Power Control Device Overvoltage Suppression via Arm Segmentation
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Solution Overview
Problem
The existing power control devices face issues with overvoltage on both the primary and secondary sides during discharge control, leading to potential device protection failures and incomplete discharge of residual charge from the second capacitor.
Innovation Solution
A power control device configuration that includes a step-up/down converter with switching elements and a reactor, along with capacitors and sensors, where the control device fixes the lower arm in an off state and controls the upper arm at a predetermined duty ratio to manage voltage and current, preventing overvoltage and ensuring complete discharge of the second capacitor's residual charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discharge control is executed by alternately turning on upper arm and lower arm, then residual charge of second capacitor is discharged, but voltage on primary side becomes overvoltage
Solution Approach 1:
The patent segments the discharge control into two independent control modes: one for the upper arm and one for the lower arm. By fixing the lower arm in off state and controlling only the upper arm, or vice versa, the patent avoids the overvoltage issue that occurs when both arms are alternately switched. This segmentation allows independent optimization of each switching element's control strategy to prevent harmful overvoltage while maintaining discharge functionality.
Solution Approach 2:
Instead of the conventional approach of alternately turning on both upper and lower arms for discharge control, the patent inverts the strategy by fixing one arm in off state and controlling only the other arm. This inverted control method fundamentally changes the discharge mechanism to avoid the overvoltage problem that arises from simultaneous alternating switching of both arms.
2Object-affected harmful factors
If step-up/down converter operation is stopped for device protection, then overvoltage is prevented, but residual charge cannot be completely discharged
Solution Approach 1:
The patent enables the step-up/down converter to discharge its own residual charge through controlled switching of one arm while the other remains off. This self-service mechanism allows the converter to safely dissipate stored energy in the capacitors without requiring external intervention or complete shutdown, thereby preventing overvoltage while achieving complete discharge of residual charge.
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 configuration effectively suppresses overvoltage on both sides, ensuring safe and complete discharge of the second capacitor's residual charge without stopping the step-up/down converter's operation, thereby enhancing device protection and efficiency.
Implementation Method 1
a reactor L, switching elements T1 and T2 connected in series, and diodes D1 and D2 connected in parallel in a direction opposite to the switching elements T1 and T2
Implementation Method 2
a first capacitor 3 that is provided between the battery BT and the step-up/down converter 4; a second capacitor 6 that is provided between the step-up/down converter 4 and the inverter 9
Data Source
AI summary
The present power control device includes an inverter, a step-up/down converter, a first capacitor, a second capacitor, and a control device. The step-up/down converter includes an upper arm and a lower arm that are switching elements, and a reactor that has a first end and a second end, the first end being connected to the first capacitor, and the second end being connected between the upper arm and the lower arm. The control device is configured to fix the lower arm in an off state and control the upper arm such that the upper arm switches at a predetermined duty ratio.