Signal Injection Technique Research Articles

Investigation of Impedance Determination using Two-Point High Frequency Injection Technique for Non-Contact Voltage Measurement System

Energy management facilities are becoming more necessary due to the growth of smart energy and microgrid technologies. Convenient access to information on energy consumption is an advantage for energy planning and management and secure for the operators. Consequently, these conceive the idea of developing non-contact sensor approach to replace the conventional energy measurement while maintain full accessibility to voltage and current information. This paper proposes a method of non-contact conductive voltage measurement with an automated calibration system. The previous application of non-contact voltage measurement systems in the low-voltage range used a method based on the capacitive coupling principle by covering a metal plate around an insulated power line cable. The important factor of measurement accuracy depends on the determination of impedance occurring between the conductors within the cable and the metal plates attached to the cable surface by insulating as a dielectric. The proposed impedance determination process employs a two-point high-frequency signal injection technique that transmits a reference signal to calculate the established parasitic impedance value. From the high-frequency injection technique, the resulting impedance can be calibrated throughout the reverse calculation to measure the actual voltage of the power line. The experimental results of the proposed voltage measurement system can measure the actual voltage of the power line with the capability to calibrate the impedance due to the variation in the environment and eliminate noise errors from the instability under various conditions.

MTPA Control for DC-Biased Hybrid Excitation Machine Using MTPA Control Law and Virtual Signal Injection

This paper proposes an overall maximum torque per ampere (MTPA) control for dc-biased hybrid excitation machine (dc-biased HEM) using MTPA control law and virtual signal injection. The mathematical model of the machine is first analyzed in synchronous rotating reference frame. According to the characteristic of the mathematical model, a control strategy is proposed and consists of two parts, i.e., an MTPA control law and a virtual dc-biased signal injection. The MTPA control law is employed to calculate the dominant current references while ensuring the rapid dynamic performance. The virtual dc-biased signal injection method is a correction scheme for MTPA current deviation caused by parameter variations. Unlike conventional signal injection techniques, this signal injection method considers the nonlinearity of inductance and does not involve any filters. Thus, it can extract MTPA criterion more accurately and easily. In general, simulation and experimental results validate that the control strategy combined with MTPA control law and virtual signal injection can achieve accurate MTPA operation and rapid dynamic magnetization capability for the dc-biased HEM in real time.

The Breakthrough Listen Search for Intelligent Life: Technosignature Search of 97 Nearby Galaxies

The Breakthrough Listen search for intelligent life is, to date, the most extensive technosignature search of nearby celestial objects. We present a radio technosignature search of the centers of 97 nearby galaxies, observed by Breakthrough Listen at the Robert C. Byrd Green Bank Telescope. We performed a narrowband Doppler drift search using the turboSETI pipeline with a minimum signal-to-noise parameter threshold of 10, across a drift rate range of ±4 Hz s−1, with a spectral resolution of 3 Hz and a time resolution of ∼18.25 s. We removed radio frequency interference (RFI) by using an on-source/off-source cadence pattern of six observations and discarding signals with Doppler drift rates of 0. We assess factors affecting the sensitivity of the Breakthrough Listen data reduction and search pipeline using signal injection and recovery techniques and apply new methods for the investigation of the RFI environment. We present results in four frequency bands covering 1–11 GHz, and place constraints on the presence of transmitters with equivalent isotropic radiated power on the order of 1026 W, corresponding to the theoretical power consumption of Kardashev Type II civilizations.

An Improved High-Frequency Voltage Injection Method for Interturn Short-Circuit Fault Detection in PMSMs

The inter-turn short-circuit fault (ITSCF) is a common incipient fault for the permanent magnet synchronous machine (PMSM) drive system. In recent years, the high-resolution ITSCF detection method that combines the high frequency (HF) signal injection and zero-sequence voltage measurement has been put forward. However, for the traditional HF signal injection technique, nonnegligible voltage distortion may occur when the injection frequency is close to the PWM carrier-frequency. In addition, the injected voltage varies with the operating conditions of the PMSM. These drawbacks of the traditional HF signal injection technique greatly limit the ITSCF detection performance using HF signal injection. To further improve the ITSCF detection performance, an improved HF injection scheme is proposed in this paper. In the proposed method, the six active voltage vectors are injected into the PMSM in certain orders to realize a rotating voltage injection, and the injection frequency is up to five-sixth of the PWM carrier-frequency. By employing the proposed injection method, the ITSCF detection sensitivity can be much improved. And the ITSCF detection performance is not affected by the operation conditions of the PMSMs. Finally, the simulations and experiments are carried out to verify the proposed method.

