy used by filter capacitors during idle periods and efficiently limiting the charging current when the device is activated.
Implementation Method 1
a filter capacitor (141) for filtering the supply voltage
Implementation Method 2
limit the charging current (which flows into the filter capacitor)
Data Source
Figure 1a~2
AI summary
A switching arrangement (120) for switching a filter capacitor (141) is described. The switching arrangement (120) comprises a first supply line (131) and a second supply line (132), between which a supply voltage (103) is applied. The switching arrangement (120) further comprises a first electrical load (111), one or more switching elements (122, 221) configured to couple or decouple the first electrical load (111) with the supply voltage (102) in order to switch the first electrical load (111) on or off, and a filter capacitor (141) for filtering the supply voltage (103).Furthermore, the switching arrangement (120) includes a control unit (200) which is configured to cause the filter capacitor (141) to be decoupled from the supply voltage (102) in a standby mode; and to cause the filter capacitor (141) to be coupled to the supply voltage (103) at least temporarily via the first electrical load (111) when the standby mode is terminated in order to limit a charging current.