Maglev Blood Pump Impeller Orbit Control for Thrombus Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing magnetically levitated blood pumps face challenges in detecting and preventing thrombus formation, which is exacerbated by blood viscosity and temperature variations, leading to complications such as embolization.
Innovation Solution
A drive control method and device for magnetically levitated blood pumps that rotate and revolve the impeller in a radial direction, using sine and cosine wave currents to excite the impeller in orbits, allowing for precise detection of thrombus position through phase difference analysis independent of viscosity and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetically levitated blood pump is used to eliminate mechanical bearing contact, then durability is improved and blood cell damage is reduced, but thrombus formation still occurs
Solution Approach 1:
The patent applies mechanical vibration by reciprocally exciting the impeller in the radial direction at a frequency of 50-500 Hz with an amplitude of 1-10 μm. This vibration prevents thrombus formation by disrupting blood stasis and reducing platelet adhesion to the impeller surface, while maintaining the non-contact magnetic levitation that ensures durability and reduces hemolysis.
Solution Approach 2:
The patent implements periodic action by applying reciprocal excitation forces to the impeller in the radial direction. The periodic vibration cycles create continuous disturbance in the blood flow pattern around the impeller, preventing thrombus formation through repeated disruption of stagnant blood regions and platelet aggregation sites.
2Measurement precision
If phase difference detection is used to detect thrombus position, then detection accuracy is improved, but detection reliability deteriorates due to influence of blood viscosity and temperature variations
Solution Approach 1:
The patent uses feedback by continuously monitoring the phase difference between the excitation force and impeller displacement, and comparing it against reference values. The system detects deviations caused by thrombus formation while compensating for variations due to blood viscosity and temperature changes through continuous measurement and comparison, thereby maintaining reliable thrombus detection.
Solution Approach 2:
The patent applies parameter changes by measuring phase difference variations across different operating conditions. By analyzing how phase difference changes with excitation frequency and comparing against baseline values, the system distingu between phase changes caused by thrombus formation versus those caused by normal variations in blood viscosity and temperature, enabling reliable detection.
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
Enables reliable thrombus detection and prevention by distinguishing phase changes due to thrombus formation from those caused by viscosity and temperature, enhancing safety in blood circulation systems.
Implementation Method 1
an impeller 201 for discharging blood is magnetically levitated by electromagnets 202 for magnetic levitation without using a mechanical bearing
Implementation Method 2
the impeller 201 in a housing 205 is rotated by an electric motor 204 with a magnetic coupling force 203 in a Z direction
Implementation Method 3
a drive control device 30...supplying a sinusoidal voltage as a revolution drive control current to electromagnets 25X, 25Y for magnetic levitation
Data Source
AI summary
The purpose of the present invention is to provide a drive control method for a magnetically levitated blood pump, a drive control device for a magnetically levitated blood pump, and a magnetically levitated blood pump system for preventing a formation of thrombus in a housing, and also, for detecting a position of thrombus surely from a phase difference Δφ between a phase of a waveform of an electromagnet current and a phase of a displacement of an impeller (phase of vibration waveform) without depending on a viscosity μ and a temperature of blood. In a magnetically levitated blood pump 20 comprising an electric motor 24 for rotating an impeller 23 in a housing 22 by a magnetic coupling force in a Z axis direction in a state that the impeller 23 is magnetically levitated by electromagnets 25X, 25Y for magnetic levitation, the impeller 23 is rotated and revolved in the housing 22 by a drive control device 30 comprising a rotation drive control unit 31 functioning as a rotation drive control means for rotating the impeller 23 and a revolution drive control unit 32 functioning as a revolution drive control means for revolving the impeller 23 by moving the impeller 23 to trace a revolving locus in which a rotation center of the impeller 23 is moved in a radial direction.