A new ECE model is proposed to reflect the tolerance of manufacturing and material, etc. The proposed new ECE model is developed by combining the ECE model derived from ANSYS in the motor design (original ECE model) and calibration of flux linkage and inductor parameters from real motor test. The calibration of flux linkage and inductor parameters are carried out based upon back EMF coefficient calibration under no load condition and MTPA test with current excitation under zero, 45 degrees and 90 degrees. The former one is used to correct the flux without excitation current to the motor. The later one is used to consider the self- and mutual- cross-coupling inductances and saturation effect. The proposed method provides accurate results while not requiring intensive tests. The proposed new ECE model can be applied to motor drives control. A 60kW IPM motor with maximum speed of 13000 rpm is designed for verification. The results for the proposed new ECE model, original ECE model and real motor are presented. And the error for the original ECE model and real motor is reduce from 10% to 1% for using the proposed new ECE model. The improvement becomes more relevant under high speed application with field weakening control by considering the tolerance of manufacturing and material etc.

The proposed concept in this paper was composed of the prototype verification technologies from different fields, included numerical model, embedded software, and virtually physical test for the interior permanent magnet synchronous motor (IPMSM) drive systems. The proposed developmental framework is comprised of model-in-the-loop (MIL), software-in-the-loop (SIL), and hardware-in-the-loop (HIL) and achieves rapid prototype verification through the collaboration and coordination between each other. The MIL is based upon the IPMSM model, including motor parameters variable by magnet saturation and cross-coupling effects, under different operating conditions. As part of motor control software development, the SIL uses motor control modules that take non-linear motor parameters into account. The proposed speed-up modeling to HIL is based on the code generator function, which is popularly used for software development, which allows the hardware model in MIL to be quickly converted into program code and then performed in HIL. Similarly, the motor control modules from SIL can be converted into source code and implanted into the DSP based control board. Finally, the HIL platform will test with the DSP based control board to achieve rapid verification of motor control technology and improve the development cycle of motor drives. The proposed framework is validated by comparison with a 2 kW IPMSM system in which the motor control methods are implemented in DSP based inverter-fed drives. The experimental results present the deviation between the proposed rapid development framework and the actual IPMSM drives, the lower deviation up to 1.16 % under rated speed with half load condition. The results show the time-saving and cost reduction of the process for motor control technology development.

The purpose of this paper is to propose an efficiency improvement method for motor drives with DC-link voltage optimization control. A four-switch buck-boost DC/DC converter is used for DC-link voltage regulation in front of the inverter to provide regulated voltage. The advantages of bidirectional buck-boost converter include providing wider voltage regulation range and energy recovery capability. The proposed method is developed based upon the minimization of Total Harmonic Distortion of motor current and tuning the DC-link voltage on-line adaptively. Neither motor parameter nor look-up table is required.Experimental results for permanent-magnet synchronous motor drives are presented to validate the effectiveness of the proposed method. The overall efficiency improvement of motor drives with buck-boost converter can go up to 23.55% under low speed as compared with that without DC-link voltage regulation and buck-boost converter for the proposed DC-link voltage optimization method.

The main theme of this paper is to propose an online parameter identification and self-commissioning of current controller for servo motor drives as time delay is taken into consideration. The advantages of considering time delay include increase of current controller bandwidth and easy to achieve delay compensation. The electrical parameters and time delay required for self-commissioning of current controller are identified on-line through injecting signal and real-time Fast Fourier Transform (FFT) under standstill. The current controller gains are determined based upon the magnitude optimal method as the delay is considered while retaining the maximum phase margin. The experimental results will be shown, which are derived from DSP-controlled PMSM servo drives. With the proposed parameter identification method, in which time delay identification is included, the measured bandwidth of current loop is improved as compared with that without such consideration. These results confirm the effectiveness and claims of the proposed method.

The main theme of this paper is to propose a novel switching control method for bridgeless PFC converter to improve the efficiency by reducing both switching and conduction losses. Comparing to the conventional method, the power device is always on (no switching loss) to provide a current path via the turn-on resistor of MOSFET to reduce conduction losses under light load condition. As the load increases, the power device is always off (no switching loss) to provide a current path via the body diode of MOSFET to reduce conduction losses under heavy load condition. In this paper, both simulation and experimental results will be shown to confirm the effectiveness of the proposed switching control method. Test results derived from a digital-controlled 1.2 kW PFC show the efficiency improvement can go up to 0.73% and 0.57% under full load and light load conditions, respectively. It will also be confirmed this efficiency improvement has no impact on the power factor and just simply changing the switching control method. Both measured steady state and transient waveforms will be shown for confirmation.

The objective of this paper is to present a new hybrid predictive current-mode control for power factor corrector with on-line parameter tuning. The proposed method can effectively solve the problems caused by inductance variation due to manufacturing tolerances, load current, magnetic intensity and temperature etc. for the power factor corrector with hybrid predictive current-mode control. The inductance variation may result in the predicted duty error and conduction mode switching error. Analysis of predicted duty error and conduction mode switching error contributed by the inductance variation for hybrid predictive current-mode control will be presented. The conduction mode switching error and duty error will deteriorate the power rating and reduce the efficiency. An on-line inductance tuning method for the power factor corrector with hybrid predictive current-mode control will be proposed in this paper. And this tuned parameter is used to correct the predicted duty error. The specifications of the converter include: input voltage 100 V/60 Hz, output voltage 380 VDC, output power 760 W, switching frequency 65 kHz. The control software is developed and verified using a microprocessor, TMS320F28335. Details of the controller design, simulation and experimental results are presented to fully support the theoretical analysis and validate the proposed method.