A Novel Control-Independent Online Fault Diagnosis of Interturn Short Circuits in SRMs Using Signal Injection Technique

Most of the existing diagnosis techniques for interturn short circuits (ITSCs) in switched reluctance motors (SRMs) suffer from three major issues. 1) The problem of lower sensitivity where the system cannot detect an ITSC if a lower number of turns are short-circuited; 2) Interference of load variation on the detection reliability in which the fault index might initiate false alarm without any fault; 3) The dependency of the diagnosis system on the control strategy on which the motor is operating. This article proposes a novel method to diagnose ITSCs in SRMs independent of control schemes with better sensitivity and reliability using the signal injection technique. In SRMs, not all the phases take part in the torque production at any instant. The idle or inactive phase is injected with a high-frequency (HF) voltage signal for a preselected injection ratio within an electrical cycle. Any change in the winding parameters owing to an ITSC fault is deciphered by monitoring the HF currents generated in the phase windings. The results are validated experimentally for a four-phase 8/6 SRM employing two control strategies: 1) chopped current control and 2) angle position control.

Theory and Time-Domain Simulation of Third-Order Intermodulation Suppression by Signal Injection

This letter reports a new theoretical analysis of third-order intermodulation (IM3) reduction in nonlinear communication amplifiers by signal injection. On the basis of well-known Volterra series analysis, we put forward a general model that can analyze both the qualitative and quantitative effects of injected signal parameters on output IM3s, which previous literatures failed to achieve. Our theory can directly calculate the optimal amplitude and phase of single injected signal and points out the duality for some dual-signal injections which can help reduce their parameter scanning complexity from 4-D to 2-D. These conclusions are in good agreement with the simulation of two traveling wave tube (TWT) amplifiers by 3-D-FDTD-PIC code and CST and MTSS. Our work proposes an original analysis about how to adjust injected external signals to obtain best IM3 cancellation in communication systems, and boosts the research efficiency for new signal injection techniques from a novel perspective.

Design and analysis of a speed controller for fractional‐order‐modeled voltage‐source‐inverter‐fed induction motor drive

SummaryThis paper presents the fractional‐order voltage‐source‐inverter‐controlled induction machine (FO‐VSI‐IM) model extraction and integration to improve the closed‐loop speed control performance of variable speed drives. In the operating range of variable speed drive, it is susceptible to load disturbance and speed tracking error. This paper provides the practical approach to obtain the fractional‐order model of VSI‐fed induction motor (IM) drive by using PWM signal injection technique. The injected PWM signals and speed encoder response signals are recorded using the dSPACE 1104 platform. This model is used in constructing the closed‐loop speed control of VSI‐IM with designed integer‐order PI speed controller. The comparative performance is evaluated for FO‐VSI‐IM and integer‐order voltage‐source‐inverter‐controlled induction machine (IO‐VSI‐IM) with feed‐forward gain variations and load disturbances. It is observed that the robust speed tracking capability with the controller designed using the FO‐VSI‐IM model over the controller with IO‐VSI‐IM model under load disturbances. The improvement in speed tracking with less control effort in the FO‐VSI‐IM model is advantageous in field‐oriented control (FOC) drives.

