EPE Association: EPE 1991 - 03 - Session 1.3: INDUSTRY APPLICATIONS

EPE 1991 - 03 - Session 1.3: INDUSTRY APPLICATIONS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 03 - Session 1.3: INDUSTRY APPLICATIONS

   [return to parent folder]

   A CONCEPT OF DECENTRALIZED POWER CONDITIONING FOR ROBOTS
By Albert Esser; Hans-Christoph Skudelny [View]
[Download]

Abstract: For the movement of robot arms electric drives employing permanent magnet synchronous motors are increasingly used, because they offer a lot of advantages due to the DC-Motors. At present the power conditioning is performed in a converter cabinet near the robot while the drive motors are located in the robot arm. The necessary wiring is inconvenient in some respects. In our concept the wiring is completly replaced with a middle frequency power bus without any movable parts. Rotatable transformers in the robot joints transfer the energy without any restriction to the motion of the arm. Decentralized power converters transfer the fixed voltage fixed frequency of the bus into variable voltage variable frequency for the drive motors. Experimental results obtained from a test setup of some ten kilowatts are presented.

   QUICK RESPONSE AND LOW-DISTORTION CURRENT CONTROL FOR MULTIPLE INVERTER-FED INDUCTION MOTOR DRIVES
By M. Hombu; T. Ikimi; A. Ueda; N. Kawakami; J. Takahashi; K. Kamiyama [View]
[Download]

Abstract: This paper describes a PWM control method to balance two unit inverter currents and to reduce the distortion of motor currents in a multiple GTO inverter for large capacity ac variable-speed drive systems. For an 11-kW induction motor driven by a 15-kVA multiple inverter, the imbalance current can be reduced to less than 5 % of the rated motor current and the motor current waveform can be made very close to sinusoidal. The GTO switching frequency in the multiple inverter can be lowered to a quarter of that in the single inverter. In a 2750-kVA GTO inverter drive system which was developed based on the 15-kVA multiple inverter, excellent performance is obtained including unity power factor operation at an ac power source, smooth 4-quadrant operation and quick speed response of 87 rad/s. The quick response is realized by field oriented control with decoupling control between torque and exciting currents, and direct control of three-phase ac currents. In the future, the multiple GTO inverter is expected to be applied to rolling mill drives instead of cycloconverters.

   PWM FREQUENCY CONVERTERS IN THE METAL INDUSTRY
By R. A. Timmer [View]
[Download]

Abstract: Using GTOs and microprocessor based control algorithms voltage source PWM frequency converters of up to 10000 kVA have been developed that can succesfully meet the requirements set by the metal industry. This paper describes the design and application of sectional drives for processing lines in the metal industry. First design and control of present day PWM frequency converters are examined. This is followed by a description of common DC bus system drives. Attention is paid to the communication of frequency converters with higher level automation systems. Practical examples serve to illustrate the application of PWM frequency converters in the metal industry. These include a galvanizing line consisting of 35 sections at the steel mill of Rautaruukki in Hämeenlinna, Finland, and an annealing and pickling line at the steel mill of Outokumpu in Tornio, Finland.

   IMPROVEMENTS ON A DISTRIBUTED CONTROL SYSTEM FOR CONTINUOUS ROLLING MILLS
By A.I. Rais; C. Urbani; P. F. Cappellari [View]
[Download]

Abstract: This paper presents a microprocessor based distributed control system for the control of continuous rolling mills, which is under development at the SCE Elettronica. The controller is of the master and slave type. The task of the master unit is to transmit the cascade reference values for the slave units. These are direct drive control units with on board microcontrollers. They have the task of controlling either motor velocity or material tension or loop height. The aim was to create a versatile system which is easy to compose and applicable to different plants. In this paper a scheme for the communication protocol via a single loop is described, as well as a tension control system.

   PARALLEL OPERATION OF VOLTAGE SOURCE INVERTERS BY REAL-TIME DIGITAL PWM CONTROL
By Y. H. Chung; S. S . Kim; H. J. Cha; M. G. Kang; S. K. Sul [View]
[Download]

Abstract: This paper proposes a new control method for parallel operation of voltage source inverters by using real-time digital PWM control. Each inverter is controlled by measuring only two variables of common output voltage and its own load current while minimizing the circulating currents between inverters. Load sharing between inverters is obtained by instantaneous control of the respective inverter current. In the proposed control, digital signal processor (DSP) carries out the real-time calculation of the inverter pulse-width for the next sampling time whereby the maximum pulse-width is obtained. Also a robustness to the system parameter variation is obtained by employing an additional PI controller. The proposed control algorithm is verified through the computer simulation and experiment in various cases such as the non-linear load and the short circuit conditions.

   MICROPROCESSOR BASED CONTROL SYSTEM FOR ROLLING MILLS
By A. Pollmann; A. Tosetto; P. Brea [View]
[Download]

Abstract: A microprocessor-based distributed control system is presented showing the advantages as compared to concentrated control units and/or analog solutions in process control. A powerful optical fiber communication link enables data exchange in real time between the control units and enables overall process sampling time in less than 5 rnsec. Using microprocessors, the advantage of digital control techniques and signal processing can be applied to continuous process control: autotuning and troubleshooting facilities and a parametrized block architecture enable short commissioning times . A menu-guided man-machine interface allows an user friendly parameter adjustment and data handling. Results of the system -installed in two rolling mills (one for profiles and the second for round bars) - are reported.

