IEEE Power Engineering Society. 1999 Winter Meeting (Cat. No.99CH36233), 1999
Investigations into the effects of PWM techniques on common mode voltage for inverter-controlled ... more Investigations into the effects of PWM techniques on common mode voltage for inverter-controlled induction motor drives is presented. It is demonstrated by theoretical analysis and confirmed by experimental results that the zero switching states of inverter control invoke larger common mode voltage in comparison with the nonzero switching states of inverter control. New inverter control techniques without using zero voltage
We report the freshwater heteronemertean Apatronemertes albimaculosa Wilfert & Gibson, 1974 for t... more We report the freshwater heteronemertean Apatronemertes albimaculosa Wilfert & Gibson, 1974 for the first time from Taiwan based on specimens collected under stones and rocks on gravelly bottom near the shore of a brook in Nantun District, Taichung City. Species identification was corroborated by mitochondrial cytochrome c oxidase subunit I gene sequences. The species had been reported from aquaria with tropical freshwater plants in Germany, Austria, USA, Spain, and Japan, before it was discovered from wild environment in Panama. Our report represents the second instance of field-caught A. albimaculosa in the world.
2016 IEEE International Conference on Industrial Technology (ICIT), 2016
The purpose of this paper is to present a new predictive current control method for three-phase A... more The purpose of this paper is to present a new predictive current control method for three-phase AC/DC converters. The special features of the proposed predictive current control method include no need of converter model in prior and reduction of calculation time required for control. Since the proposed control method is modeless predictive control, the parameter variation will not affect the control performance as compared to model-based control approaches. Both simulation and experimental results will be presented to confirm the effectiveness of the proposed modeless predictive current control method. Experimental results are derived from a DSP-based three-phase AC/DC converter with the following specifications: the output voltage = 380 V, input voltage = 220 V/AC, and output power = 1000 W. The measured harmonics results are shown to meet IEC61000-3-2 Class A standard.
IECON 2014 - 40th Annual Conference of the IEEE Industrial Electronics Society, 2014
A new open loop control technique of boost converter to mitigate the temperature effect on curren... more 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.
Conference of the Industrial Electronics Society, Nov 2, 2004
Page 1. the 30th Annual Conference of Ihe IEEE Industrial Electronics Soclety, November 2 - 6,200... more Page 1. the 30th Annual Conference of Ihe IEEE Industrial Electronics Soclety, November 2 - 6,2004, Busan, Korea Design of an Integrated Circuit of PWM Controller for Three-phase Inverter Yen-Shin Lai, Senior Member, iEEE Wei-Hwa Rao Dept. of Electrical Eng. ...
This paper presents a new back-EMF detection technique which provides wide range control for brus... more This paper presents a new back-EMF detection technique which provides wide range control for brushless DC motor (BLDCM) drives. As compared with previous techniques which can be used either for low duty-ratio control or for high duty-ratio control only, the proposed technique deals with the above-mentioned problem to give both low and high duty-ratio control while not invoking any position
2007 7th Internatonal Conference on Power Electronics, 2007
This paper presents a novel method to reduce the current ripple caused by the variation of induct... more This paper presents a novel method to reduce the current ripple caused by the variation of inductor for a DC/DC converter. The presented method is to increase the switching frequency to keep constant current ripple when the inductance changes. Therefore, no extra component is required. The problem will be described first and the related method is presented. An experimental DC/DC converter is implemented which is with input voltage of 12 V, output voltage of 1.5 V, output current of 10 A, and switching frequency of 200-250 kHz. Finally, experimental results derived from the designed digital-controlled DC/DC converter are included for confirmation.
2014 IEEE 23rd International Symposium on Industrial Electronics (ISIE), 2014
The main theme of this paper is to present the laboratory course design for magnetic components l... more The main theme of this paper is to present the laboratory course design for magnetic components learning and hands-on. These magnetic components which are widely used in power conversion applications include inductor, drive transformer, and transformer with and without center-tapped windings for power conversion. The designed course is based upon modular concept and these modules include forward converter module for inductor and transformer with center-tapped winding, flyback converter module for transformer with air-gap acting as inductor and transformer, push-pull converter module for transformer with center-tapped winding and full-bridge converter module for drive transformer. The specifications for all modules are the same and the designed modular course has been applied to R and D Master Program sponsored by the industry. As acknowledged by the students, the designed modular course provides practical training and covers the wide range of magnetic components in power conversion applications.