A 28-GHz High Linearity Up-Conversion Mixer Using Second-Harmonic Injection Technique in 28-nm CMOS Technology

A 28-GHz high linearity active up-conversion mixer using 28-nm CMOS is presented in this letter. To enhance the modulated output power level under high-order modulation with IM3 improvement in the high IF input power region, the second-order intermodulation (IM2) signal injection technique is adopted. The positive third-order intermodulation (IM3) signal is generated by mixing the IM2 signal and IF input signal with transistors in the transconductance stage biasing in triode region. Therefore, by combining these opposite IM3 signal at the output of transconductance stage, the IM3 distortion can be alleviated. Besides, the proposed mixer achieves an IM3 distortion improvement in a wide IF power range. The measurement results demonstrate conversion gain (CG) of −6.4 dB and output 1-dB compression point (OP1 dB) of −2.2 dBm with 19 mW. The two-tone measurement results exhibit 10.2 dBm output third-order intercept point (OIP3). Furthermore, with the modulation measured results using single-carrier 256-QAM signal, the proposed mixer also exhibits a distinguished output power enhancement when the linearizer turns on. To the best of the author’s knowledge, this design is the first demonstration and implemented of an IM2 signal injection technique in millimeter-wave frequency, which also improves the output power level of the high-order modulation measurement.

Cladding-Pumped Erbium-Ytterbium Co-Doped Fiber Amplifier With Dual-Wavelength Auxiliary Signal Injection of 1030 and 1040 nm

We propose and demonstrate a cladding-pumped, erbium-ytterbium co-doped fiber amplifier (EYDFA) scheme based on dual wavelength auxiliary signal injection technique to solve the issue of the backward Yb-ASE self-lasing under strong pumping for the high-power fiber amplification of 1.5-μm kHz-linewidth linearly-polarized laser signal. With the dual wavelength auxiliary signal of 1030 and 1040 nm injection, the allowable maximum pump power without triggering the backward Yb-ASE self-lasing can be greatly increased due to the relieving effect on the inhomogeneous gain broadening. For an EYDFA with 3.8-m erbium-ytterbium co-doped double-clad fiber, the net output power is improved to 13.8 W, while the linewidth of the amplified single-transverse-mode linearly-polarized 1560 nm laser signal is still only 3.5 kHz. The SBS effect is observed to be trivial during the fiber amplification.

Economic Power Sharing to Minimize Generation Cost in a DC Microgrid

This study developed an economic power-sharing method to minimize the total generation cost (TGC) in a DC microgrid based on an AC signal injection technique. Economic power sharing for each distributed generator (DG) is achieved by means of a small AC frequency without a communication network. The AC frequency is proportional to the DG’s incremental cost and is injected into the output voltage of the DG. The AC signal frequency is indirectly regulated to have economic power sharing with equivalent incremental cost for each DG, so the minimization of TGC is achieved instead of a straightforward optimization solution. Therefore, the control scheme is simple and easy to implement. The proposed power-sharing method overcomes the impact of differences in line resistance and is realized in a decentralized manner without a communication network and with plug-and-play capability. The proposed control method was investigated theoretically and verified experimentally.

A Robust Sensorless Controller-Observer Strategy for PMSMs with Unknown Resistance and Mechanical Model

In this work, we present a mixed sensorless strategy for Permanent Magnet Synchronous Machines, combining a torque/current controller and an observer for position, speed, flux, and stator resistance. The proposed co-design is motivated by the need for an appropriate signal injection technique to guarantee full state observability. Neither the typical constant or slowly-varying speed assumptions, nor a priori mechanical model information are required. Instead, the rotor speed is modeled as an unknown input disturbance with constant (unknown) sign and uniformly non-zero magnitude. With the proposed architecture, we show that the torque tracking and signal injection tasks can be achieved and asymptotically decoupled. Because of these features, we refer to this strategy as a sensorless controller-observer with no mechanical model. Employing a gradient descent resistance/back-EMF estimation, combined with the unit circle formalism to describe the rotor position, we prove regional practical asymptotic stability of the overall scheme. In particular, the domain of attraction can be arbitrarily large, without including a lower-dimensional manifold. The effectiveness of this design is further validated with numerical simulations, related to a challenging application of UAV propellers control.

