Due to the small inductance, modulation of three-phase inverter induces serious torque ripple. In addition, increase in frequency is limited by processor speed. Therefore, traditional control approaches are not suitable. order solve aforementioned problems, a new instantaneous method for inductance brushless dc motor proposed improving estimation and control. First, estimated through improved position information back electromotive force (EMF) coefficient estimation. The former achieved hall...

A sensorless control method for a high-speed brushless DC motor based on the line-to-line back electromotive force (back EMF) is proposed in this paper. In order to obtain commutation signals, voltages are obtained by low-pass filters. However, due filters, wide speed range, and other factors, actual signals significantly delayed more than 90 electrical degrees which limits acceleration of motor. novel algorithm hysteresis transition between "90-α" "150-α" introduced handle severe retarding...

Winding currents contain lots of harmonics if motors rotate at a high speed. This paper addresses two key challenges on the harmonic suppression: 1) using multiple synchronous rotating frame transformations (MSRFTs) to get primary signals, and 2) proposing closed-loop detection system (CDS) extract accurately. First, mathematical model containing was built. Second, MSRFTs were introduced high-precision method called CDS analyzed. The has higher accuracy than open-loop can enhance disturbance...

The brushless dc (BLDC) motor can be driven by either pulse-width modulation (PWM) or pulse-amplitude (PAM) techniques. Unfortunately, neither of them the most suitable method for high-speed BLDC in wide speed range, so a hybrid drive combining PWM and PAM is first introduced. Then, this paper proposes new sensorless control based on virtual neutral voltage to suit method. In order obtain commutation signals from seriously unclear signal due notches electromagnetic interference, low-pass...

We demonstrate a single-beam atomic magnetometer (AM) capable of measuring three-axis magnetic field with high-sensitivity, achieved by applying small DC offset and high frequency modulation field. To satisfy the miniaturization demand AMs, an elliptically polarized light detuned 50 GHz from resonance transition center is employed. The circularly component used to polarize alkali-metal atoms, while linearly detect dynamics spin under Based on theoretical analysis, parameters that...

The sensorless drive method of the permanent magnet synchronous motor (PMSM) has attracted wide attention for its low cost and high reliability. As a critical technology, fast high-precision rotor-position estimation is essential. This article addresses position-estimation deviation issue based on sliding-mode observer (SMO) phase-locked loop (PLL). A nonlinear equivalent model SMO established to analyze compensate caused by SMO, feed-forward PLL employed suppress steady-state position...

We propose a three-axis closed-loop optically pumped magnetometer with high sensitivity. The has sensitivity of approximately 30 fT/Hz1/2 using two orthogonal laser beams for pumping and probing the alkali metal atoms. In mode, dynamic range is improved from ±5 nT to ±150 nT. bandwidth increased about 100 Hz over 2 kHz 10 modulation fields in x- y-axes another 6 field along z-axis. Compared single-axis or dual-axis magnetometers, proposed not only provides direction magnitude magnetic but...

We demonstrate the bandwidth enhancement of an all-optical spin-exchange relaxation-free (SERF) magnetometer based on amplitude-modulated (AM) light. Alkali metal atoms are modulated directly by pump beam instead modulation field or radio frequency field. The first harmonic demodulation AM SERF with a intensity 15 kHz results in high over 11 sensitivity 20 fT/Hz1/2 at 30 Hz and 60 10 kHz. Meanwhile, DC presents same as traditional (6 Hz). presented technique for modulating amplitude allows...

In this paper, precise accelerated torque control for a small inductance brushless dc motor (BLDCM) is achieved by electromagnetic and disturbance suppression. First, the ripple reduced in commutation conduction regions. former region, suppressed overlapping optimizing duty ratio of active controller. latter unbalance caused unbalanced three phase windings proposed asymmetry compensation function, created back electromotive force (EMF) compensated feedforward control. Second, has been...

In this paper, a novel drive method, which is different from the traditional motor techniques, for high-speed brushless DC (BLDC) proposed and verified by series of experiments. It well known that BLDC can be driven either pulse-width modulation (PWM) techniques with constant dc-link voltage or pulse-amplitude (PAM) an adjustable voltage. However, to our best knowledge, there rare study providing proper method large power over wide speed range. Therefore, detailed theoretical analysis...

