To improve the control performance of the permanent magnet synchronous motor speed control system, the fractional order calculus theory is combined with the sliding mode control to design the fractional order integral sliding mode sliding mode surface (FOISM) to improve the robustness of the system. Secondly, considering the existence of chattering phenomenon in sliding mode control, a new second-order sliding mode reaching law (NSOSMRL) is designed to improve the control accuracy of the system. Finally, the effectiveness of the proposed strategy is demonstrated by simulation.

Model-based sensorless control of permanent magnet synchronous motor (PMSM) is promising for high-speed operation to estimate motor state, which is the speed and the position of the rotor, via electric signals of the stator, beside the inevitable fact that estimation accuracy is degraded by electromagnet interference (EMI) from switching devices of the converter. In this paper, the simulation system based on Luenberger observer and phase-locked loop (PLL) has been established, analyzing impacts of EMI on motor state estimations theoretically, exploring influences of EMI with different cutoff frequency, rated speeds, frequencies and amplitudes. The results show that Luenberger observer and PLL have strong immunity, which enable PMSM can still operate stably even under certain degrees of interference. EMI produces sideband harmonics that enlarge pulsation errors of speed and position estimations. Additionally, estimation errors are positively correlated with cutoff frequency of low-pass filter and the amplitude of EMI, and negatively correlated with rated speed of the motor and the frequency of EMI.  When the frequency is too high, its effects on motor state estimations are negligible. This work contributes to the comprehensive understanding of how EMI affects motor state estimations, which further enhances practical application of sensorless PMSM.

Triboelectric generators have been attracting much attention as electrical power sources in scientific communities and industries. Based on dielectric physics, two microscopic routes are available as current sources: One is charge displacement and the other is dipolar rotation. We have been investigating these routes as power sources for triboelectric generation. In other words, dipolar energy transfer process during a course of depolarization has the potentiality to be utilized as triboelectric generator. In this paper, we show that polyimide polymer film with permanent dipoles, i.e., PMDA-ODA polyimide, can provide current source capacity enhanced at elevated temperature, which is in good agreement with our idea based on dipolar energy mode of triboelectric generator. That is, permanent dipoles rotate quickly at elevated temperature, and act as an enhanced current source in the dipolar energy source model of triboelectric generator.

Silver electrical contacts were separated at constant opening speed in a 200V-500VDC/10A resistive circuit. Break arcs were extinguished by magnetic blowing-out with transverse magnetic field of a permanent magnet. The permanent magnet was appropriately located to simplify the lengthened shape of the break arcs. Magnetic flux density of the transverse magnetic field was varied from 20 to 140mT. Images of the break arcs were observed from the horizontal and vertical directions using two high speed cameras simultaneously. Arc length just before extinction was analyzed from the observed images. It was shown that shapes of the break arcs were simple enough to trace the most part of paths of the break arcs for all experimental conditions owing to simplification of the shapes of the break arcs by appropriate arrangement of the magnet. The arc length increased with increasing supply voltage and decreased with increasing magnetic flux density. These results will be discussed in the view points of arc lengthening time and arc lengthening velocity.

Electrical contacts are separated at constant speed and break arcs are generated in nitrogen or air in a 200V-450VDC/10A resistive circuit. The break arcs are extinguished by magnetic blow-out. Arc duration for the silver and copper contact pairs is investigated for each supply voltage. Following results are shown. The arc duration for Cu contacts in nitrogen is the shortest. For Cu contacts, the arc dwell time in air was considerably longer than that of nitrogen. For Ag contacts, the arc duration in nitrogen was almost the same as that in air.

Silver electrical contacts are separated at constant speed and break arcs are generated between them in a 200V-450VDC and 10A resistive circuit. The motion of the break arcs is restricted by some surrounding alumina plates. Transverse magnetic field of a permanent magnet is applied to the break arcs. Changing the supply voltage and the height of a wall located at the upper side of the break arcs, the arc lengthening time and motion of the break arcs are investigated. As a result, the higher supply voltage causes an increase of the arc lengthening time. The arc lengthening time increases significantly when the break arcs expand into the whole of the surrounding walls.