Conference Record of the 2004 IEEE Industry Applications Conference, 2004. 39th IAS Annual Meeting.
This work presents a novel detection technique of initial position for three-phase brushless DC m... more This work presents a novel detection technique of initial position for three-phase brushless DC motor (BLDCM), which doesn't require any current and voltage sensors, and thereby significantly reducing the cost. The fundamental principle of the technique is to determine the initial position of permanent magnet by the difference of falling times of unexcited stator windings. As compared to previous research result Y.S. Lai et al., (2003), the error caused by the nonsaturation effect of excited windings can be avoided. Therefore the accuracy can be significantly improved. Experimental results derived from an FPGA-based control system will be presented to demonstrate the feasibility of the presented technique.
8th International Conference on Power Electronics - ECCE Asia, 2011
The main theme of this paper is to study the current sensing methods for standby power reduction ... more The main theme of this paper is to study the current sensing methods for standby power reduction control of digital-controlled DC/DC converter. These methods include using transformer of full-bridge converter, coupling inductor and ORing MOSFET. The most suitable sensing method was verified with a digital-controlled 500W class DC/DC converter (input/output voltage: 400V/12V). Experimental results derived from digital-controlled DC/DC converter using the TI DSP (TMS320F2812) as the control platform show that current sensed by voltage across ORing MOSFET method provides superb solution. This method offers linear relationship between output voltage of sensing circuit and load current while not causing response delay under standby conditions and thereby truly reflecting accurate standby conditions.
ABSTRACT The paper contributes to the presentation of a compensation technique for brushless DC m... more ABSTRACT The paper contributes to the presentation of a compensation technique for brushless DC motor drives. The presented technique overcomes the time delay issue caused by the time constant of stator windings of brushless DC motor. The time delay issue results in phase shift between back-EMF and phase current; and thereby reducing the output torque and efficiency. The basic idea for the presented technique is to shift the commutation instant forward such that the back-EMF and the current can be in phase even under the influence of time delay caused by stator windings. It will be shown that no current sensor is required for the presented torque compensation technique. Comparison results derived from experimental system with and without torque compensation technique are presented to support our claims. It will be shown that the presented technique increases efficiency in the whole output range.
2007 IEEE Industry Applications Annual Meeting, 2007
The purpose of this paper is to present AC driver and protection circuits of Light Emitting Diode... more The purpose of this paper is to present AC driver and protection circuits of Light Emitting Diodes. For the presented circuits, AC power source can be applied to drive LED without further conversion stage and the circuits provide failure indication and protection. The presented system consists of a full-bridge LED modules, power device and control circuit for dimming control and
2011 IEEE Energy Conversion Congress and Exposition, 2011
A PWM technique for three-phase inverter current reconstruction using only one current sensor is ... more A PWM technique for three-phase inverter current reconstruction using only one current sensor is presented. As compared to previous work, the proposed technique not only can extend the current reconstruction range, but also decrease the common mode voltage of inverter output. Moreover, the theoretical analysis for the limitation to current reconstruction using only one current sensor is included in this paper. It will be shown that reduction of PWM switching frequency and acquisition time of AD conversion will extend the current reconstruction range for a given PWM technique. Experimental results derived from an FPGA-based controlled inverter show that using the presented PWM technique the three-phase current signals of inverter can be reconstructed even under very low modulation index range while reducing the common-mode noise of inverter output.
2013 1st International Future Energy Electronics Conference (IFEEC), 2013
The main theme of this paper is to propose a self-commissioning method for digital-controlled pow... more The main theme of this paper is to propose a self-commissioning method for digital-controlled power factor corrector. The power factor corrector is with critical current mode control in order to reduce the reverse recovery loss of diode. Moreover, two-phase interleaved control is used for the power factor corrector to reduce the output current ripple and the value of output capacitor. For a given specifications, including bandwidth and phase margin, the controller parameters are derived by the identified inductance, capacitance and look up table. The identification of PFC inductance and capacitance, and calculation of controller parameters are realized before the system start up. It is no need to know the circuit parameters in prior, the controller parameters can be derived by the presented self-commissioning technique. This proposed technique is therefore very promising to solving the circuit component variation issue which will result in the change of digital controller. The specifications of the front-end PFC converter include: AC input voltage = 178 V to 264 V/ 50 Hz, DC output voltage = 400 V and output current = 1.3 A. Experimental results will fully confirm the effectiveness of the proposed self-commissioning technique.
Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344)
ABSTRACT It is well known that small power brushless DC motor (BLDCM) drives have been widely app... more ABSTRACT It is well known that small power brushless DC motor (BLDCM) drives have been widely applied to the information technology industry, especially for fan and spindle applications. For small power applications of BLDCM drives, due to the use of battery and limited space for heat dissipation, reduction of power consumption is one of the main concerns for the development of pulse-width modulation (PWM) technique. This paper presents a novel PWM technique for small power BLDCM drives, which significantly reduces the conduction losses, and thereby dramatically reducing the heat dissipation. Comparative results with conventional PWM technique are fully explored to highlight the advantages of the presented novel technique. Experimental results derived from an FPGA-based spindle drive are presented to confirm the theoretical analysis.
SUMMARYSeasonal life cycle of body cavity dwelling (BCD) Philometra ovata (Nematoda: Philometrida... more SUMMARYSeasonal life cycle of body cavity dwelling (BCD) Philometra ovata (Nematoda: Philometridae) has been reported in southern and central European countries, but its swim bladder dwelling (SBD) stage and northern populations have remained unstudied. In this study, we investigated the seasonal life cycle and infection ecology of P. ovata in both swim bladder and body cavity in the European minnow (Phoxinus phoxinus) in Finland. The larval P. ovata infected the swim bladder of minnows mainly in August. Female SBD P. ovata emigrated to body cavity mostly in September, grew to their full size by the end of the next June, and evacuated from minnows in July. In addition, female SBD P. ovata retarding their development and staying in swim bladder were found commonly in minnows, thus the mean monthly prevalence (6·7 ± 3·9%) and mean intensity (1·4 ± 0·8) of BCD P. ovata was lower than that of SBD P. ovata (37·8 ± 15·1% and 2·0 ± 1·5, respectively). Finally, despite the large size of BCD...
IEEE Power Engineering Society. 1999 Winter Meeting (Cat. No.99CH36233), 1999
Investigations into the effects of PWM techniques on common mode voltage for inverter-controlled ... more Investigations into the effects of PWM techniques on common mode voltage for inverter-controlled induction motor drives is presented. It is demonstrated by theoretical analysis and confirmed by experimental results that the zero switching states of inverter control invoke larger common mode voltage in comparison with the nonzero switching states of inverter control. New inverter control techniques without using zero voltage
We report the freshwater heteronemertean Apatronemertes albimaculosa Wilfert & Gibson, 1974 for t... more We report the freshwater heteronemertean Apatronemertes albimaculosa Wilfert & Gibson, 1974 for the first time from Taiwan based on specimens collected under stones and rocks on gravelly bottom near the shore of a brook in Nantun District, Taichung City. Species identification was corroborated by mitochondrial cytochrome c oxidase subunit I gene sequences. The species had been reported from aquaria with tropical freshwater plants in Germany, Austria, USA, Spain, and Japan, before it was discovered from wild environment in Panama. Our report represents the second instance of field-caught A. albimaculosa in the world.
2016 IEEE International Conference on Industrial Technology (ICIT), 2016
The purpose of this paper is to present a new predictive current control method for three-phase A... more The purpose of this paper is to present a new predictive current control method for three-phase AC/DC converters. The special features of the proposed predictive current control method include no need of converter model in prior and reduction of calculation time required for control. Since the proposed control method is modeless predictive control, the parameter variation will not affect the control performance as compared to model-based control approaches. Both simulation and experimental results will be presented to confirm the effectiveness of the proposed modeless predictive current control method. Experimental results are derived from a DSP-based three-phase AC/DC converter with the following specifications: the output voltage = 380 V, input voltage = 220 V/AC, and output power = 1000 W. The measured harmonics results are shown to meet IEC61000-3-2 Class A standard.
IECON 2014 - 40th Annual Conference of the IEEE Industrial Electronics Society, 2014
A new open loop control technique of boost converter to mitigate the temperature effect on curren... more 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.
