Uninterruptible DC Supply Capacitance Measurement
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Solution Overview
Problem
Existing methods for determining the capacity and service life of energy stores in DC power supply units are inaccurate and disrupt buffer operation, making it difficult to assess performance and predict impending failures in uninterruptible power supplies.
Innovation Solution
A method using two identical energy stores, where one is completely discharged and then recharged under controlled conditions, allowing for precise capacity measurement while maintaining buffer operation capability, with the capacity and voltage level of each store being measured during controlled discharging and charging processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complete discharge measurement is performed to accurately determine accumulator capacity, then measurement precision is improved, but the power supply unit becomes unavailable for buffer operation during the measurement period
Solution Approach 1:
The power supply system is divided into two separate energy stores (accumulators), allowing one to be measured while the other maintains buffer operation. This segmentation enables simultaneous capacity determination and uninterrupted power supply functionality.
Solution Approach 2:
A second energy store acts as an intermediary that temporarily takes over buffer operation while the first energy store undergoes complete discharge measurement. This mediator enables accurate measurement without compromising system availability.
2Reliability
If brief partial discharge is used to determine capacity, then buffer operation availability is maintained, but measurement precision and significance of capacity determination deteriorates
Solution Approach 1:
By segmenting the energy storage into two separate accumulators, the system enables complete discharge measurement of one unit while the other maintains buffer operation, achieving both measurement accuracy and system availability simultaneously.
3Device complexity
If detailed modeling with environmental parameters is used to calculate capacity and service life, then device complexity is reduced, but measurement precision and reliability of capacity determination deteriorates
Solution Approach 1:
The accumulators themselves perform the measurement function through controlled complete discharge and charging cycles. This self-service approach eliminates the need for complex external measurement systems while achieving accurate capacity determination through direct operational testing.
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 method provides accurate and continuous monitoring of energy store capacity and service life, ensuring uninterrupted power supply and timely warnings of potential failures, with the capacity and charging efficiency of each store being determined without impacting normal operation.
Implementation Method 1
two identical energy stores which are charged with a charging current via the input
Implementation Method 2
which provide a replacement DC output voltage in buffer mode
Data Source
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AI summary
The invention relates to a method for determining the capacitance of an energy store (A1, A2) of a direct current supply unit for the uninterruptible supply of direct current to a load (L), the direct current supply unit comprising at least one input (E) for an input voltage, one output (A) for a DC output voltage, and two identical energy stores (A1, A2) which provide a standby DC output voltage in buffer mode. To determine the actual capacitance without jeopardising a buffer mode, the following steps are provided: in a first step, a charged first energy store (A1) is fully discharged at predefined intervals via a load (L) applied to the output (A); in a second step, the first energy store (A1) is charged from the fully charged second energy store (A2); and in a third step, the second energy store (A2) is fully charged again via the input (E); wherein the capacitance taken from the second energy store (A2) is measured in the second step and/or the capacitance in the charged second energy store (A2) is measured in the third step.