The superconducting coil with high current carrying capacity and DC resistance-free characteristics is used to replace the copper coil on the traditional motor rotor, which can greatly improve the air gap flux density and power density of the motor. This paper introduces the cryogenic system of a high-temperature superconducting (HTS) Synchronous Condenser rotor. The HTS magnet in the rotor is cooled centrally by embedding Gas-Helium pipes in each coil, and cold rings are set at both ends of the magnet for temperature partitioning to reduce the temperature influence of other components on the magnet. According to the theoretical formula of heat transfer, the total thermal power of the cryogenic system in the rotor was calculated, and the Gas-Helium input parameters required by the rotor are deduced. Subsequently, the temperature distribution of the HTS coils inside the rotor was simulated by the fluid thermodynamic method. The simulation results show that the HTS coils and cold rings are separately cooled to 27.05 K and 36.35 K by the externally introduced 25 K Gas-Helium, and the temperature difference of the coils is only 0.2 K, which shows the reliability of the cryogenic system in the HTS synchronous condenser rotor.

Titanium (Ti) and its alloys have been widely used as clinical implant biomaterials. However, protein adhesion and bacterial infection can negatively impact the efficacy of these implants. To combat this, a promising strategy is to develop a versatile coating on Ti materials that endows them with antifouling and antibacterial capabilities. This work focused on the development of a polydopamine (PDA) and poly(sulfobetaine methacrylate) (PSBMA) co-deposition coating on Ti substrates. The coating contained copper ions, iron ions, and catechol groups, which coordinated to assemble bimetal-phenolic networks (bMPNs). Digital imaging, SEM, AFM, XPS, water contact angle, and film thickness tests confirmed the success of the modification. The antibacterial properties of the coating were evaluated using Gram-positive Staphylococcus aureus, while the cytotoxicity of the coating on human umbilical vein endothelial cells was also examined. The results demonstrated an excellent improvement in hydrophilicity, antibacterial properties, and benign biocompatibility of the coated Ti substrate, making it suitable for bioimplants and medical devices.

Centrifugal blood pumps are important devices used to treat heart failure. However, they are prone to high-risk suction events that pose a threat to human health when operating at high speeds. To address these issues, a normal suction detection method and a suction suppression method based on the FFT-GAPSO-LSTM model and speed modulation were proposed. The innovation of this suction detection method lies in the application of the genetic particle swarm optimisation (GAPSO) and the fast Fourier transform (FFT) feature extraction method to the long-term and short-term memory (LSTM) model, thereby improving the accuracy of suction detection. After detecting signs of suction, the suction suppression method designed in this study based on variable-speed modulation immediately takes effect, enabling the centrifugal blood pump to quickly return to its normal state by controlling the speed. The suction detection method was divided into four steps. First, a mathematical model of the coupling of the cardiovascular system and the centrifugal blood pump was established, and a real-time blood flow curve was obtained through model simulation. Second, the signal was preprocessed by adding Gaussian white noise and low-pass filtering to make the blood flow signal close to actual working conditions while retaining the original characteristics. Subsequently, through fast Fourier transform (FFT) analysis of the processed curve, the spectral characteristics that can characterise the working state of the centrifugal blood pump were extracted. Finally, the parameters of the LSTM model were optimised using the GAPSO, and the improved LSTM model was used to train and test the blood flow spectrum feature set. The results show that the suction detection method of the FFT-GAPSO-LSTM model can effectively detect whether centrifugal blood pump suction occurs and has certain advantages over other methods. In addition, the simulation results of the suction suppression were excellent and could effectively suppress the occurrence of suction. These results provide a reference for the design of centrifugal blood pump control systems.