Synchronous vibration due to rotor unbalance is a main disturbance source that drastically reduces the performance of rotating shaft supported by active magnetic bearings. To suppress imbalance force without rotational sensor, novel adaptive notch filter (ANF) for frequency estimation based on information radial displacement signals in X- and Y-directions together proposed. The structure principle proposed technique used online extraction synchronous are presented, convergence properties...

To effectively reject the influence of moving gimbal effect and parameter variation on control performance rotor-active magnetic bearings (AMBs) system in a double magnetically suspended moment gyro (MSCMG), this paper proposes feedback linearization extended state observer (ESO) based (FLESOBC) strategy, which can attenuate matched mismatched uncertainties simultaneously. First, considering voltage-type power amplifier used MSCMG for space applications, rotor dynamics is modeled completely...

A sensorless control strategy of a high-speed 315 kW brushless dc (BLDC) motor based on speed-independent flux linkage function is proposed in this paper. It addresses the two key challenges BLDC motor: proposing to ensure reliable operation low-speed range, and presenting correction provide accurate commutation points range. First, detection circuit model discussed. The analysis shows that really suitable for Then, an improved closed-loop system change current full speed range proposed....

Spin-exchange relaxation-free gyroscope (SERFG) is a promising rotation sensor, and the bias error one of its most important characteristics. It identified that measurement noise induced by thermal magnetization fluctuations inherent in ferrite shield SERFG limits stability. The root cause this lies low-frequency magnetic field sensitivity dominated nuclear spin relaxation rate. In paper, steady state response model modified considering non-negligible rate pressure-dependent experimentally...

Atomic magnetometers operated in spin-exchange relaxation-free (SERF) have the potential to replace superconducting quantum interference devices (SQUIDs) field of biomagnetism. Here, we demonstrate dual-axis closed-loop control a single-beam SERF magnetometer that allows sensing two orthogonal magnetic fields simultaneously and independently with suppressed cross-talk effect, achieved by applying rotating modulation using negative feedback. Operating mode miniature 4 × mm 87Rb cell, achieve...

Because of the low cost and convenient installation, bipolar Hall-effect sensors are commonly applied to permanent magnet synchronous motors. Generally, speed position estimated inaccurately due installation error sensors. This paper addresses two key challenges on improving estimation precision: 1) proposing coordinate transformation get Hall rotary vector 2) designing frequency tracking method estimate position. First, which is related obtained by transformation. Second, filter (SFTF) used...

A novel method to determine the spin polarization and its distribution for a spin-exchange relaxation-free (SERF) atomic magnetometer are proposed in this paper. The Larmor precession frequency is measured using fast Fourier transform (FFT) analysis result of transient response under excitation series step-changed magnetic field. extracted from slow-down factor frequency. variation with different pump light intensities along direction analyzed, experimental results well consistent...

A nuclear spin co-magnetometer operated in the spin-exchange relaxation-free (SERF) regime is a promising tool for long-term navigation application its abilities to sense inertial rotation and suppress environmental magnetic field disturbance. The response model of K-Rb- <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sup> Ne derived based on state space method experimentally validated tabletop SERF co-magnetometer. theoretical experimental...

An innovative design method is proposed for highly uniform magnetic field coils using a particle swarm optimization (PSO) algorithm. We use an approach instead of the conventional solving closed-form equations to obtain coil geometric parameters. apply PSO algorithm structure and set appropriate penalty function boundary conditions. A discrete employed avoid obtaining parameters with large number decimal places. Compared method, our solves problem how produce under various structural process...

A novel circuit is presented for the design of transmission-type negative group delay (NGDC) with low signal attenuation. By loading a lumped resistor at specific point on loose-coupling microstrip (MS) resonator, lossy coupled-line resonator proposed, size which effectively reduced by employing an open radial patch. cascaded two-stage NGDC scheme to realise enhanced (NGD) value and better reflection coefficients. The layout designed in anti-symmetrical back-to-back manner. To validate...

We constructed a compact single-beam atomic magnetometer operated in transverse magnetic-modulation mode or DC-offset mode. By coupling the laser beam into polarization maintaining fiber, with vapor cell of dimensions 4 mm × mm, sensitivity 30 fT/Hz1/2 has been achieved configuration. In addition to experimental study sensitivity, we perform theoretical analysis and The results indicate both two modes have almost same scale factor. also studied dynamic working range sensor found,...