EPE 1991 - 03 - Session 1.3: INDUSTRY APPLICATIONS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 03 - Session 1.3: INDUSTRY APPLICATIONS
	[return to parent folder]

	A CONCEPT OF DECENTRALIZED POWER CONDITIONING FOR ROBOTS By Albert Esser; Hans-Christoph Skudelny	[View] [Download]
Abstract: For the movement of robot arms electric drives employing permanent magnet synchronous motors are increasingly used, because they offer a lot of advantages due to the DC-Motors. At present the power conditioning is performed in a converter cabinet near the robot while the drive motors are located in the robot arm. The necessary wiring is inconvenient in some respects. In our concept the wiring is completly replaced with a middle frequency power bus without any movable parts. Rotatable transformers in the robot joints transfer the energy without any restriction to the motion of the arm. Decentralized power converters transfer the fixed voltage fixed frequency of the bus into variable voltage variable frequency for the drive motors. Experimental results obtained from a test setup of some ten kilowatts are presented.

	QUICK RESPONSE AND LOW-DISTORTION CURRENT CONTROL FOR MULTIPLE INVERTER-FED INDUCTION MOTOR DRIVES By M. Hombu; T. Ikimi; A. Ueda; N. Kawakami; J. Takahashi; K. Kamiyama	[View] [Download]
Abstract: This paper describes a PWM control method to balance two unit inverter currents and to reduce the distortion of motor currents in a multiple GTO inverter for large capacity ac variable-speed drive systems. For an 11-kW induction motor driven by a 15-kVA multiple inverter, the imbalance current can be reduced to less than 5 % of the rated motor current and the motor current waveform can be made very close to sinusoidal. The GTO switching frequency in the multiple inverter can be lowered to a quarter of that in the single inverter. In a 2750-kVA GTO inverter drive system which was developed based on the 15-kVA multiple inverter, excellent performance is obtained including unity power factor operation at an ac power source, smooth 4-quadrant operation and quick speed response of 87 rad/s. The quick response is realized by field oriented control with decoupling control between torque and exciting currents, and direct control of three-phase ac currents. In the future, the multiple GTO inverter is expected to be applied to rolling mill drives instead of cycloconverters.

	PWM FREQUENCY CONVERTERS IN THE METAL INDUSTRY By R. A. Timmer	[View] [Download]
Abstract: Using GTOs and microprocessor based control algorithms voltage source PWM frequency converters of up to 10000 kVA have been developed that can succesfully meet the requirements set by the metal industry. This paper describes the design and application of sectional drives for processing lines in the metal industry. First design and control of present day PWM frequency converters are examined. This is followed by a description of common DC bus system drives. Attention is paid to the communication of frequency converters with higher level automation systems. Practical examples serve to illustrate the application of PWM frequency converters in the metal industry. These include a galvanizing line consisting of 35 sections at the steel mill of Rautaruukki in Hämeenlinna, Finland, and an annealing and pickling line at the steel mill of Outokumpu in Tornio, Finland.

	IMPROVEMENTS ON A DISTRIBUTED CONTROL SYSTEM FOR CONTINUOUS ROLLING MILLS By A.I. Rais; C. Urbani; P. F. Cappellari	[View] [Download]
Abstract: This paper presents a microprocessor based distributed control system for the control of continuous rolling mills, which is under development at the SCE Elettronica. The controller is of the master and slave type. The task of the master unit is to transmit the cascade reference values for the slave units. These are direct drive control units with on board microcontrollers. They have the task of controlling either motor velocity or material tension or loop height. The aim was to create a versatile system which is easy to compose and applicable to different plants. In this paper a scheme for the communication protocol via a single loop is described, as well as a tension control system.

	PARALLEL OPERATION OF VOLTAGE SOURCE INVERTERS BY REAL-TIME DIGITAL PWM CONTROL By Y. H. Chung; S. S . Kim; H. J. Cha; M. G. Kang; S. K. Sul	[View] [Download]
Abstract: This paper proposes a new control method for parallel operation of voltage source inverters by using real-time digital PWM control. Each inverter is controlled by measuring only two variables of common output voltage and its own load current while minimizing the circulating currents between inverters. Load sharing between inverters is obtained by instantaneous control of the respective inverter current. In the proposed control, digital signal processor (DSP) carries out the real-time calculation of the inverter pulse-width for the next sampling time whereby the maximum pulse-width is obtained. Also a robustness to the system parameter variation is obtained by employing an additional PI controller. The proposed control algorithm is verified through the computer simulation and experiment in various cases such as the non-linear load and the short circuit conditions.

	MICROPROCESSOR BASED CONTROL SYSTEM FOR ROLLING MILLS By A. Pollmann; A. Tosetto; P. Brea	[View] [Download]
Abstract: A microprocessor-based distributed control system is presented showing the advantages as compared to concentrated control units and/or analog solutions in process control. A powerful optical fiber communication link enables data exchange in real time between the control units and enables overall process sampling time in less than 5 rnsec. Using microprocessors, the advantage of digital control techniques and signal processing can be applied to continuous process control: autotuning and troubleshooting facilities and a parametrized block architecture enable short commissioning times . A menu-guided man-machine interface allows an user friendly parameter adjustment and data handling. Results of the system -installed in two rolling mills (one for profiles and the second for round bars) - are reported.