Conference of the Industrial Electronics Society, Nov 2, 2004
Page 1. the 30th Annual Conference of Ihe IEEE Industrial Electronics Soclety, November 2 - 6,200... more Page 1. the 30th Annual Conference of Ihe IEEE Industrial Electronics Soclety, November 2 - 6,2004, Busan, Korea Design of an Integrated Circuit of PWM Controller for Three-phase Inverter Yen-Shin Lai, Senior Member, iEEE Wei-Hwa Rao Dept. of Electrical Eng. ...
This paper presents a new back-EMF detection technique which provides wide range control for brus... more This paper presents a new back-EMF detection technique which provides wide range control for brushless DC motor (BLDCM) drives. As compared with previous techniques which can be used either for low duty-ratio control or for high duty-ratio control only, the proposed technique deals with the above-mentioned problem to give both low and high duty-ratio control while not invoking any position
2007 7th Internatonal Conference on Power Electronics, 2007
This paper presents a novel method to reduce the current ripple caused by the variation of induct... more This paper presents a novel method to reduce the current ripple caused by the variation of inductor for a DC/DC converter. The presented method is to increase the switching frequency to keep constant current ripple when the inductance changes. Therefore, no extra component is required. The problem will be described first and the related method is presented. An experimental DC/DC converter is implemented which is with input voltage of 12 V, output voltage of 1.5 V, output current of 10 A, and switching frequency of 200-250 kHz. Finally, experimental results derived from the designed digital-controlled DC/DC converter are included for confirmation.
2014 IEEE 23rd International Symposium on Industrial Electronics (ISIE), 2014
The main theme of this paper is to present the laboratory course design for magnetic components l... more The main theme of this paper is to present the laboratory course design for magnetic components learning and hands-on. These magnetic components which are widely used in power conversion applications include inductor, drive transformer, and transformer with and without center-tapped windings for power conversion. The designed course is based upon modular concept and these modules include forward converter module for inductor and transformer with center-tapped winding, flyback converter module for transformer with air-gap acting as inductor and transformer, push-pull converter module for transformer with center-tapped winding and full-bridge converter module for drive transformer. The specifications for all modules are the same and the designed modular course has been applied to R and D Master Program sponsored by the industry. As acknowledged by the students, the designed modular course provides practical training and covers the wide range of magnetic components in power conversion applications.
Conference Record of the 2004 IEEE Industry Applications Conference, 2004. 39th IAS Annual Meeting.
This work presents a novel detection technique of initial position for three-phase brushless DC m... more This work presents a novel detection technique of initial position for three-phase brushless DC motor (BLDCM), which doesn't require any current and voltage sensors, and thereby significantly reducing the cost. The fundamental principle of the technique is to determine the initial position of permanent magnet by the difference of falling times of unexcited stator windings. As compared to previous research result Y.S. Lai et al., (2003), the error caused by the nonsaturation effect of excited windings can be avoided. Therefore the accuracy can be significantly improved. Experimental results derived from an FPGA-based control system will be presented to demonstrate the feasibility of the presented technique.
8th International Conference on Power Electronics - ECCE Asia, 2011
The main theme of this paper is to study the current sensing methods for standby power reduction ... more The main theme of this paper is to study the current sensing methods for standby power reduction control of digital-controlled DC/DC converter. These methods include using transformer of full-bridge converter, coupling inductor and ORing MOSFET. The most suitable sensing method was verified with a digital-controlled 500W class DC/DC converter (input/output voltage: 400V/12V). Experimental results derived from digital-controlled DC/DC converter using the TI DSP (TMS320F2812) as the control platform show that current sensed by voltage across ORing MOSFET method provides superb solution. This method offers linear relationship between output voltage of sensing circuit and load current while not causing response delay under standby conditions and thereby truly reflecting accurate standby conditions.
ABSTRACT The paper contributes to the presentation of a compensation technique for brushless DC m... more ABSTRACT The paper contributes to the presentation of a compensation technique for brushless DC motor drives. The presented technique overcomes the time delay issue caused by the time constant of stator windings of brushless DC motor. The time delay issue results in phase shift between back-EMF and phase current; and thereby reducing the output torque and efficiency. The basic idea for the presented technique is to shift the commutation instant forward such that the back-EMF and the current can be in phase even under the influence of time delay caused by stator windings. It will be shown that no current sensor is required for the presented torque compensation technique. Comparison results derived from experimental system with and without torque compensation technique are presented to support our claims. It will be shown that the presented technique increases efficiency in the whole output range.