Maximum Torque per Ampere (MTPA) Control for IPMSM Drives Using Signal Injection and an MTPA Control Law

This paper presents a maximum torque per ampere (MTPA) control scheme for interior permanent magnet synchronous motor drives. In this scheme, an enhanced signal injection technique is responsible for correcting the MTPA reference deviation due to motor parameter variations, and a derived MTPA control law is responsible for generating constant-parameter model-based MTPA current references to enhance the dynamic performance of the MTPA operation. Unlike previous signal injection techniques, the enhanced injection technique directly injects signals into the d - and q -axis currents and extracts the MTPA indicator from the reconstructed dc-link current. Hence, this enhanced injection technique avoids any transformations associated with polar coordinates, and it does not depend on a dc-link voltage sensor or a high-resolution speed sensor. The derived MTPA control law, unlike conventional MTPA control laws, can be realized in real time without mathematical approximations or lookup tables. With the combination of the enhanced signal injection technique and the derived MTPA control law, the proposed MTPA scheme can achieve an accurate and fast MTPA operation. Simulation and experimental results confirm the validity of the proposed MTPA scheme.

Robust adaptive sliding mode observer for self-sensing IPMSM control based on optimized HF injection method

Classical tracking algorithms often employed for HF injection techniques used to estimate position of ac machine depend on machine inductances. To overcome this dependency, a new approach to extract the sign of the rotor position estimation error is developed and then, a new adaptive step-by step sliding mode observer is proposed as an alternative solution to estimate the rotor position, speed and acceleration of the machine. The gains of this observer are made variable in order to reduce the chattering effects. Moreover, Low-pass-filters usually used in the pulsating-wave signal injection technique are removed leading to reduce the cost and complexity of implementation and improve the estimation in term of delays. The performance of the proposed algorithm is compared with respect to the existing tracking algorithms and the step by step sliding without gains variation in simulations and experiments.

Observer-Based Pulsed Signal Injection for Grid Impedance Estimation in Three-Phase Systems

This paper addresses the estimation of the grid impedance and the control of grid-tied converters by combining pulsed signal injection (PSI) and observer-based techniques. A Luenberger-based observer is used for controlling the grid-side current of an LCL filter by only measuring the converter-side currents and the grid-side voltage. This configuration mitigates the effects of parameter variation at the LCL filter. Under grid impedance changes, the observer control signal will be used for triggering the signal injection. A PSI approach is employed for estimating online the grid impedance using a recursive least square algorithm. Compared with existing grid-impedance estimation techniques, the proposed method can: 1) identify a generic RL grid impedance, even under unbalanced conditions; 2) reduce the distortion induced by the excitation signal by relying on the observer to triggering the injection when a grid impedance change is detected; and 3) identify grid impedance values much lower than the converter filter impedance, which is the usual situation when the converter rated power is well below the grid rating. Finally, it is worth pointing out that the proposed estimation technique is well-suited to be incorporated into an adaptive current controller scheme.

Rotor Geometry Design of Saliency-Based Sensorless Controlled Distributed-Winding IPMSM for Hybrid Electric Vehicles

This paper presents the design process of a sensorless-oriented interior permanent magnet synchronous motor (IPMSM). The motor uses spatial saliency for the position-sensorless traction drive in a hybrid electric vehicle (HEV). The sensorless control consists of two signal-injection techniques to achieve wide-torque-range operation at low speed. Realization of a stable sensorless drive necessitates a design capable of expanding the transition region between the two techniques. This paper describes our proposed design methods that can achieve the self-sensing capability while retaining the required torque-speed capability. Finite element analysis is used to evaluate both the self-sensing capability and the torque-speed capability. Under the restricted specifications of dimensions and requirements, the 350 N·m-36 kW IPMSM is optimally designed for HEV applications. The validity of the proposed design method and the expected drive characteristics are experimentally verified by using the prototype.

Linearization of traveling-wave tube amplifiers using digitally supported signal injection technique

This paper presents a digitally supported signal injection technique for the intermodulation distortion terms (IMDs) resulting from the non-linearity of Traveling-wave tube amplifiers. It is shown that the state-of-the art analog techniques have inherent limitation due to the inaccuracy of analog components. The proposed technique provides more accurate cancellation of third-order IMD as compared to its analog counterpart. Moreover, it is shown that the presented technique can be easily extended to compensate for higher order IMDs simultaneously.

