“How can we control object characteristics of a control system?”
When we have control systems, we often have object characteristics that we desire but are not implemented. For example, we might want to have the phase shift of an output signal to achieve peak frequency at a certain value. Well, after many years of hard work, engineers have invented compensators to accomplish this task. Compensators can be commonly found in PID control systems and electrical power systems.
Minimum Phase Systems
“What do we call systems that have all poles and zeros inside the unit circle?”
Systems that have all poles and zeros inside the unit circle are very special. Why? Well, because with these systems, their causal system will be completely stable and will have a phase lag less than a system of identical magnitude. Since these systems are so special, controls and signal engineers have termed them Minimum Phase Systems.
Bandwidth (signal processing)
“How can we classify a set of frequencies?”
In signal processing, we will often receive signals of varying frequencies. So how can we organize all of these frequencies? Well, why don’t we just take the difference between the upper and lower limit of these frequencies? This is known as bandwidth, is measured in Hertz and is used everywhere in signal processing.
Electric power systems
“What is the framework that powers our infrastructure?”
A great proportion of our modern infrastructure is contingent upon electricity for operation. However, what exactly is the fundamental framework behind all of it? Well, let’s take a close look. We know that we can simplify the course of electricity into 3 components: generation of power (through means such as solar panels and wind turbines), transmission of power (with means like HVDC), and distribution of power(using machines like transformers and grid tied inverters). If any framework has these three components, then it can be classified as an electric power system. The most famous example of an electric power system is the grid, which permeates nearly every aspect of our daily lives.
“When is the output unchanged from the input of a control block?”
In control systems, the output of a control block is usually modified from the input. However, when there is no change, the process is said to be in unity feedback
Closed-loop Summing Points
“What are the points on a control diagram for comparing the output and the setpoint?”
What makes a closed-loop control system truly closed loop is the comparison of the output and setpoint for making the error value. However, how is this represented on a control diagram? Well, Control Engineers like to use something called a Closed-loop Summing Point. Closed-loop Summing Points are small circular elements on a diagram that takes in an input on one quadrant, the setpoint on another and then produce the error term. Depending on the signs of the quadrant, the input value might be positive (for a + sign) or negative (for a – sign)
“How can we measure the disturbance between a setpoint and an output?”
When a closed loop control system sends an output, it must be compared to an initial setpoint. This process is known as tracking control and is one of the most fundamental parts of every control system