Power Supply Control Device Pre-Charge Voltage Correction
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Solution Overview
Problem
Existing control devices for power supply systems in hybrid vehicles face challenges in accurately correcting target voltages due to detection errors, leading to potential damage from large currents when switching the system on, especially when the voltage of the capacitor differs from the main battery voltage after pre-charge.
Innovation Solution
A control device with a pre-charge unit, step-up circuit, open-close switch, voltage source, and regulation element, where the step-up circuit increases voltage from the main electric storage device and outputs it to a smooth capacitor, and the regulation element manages currents to prevent damage by regulating flows between the switch and capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target voltage of pre-charge is set to be equal to the voltage of the main battery and the SMR is turned on after the pre-charge is finished, then the SMR is restricted from being damaged, but there is a possibility that large current flows when the voltage of the capacitor after pre-charge differs from the voltage of the main battery due to detection error
Solution Approach 1:
The patent applies preliminary action by performing pre-charge of the capacitor through the pre-charge relay before turning on the SMR. The control device calculates a corrected target voltage by adding a predetermined correction value to the detected battery voltage, ensuring the capacitor is charged to an appropriate voltage level before SMR activation, thus preventing large current damage.
Solution Approach 2:
The patent implements feedback by detecting the battery voltage, calculating the corrected target voltage based on detected voltage plus correction value, and controlling the pre-charge process to reach this corrected target. This closed-loop control ensures accurate voltage matching between capacitor and battery, preventing large current flow when SMR is turned on.
2Measurement precision
If a control device records the correction value for next pre-charge, then the target voltage can be corrected, but a memory circuit needs to be added to the control device
Solution Approach 1:
The patent applies self-service by having the control device use its own detected voltage information and a predetermined correction value to calculate the corrected target voltage for pre-charge. The control device serves itself by integrating the correction function within the control logic, eliminating the need for separate memory circuits to store correction values.
Solution Approach 2:
The patent changes the voltage parameter by calculating a corrected target voltage (detected voltage + correction value) instead of using the detected voltage directly. This parameter transformation compensates for detection errors and ensures accurate pre-charge voltage without requiring complex memory storage mechanisms.
3Adaptability or versatility
If the detection error varies depending on usage environment such as temperature, then accurate correction becomes difficult, but the control device needs to adapt to different environments
Solution Approach 1:
The patent applies partial action by using a predetermined correction value that provides sufficient compensation for typical detection errors across different environments. Rather than attempting to perfectly correct for all possible environmental variations, the correction value is set to provide adequate compensation for normal operating conditions, achieving practical accuracy without excessive complexity.
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 effectively restricts large currents during the switching process, preventing damage to the open-close switch while executing simple control, and ensures the target voltage is set within an allowable variation range, reducing the risk of damage from detection errors.
Implementation Method 1
a step-up circuit (50), the step-up circuit (50) increases a voltage on a side of the main electric storage device (10) and outputs the voltage being increased toward a side of the smooth capacitor (60)
Implementation Method 2
a regulation element, the regulation element does not regulate a current flowing from the open-close switch toward the smooth capacitor, and regulates a current flowing from the smooth capacitor toward the open-close switch
Data Source
AI summary
A control device for a power supply system includes a pre-charge unit, the power supply system having a main electric storage device, a smooth capacitor, a step-up circuit, an open-close switch, a voltage source and a regulation element. The regulation element regulates a current flowing from the smooth capacitor toward the open-close switch. The voltage source is connected to a connection portion between the open-close switch and the step-up circuit, and outputs an output voltage higher than a voltage of the main electric storage device before the open-close switch is shifted from a disconnection state to a connection state. The pre-charge unit executes a pre-charge of the smooth capacitor by supplying electric power from the voltage source to the smooth capacitor before the open-close switch is shifted from the disconnection state to the connection state.