Rockwell Automation (Switzerland)

High-power pulsewidth-modulated inverters for medium-voltage applications operate at switching frequencies below 1 kHz to keep the dynamic losses of the power devices at a permitted level. Also, the sampling rate of the digital signal processing system is then low, which introduces considerable signal delays. These have adverse effects on the dynamics of the current control system and introduce undesired cross coupling between the current components i/sub d/ and i/sub q/. To overcome this problem, complex state variables are used to derive more accurate models of the machine and the inverter. From these, a novel current controller structure employing single-complex zeros is synthesized. Experimental results demonstrate that high dynamic performance and zero cross coupling is achieved even at very low switching frequency.

This article reviews investigations into reduced bearing life due to voltage source adjustable speed drive (ASD) AC motor operation. Relevant bearing failure mechanisms and indicators are discussed. dv/dt and electric discharge machining (EDM) contributions are discussed and experimental data presented showing the voltage levels on motor shafts when operating with ASDs. Finally, techniques to reduce shaft voltage are discussed, along with the electrical characteristics and interaction of system components. The example chosen is electrostatic shielded induction motors.

In development of low voltage switchgear, proper thermal design becomes more and more important to provide safe function and reliability in spite of miniaturization and increasing performance demanded of modern devices. Due to the high complexity of heat generation and loss processes it is not easy to predict the thermal behavior of devices under various load conditions, i.e., usually numerous tests are required. Rockwell Automation has started thermal simulations of contactors some time ago, and now is working on a three-dimensional (3-D) thermal model of a manual motor controller. This paper describes how to transform well known contact physics into an application oriented thermal simulation. Linking relations of mechanical engineering with contact physics, the influence of the applied tightening torque at the field wiring terminals on the thermal behavior of the device is considered, as well as the modeling of the contact area, taking into account switching arcs during breaking of various load currents. The simulation results are compared with infrared (IR) pictures and thermocouple measurements of existing devices to validate the theory and furthermore reflect its quality.

High-power PWM inverters for medium voltage applications operate at switching frequencies below 1 kHz to keep the dynamic losses of the power devices at permitted level. Also the sampling rate of the digital signal processing system is then low, which introduces considerable signal delays. These have adverse effects on the dynamics of the current control system and introduce undesired cross-coupling between the current components i/sub d/ and i/sub q/. To overcome this problem, complex state variables are used to derive more accurate models of the machine and the inverter. From these, a novel current controller structure employing single-complex zeroes is synthesized. Experimental results demonstrate that high dynamic performance and zero cross-coupling is achieved even at very low switching frequency.

The quality of thermal simulation results depends on the accuracy of both the modelled heat sources and heat sinks. Starting from an existing simplified thermal simulation model, This work describes further steps towards a more accurate representation of the heat sinks in a circuit breaker. Heat generated in switchgear can leave the system either along the metallic conducting path to the connecting wires or through the case to the surrounding air. The former simulation model accurately represented the heat generation and the thermal path along the metallic conductor. However, the path through the case was only summarized by convection coefficients on the metallic parts' surfaces. Due to the high performance requirements of modern breakers it is interesting to know not only the temperatures of the conducting parts but also the thermal impact on the plastic components supporting the conductors or providing essential functions. Therefore, the non-metallic parts of the circuit breaker (including the air within the device) are now part of the model. Consequently, the heat flux through the housing is a result of the simulation and not an estimated boundary condition any more. Moreover, conclusions can be drawn about the thermal stress of the plastic parts of the breaker.

The paper discusses the requirements put on simulation environments for agent-based manufacturing systems. Such a simulation environment should consist of the agent control part, the emulation part (emulating the physical controlled equipment), a run-time interface and a GUI. A Rockwell-specific universal run-time interface solution for PLC (programmable logic controller) is briefly described. The MAST simulation environment for material handling purposes designed and implemented in Java is presented. The main advantage of this environment is the fact it enables to re-use the simulation code in the real physical control.

In development of low voltage switchgear, proper thermal design becomes increasingly important to provide safe function and reliability in spite of the miniaturization and increasing performance demanded of modern devices. Due to the high complexity of heat generation and loss processes, it is not easy to predict the thermal behavior of devices under various load conditions, i.e. usually numerous tests are required. Rockwell Automation started thermal simulations of contactors some time ago, and is now working on a 3D thermal model of a manual motor controller. This paper describes how to transform well known contact physics into an application oriented thermal simulation. Linking relations of mechanical engineering with contact physics, the influence of the applied tightening torque at the field wiring terminals on the thermal behavior of the device is considered, as well as the modeling of the contact area, taking into account switching arcs during breaking of various load currents. The simulation results are compared with infrared (IR) pictures and thermocouple measurements of existing devices.