Silver electrical contacts are separated at a constant speed and break arcs are generated in a DC300V-450V/10A resistive circuit. The transverse magnetic field formed by a permanent magnet is applied to the break arcs. Alumina pipes are placed around the contacts to restrict the motion of break arcs. The dependences of the arc lengthening time and arc length just before arc extinction L on the strength of the magnetic field and supply voltage are investigated. It was found that the arc lengthening time increases with increasing supply voltage E and tends to decrease when the magnetic flux density Bx is increased. The arc length just before arc extinction L increases with increasing E and decreasing Bx. It also increases linearly with increasing arc lengthening time tm when no reignitions occur.

Silver electrical contacts are separated at constant speed and break arcs are generated in a DC100 V–450 V/10 A resistive circuit. The transverse magnetic field of a permanent magnet is applied to the break arcs. Dependences of the arc duration, arc dwell time and arc lengthening time on the strength of the magnetic field and supply voltage are investigated. The characteristics of the re-ignition of the break arc are also discussed. Following results are shown. The arc duration D is increased due to the increase of the arc lengthening time tm when the supply voltage E is increased for each magnetic flux density Bx, because the arc dwell time ts is almost constant. The arc duration D is increased due to the increase of both of the arc lengthening time tm and the arc dwell time ts when the magnetic flux density Bx is decreased. The arc lengthening time tended to become long when the re-ignition of the break arc is occurred. The lengthening time tends to become longer when the duration tm1 from the start of the arc lengthening to the start of the re-ignition is increased. Re-ignitions occurred frequently when the magnetic flux density of the transverse magnetic field is increased and the supply voltage is increased.

Break arcs are rotated by the radial magnetic field formed by a magnet embedded in the pipe-shaped cathode. The arcs are generated in switching a DC42 V resistive circuit. The closed contact current varies from 5 A to 21 A. The curvature of the anode surface is varied to study the dependence of the arc length and the positions of the break arcs in the contact gap. The following results are obtained: (i) as current decreases, there is more difference in arc duration among different curvatures; (ii) as current decreases, the arc duration decreases with decrease of the radius of curvature; (iii) in each contact curvature, the anode spots region is located nearer to the center axis than the cathode spots region; (iv) the arc length just before arc extinction is independent of the curvature of the contacts.

Break arcs are rotated with the radial magnetic field formed by a magnet embedded in the fixed contact. They are generated in a DC42 V resistive circuit. The circuit current when the contacts are closed varies from 5 A to 21 A. The strength of a radial magnetic field for rotating break arcs changes. Arc duration is investigated. Then rotational frequency, arc length and Lorentz force when the periodic rotation of break arcs starts are analyzed to investigate the conditions required to rotate break arcs. The following results are obtained. The arc length L when the rotational motion of the break arc starts is almost constant at a constant magnetic flux density with an increase in circuit current. The arc length L decreases with an increase in the magnetic flux density of the radial magnetic field. The rotational motion of break arcs starts when the arc length L reaches a certain value determined by magnetic flux density. Rotational frequency and Lorentz force increase linearly with an increase in circuit current.

Break arcs are generated between electrical contacts in a DC 42 V resistive circuit. Contact materials are Ag/SnO2 and Ag/ZnO. Circuit current when contacts are closed is varied from 5 A to 21 A. The radial magnetic field to drive break arcs is formed between the contact gap with a permanent magnet embedded in the cathode. The arc motion is observed with a high-speed camera. Experimental results with the magnet are compared with those without the magnet. Following results are shown. Similar experimental results to pure silver contacts are obtained for Ag/SnO2 and Ag/ZnO contact pairs. The rotational motion of the break arcs and the shortening effect of the arc duration are confirmed. The ring-shaped, wide and uniform traces are observed on the contact surfaces after break operations. This result shows the prevention effect of local erosion of electrical contacts and the reduction of total amount of contact erosion. The rotational frequency f is increased with the increase of the arc current Iarc. These results for Ag/SnO2 and Ag/ZnO contact pairs are similar to the results for pure silver contacts in our previous experiments. The rotational frequency of the break arc for the Ag/SnO2 and Ag/ZnO contacts is lower than that for the pure silver contacts.

