Vacuum Pump Overspeed Protection via Sensorless Speed Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vacuum pump systems with brushless motors face challenges in ensuring reliable overspeed protection without relying on multiple microcontrollers and speed sensors, which increases component complexity, radiation exposure risks, and maintenance costs, while limiting the interchangeability of vacuum pumps and control electronics.
Innovation Solution
A vacuum pump system with a control unit containing a drive microcontroller that activates a brushless motor and a second microcontroller within the control unit for pump type recognition, allowing the system to determine and enforce the maximum permissible speed without sensors, ensuring reliable overspeed protection and reducing electronic components in the pump, enabling free combination of vacuum pumps and control electronics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple microcontrollers and speed sensors are used for overspeed protection, then reliability of speed monitoring is improved, but device complexity and component quantity increase
Solution Approach 1:
The patent extracts the speed sensing function from the motor control system and relocates it to the vacuum pump's mechanical structure. The encoder is integrated into the pump's rotor assembly, and the speed information is transmitted via magnetic coupling through the pump wall, eliminating the need for separate speed sensors and reducing electronic components in the control unit.
Solution Approach 2:
The vacuum pump's mechanical structure serves multiple functions: it performs the primary pumping function while also housing the speed sensing mechanism. The rotor assembly not only drives the pump but also carries the encoder that generates speed signals, making the pump itself a multi-functional component that eliminates the need for separate monitoring devices.
2Reliability
If electronic components are placed within the vacuum pump, then overspeed protection reliability is improved, but radiation resistance deteriorates in high radiation environments
Solution Approach 1:
The patent segments the speed sensing function from the electronic control system. The encoder is mechanically integrated into the pump's rotor, while the electronic processing remains in the external control unit. This separation allows the pump to operate in radiation environments without exposing sensitive electronic components to radiation, as only the radiation-hardened mechanical encoder remains in the pump.
3Reliability
If pump-specific electronic components are integrated into the vacuum pump, then overspeed protection is improved, but interchangeability between vacuum pumps and control electronics deteriorates
Solution Approach 1:
The patent applies local quality by making only the necessary minimal integration - the encoder is integrated into the pump's rotor assembly, while all other electronic components remain external. This localized integration provides sufficient overspeed protection through mechanical encoding while maintaining the interchangeability of both the pump and control electronics, as neither requires pump-specific electronic modifications beyond the encoder.
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 design provides reliable overspeed protection with reduced electronic components, allowing for easier maintenance and interchangeability, and operates safely in environments with high radiation exposure, while eliminating the need for additional sensors and simplifying repairs.
Implementation Method 1
EP 1 311 047 A2 discloses the measurement of motor speed using voltages and currents
Data Source
Figure 1
AI summary
A vacuum pump system comprising a vacuum pump (1) and a control unit (2), wherein the vacuum pump has a brushless, multi-phase synchronous motor (3) with a permanent magnet excited rotor, and wherein the control unit includes a drive microcontroller (5) and a power stage (6a, 6b), and a second microcontroller monitoring the motor speed. To enable the combination of different control units and vacuum pumps and to ensure reliable overspeed protection, it is proposed that the second microcontroller (7), which switches off the power stage (6a, 6b) upon detecting that the speed has been exceeded, be located in the control unit, that the vacuum pump has pump type recognition means (4), and that the drive microcontroller (5) determines the motor speed from a motor model and the currents established in the phases.