Switching Circuit Control Apparatus for Electric Vehicle Inverter
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Solution Overview
Problem
Existing control apparatuses for switching circuits in electric vehicles fail to efficiently manage power conversion between DC power sources and AC motors, leading to increased losses due to fixed dead times and uncompensated commutation currents, which complicates control processing and reduces efficiency.
Innovation Solution
A control apparatus for a switching circuit that includes bidirectional conduction switching devices connected in series and reverse conducting devices in parallel, featuring a controller, target-rotational-speed acquiring device, and ON-time varying device to adjust the ON time of switching devices based on target rotational speed and torque, thereby optimizing power conversion and reducing losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed dead time is used for switching devices, then control processing is simplified, but power conversion efficiency deteriorates due to uncompensated commutation currents
Solution Approach 1:
The patent implements dynamic adjustment of the ON time period for bidirectional conduction switching devices based on commutation current characteristics. The control apparatus varies the ON time period according to target rotational speed and target torque, transforming the fixed dead time into a dynamic parameter that adapts to different operating conditions, thereby reducing power conversion losses while maintaining controllable complexity
Solution Approach 2:
The patent changes the parameter of ON time period for switching devices based on commutation current characteristics, target rotational speed, and target torque. By adjusting this parameter dynamically, the system optimizes power conversion efficiency without requiring complex control processing, as the adjustment follows established relationships between these parameters
2Reliability
If ON time of switching devices is increased, then commutation current is better managed, but switching losses increase
Solution Approach 1:
The patent dynamically adjusts the ON time period based on commutation current characteristics and operating conditions (target rotational speed and target torque). This dynamic adjustment allows the system to extend ON time when commutation current requires it for reliable control, while limiting the extension to minimize switching losses, achieving an optimal balance between reliability and efficiency
Solution Approach 2:
The control apparatus uses feedback from commutation current characteristics and motor operating parameters (rotational speed and torque) to adjust the ON time period. This feedback mechanism ensures that the ON time is extended only when necessary for proper commutation current management, preventing excessive switching losses while maintaining reliable current control
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 reduces losses in the switching circuit by dynamically controlling the ON time of switching devices according to target motor parameters, enhancing efficiency and simplifying control processing while considering motor and inverter properties.
Implementation Method 1
a plurality of bidirectional conduction switching devices connected in series to each other and a plurality of reverse conducting devices respectively connected in parallel to the bidirectional conduction switching devices
Implementation Method 2
reverse conducting devices respectively connected in parallel to the bidirectional conduction switching devices with respect to forward conduction of the bidirectional conduction switching devices
Data Source
AI summary
A control apparatus for a switching circuit includes a controller, a target-rotational-speed acquiring device, a target-torque acquiring device, and an ON-time varying device. The controller is configured to turn on a bidirectional conduction switching device provided parallel to a reverse conducting device through which a commutation current flows. The target-rotational-speed acquiring device is configured to acquire a target rotational speed of an alternating current motor. The target-torque acquiring device is configured to acquire a target torque of the alternating current motor. The ON-time varying device is configured to vary, on a basis of the target rotational speed and the target torque, an ON time period during which the bidirectional conduction switching device provided parallel to the reverse conducting device through which a commutation current flows is turned on.