Title of Invention

AN ENHANCED CONTROLLER TO CONTROL AND MONITOR THE OPERATION OF ELECTROSTATIC PRECIPITATOR

Abstract

The invention relates to an enhanced controller to control and monitor the operation of electrostatic precipitator adaptable to industrial plants. The precipitator (04) comprising a plurality of fields with collecting and emitting electrodes, each field being energized with atleast one high-voltage transformer (03) via a firing circuit (02) including a thyristor circuit (01), and a plurality of electrical rapping motors being controlled through a rapping circuit (05), a plurality of micro-controller based controllers controlling the plurality of fields, the plurality of microbased controllers connected through a communication area network (CAN) via a bus. The enhanced controller (06) comprising a monitoring device (07) capturing field signals from the electrostatic precipitator (04), a control device (08) controlling ON/OFF operation of the plurality of rapping motors, a communication device (09) providing communication interface between the other precipitator controllers including the remote controllers and the distributed controllers over the communication area network (CAN), and a micro controller (15) having an embedded memory device (10) stored with an inbuilt optimization algorithm enabling the peripheral devices (07,08,09) measuring the field parameters including sharing of the parameters among the plurality of other micro controllers so as to effect a coordinated control for optimum performance of the precipitator (04).

Full Text

FIELD OF THE INVENTION The present invention relates to an electrostatic precipitator (ESP), which is a dust-collection equipment widely used in thermal plants, cement plants, steel plants, sugar plants etc., and having electronic controllers for control and monitoring of its operation. In particular, the invention relates to the electronic controller for a controlled operation of the high voltage transformer rectifier and the rapping motor, which are all controllable parts of ESP. Also, the invention relates to the electronic controller for on-line monitoring and sharing of operating status with peer controllers to have coordinated operation of ESP by adapting an open-standard multi-master communication protocol interface. BACKGROUND OF THE INVENTION The electrostatic precipitators (ESP) are basically segmented into number of electrical fields depending upon the size. Each field consists of a collecting and emitting electrode system pair with collecting electrode at negative polarity and emitting at positive polarity typically. The field is electrically energized by applying high voltage between positive and negative electrodes using a high voltage power supply system. The applied voltage produces necessary high electric field and electrostatic forces between electrodes, which ionizes and charges dust particles when pass between the electrodes and collected in the surface of the electrodes with opposite polarity. Typically, collected dust is removed from the electrodes by a tumbling hammed based rapping mechanism driven by rapping motors. Each of the fields of ESP needs to be individually controlled with respect to applying high voltage and rapping system. Normally high voltage power supply and rapping motors of fields of ESP are controlled and monitored by a plurality of micro-controller based controllers. The micro-controller based controllers are connected through a data communication bus and often controlled from a remote controller or a central controller. Normally the micro-controller based controllers are slave controllers, wherein the remote controller or the central controllers are master controllers. The remote /central computer is responsible for the overall performance of the ESP. In the prior art, mechanism exists to control the high voltage power supply individually for each field through electronic controller. Also, the rapping motors are controlled by a separate electronic controller. However, no mechanism exists to control and monitor each ESP field in complete using a single common electronic controller by controlling both high voltage power supply and rapping motors. This method also enhances efficiency of ESP by synchronizing energization and rapping system. The position of each field with respect to gas flow direction, decides the amount of dust collected in that field. Fields facing gas flow early is set to collect more dust. Any failures of a field will immediately need to be communicated to the subsequent fields to adjust to new load input to those fields so that they can adjust their control parameters to maintain desired efficiency of ESP. In the prior art mechanism exist to connect all electronic controllers through communication network in master-slave mechanism, where the slave will have to wait for its turn for communication with master. Also, mechanism do exists, that the communication is provided with proprietary communication protocol over different physical layer topologies including RS-485 and current loop communication. But, no mechanism exist, where all electronic controllers are interfaced in MASTER-MASTER (multi-master) mechanism. This will enable faster communication between peers of electronic controllers and subsequently making ESP responding to the changes in field conditions quickly thereby increasing its effectiveness. Also, no mechanism exists, where such communication interfaces are provided with open-standard communication protocol. This will enable for any third-party system to interact with electronic controller directly. Also, no mechanism exists, where the electronic controllers are equipped with reading boiler-load and opacity signals directly and communicate them among peers thereby avoiding a third-party system like central computer to those signals. OBJECTS OF THE INVENTION The object of the invention is to provide an enhanced controller for control and monitoring of both power supply unit and rapper motors of ESP field for synchronized operation for improving collection efficiency. Yet another objective of the invention is to provide a master-master (multi- master) communication mechanism between electronic