Motor Drive Regenerative Circuit Emergency Stop Protection
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Solution Overview
Problem
Existing motor drive devices suffer damage to their regenerative circuits during frequent emergency stops due to the consumption of electric power through resistors in the regenerative circuit.
Innovation Solution
A motor drive device configuration that includes a regenerative circuit with a first resistor and a first switch, where the first switch is kept in an OFF state during emergency stops to prevent short-circuiting of the smoothing capacitor, thereby reducing damage and allowing for controlled discharge of accumulated energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the regenerative circuit uses a resistor to consume regenerative current during emergency stops, then the motor can be stopped quickly, but the regenerative circuit suffers serious damage due to frequent emergency stops
Solution Approach 1:
The patent extracts the harmful function of the regenerative circuit during emergency stops by introducing a bypass switch that disconnects the regenerative circuit from the smoothing capacitor. This allows the emergency stop function to operate independently without damaging the regenerative circuit, effectively separating the emergency stop pathway from the regenerative energy dissipation pathway.
Solution Approach 2:
The bypass switch acts as an intermediary element between the smoothing capacitor and the regenerative circuit. During emergency stops, this intermediary component redirects the current flow away from the regenerative circuit, preventing damage while still enabling quick motor stopping. The switch mediates between the conflicting requirements of fast stopping and circuit protection.
2Loss of energy
If the first switch is turned on to short-circuit the smoothing capacitor through the first resistor, then regenerative current can be dissipated, but the regenerative circuit receives serious damage during frequent emergency stops
Solution Approach 1:
The patent applies dynamic control by making the connection between the smoothing capacitor and regenerative circuit conditional rather than fixed. The bypass switch dynamically adjusts the circuit configuration based on operating conditions: during normal operation, the regenerative circuit functions as intended; during emergency stops, the bypass switch disconnects it. This dynamic adaptability allows the system to optimize for energy dissipation when needed and protect the circuit when emergency stops 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 configuration effectively suppresses damage to the regenerative circuit and allows for quick motor restarts by managing energy discharge during emergency stops, enhancing the device's reliability and safety.
Implementation Method 1
a converter configured to convert an alternating current (AC) voltage supplied from an AC power supply into a direct current (DC) voltage
Implementation Method 2
a smoothing capacitor configured to smooth the DC voltage output from the converter
Implementation Method 3
an inverter configured to convert the DC voltage smoothed by the smoothing capacitor into an AC voltage to drive a motor
Implementation Method 4
a regenerative circuit that is disposed between the smoothing capacitor and the inverter, includes a first resistor and a first switch, and is configured to short-circuit ends of the smoothing capacitor through the first resistor by turning on the first switch
Data Source
AI summary
A motor drive device includes: a converter converting an AC voltage supplied from an AC power supply into a DC voltage; a smoothing capacitor smoothing the DC voltage output from the converter; an inverter converting the DC voltage smoothed by the smoothing capacitor into an AC voltage to drive a motor; a regenerative circuit that is disposed between the smoothing capacitor and the inverter, includes a first resistor and a first switch, and short-circuits the ends of the smoothing capacitor through the first resistor by turning on the first switch; and a control unit keeping the first switch in the OFF state during an emergency stop.