Bidirectional Charging Bridge Control for Primary-Side Voltage Stress
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Solution Overview
Problem
Components such as switching transistors and high-voltage electrolytic capacitors in the primary-side circuit of bidirectional charging systems are damaged due to power and high voltage transfer in the DC-DC mode, as closed-loop control does not involve the primary-side circuit.
Innovation Solution
A charging system with a primary-side bridge circuit, a transformer, and two secondary-side bridge circuits, where switching transistors of the first secondary-side bridge circuit are turned on once the primary-side bridge circuit's transistors are on for a duration Td, allowing advanced on-duration control to reduce voltage and current applied to the primary-side circuit, thereby minimizing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If closed-loop control only relates to the two secondary-side circuits in DC-DC mode, then power transfer between secondary-side circuits is enabled, but the primary-side circuit components (switching transistors and capacitors) are damaged by transferred power or high voltage
Solution Approach 1:
The control method turns on the primary-side switching transistors before the secondary-side switching transistors in DC-DC mode. This preliminary action ensures that the primary-side circuit is ready to handle the transferred power and voltage, preventing component damage while enabling power transfer between secondary-side circuits.
Solution Approach 2:
The control method implements closed-loop control that includes the primary-side circuit by detecting the on-state of primary-side switching transistors and using this feedback to control the timing of secondary-side switching transistor activation. This feedback mechanism ensures safe operation while maintaining power transfer capability.
2Object-affected harmful factors
If switching transistors of the first secondary-side bridge circuit are turned on once switching transistors of the primary-side bridge circuit are on for a duration Td, then voltage and current applied to the primary-side circuit is reduced, but control complexity increases
Solution Approach 1:
The control method applies preliminary action by turning on primary-side switching transistors for a predetermined duration Td before activating secondary-side switching transistors. This time-based preliminary action reduces voltage and current stress on primary-side components without requiring complex real-time detection or control logic.
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 reduces the risk of damage to primary-side circuit components by controlling the switching transistors' on-duration, allowing zero-voltage switching and stabilizing output voltages, thus protecting the high-voltage electrolytic capacitor and other components.
Implementation Method 1
power supplied by one secondary-side circuit is also transferred to the primary-side circuit through a transformer
Data Source
AI summary
A charging system, a charging method, and a vehicle are provided. The charging system includes a primary-side bridge circuit, a transformer, a first secondary-side bridge circuit, and a second secondary-side bridge circuit. The primary-side bridge circuit is connected with a primary winding of the transformer. The first secondary-side bridge circuit and the second secondary-side bridge circuit are connected with a secondary winding of the transformer respectively. On condition that power is transferred from the first secondary-side bridge circuit to the second secondary-side bridge circuit, switching transistors of the first secondary-side bridge circuit are turned on once switching transistors of the primary-side bridge circuit are on for a duration Td.