Novel Compensation Method to Reduce Rotor Position Estimation Error and Torque Reduction in Signal Injection Based PMSM Drives

High frequency signal injection techniques are widely used to extract rotor position information from low speed to stand still. Accuracy of estimated rotor position is decreased when stator winding resistance is neglected. Position estimation error also results in output Torque reduction. Parasitic resistance of stator winding causes significant position estimation error <br /> and Torque reduction, if not compensated. Signal injection techniques developed in the literature does not provide detailed analysis and compensation methods to improve rotor position estimation of PMS Motors, where stator winding resistance cannot be neglected. This work analyzes the stator winding resistance effect on position estimation accuracy and proposes novel compensation technique to reduce the position estimation error and torque reduction introduced by stator winding resistance. Prototype hardware of a self-sensing PMSM drive is developed. The effectiveness of the proposed method is verified with the MATLAB/Simulink simulations and experimental results on a prototype self-sensing PMSM drive.

Saliency-Based Position Estimation of Permanent-Magnet Synchronous Machines Using Square-Wave Voltage Injection With a Single Current Sensor

This paper presents a saliency-based position sensorless drive of permanent-magnet (PM) machines using a single current sensor for cost-effective applications. For the single current sensor system, the dc-link current is measured for the reconstruction of three-phase currents. The phase current reconstruction can only be realized when active voltages are applied. This limitation results in six immeasurable areas for the current reconstruction using the pulsewidth modulation. In order to implement the saliency-based sensorless drive, a square-wave voltage is injected to minimize the harmonics of reconstructed saliency current for the rotor position estimation. By injecting a square-wave voltage on the direction of the rotor $d$ -axis, the injection voltage vector is nearly perpendicular to the fundamental voltage vector at low speed. The saliency reflected current or the fundamental current can be separately reconstructed by the dc-link current, leading to the reduced reconstruction errors and improved sensorless performance. By using the proposed signal injection technique on a single sensor system, the saliency-based sensorless drive can work on an interior PM machine with a salient ratio of $L_{q}/L_{d} = 1.35$ at 1% rated speed (60/6000 r/min) under full torque load based on the experimental evaluation.

FPGA Implementation of a Hybrid Sensorless Control of SMPMSM in the Whole Speed Range

This paper presents an FPGA-based (Field Programmable Gate Array) sensorless controller for Surface Mounted Permanent Magnet Synchronous Machines (SMPMSM). A hybrid sensorless controller combining the signal injection technique and a linearly compensated flux observer is proposed. Using a Delta-Sigma A/D converter and FPGA oversampling technique, this work realizes a high performance high frequency (HF) injection sensorless control method which needs lower HF current response and introduces lower acoustic noises. The linearly compensated flux observer, based on back electromotive force (EMF) is used for sensorless control in the high speed range. The flux observer exhibits high dynamic and steady-state performance and is robust to parameter variation. Using model-based design, with the tools of MATLAB/Simulink and Simulink HDL (hardware description language) Coder, the whole control system is designed and implemented in a single chip. Experimental results demonstrate that the developed sensorless controller has high performance in the whole speed range.

High-Frequency-Injection-Assisted “Active-Flux”-Based Sensorless Vector Control of Reluctance Synchronous Motors, With Experiments From Zero Speed

This paper presents a hybrid motion sensorless control of an axially laminated anisotropic reluctance synchronous machine (RSM). The zero- and low-speed sensorless method is a saliency-based high-frequency signal injection technique that uses the motor itself as a resolver. The second method is based on a state observer incorporating the “active-flux” concept used to deliver RSM rotor position and speed information for medium- and high-speed range. Even if both methods perform successfully in separate speed regions, estimation of the two algorithms is combined as a sensor fusion to improve the performance at zero and very low speeds. Experimental results validate the proposed control strategies.