Vehicle Power Converter Control Device for Overvoltage Suppression
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Solution Overview
Problem
Conventional vehicle power converter control devices face instability in electric power supply due to undesired reactivation of overvoltage at the B-terminal after cancellation of negative pole-side arm short-circuit, leading to repeated overvoltage generation and disrupted power generation.
Innovation Solution
A control device for a vehicle power converter that includes B-terminal voltage detection, field current detection, and abnormal voltage detection mechanisms to short-circuit the negative pole-side arm and limit field current when overvoltage is detected, ensuring stable power supply by preventing reactivation of overvoltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the switching elements of the negative pole-side arm are brought into conduction to short-circuit the armature winding when overvoltage is detected, then the overvoltage is suppressed, but the power-generating operation is restarted after a predetermined period causing overvoltage to generate again
Solution Approach 1:
The control device continuously monitors the B-terminal voltage and dynamically adjusts the switching state of the negative pole-side arm based on real-time voltage feedback. When overvoltage is detected, the switching elements are brought into conduction to short-circuit the armature winding. This feedback mechanism ensures that the short-circuit state is maintained as long as overvoltage persists, preventing the undesired cancellation and re-generation of overvoltage that occurs in conventional fixed-time approaches.
Solution Approach 2:
The system transitions from a static fixed-time short-circuit approach to a dynamic state-based control approach. The switching elements of the negative pole-side arm are controlled to change state based on the actual voltage condition rather than a predetermined time schedule. This dynamic adjustment allows the system to adapt to continuous disconnection conditions, maintaining the short-circuit state indefinitely until the abnormal condition resolves, thereby ensuring stable power supply.
2Ease of operation
If the short-circuit of the negative pole-side arm is cancelled after a predetermined period, then the system returns to normal operation, but repeated overvoltage generation occurs if disconnection is continuous
Solution Approach 1:
The control device uses continuous voltage monitoring to determine when to cancel the short-circuit state. Instead of using a fixed predetermined period, the system waits until the B-terminal voltage falls below the threshold level, indicating that the disconnection condition has resolved. This feedback-based cancellation prevents premature resumption of power-generating operation that would cause repeated overvoltage generation.
Solution Approach 2:
The control device takes preliminary action by maintaining the short-circuit state beyond what conventional fixed-time systems would do, specifically continuing the short-circuit until voltage feedback confirms the disconnection condition has resolved. This preliminary anti-action counteracts the potential harmful effect of premature operation resumption that would lead to repeated overvoltage generation.
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
The solution effectively suppresses overvoltage at the B-terminal and ensures stable electric power supply even after cancellation of the short-circuit, preventing repeated overvoltage issues and maintaining consistent power generation.
Implementation Method 1
the control device controls ON/OFF of the switching elements to convert DC power supplied from the battery into AC power
Implementation Method 2
the AC power generated by the generator-motor is rectified by the diodes or the switching elements into the DC power
Implementation Method 3
a field circuit for controlling energization of the field winding
Data Source
AI summary
The control device detects the B-terminal voltage by a B-terminal voltage detection section. When an abnormal voltage detection section detects that a voltage value of the detected B-terminal voltage is equal to or higher than a predetermined voltage value, all switching elements of the negative pole-side arm in a power conversion section are brought into conduction by a negative pole-side arm short-circuiting section, whereas all switching elements of a positive pole-side arm are interrupted. In addition, a field current is limited to zero or to a limit value by a field current control section.