Integrated ship system control is a challenging domain as it involves a set of highly complex and interdependent systems, including electrical power, electric drive propulsion, high-energy weapon systems, various auxiliary systems, and an underlying communications network. Many of the high-level system management questions demanding answers for the electric ship power system and ship service are directly related to control system architecture. As we move toward more decentralized, hierarchical systems, much work remains to be done to optimally determine the appropriate level of control and intelligence at each tier of the architecture. The body of knowledge in this area is limited with respect to power systems and is only slightly more developed for ship service systems. There is a significant need not only to address methods and algorithms from the standpoint of pure decentralization but also to address ways to migrate these methods into an actual distributed, fault-tolerant supervisory control structure that meets the requirements for implementation on the electric ship.

In this paper, the design of switching modulators that provide gating signals to the semiconductor devices in a power electronics converter is addressed. Specifically, modulators for permanent magnet synchronous machine drives are considered. Both current source-based and voltage source-based modulators may be used in a current-regulated drive application. The choice of the class of modulator, the specific type of modulator, and the parameters of the modulator and control constitute a significant design problem. Performance metrics to assess the quality of a design are set forth. They are used in conjunction with a genetic algorithm to automatically select the class, type, and parameters of the modulator.

Abstract In oil and gas production, the multiphase flow rate is one of the most important measurements at the wellhead because it is essential for production allocation, flow assurance, and production surveillance. Multiphase flowmeter devices (MPFM) provide accurate measurements. However, this performance comes at high capital and operating costs that are not economically viable for all wells within aging or on mature fields. A real-time platform based on current technologies offers methods to deploy and automatically update the reduced-order models (ROM) to edge field devices. This approach is used specifically to provide a solution to estimate flow rates in real time at the field level, with and accuracy performance close to what the MPFM delivers, but at a reduced capital and operating costs. Edge field devices can provide the required computing power to run data-driven ROM models on the field side using neural network algorithms, trained to calculate well multiphase flow rate with acceptable accuracy. Periodic updates are performed on the data-driven models on the cloud, and the updated models are downloaded to the edge field device. In this way, the models based on neural networks, deployed and running at the edge field device level, are automatically adapted to changes of the well flow regime over the well's life cycle. An auto-trainable, machine-learning-based, multiphase estimated flow metering system running at the wellsite has been deployed and implemented. The system uses real-time and well test data, mathematical well models, neural-network-based data-driven models, which are automatically trained and updated on the cloud. The solution includes implementation in a real-time digital oil field automation system, which provides the technology platform required by this virtual flow metering system. The system offers a cost-effective way to obtain well flow rate measurement estimates with an acceptable accuracy. This virtual metering system can be used on hundreds or thousands of oil wells simultaneously using real-time data. The system provides oil and gas operators with good real-time flow metering estimates of their wells, accurate enough for production surveillance and allocation.

Wind turbine system boasts strong nonlinearity and coupling,and the disturbance from the wind is very strong. The model free adaptive control based on dynamically estimating the system's characteristic value was proposed to overcome the system's time-varying and nonlinearity by optimizing internal parameters. Its capacity of resisting disturbance outperforms that of PID and is more suitable for the nonlinear and strong coupling system. Comparing the control effect of the model-free adaptive pitch control with that of the PID control and then simulating it indicate that the model-free control can keep a constant power for the turbine generator better.

Electrical field and partial discharge (PD, corona) considerations usually are not in the foreground with low voltage switch- and control gear as per the product standards of IEC, UL and CSA. The design is mainly based on creepage and clearance dimensions, material categories described through CTI and RTI values. IEC product standards refer to the subject of insulation coordination as per the horizontal IEC 60664-family in their normative references. These standards, in principle, require PD measurements for rated voltages exceeding 500 VAC at room temperature. IEC 60664-2 gives some rules for consideration and electrical dimensioning of solid insulation. Miniaturization accompanied by increased power density and raised operational voltage as well as (non-sinusoidal) power supply generated by pulse width modulated (PWM) converters require to reconsider the relevance of electrical field stress in low voltage equipment. With variable frequency drive (VFD) fed motors reflected voltage waves were observed, causing partial discharge effects and insulation damages. Meanwhile motors and cables are available as VFD-proof versions. PD measurements on commercial manual motor controllers with sinusoidal voltages at both room temperature and a more severe elevated temperature related to the maximal operational temperature of the internal components (bimetal trip units) are presented. Conclusions are drawn and recommendations for future designs and testing are proposed.

Motor Protection Circuit Breakers (MPCB) are used in multi motor applications with Variable Frequency Drives (VFD). Devices positioned load side of a drive failed after only several months through thermal degradation. Investigations showed that MPCBs rated lower than 10 A suffer most. Similar designs of different brands were compared and showed in principle the same behaviour. Steep slopes of the DC voltage pulses in combination with the surge impedance of the motor and MPCB are responsible for excessive heat generation in the switchgear destroying the short circuit protection function. Similar effects are known in motors directly connected to drives with cables when exceeding a critical length above which reflected voltage waves occur. It is shown that chopping frequencies should not exceed 4 kHz and critical wire lengths of about 20 m should be respected to avoid damage.