An efficiency improvement method for two-stage server power by auto-tuning of bus voltage based upon new on-line switching frequency tracking technique is presented in this paper. The basic idea is to let the switching frequency to track the resonant frequency of converter to either reduce the turn-off losses or circulating losses of converter, and thereby improving the efficiency. The proposed on-line switching frequency tracking technique includes resonant frequency detection and DC-bus voltage tuning. A digital-controlled power factor correction and full bridge series LLC resonant converter are build up for test and confirmation. The designed and implemented 540 W/12V server power is with AC input voltage of 115/230 V. It will be shown by the test results that frequency tracking can be well achieved and the efficiency can be improved from 20% load to 100% load. The effectiveness of the proposed control method is fully supported by these measured results.

A new open loop control technique of boost converter to mitigate the temperature effect on current control of LED driver will be presented. The presented open loop control technique achieves zero voltage turn on in order to significantly reduce the reverse recovery loss of diode and mitigates the temperature impact on the constant current control. The basic idea of the presented control technique is to on-line calculate the on-time of power device as input voltage changes and then tune the off-time to achieve zero voltage switching even with temperature variation. Experimental results derived from a digital-controlled boost converter for LED driver will be presented. The specifications include: input voltage = 15 V and output current is 280 mA. Experimental results show the current can be retained even though the temperature of LED varies using the proposed open loop control technique.

The paper presents infinite speed drives with both maximum torque per amp control and maximum torque per volt control for interior permanent magnet synchronous motor. The presented method controls infinite speed drives MTPA before flux weakening occurs. As the speed goes up further to flux weakening region II, maximum torque per volt control is achieved to give more output torque. Moreover, smooth and automatic transition among constant torque control with MTPA, flux weakening control in region I and flux weakening with MTPV control in region II are achieved by the presented control method. All of these control approaches are under vector control. Experimental results are derived from a DSP-based controlled infinite speed drives. The specifications of the IPMSM include 750 W, 3000 rpm and 4 poles. Experimental results show the presented control method can achieve both MTPA and MTPV control to fully support the theoretical development.

This paper proposes a new voltage trajectory control for vector-controlled induction motor drives to achieve six-step operation in order to fully utilize the DC-link voltage. Based upon vector-controlled method, additional blocks for the presented method include field weakening control block and voltage command boost block. The special features for the proposed method include: not requiring look-up-table, reducing parameter sensitivity, and no need to freeze the current controllers and over boost voltage command. Moreover, the voltage moves along the hexagon trajectory of space vector of voltage and even achieves six-step operation such that the DC-link voltage can be fully utilized. Experimental and simulation results will be presented to fully support the claims.

PWM techniques for full-bridge DC/DC converter are investigated and a new multi-dimension random PWM technique is proposed in this paper. Three PWM techniques with constant switching frequency are discussed and the related random PWM techniques are which spread the harmonic clusters and give constant average inductor current to reduce the output voltage ripple are discussed. The pros and cons of three constant switching frequency PWM techniques and the related random counterparts are investigated. Experimental results show there is significant efficiency drop of the random PWM technique due to significant increase of switching counts. Therefore, this paper presents a two-dimensional random PWM technique to significantly reduce the harmonic intensity while not causing relevant impact on the efficiency. An FPGA-based digital controlled isolated full-bridge DC/DC converter prototype is built to verify the performance of conventional and proposed PWM techniques. The specifications of the converter include: input voltage = 400 V, output voltage = 12 V, output power = 120 W and switching frequency = 100 kHz. Measured efficiency and Harmonic Spread Factor will be used for the evaluation of these PWM techniques.

The main theme of this paper is to propose a novel on-line maximum duty point tracking technique to improve the efficiency of the server power. The server power consists of PFC and phase-shift full-bridge converter. The proposed MDPT technique controls the DC-link bus voltage of power factor corrector (PFC) to retain maximum duty ratio of phase-shift full-bridge converter. It will be shown that the efficiency can therefore be improved significantly and meet the 80 plus Gold code. Experimental system using TI DSP (TMS320F2812) as the control platform has been set up. The specifications of the server power supply include: AC input voltage = 110 / 220 V, DC output voltage = 12 V and output power = 480W. Experimental results show that the efficiency can be improved from light load to full load conditions. It will be shown that the efficiency can therefore be improved up to 2.3% to meet the 80 PLUS Gold code. These results confirm the effectiveness of the proposed maximum duty point tracking technique.

One of the advantages of power factor corrector with boundary current mode control is the reduction of reversal recovery loss of diode. This paper proposes a family of predictive methods adapted to digital pulse-width modulations for digital-controlled PFC operated under boundary current mode. The DPWM methods include leading-edge modulation, trailing-edge modulation and triangular modulation. For the proposed control method, the switching period retaining zero current switching is predicted and the turn-on period is determined by the voltage controller. Therefore, neither zero-current detection nor high-frequency A/D converter for current sampling is required for the proposed control method.proposed control method. Experimental results derived from a DSP-based controller are presented for confirmation. The power factor corrector is with 250 W power rating, 100 V/AC/50 Hz input, and 385 V/DC output. Experimental results demonstrate the effectiveness of the proposed predictive digital-controlled PFC under boundary current mode control.