Elevator Drive Device Solid-State Safety Logic
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Solution Overview
Problem
Elevator safety systems rely on mechanical contactors, which are unreliable and occupy significant space, posing challenges in efficient use of built space and safety integrity.
Innovation Solution
A drive device for elevators that uses solid-state switches and control circuits to manage power supply to the motor and brake without mechanical contactors, integrating power supply and brake control into a single unit, enabling fail-safe operation and reduced size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical contactors are used to disconnect power supply and control brake, then the system can achieve safety stop function, but the reliability is reduced and device size increases
Solution Approach 1:
The patent replaces mechanical contactors with solid-state electronic switches (IGBTs and MOSFETs) controlled by control circuits. The power supply disconnection is achieved by controlling the switching states of solid-state switches in the motor bridge, and brake control is achieved through solid-state switches in the brake controller, eliminating mechanical moving parts and improving reliability while reducing size.
Solution Approach 2:
The patent extracts the mechanical contactor component from the safety system and replaces its functionality with electronic control circuits. The contactor's power disconnection function is separated into motor bridge control and brake controller functions, both implemented with solid-state devices, removing the unreliable mechanical element while maintaining safety functionality.
2Reliability
If mechanical contactors are used for safety disconnection, then safety function is achieved, but built space utilization becomes inefficient
Solution Approach 1:
The patent substitutes mechanical contactors with compact solid-state electronic switches and control circuits. The solid-state switches (IGBTs, MOSFETs) and integrated control circuits occupy significantly less volume than mechanical contactors, enabling efficient use of built space while maintaining safety disconnection functionality through electronic control.
Solution Approach 2:
The patent merges the power supply control and brake control functions into a single integrated drive device. Both the motor bridge and brake controller use solid-state switches and share common control circuitry, consolidating what would have been separate contactor-based systems into one compact unit, improving space utilization.
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 enhances safety and reliability by eliminating mechanical contactors, simplifying the system, reducing size, and minimizing noise and electromagnetic interference, while allowing for efficient energy management and integration with existing safety arrangements.
Implementation Method 1
an electromagnetic brake (9), with which the motion of the elevator can be held or braked
Data Source
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AI summary
The invention relates to the drive device (1) of an elevator. The drive device comprises a DC bus (2A, 2B), a motor bridge (3) connected to the DC bus for the electricity supply of the elevator motor (6), which motor bridge (3) comprises high-side (4A) and low-side (4B) switches for supplying electric power from the DC bus (2 A, 2B) to the elevator motor (6) when driving with the elevator motor (6), and also from the elevator motor (6) to the DC bus (2A, 2B) when braking with the elevator motor (6), a control circuit (5) of the motor bridge, with which control circuit the operation of the motor bridge (3) is controlled by producing control pulses in the control poles of the high-side (4A) and low-side (4B) switches of the motor bridge, a brake controller (7). which comprises a switch (8A, 8B) for supplying electric power, to the control coil (10) of an electromagnetic brake (9), a brake control circuit (11), with which the operation of the brake controller (7) is controlled by producing control, pulses in the control pole of the switch (8 A, 8B) of the brake controller, an input circuit (12) for the safety signal (13) to be disconnected/connected from outside the drive device, drive prevention logic (15), which is connected to the input circuit (12) and is configured to prevent the passage of control pulses to the control poles of the high- side (4 A) and/or Jow-side (4B) switches of the motor bridge when the safety signal (13) is disconnected, and also brake drop-out logic (16), which is connected to the input circuit (12) and is configured to prevent passage of the control pulses to the control pole of the switch (8A, 8B) of the brake controller when the safety signal (13) is disconnected.