Blood pumps are the most important medical devices for treating heart failure. Haemolysis is an important factor affecting the performance of blood pumps. Excessive temperatures can damage red blood cells, thereby reducing blood compatibility. To solve the problem of haemolysis caused by temperature increase in an electromagnetic suspended blood pump, the influence of temperature increase in an electromagnetic suspended blood pump motor was studied. First, an electromagnetic levitation blood pump model and a mathematical model of the temperature field were established. Subsequently, the influences of two key factors (stator winding phase resistance and blood pump speed) on the overall temperature increase of the electromagnetic levitation blood pump were explored. Finally, based on the law of temperature increase, a temperature optimisation scheme for the motor of an electromagnetic levitation blood pump was proposed. The results show that, on the one hand, the temperature rise of the electromagnetic levitation blood pump can be effectively reduced by properly reducing the stator winding phase resistance and rotating speed. Conversely, optimising commutation and controllers can further reduce the temperature rise. This method can be used as a guide for the optimal design of blood pumps.

Infections and thrombosis remain unsolved problems for implanted cardiovascular devices, such as left ventricular assist devices. Hence, the development of surfaces with improved blood compatibility and antimicrobial properties is imperative to reduce complications after artificial heart implantation. In this work, we report a novel approach to fabricate multifunctional surfaces for left ventricular transplanted ventricular assist devices (LVADs) by immobilizing nitric oxide (NO) generation catalysts and heparin and reducing silver nanoparticles in situ. The general view, structure, and chemical compositions of the pure/modified surfaces were characterized using digital imaging, scanning electron microscope (SEM), atomic force microscope (AFM), water contact angle (WCA), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma (ICP). All of the results demonstrated that the AgNPs and heparin were successfully immobilized on the surface. The Cu ions and NO release experimental results showed that the immobilized copper ions could catalyze the production of NO from S-nitrosothiols within the biological system. Meanwhile, due to the synergistic anticoagulant effect of NO and surface-immobilized heparin, the fabricated modified surfaces exhibited antiplatelet adhesion activities and good hemocompatibility. Finally, the antimicrobial activity of the samples was evaluated by Escherichia coli and Staphylococcus aureus, and cytocompatibility was measured using human umbilical vein endothelial cells (HUVECs). The results demonstrated that silver nanoparticles (AgNPs) immobilized by surface reduction reaction did not cause any significant inhibition of cell proliferation while providing stable and effective antimicrobial properties. We envision that this simple surface modification strategy with bifunctional activities of antimicrobial and anticoagulant will find widespread use in clinically used indwelling left ventricular assist devices.

To solve the stability problem of bearingless permanent magnet thin film motor rotor suspension for heart pumps, electromagnetic design and related simulation work of bearingless permanent magnet motor for heart pumps were carried out. First, electromagnetic schemes for radial electromagnetic active suspension and axial permanent magnet passive suspension were designed for the power source of heart pumps. Second, a bearingless permanent magnet thin film motor for heart pumps was designed based on the electromagnetic scheme, and electromagnetic simulation work was carried out using Maxwell. Finally, a bearingless permanent magnet thin film motor that meets the requirements was assembled with a centrifugal pump, and a heart pumps prototype was composed of sensors. The results indicate that the bearingless permanent magnet thin film motor designed in this paper for the heart pumps has good torque and suspension performance and can achieve stable suspension of the heart pumps rotor at 5 degrees of freedom. This design method has strong universality and flexibility, and its design ideas and simulation analysis process provide a reference for researchers in the field of the design of heart pumps.

Background: Increase in volume in the bearingless permanent magnet slice motor (BPMSM) control system for artificial hearts is the major problem in the existing works.Objective: A sensorless control method of the BPMSM for the artificial heart is proposed in the study based on an improved sliding mode observer (SMO) and improved high-frequency injection method. Also, a full-speed rotor position detection method combining the high-frequency injection (FHI) method and sliding mode observer is designed.Methodology: In this method, an improved high-frequency injection method was designed in the low-speed domain, and an improved sliding-mode observer was designed in the medium-high-speed domain. Besides, the speed domain switching method based on the genetic particle swarm optimization (GAPSO) algorithm was adopted at the critical point of the low-speed domain and the medium and high-speed domain to realize the smooth switching between different estimation methods, and then realize the sensorless control of the rotor in the full speed domain. Secondly, the simulation study by Simulink was used to compare the detection effects of the BPMSM rotor position and speed of the artificial heart pump under different methods are compared in this work.Result: The results show that the speed estimation value and rotor position estimation value of the new method in this paper were closer to the actual value, the position estimation error is 3%, and the speed estimation error was within 1.5%. Further, the experimental study was carried out on the principal prototype of the sensorless control part of the artificial heart to verify the effectiveness of the proposed method.Conclusion: The method proposed in this paper has certain generality in the field of motor sensorless control technology, and has important reference value for researchers in this field.

