UPS Control Device Voltage Variation Suppression
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Solution Overview
Problem
Power conversion systems face voltage variations and voltage rise issues during mode changes from system interconnection to self-contained run due to instantaneous voltage drops or service interruptions, which can hinder power supply stability and require additional circuitry like snubber circuits.
Innovation Solution
Implementing a control method that performs a constant current discharge run for a predetermined time duration during mode changes, equal to the important load current, to suppress induced electromotive forces from leakage inductance, thereby reducing voltage variations and eliminating the need for snubber circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the run mode changes from system interconnection to self-contained run during instantaneous voltage drop or service interruption, then power supply continuity to important load is maintained, but voltage variations and voltage rise occur due to induced electromotive force from leakage inductance
Solution Approach 1:
The control device performs preliminary action by detecting the instantaneous voltage drop or service interruption and proactively controlling the alternating current and direct current conversion device to switch to self-contained run mode before the power supply is completely interrupted. This preliminary switching action maintains power supply continuity to the important load by pre-establishing the backup power path through the power storage section.
Solution Approach 2:
The control device applies parameter changes by dynamically adjusting the discharge current of the power storage section during the transition to self-contained run mode. By controlling the discharge current to match the load current requirements and managing the current transformation through the alternating current and direct current conversion device, the system suppresses voltage variations caused by induced electromotive force from the interconnection transformer's leakage inductance.
2Productivity
If conventional control methods are used during mode change, then power conversion is achieved, but additional circuitry like snubber circuits is required to handle voltage rise at high-speed switch
Solution Approach 1:
The control device implements self-service by using the alternating current and direct current conversion device itself to manage the voltage rise issue during mode transition. Instead of requiring external snubber circuits, the control device autonomously controls the conversion device to regulate the discharge current and suppress voltage variations, making the system self-sufficient in handling its own electrical transient problems.
Solution Approach 2:
The invention extracts and eliminates the need for additional protective circuitry by removing snubber circuits from the system. Through intelligent control of the alternating current and direct current conversion device, the system achieves voltage rise suppression without the extra components, thereby reducing device complexity while maintaining power conversion functionality.
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 approach stabilizes power supply, reduces voltage variations, and prevents voltage rises at the high-speed switch, achieving cost and space savings by eliminating the need for additional circuitry like snubber circuits.
Implementation Method 1
an induced electromotive force due to a leakage inductance of an interconnection transformer developed during a change of a run mode
Data Source
AI summary
[Task]In a power conversion system, a variation in PCS alternating current voltage is suppressed during a change operation to a self-contained run according to an instantaneous voltage drop-service interruption.[Means for solving the task]During an ordinary system voltage stabilization, with change switch 25 changed to the output side of APR control circuit 22 and change switch 400 changed to the output side of charge/discharge run PWM command value preparing section 200, the power conversion system is run in a charge/discharge run mode. If the instantaneous voltage drop or the service interruption occurs, change switch 25 is changed to the output side of the self-contained run change prior current command value preparing section 60 and the constant current discharge run is carried out in which the electric power is discharged for a predetermined time duration in response to the current command value of the self-contained run change prior current command value preparing section 60. Thus, after a predetermined time has elapsed, change switch 400 is changed to the output side of the self-contained run PWM command value preparing section 30 to perform the self-contained run. At this time, the variation in PCS alternating current voltage in the power conversion system is suppressed.