top of page

Support Group

Public·62 members
Benjamin Wood
Benjamin Wood

Digital Control And State Variable Methods By M Gopal Pdf 11

5.10 Taking outputs of integrators as state variables (x1 and x2are outputs of top two integrators from left to right; x3 and x4are corresponding variables for other integrators): & & x1= 4x4 + 3u1; x 2 = x1 3x2 + u1 + 2u2; & & x 3 = x2 + 3u2; x4 = 4x4 + x3;

Digital Control And State Variable Methods By M Gopal Pdf 11

The given state model is in controllable companion form. Sincethere is a pole-zero cancellation, the model is unobservable. 5.41(a) lI A = (l 1) (l + 2) (l + 1) The system is unstable. (b) G(s)= c(sI A)1 b =

Choosing e(k 1) as controller state variable, xc(k), we obtain,xc(k + 1) = e(k), u(k) = 41xc(k) + 50e(k) as the state model of thecontroller. The plant difference equations are given by (solutionto Problem 6.16) x(k + 1) =

(c) Since there is a pole-zero cancellation, the system iseither uncontrollable or unobservable or both. Given state model isin controllable canonical form. Therefore, the model iscontrollable but not observable.

A variable-frequency drive (VFD) is a type of motor drive used in electro-mechanical drive systems to control AC motor speed and torque by varying motor input frequency and, depending on topology, to control associated voltage or current variation.[1][2][3][4][5] VFDs may also be known as 'AFDs' (adjustable-frequency drives), 'ASDs' (adjustable-speed drives), 'VSDs' (variable-speed drives), 'AC drives', 'micro drives', 'inverter drives' or, simply, 'drives'.

The VFD controller is a solid-state power electronics conversion system consisting of three distinct sub-systems: a rectifier bridge converter, a direct current (DC) link, and an inverter. Voltage-source inverter (VSI) drives (see 'Generic topologies' sub-section below) are by far the most common type of drives. Most drives are AC-AC drives in that they convert AC line input to AC inverter output. However, in some applications such as common DC bus or solar applications, drives are configured as DC-AC drives. The most basic rectifier converter for the VSI drive is configured as a three-phase, six-pulse, full-wave diode bridge. In a VSI drive, the DC link consists of a capacitor which smooths out the converter's DC output ripple and provides a stiff input to the inverter. This filtered DC voltage is converted to quasi-sinusoidal AC voltage output using the inverter's active switching elements. VSI drives provide higher power factor and lower harmonic distortion than phase-controlled current-source inverter (CSI) and load-commutated inverter (LCI) drives (see 'Generic topologies' sub-section below). The drive controller can also be configured as a phase converter having single-phase converter input and three-phase inverter output.[9]

In variable-torque applications suited for Volts-per-Hertz (V/Hz) drive control, AC motor characteristics require that the voltage magnitude of the inverter's output to the motor be adjusted to match the required load torque in a linear V/Hz relationship. For example, for 460 V, 60 Hz motors, this linear V/Hz relationship is 460/60 = 7.67 V/Hz. While suitable in wide-ranging applications, V/Hz control is sub-optimal in high-performance applications involving low speed or demanding, dynamic speed regulation, positioning, and reversing load requirements. Some V/Hz control drives can also operate in quadratic V/Hz mode or can even be programmed to suit special multi-point V/Hz paths.[14][15]

Although space vector pulse-width modulation (SVPWM) is becoming increasingly popular,[17] sinusoidal PWM (SPWM) is the most straightforward method used to vary drives' motor voltage (or current) and frequency. With SPWM control (see Fig. 1), quasi-sinusoidal, variable-pulse-width output is constructed from intersections of a saw-toothed carrier signal with a modulating sinusoidal signal which is variable in operating frequency as well as in voltage (or current).[11][18][19]

An embedded microprocessor governs the overall operation of the VFD controller. Basic programming of the microprocessor is provided as user-inaccessible firmware. User programming of display, variable, and function block parameters is provided to control, protect, and monitor the VFD, motor, and driven equipment.[11][21]

Depending on the model a VFD's operating parameters can be programmed via: dedicated programming software, internal keypad, external keypad, or SD card. VFDs will often block out most programming changes while running. Typical parameters that need to be set include: motor nameplate information, speed reference source, on/off control source and braking control. It is also common for VFDs to provide debugging information such as fault codes and the states of the input signals. 350c69d7ab


Welcome to the group! You can connect with other members, ge...


Group Page: Groups_SingleGroup
bottom of page