Hemolysis is an important factor affecting the performance of artificial heart. Excessive temperature can damage red blood cells, thereby reducing blood compatibility. To solve the problem of hemolysis caused by the temperature rise of an electromagnetic suspended artificial heart, the influence of the temperature rise of an electromagnetic suspended artificial heart motor was studied in this paper. The influence of two key factors (stator winding phase resistance and blood pump speed) on the overall temperature rise of the electromagnetic levitation artificial heart was explored. Then, based on the law of temperature rise, the temperature optimization scheme of the motor for electromagnetic levitation artificial heart is proposed. The results show that, the temperature rise of electromagnetic levitation artificial heart can be effectively reduced by properly reducing the stator winding phase resistance and rotating speed.

Introduction: Titanium (Ti) and Ti-based alloy materials are commonly used to develop artificial hearts. To prevent bacterial infections and thrombus in patients with implanted artificial hearts, long-term prophylactic antibiotics and anti-thrombotic drugs are required, and this may lead to health complications. Therefore, the development of optimized antibacterial and antifouling surfaces for Ti-based substrate is especially critical when designing artificial heart implants.Methods: In this study, polydopamine and poly-(sulfobetaine methacrylate) polymers were co-deposited to form a coating on the surface of Ti substrate, a process initiated by Cu2+ metal ions. The mechanism for the fabrication of the coating was investigated by coating thickness measurements as well as Ultraviolet-visible and X-ray Photoelectron (XPS) spectroscopy. Characterization of the coating was observed by optical imaging, scanning electron microscope (SEM), XPS, atomic force microscope (AFM), water contact angle and film thickness. In addition, antibacterial property of the coating was tested using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as model strains, while the material biocompatibility was assessed by the antiplatelet adhesion test using platelet-rich plasma and in vitro cytotoxicity tests using human umbilical vein endothelial cells and red blood cells.Results and discussion: Optical imaging, SEM, XPS, AFM, water contact angle, and film thickness tests demonstrated that the coating was successfully deposited on the Ti substrate surface. The biocompatibility and antibacterial assays showed that the developed surface holds great potential for improving the antibacterial and antiplatelet adhesion properties of Ti-based heart implants.

In this paper, we proposed a sliding mode control method for the bearingless permanent magnet slice motor for the blood pump based on the genetic particle swarm algorithm, which aims to solve the problems of strong coupling, strong interference, nonlinearity and uncertainty. Firstly, the mathematical model of rotor torque and suspension force of the bearingless permanent magnet slice motor is established. Secondly, the structure of sliding mode observer is deduced by designing sliding mode surface and control law. And, the performance parameters of sliding mode observer are optimized by the genetic particle swarm optimization algorithm. Thirdly, electromagnetic torque and suspension force control under this control method is studied by Simulink. Finally, the control method is applied to the control of the blood flow of the blood pump, and the rotation speed can effectively control the blood flow. The results indicate that compared with PID control and traditional sliding mode control methods, the sliding mode control method optimized by the genetic particle swarm optimization algorithm greatly improves the control performance of bearingless permanent magnet slice motor. The results show that the blood flow can meet expectations with a small error, which fully meets the blood perfusion requirements of the blood pump.

A three-dimensional carbon nanofiber (CNF) with a high graphitization degree was fabricated via high temperature treatment of polyaniline network. The CNF-1200 used as platinum-based catalyst ORR support exhibited excellent corrosion resistance.

