Spring-Loaded DC Drive Power Failure Recovery
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Solution Overview
Problem
Existing electric drives with spring-loaded mechanisms face issues such as mechanical impact and high short-circuit currents during power failures, which can lead to mechanical damage and electrical overload, and existing solutions only partially address these problems.
Innovation Solution
The electric drive is designed to supply the control device with energy from a backup capacitor, allowing it to set the target deflection to the rest position and control the switching elements to feed energy back into the capacitor, thereby managing excessive voltage and reducing mechanical stress, and this control method is maintained even during power failures, allowing for smooth operation without changes in control behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the spring drives the rotor back to rest position during power failure, then the valve or flap is transferred to a defined position, but mechanical impact and high short-circuit currents occur causing mechanical damage and electrical overload
Solution Approach 1:
The invention converts the harmful regenerative energy generated during spring-driven rotor return into a beneficial resource by feeding it back to charge the backup capacitor. The control device detects power failure conditions and activates switching elements to create a rectification path, transforming the previously harmful high current into useful charging current that extends backup operation time and reduces mechanical impact.
Solution Approach 2:
The control device acts as an intermediary between the motor and backup capacitor, managing the energy flow during power failure. It detects the power failure condition, sets the target position to rest position, and controls the switching elements to enable controlled energy transfer from the motor to the capacitor, preventing direct short-circuit conditions.
2Speed
If the motor is designed to handle high short-circuit currents during spring-driven return, then the rotor can be brought to rest position, but the motor and switching device must be oversized to cope with the currents and voltages
Solution Approach 1:
The motor serves a dual function: it acts as both the drive motor during normal operation and as a generator during power failure to charge the backup capacitor. This self-service approach eliminates the need for separate components to handle the regenerative energy, allowing the motor and switching device to operate within their normal ratings by redirecting energy flow through the control device.
3Duration of action of stationary object
If the control device is supplied with energy from the backup capacitor during power failure, then it can maintain operation, but the voltage in the DC voltage circuit rises excessively
Solution Approach 1:
The control device implements feedback control by monitoring the power supply status and dynamically adjusting the target position and switching element control accordingly. During power failure, it detects the condition, sets the target to rest position, and controls the switching elements to enable controlled energy transfer, preventing uncontrolled voltage rise while maintaining operation.
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 prevents mechanical stresses and overloading, simplifies control methods, and allows for smaller dimensions of switching elements and backup capacitors, ensuring safe and efficient operation during power failures by managing voltage and current flow.
Implementation Method 1
a backup capacitor (4) being arranged in the DC voltage circuit (3), wherein the DC voltage circuit (3) is connected to a supply network (5) for feeding energy into the backup capacitor (4)
Implementation Method 2
the switching elements of the switching device (7) controls in such a way that the motor (1) feeds energy into the back-up capacitor (4)
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An electric drive comprises a motor (1) and a motor connection (2). The motor connection (2) includes a DC circuit (3) with a buffer capacitor (4) and a switching device (7). The DC circuit (3) is connected to a power supply network (5) for supplying energy to the buffer capacitor (4), and the motor (1) can be connected to the buffer capacitor (4) via the switching device (7). A rotor (13) of the motor (1) is connected to a spring assembly (14) which exerts a restoring force on the rotor (13) when it is deflected from its rest position. When energy is supplied to the backup capacitor (4) from the supply network (5), a control unit (17) actuates switching elements (8, 9) of the switching device (7) such that the actual deflection of the rotor (13) is adjusted to match a target deflection (x*). The control unit (17) can be supplied with energy via the backup capacitor (4).If, in the rotor (13) deflected from its rest position, the supply of energy to the support capacitor (4) from the supply network (5) fails, the control device (17) sets the target deflection (x*) to the rest position and controls the switching elements (8, 9) in such a way that the motor (1) at least at the beginning of the return stroke by the spring device (14) feeds energy into the support capacitor (4) via the switching elements (8, 9).