Inductive Converter Supply Unit for Single-Fault Safety
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Solution Overview
Problem
Existing power electronics circuits for electric motors lack single-fault safety, leading to potential damage from overvoltages and high loading when attempting to safely stop and restart the motor, as they rely on mechanical relays that are prone to wear and do not allow for immediate fault detection and response.
Innovation Solution
A method and supply unit using inductive converters with two switches and free-wheeling current paths, where the operation of each switch is checked during each switching cycle to ensure correct interruption of the current path, allowing for immediate fault detection and prevention of further power transmission, thereby achieving single-fault safety by interrupting the power supply if a fault is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical relay is used to interrupt the supply voltage at the driver circuit, then the motor can be stopped safely, but the relay is subject to wear and does not allow for single-fault safety
Solution Approach 1:
The patent replaces the mechanical relay with an electronic switching mechanism comprising two electronic switches (first and second switches) controlled by control signals. This substitution eliminates mechanical wear and enables reliable fault detection through electronic monitoring of switching states, thereby achieving single-fault safety while maintaining the ability to safely stop the motor.
Solution Approach 2:
The patent implements feedback by monitoring the switching states of the first and second switches and using this information to control the power supply to the driver circuit. The control device detects whether the switches are in the desired state and adjusts the power supply accordingly, enabling automatic fault detection and response without mechanical components.
2Reliability
If the power supply is turned off by a mechanical relay, then the motor can be reliably stopped, but the entire power electronics circuit needs to be turned on again which takes considerable time
Solution Approach 1:
The patent segments the power supply control into two independent parts: the power supply to the driver circuit and the power supply to the rest of the power electronics circuit. By using two separate switches controlled by the same control signals, the driver circuit can be powered down independently for safe stopping while leaving the main power electronics circuit ready for immediate restart, thereby reducing restart time while maintaining safe stopping capability.
3Reliability
If an electromechanical switch is used to isolate the motor from the power electronics circuit, then the motor can be stopped, but the sudden switching can damage the power electronics circuit on account of overvoltages and the loading is very high
Solution Approach 1:
The patent applies preliminary action by gradually reducing the power supply voltage to the driver circuit before complete interruption, and by coordinating the switching of the first and second switches to avoid sudden current changes. This controlled transition prevents overvoltages and high loading conditions that would occur with abrupt mechanical switching, while still achieving reliable motor isolation when faults occur.
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 approach ensures immediate and safe shutdown of the power stage, preventing damage from overvoltages and high loading, and allows for quick identification and response to faults, ensuring the power electronics circuit operates safely and efficiently.
Implementation Method 1
A control current is switched by an inductive converter using a first and a second switch on the basis of a first control signal and a second control signal in order to generate a power supply for the driver circuit
Data Source
AI summary
A power supply and method of operating the same. The method includes the steps of: operating first and second switches to an “On” position; operating said first switch to a “Off” position, causing a flow of a first free-wheeling current through a first free-wheeling current path; measuring a value of said free-wheeling current; controlling the switching of said second switch responsive to said value of said free-wheeling current; and regulating power from said power supply unit. The power supply includes: an inductive converter; a first free-wheeling current path comprising: a first switch connected in series with said inductive converter and a first means for measuring a first free-wheeling current flowing through said first free-wheeling current path; and a second free-wheeling current path comprising: a second switch connected in series with said inductive converter and a second means for measuring a second free-wheeling current flowing through said second free-wheeling current path.