The third-generation magnetically levitated artificial heart pump uses magnetic force to achieve complete levitation of the rotor. In practice, artificial heart pump often works at the off-design operating conditions of centrifugal pumps, which will result in large radial thrust and fluctuations of radial thrust on the impeller rotor, this will seriously affect the stability of rotor levitation and hemocompatibility. Therefore, in this paper, computational fluid dynamics (CFD) is used to calculate the flow field of a double-volute artificial heart pump to investigate the advantages and disadvantages of the double-volute casing. First, a 3D model of the flow passage components of an artificial heart pump is established; second, the advantages of the double-volute casing in terms of radial thrust optimization are investigated by applying CFD methods; finally, the effects of the double-volute casing on the pumping performance and hemocompatibility are discussed. The results show that the double-volute casing has significant advantages in the optimization of radial thrust and radial thrust fluctuations, and has a slightly negative impact on the pumping performance and hemocompatibility, but it is within acceptable limits.

Purpose Artificial heart pumps are widely used for medical auxiliary blood supply, but the existing technology has some defects. To solve the problems of traditional artificial heart pumps, such as weak pulsation, easy suction and reflux, this paper proposes a new control method. Methods First, we designed a sliding mode controller for aortic pressure and formulated the feedback adjustment mechanism: two mutually converted reference values of aortic pressure were introduced to make the aortic pressure jump between the two extreme values, thereby improving blood pulsatility. Second, the target value of the average aortic pressure was set according to the actual situation of patients with heart failure. Based on the target value, a sliding mode controller (SMC) was designed to stabilize the average aortic pressure near the target value. For the second and third steps, a genetic algorithm particle swarm optimization (GAPSO) was introduced to optimize the parameters of the sliding mode controller. Finally, a prevention mechanism for regurgitation and suction was proposed to avoid possible regurgitation and suction phenomena. Results When the artificial heart pumps is assisted by the new control, the aortic pressure difference can reach 31 mmHg. Additionally, suction and reflux do not appear in new control method. Conclusion The results show that this method can improve blood pulsatility in addition to satisfying the blood perfusion required by the human body. It can also prevent reflux and suction, which promotes the functional recovery of a damaged heart.

In order to solve the problem that the traditional artificial heart pump has poor dynamic bionic performance and cannot respond to blood perfusion in real time according to the patient’s state, this paper proposes a new physiological control method based on adaptive adjustment of heart rate. Firstly, a coupled model of the cardiovascular circulatory system and artificial heart pump was established, and the correctness of the model is verified by hemodynamic simulation. Secondly, according to the model-free adaptive control theory, the artificial heart pump physiological control strategy for adaptive regulation of heart rate is designed, including pseudo partial derivative estimation algorithm and adaptive control law. Then, the parameters of the adaptive controller are optimized by the improved beetle antennae search algorithm. Finally, the auxiliary effect and dynamic performance of the adaptive control strategy are studied by numerical methods. The results show that the physiological control method based on adaptive regulation of heart rate realizes the adaptive modulation of heart rate and blood flow, which can meet the needs of blood perfusion in different states and help to promote the recovery of damaged heart.

A multi-objective physiological control method of artificial heart pump based on hierarchical thinking and variable universe fuzzy algorithm is proposed in this paper. Its innovation lies in that the control system is divided into three layers: motor speed control layer, heart pump flow feedback control layer, and multi-objective physiological control layer. Firstly, for the multi-objective physiological control layer, with heart rate, mean arterial pressure, minimum pump flow, physical activity level and clinical status as inputs, and the target value of the cardiac pump flow feedback control layer as output, a variable universe fuzzy controller is designed. Secondly, for the heart pump flow feedback control layer, a flow adaptive feedback adjustment mechanism is introduced to stabilize the blood flow at the target value. Finally, for the motor speed control layer, a sliding-mode double closed-loop control method for the motor of artificial heart pump is proposed, so that the pump speed can respond quickly and stably to provide stable blood flow output. The results show that this method can not only improve blood pulsatility while satisfying blood perfusion, but also dynamically adjust the pump speed according to the patient’s state, thereby improving the patient’s quality of life.