Hybrid Vehicle Voltage Stabilizing Circuit for DC-DC Converter
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Solution Overview
Problem
In hybrid electric vehicles, the voltage output by the motor becomes uncontrollable when the power battery is disconnected, leading to significant voltage fluctuations and high losses due to the variation in counter electromotive force with load changes, affecting the stability and efficiency of the DC-DC converter.
Innovation Solution
A power system is introduced that includes an engine, power motor, auxiliary motor, DC-DC converter, and a voltage stabilizing circuit, where the auxiliary motor controller and power motor controller regulate the voltage stabilizing circuit to maintain stable voltage input to the DC-DC converter even when the power battery is disconnected, ensuring continuous operation and low-speed balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power battery is disconnected, then the system can operate independently of the battery, but the voltage output by the motor becomes uncontrollable and voltage fluctuations increase significantly
Solution Approach 1:
The patent introduces a voltage stabilizing circuit as an intermediary component between the motor and the DC-DC converter. This circuit actively regulates the voltage output from the motor, preventing uncontrolled voltage fluctuations when the power battery is disconnected. The stabilizing circuit acts as a mediator that ensures stable voltage supply to the DC-DC converter regardless of battery connection status.
Solution Approach 2:
The voltage stabilizing circuit dynamically adjusts electrical parameters (voltage levels) based on the operating conditions. When the power battery is disconnected, the circuit modifies the voltage output characteristics of the motor to maintain stable operation of the DC-DC converter, effectively changing the electrical parameters to resolve the instability issue.
2Productivity
If uncontrolled rectification is used when the power battery is disconnected, then the system can continue operating, but losses increase significantly
Solution Approach 1:
The voltage stabilizing circuit incorporates feedback control mechanisms that monitor the voltage output and adjust the rectification process accordingly. This feedback control enables the system to maintain efficient operation during uncontrolled rectification scenarios by dynamically optimizing the conversion process, thereby reducing energy losses while ensuring continuous operation.
3Device complexity
If the voltage stabilizing circuit is controlled by the auxiliary motor controller, then the system has centralized control, but the system fails when the auxiliary motor controller fails
Solution Approach 1:
The control function is segmented and distributed between multiple controllers rather than being centralized in the auxiliary motor controller. The power motor controller and auxiliary motor controller can independently control the voltage stabilizing circuit, creating a segmented control architecture that improves fault tolerance. If one controller fails, the other can maintain system operation.
Solution Approach 2:
The system is designed with redundant control capability beforehand to cushion against potential failures. By enabling both controllers to manage the voltage stabilizing circuit, the system prepares in advance for possible controller failures, ensuring continuous stable operation even when one controller becomes inoperative.
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 maintains low-speed electric balance and smoothness, improves vehicle performance, and keeps the DC-DC converter input voltage stable, enabling normal operation and travel even when the power battery or auxiliary motor controller fails.
Implementation Method 1
the voltage stabilizing circuit performs voltage stabilizing on a direct current output by the auxiliary motor to the DC-DC converter during power generation
Implementation Method 2
the power battery is equivalent to a huge capacitive load and can stabilize a voltage on a main circuit
Implementation Method 3
a voltage output by a motor is rectified by an inverter for charging a power battery
Implementation Method 4
a high voltage can be directly bucked to a low voltage, such as 12 V, through the DC-DC converter
Data Source
Figure 1
Figure 2a~2b
Figure 2c
AI summary
The present disclosure discloses a power system of a hybrid electric vehicle. The power system includes: an engine; a power motor, where the power motor includes a power motor controller, and the power motor controller includes a first regulator; a power battery; a DC-DC converter; an auxiliary motor, where the auxiliary motor includes an auxiliary motor controller, and the auxiliary motor controller includes an inverter and a second regulator; and a voltage stabilizing circuit connected between the auxiliary motor and the DC-DC converter, where the voltage stabilizing circuit performs voltage stabilizing on a direct current output by the auxiliary motor to the DC-DC converter during power generation. The second regulator is configured to control the voltage stabilizing circuit to perform voltage stabilizing when the power battery is disconnected from the DC-DC converter, and the auxiliary motor controller is valid. The first regulator is configured to control the voltage stabilizing circuit to perform voltage stabilizing when the power battery is disconnected from the DC-DC converter, and the auxiliary motor controller fails, to keep an input voltage of the DC-DC converter stable when the power battery fails or the power battery and the auxiliary motor controller both fail.