Tag: Industrial control
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How Cascade Control System Enhances Dynamic Response to Load Changes
The major limitation of a conventional feedback control system is that the correction for disturbances does not start until the process output deviates from the setpoint. Feedforward control provides big improvements in processes with large time constraints or time delays. But, feedforward control requires that the disturbances be measured explicitly and a model must be…
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AC to AC Power Converters with Intermediate DC Link: Types, Features & Applications
This category of AC drives that is often referred to as “Variable Frequency Inverters” is one of the most extensively used drives in industrial motor control applications. Generally, the concept of these inverter drives can be summarized into three parts: We have two main classifications of these AC drives that are based on the aforementioned…
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DC to DC Power Converters: Function, Types, Operation & Applications
DC to DC power converters also referred to as choppers provide the means to change one DC voltage to another. Normally the conversion is to a lower voltage however, we also have step-up converters. DC to DC power converters are fed from a DC supply usually comprising an uncontrolled AC to DC converter or alternatively…
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6 Types of Machine Guards
What is Machine Guarding? Most machines have cutting blades or rotating/moving parts that can cause bodily harm if they come in contact with plant workers operating the equipment or working nearby. To protect workers from hazards related to machinery, machine guards are used. Machine guarding is a safety mechanism that typically comprises of a shield…
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Single-Phase & Three-Phase Inverters: Function and Operation
What is the Purpose of Inverters? Whereas dc machines are controlled by varying the voltage and current, ac machines are often controlled by varying the voltage and frequency. One way of accomplishing this is by using inverters. The process of converting ac from dc is referred to as inversion. Some of the reasons why ac…
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Insulated Gate Bipolar Transistor (IGBT) – Structure, Operation & Applications
IGBT is a voltage controlled device. It has high input impedance like a MOSFET and low on-state conduction losses like a BJT. In other words, this power device combines the voltage control of the MOSFET gate with the superior conduction characteristics of the bipolar device. Nonetheless, the IGBT utilizes injected-charge modulation in the base region…
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Telemetry in Instrumentation Systems
Telemetry can be defined as the science of gathering information at some remote location and transmitting the data to a convenient location to be examined and recorded. Importance of Telemetry Within instrumentation there is usually a requirement for telemetry in order to transmit data or information between two geographical locations. The transmission may be needed…
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Optothyristors: Features & Principle of Operation
Silicon Controlled Rectifiers (SCRs), Triacs and other solid-state devices used for switching larger voltages and currents ON and OFF are referred to as thyristors. Thyristors control switching in an ON-OFF way, in the same way to a light switch which is different from a transistor that can vary the amount of current in its emitter-collector…
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What is Optimal Control?
Optimal control is whereby the requirements are formulated as either the minimization of a cost index or the maximization of a performance index of an operational control system. Optimal control is utilized in a number of disciplines such as aircraft and spacecraft, satellites and aerospace, communications engineering, robots and robotics, electric drives, power systems, computer…
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Phase Locked Loop High Precision Motor Speed Control System
AC generators can be utilized in high precision control systems. The AC generator rotor is rotated by the rotating shaft (i.e. the shaft from the motor being controlled). The output AC frequency is proportional to shaft speed. Zero crossings per time interval can be counted to determine speed for a simple control system. If high…