Define voltage regulation

What is Voltage Regulation? Voltage regulation is defined as the change in terminal voltage expressed as a fraction of full load rated voltage when the load at a given power factor is removed while keeping the speed and field current constant. Voltage regulation formula, Voltage regulation = (E F – V T) / V T in P.U % of Voltage regulation = (E F – V T) / V T × 100 E F = No-load excitation voltage V T = full load terminal voltage Voltage regulation is always positive for lagging power factor load and E f is always increasing. For obtaining the maximum voltage regulation load power factor angle (φ) must equal to impedance angle (ϴ). For leading power factor load, voltage regulation may be positive, zero, negative and E f may decreases. Methods of Calculating voltage regulation • The electromotive force (emf) method or synchronous impedance method • MMF method (or) ampere turn method • Zero power factor method • S.A (American standards association) method. Let we see, • The electromotive force (emf) method or synchronous impedance method: Even though this method gives the inconsistent result of voltage regulation it is quite useful because we consider drop due to armature reaction as drop due to synchronous reactance. It gives regulation more than actual value so it is called a pessimistic method. • MMF method (or) ampere turn method: In MMF method, the reverse procedure is applied, i.e, each emf is replaced by an equivalent MMF. Here drop due to synchronous reactance is con...

As we saw in a few The degree of variance is affected by the primary and secondary winding inductances, among other factors, not the least of which includes winding resistance and the degree of mutual inductance (magnetic coupling) between the primary and secondary windings. For power transformer applications, where the transformer is seen by the load (ideally) as a constant source of voltage, it is good to have the secondary voltage vary as little as possible for wide variances in load current. Voltage Regulation Formula The measure of how well a power transformer maintains constant secondary voltage over a range of load currents is called the transformer’s voltage regulation. It can be calculated from the following formula: What is “Full Load”? “Full-load” means the point at which the transformer is operating at maximum permissible secondary current. This operating point will be determined primarily by the winding wire size (ampacity) and the method of transformer cooling. Taking our first SPICE transformer simulation as an example, let’s compare the output voltage with a 1 kΩ load versus a 200 Ω load (assuming that the 200 Ω load will be our “full load” condition). Recall if you will that our constant primary voltage was 10.00 volts AC: freq v(3,5) i(vi1) 6.000E+01 9.962E+00 9.962E-03 Output with 1k ohm loadfreq v(3,5) i(vi1) 6.000E+01 9.348E+00 4.674E-02 Output with 200 ohm load Notice how the output voltage decreases as the load gets heavier (more current). Now let’s ...

Understanding How a Voltage Regulator Works A voltage regulator generates a fixed output voltage of a preset magnitude that remains constant regardless of changes to its input voltage or load conditions. There are two types of voltage regulators: linear and switching. A linear regulator employs an active (BJT or MOSFET) pass device (series or shunt) controlled by a high gain differential amplifier. It compares the output voltage with a precise reference voltage and adjusts the pass device to maintain a constant output voltage. A switching regulator converts the dc input voltage to a switched voltage applied to a power MOSFET or BJT switch. The filtered power switch output voltage is fed back to a circuit that controls the power switch on and off times so that the output voltage remains constant regardless of input voltage or load current changes. What are some of the switching regulator topologies? There are three common topologies: buck (step-down), boost (step-up) and buck-boost(step-up/stepdown). Other topologies include the flyback, SEPIC, Cuk, push-pull, forward, full-bridge, and half-bridge topologies. How does switching frequency impact regulator designs? Higher switching frequencies mean the voltage regulator can use smaller inductors and capacitors. It also means higher switching losses and greater noise in the circuit. What losses occur with the switching regulator? Losses occur as a result of the power needed to turn the MOSFET on and off, which are associated w...

Most of the Integrated IC’s require a constant voltage with which it could operate. Be it a simple Logic Gate or a complex microprocessor they have their own operating voltage. The most common operating voltages are 3.3V, 5V and 12V. While we have batteries and DC Adaptors that could acts as a voltage source, most of the time they cannot be directly connected to our circuit design since the voltage from them is not regulated. Say for example, we have 9V battery but need to trigger a What is Voltage Regulator and Why Do We Use It? You recollect your school days we were taught that resistors drop voltage. Would it not be a simple fix to just use You need something better – the voltage should not depend on the load current, at least not much. The next simplest fix that comes to your head is the voltage divider. This needs two resistors, but hey, if they can be squeezed in they may as well work. Another nagging problem – the moment your component starts drawing too much current, the output of the divider sags – the top resistor is not able to keep up with the current demand. Now you really start wishing you’d learnt about this in school. You could fix this by lowering the resistor values, but that would make the two resistors draw too much current, probably ruining your current budget and getting too hot with the immediate risk of failure. What else could be done? Amplification! Of course, you had to slog through hours of lectures on those! Why not add an NPN transistor as a v...

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The line regulation is given by the equation shown below. where |V rnl | = magnitude of receiving end voltage at no load. |V rfl| = magnitude of receiving end voltage at no load. The regulation of the line depends on the power factor of the load. For lagging power factor the voltage at the sending end is more than the receiving end of the line. For leading power factor the voltage at the receiving end of the line becomes more than that of the sending end. Because of the leading power factor, the line regulation becomes negative. The voltage V S at the sending end is kept constant. It is given by When the load is removed, Therefore, Where V r0 = 0 is the receiving end voltage at no load. Line Regulation for Short Line In the case of the | V rfl | = | V r | At no load, |V rnl | = |V s| Therefore, for a short line The simplest way of measuring the line regulation is to connect all the three parallel resistors to the supply. The two resistors are attached to the switch while the remaining directly linked to the supply. The value of the resistor chosen in such a way that the resistor which directly connects to the supply has high