Summary form only given as follows. In 1993, Milwaukee School of Engineering developed, at the request of Rockwell Automation, a four week program for engineering students of Czech Technical University (Prague, Czech Republic) to study in the United States. The targeted students were electrical engineering students with a specialization in automatic control, or computer automated manufacturing who might be potential employees of Rockwell. MSOE proposal capitalized upon the excellent technical education of CTU and supplemented that foundation with an accelerated technical management program. Integrated into the course work were lectures on the products and procedures of Rockwell Automation as well as a wide variety of cultural and social experiences. In 1998, the 5 week program involved students from 9 countries (including China and Russia) representing 12 universities. Key components of the program-specifically the integration of technology with economics, humanities, and management science-have recently been described in a Czech technical publication as being representative of the university of technology of the next century. The program has proven to be of benefit to all three partners. Rockwell has made a major positive impression upon selected engineering students in key markets of Central/Eastern Europe and recently Asia. The MSOE-CTU collaboration now includes an annual faculty exchange program, and selected MSOE students participate in the summer program, then study at CTU for one semester. Further expansion of the student exchange program is being planned.

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<p>When parts of a machinery control system are required for risk reduction of a hazard, they are considered a safety function. A typical safety function is comprised of safety input and output devices which are monitored and controlled by a safety logic device. Emergency stop buttons and guard door interlocks are typical safety input devices which are often remote, and field wired. Safety relays are typical safety logic devices and safety contactors, and variable frequency drives (VFDs) are typical output devices which are commonly located inside of a Low Voltage Motor Control Center (LVMCC). Safety functions must be engineered and implemented according to relevant machinery safety standards. Despite having common design requirements, safety functions often require customized engineering when applied to a LVMCC. </p> <p>This paper serves as an overview of how to promote standardization in the implementation of safety functions when using LVMCC’s. Standardization reduces delivery times of safety rated LVMCC units, decreases overall cost of acquisition of a safety rated LVMCC, and enables users to maximize operational productivity while assuring a proper design of the safety function.</p> <p>The selection of standard safety rated motor controller units as safety function subsystems enables users to minimize personal and enterprise risk when engineering new safety functions.</p>

In order to manage and remote monitor the group ladders,agroup ladder management system based on the technology OPC(of OLE for process control)have been developed,and a new control method which the PC running complex algorithm combined with PLCs operation of logical control was proposed.The method could reduce the average waiting time.On the basis of operation rules of elevator,using C#.NET language to design monitoring interface to reach a goal of calculating the sufficiency of each elevator response for target layer approximately,and design the intelligent dispatch algorithm for saving energy and time.This realized for the communication in the terrace of.NET with PLC,inverter and other control equipment by the technology of OPC.The experimental results showed that the upper management system and PLC were running well.The intelligent dispatch algorithm could reduce the average waiting time and achieve the purpose that the management information system could carry out one-stopmanagement the ground control equipment.

When parts of a machinery control system are required for risk reduction of a hazard, they are considered a safety function. A typical safety function is comprised of safety input and output devices which are monitored and controlled by a safety logic device. Emergency stop buttons and guard door interlocks are typical safety input devices which are often remote, and field wired. Safety relays are typical safety logic devices and safety contactors, and variable frequency drives (VFDs) are typical output devices which are commonly located inside of a Low Voltage Motor Control Center (LVMCC). Safety functions must be engineered and implemented according to relevant machinery safety standards. Despite having common design requirements, safety functions often require customized engineering when applied to a LVMCC. This paper serves as an overview of how to promote standardization in the implementation of safety functions when using LVMCC’s. Standardization reduces delivery times of safety rated LVMCC units, decreases overall cost of acquisition of a safety rated LVMCC, and enables users to maximize operational productivity while assuring a proper design of the safety function. The selection of standard safety rated motor controller units as safety function subsystems enables users to minimize personal and enterprise risk when engineering new safety functions.

Offshore wind power industry develop rapidly in recent years. Offshore wind has many advantages compared with onshore wind turbine. For example, it do not take up land and can make better use of the sea wind resources. However, the flexible components of wind turbines violent vibration will cause the fatigue damage and increase the cost of the maintenance and reduce the service life. Pitch variable is an effective means of control to prevent the sea wind of the interference. In recent years, robust control has won a bigger development. In the paper a multi-objective pitch control strategy based on robust theory is proposed for large wind turbines. The experimental results shows that the robust H control has a good effect on the wind turbines variable pitch control.

The Holm Conference Prize Paper Award was established in 1970. At that time, the Conference Steering Committee recognized that at each Conference there was at least one paper that stood out from the others in its technical content and quality of presentation. Therefore, the Prize Paper Award Committee was established. The Committee’s purpose is to review each paper, listen to each presentation and then judge which paper should receive the Prize Paper Award. The award is presented to the authors of the Prize Paper at the following year’s Holm Conference. Announcement of the 2019 award and the winners and paper titles for years 1970-2019