2007 IEEE Industry Applications Annual Meeting, 2007
The purpose of this paper is to present AC driver and protection circuits of Light Emitting Diode... more The purpose of this paper is to present AC driver and protection circuits of Light Emitting Diodes. For the presented circuits, AC power source can be applied to drive LED without further conversion stage and the circuits provide failure indication and protection. The presented system consists of a full-bridge LED modules, power device and control circuit for dimming control and
2011 IEEE Energy Conversion Congress and Exposition, 2011
A PWM technique for three-phase inverter current reconstruction using only one current sensor is ... more A PWM technique for three-phase inverter current reconstruction using only one current sensor is presented. As compared to previous work, the proposed technique not only can extend the current reconstruction range, but also decrease the common mode voltage of inverter output. Moreover, the theoretical analysis for the limitation to current reconstruction using only one current sensor is included in this paper. It will be shown that reduction of PWM switching frequency and acquisition time of AD conversion will extend the current reconstruction range for a given PWM technique. Experimental results derived from an FPGA-based controlled inverter show that using the presented PWM technique the three-phase current signals of inverter can be reconstructed even under very low modulation index range while reducing the common-mode noise of inverter output.
2013 1st International Future Energy Electronics Conference (IFEEC), 2013
The main theme of this paper is to propose a self-commissioning method for digital-controlled pow... more The main theme of this paper is to propose a self-commissioning method for digital-controlled power factor corrector. The power factor corrector is with critical current mode control in order to reduce the reverse recovery loss of diode. Moreover, two-phase interleaved control is used for the power factor corrector to reduce the output current ripple and the value of output capacitor. For a given specifications, including bandwidth and phase margin, the controller parameters are derived by the identified inductance, capacitance and look up table. The identification of PFC inductance and capacitance, and calculation of controller parameters are realized before the system start up. It is no need to know the circuit parameters in prior, the controller parameters can be derived by the presented self-commissioning technique. This proposed technique is therefore very promising to solving the circuit component variation issue which will result in the change of digital controller. The specifications of the front-end PFC converter include: AC input voltage = 178 V to 264 V/ 50 Hz, DC output voltage = 400 V and output current = 1.3 A. Experimental results will fully confirm the effectiveness of the proposed self-commissioning technique.
Conference Record of the 2002 IEEE Industry Applications Conference. 37th IAS Annual Meeting (Cat. No.02CH37344)
ABSTRACT It is well known that small power brushless DC motor (BLDCM) drives have been widely app... more ABSTRACT It is well known that small power brushless DC motor (BLDCM) drives have been widely applied to the information technology industry, especially for fan and spindle applications. For small power applications of BLDCM drives, due to the use of battery and limited space for heat dissipation, reduction of power consumption is one of the main concerns for the development of pulse-width modulation (PWM) technique. This paper presents a novel PWM technique for small power BLDCM drives, which significantly reduces the conduction losses, and thereby dramatically reducing the heat dissipation. Comparative results with conventional PWM technique are fully explored to highlight the advantages of the presented novel technique. Experimental results derived from an FPGA-based spindle drive are presented to confirm the theoretical analysis.
SUMMARYSeasonal life cycle of body cavity dwelling (BCD) Philometra ovata (Nematoda: Philometrida... more SUMMARYSeasonal life cycle of body cavity dwelling (BCD) Philometra ovata (Nematoda: Philometridae) has been reported in southern and central European countries, but its swim bladder dwelling (SBD) stage and northern populations have remained unstudied. In this study, we investigated the seasonal life cycle and infection ecology of P. ovata in both swim bladder and body cavity in the European minnow (Phoxinus phoxinus) in Finland. The larval P. ovata infected the swim bladder of minnows mainly in August. Female SBD P. ovata emigrated to body cavity mostly in September, grew to their full size by the end of the next June, and evacuated from minnows in July. In addition, female SBD P. ovata retarding their development and staying in swim bladder were found commonly in minnows, thus the mean monthly prevalence (6·7 ± 3·9%) and mean intensity (1·4 ± 0·8) of BCD P. ovata was lower than that of SBD P. ovata (37·8 ± 15·1% and 2·0 ± 1·5, respectively). Finally, despite the large size of BCD...
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