The dynamic characteristics are the key issues in the optimum design of a permanent magnetic actuator (PMA). A new approach to forecast the dynamic characteristics of the multilink PMA is proposed. By carrying out further developments of ADAMS and ANSOFT, a mathematic calculation model describing the coupling of mechanical movement, electric circuit and magnetic field considering eddy current effect, is constructed. With this model, the dynamic characteristics of the multilink PMA are calculated and compared with the experimental results. Factors that affect the opening time of the multilink PMA are analyzed with the model as well. The method is capable of providing a reference for the design of the PMA.

According to a new kind of permanent contactor, this paper analyses the dynamic behavior of the contactor with and without current-feedback system. And it presents a method to obtain the dynamic characteristics of the contactor with current-feedback system. The experiments prove that the method is correct. Then, it compares the contactor without current-feedback system with the one with current-feedback system. The result shows that the contactor with current-feedback system can avoid this flaw of the contactor without current-feedback system.

A new type of permanent magnet actuator driven by electromagnetic repulsive force in breaking course and electromagnetic attraction force during closing course is presented in this paper, and the static and dynamic characteristics for contactor with this new type actuator are mainly focused on by simulation and experiment simultaneously. Firstly, the static electromagnetic attraction force in closing course and electromagnetic repulsive force in breaking course are studied by FEM simulation and experiment. Secondly, by coupling of the electrical and mechanical differential equations, the dynamic electromagnetic attraction force in closing course and dynamic electromagnetic repulsive force in breaking course are obtained respectively. Thirdly, by constructing the mechanical model of contact system and permanent magnet actuator, the displacements of moving contact and moving core while both contactors' closing and breaking are obtained by simulation and experimental study. It is indicated that simulation results coincide well with that of experiment.

We define a d-matched digraph and propose a recursive procedure for designing an optimal d-matched digraph without bidirectional edges. The digraph represents an optimal highly structured system which is a special class of self-diagnosable systems and identifies all of the faulty units independently and locally in O(|E|) time complexity. The procedure is straightforward and gives a system flexible in network connections. Hence the procedure is applicable to real systems such as the Internet or cooperative robotic systems which change their topology dynamically.

The Paper describes design and experiment of 2nd cyclotron harmonic peniotron at microwave region using a permanent magnet system. The magnet system using a cylindrical magnet magnetized along the cylindrical axis is designed and fabricated. The 2nd cyclotron harmonic peniotron operating at the π mode in a six vane magnetron waveguide resonator and at 5 GHz was constructed by using the magnet system. The peak electronic efficiency higher than 30% was achieved at the π mode in the resonator.

We show that the permanent of an m n rectangular matrix can be computed with O(n 2m 3m) multiplications and additions. Asymptotically, this is better than straightforward extensions of the best known algorithms for the permanent of a square matrix when m/n log3 2 and n .

We present a scalable parallel memory architecture with a skew scheme by which permanent-concentration-free strides, if any, do not depend on the number of ways in parallel memory interleaving. The permanent-concentration is a kind of memory access conflict. With conventional skew schemes, permanent-concentration-free strides depended on the number of banks (or bank groups) in parallel memory (=number of ways in parallel memory interleaving). We analyze two kinds of cause of conflicts: permanent-concentration occurs when memory access requests concentrate in limited number of banks (or bank groups) in parallel memory, and transient-concentration, when memory access requests transiently concentrate in some banks (or bank groups) in parallel memory. We have identified permanent-concentration-free strides, which are independent of the number of banks (or bank groups) in parallel memory, by solving two concentrations separately. The strategy is to increase the size of address block of shifting address assignment to the parallel memory in order to reduce permanent-concentrations, and make the size of the buffer for each banks (or bank groups) in the parallel memory match the size of address block of shifting in order to absorb transient-concentrations. The skew scheme uses the same size of address block of shifting address assignment for memory systems for different numbers of banks (or bank groups) in parallel memory. As a result, scalability for permanent-concentration-free strides is achieved independent of the number of banks (or bank groups) in parallel memory.