controllers for speedy communication of field data between peers so that they adjust to field changes immediately. Yet another objective of the invention is to provide a communication interface between peers using open-standard communication protocol so that any third- party systems can interact with electronic controller. Yet another objective of the invention is to enable electronic controller to read plant data like boiler-load and opacity signal and communicate to peers for any coordinated operation of ESP. And yet another object of the invention is to propose an enhanced controller in an electrostatic precipitator, which reduces the optimization time and responds quickly on variation of field parameters. SUMMARY OF THE INVENTION In the invented enhanced controller both the power supply control and rapper motor control functionalities are integrated in a single system. Also additional signals like boiler load and opacity signals are monitored in the invented controller. In order to share the operating parameters among other controllers communication interface is provided in the enhanced controller. In the invented enhanced controller an open standard multi-master communication protocol, Controller Area Network (CAN), is adopted for communicating with other controllers. In multi-master communication protocol any controller can initiate the communication. Data sharing is also possible, which enable implementation of coordinated operation schemes with-in the controller itself. This invention includes implementation of hardware and software in the aforesaid controller using STANDALONE CAN controller and CAN transceiver. The enhanced controller for control and monitoring of ESP field is developed based on embedded hardware. It comprises a hardware part and a software part. The hardware is based on 16 Bit micro-controller, memory devices, peripheral devices and Controller Area Network (CAN) communication devices. The 16-bit micro-controller enables and controls all other devices. The software part is stored in the memory. Peripheral devices interface the field signals to the micro- controller. Communication devices interface the processor with the Controller Area Network (CAN) communication physical bus. The CAN communication physical bus connects a plurality of controllers in a large plant. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Figure 1 is a block diagram of an electrostatic precipitator with enhanced controller according to the invention. Figure 2 is a block diagram of an enhanced controller of Figure 1. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Electrostatic precipitator (04) is energized with a high voltage transformer/rectifier (03) through a firing circuit (02) and a thyristor circuit (01). An enhanced controller (06) controls the high voltage transformer (03) through the thyristor circuit (01) and a plurality of rapping motors operable through a rapping motor circuit (05). The enhanced controller (06) for the electrostatic precipitator (04) comprises a micro-controller (15), a control device (08), a monitoring device (07), a communication device (09) and a memory device (10). The micro-controller (15) is the main processor which enables all other devices (07,08,09) to function. The monitoring device (07) comprises an analog input means (13) and a digital input means (11) which provide interface to the field signals. The field signals like electrostatic precipitator current and voltage, alarms are connected through the devices (13,14). The control device (08) provides interface with contactors and relays for ON/OFF operation. The communication device (09) provides communication interface between the other controllers including the remote controllers and the distributed controllers over a communication bus of the controller area network (CAN). WE CLAIM 1. An enhanced controller to control and monitor the operation of electrostatic precipitator and high-voltage power supply and rapper motors together of an ESP field for synchronized and coordinated operation of ESP field comprises:- - a precipitator (04) having a plurality of fields with collecting and emitting electrodes, each field being energized with atleast one high voltage transformer (3) via a firing circuit (2) including a thyristor circuit (03) (01) and a plurality of electrical rapping motors being controlled through a rapping circuit (05), a plurality of micro- controller based controllers controlling the plurality of fields, the plurality of micro based controllers connected through Controller Area Network (CAN) communication bus; - a control device (08),enables commanding outputs to high voltage transformer/rectifier module (3) and rapper motors (5); - a monitoring device (07) senses required input from high voltage transformer/rectifier rapper motors (5) and plant wide signals through digital (13) and analog (11) means; - a communication device (9) enables communication interface between peers based on controller area network (CAN) which is an open standard communication protocol and being a master- master(multi-master) mechanism; - a memory device (10) stores entire software of the enhanced controller and - an inbuilt 16 bit micro-controller (15) having an embedded memory device (10) stored with an inbuilt optimization algorithm enabling the peripheral devices (07,08,09) measuring the field parameters including sharing of the parameters among the plurality of other micro-controllers so as to effect a coordinated control for optimum performance of the precipitator (4); characterized in that controlling of high-voltage power supply and rapper motors together enables to reduce the energization immediately during rapping to minimize re-entrainment of dust particles without any third-party system assistance and the ESP field healthiness of each field is communicated over the communication network so that every enhanced controller can adjust its operating parameters immediately according to its electrical field position. Also characterized in that sensing of boiler- load and opacity signal of plant wide signals directly and communicate them over the network so that every enhanced controller can receive them to adjust its operating parameters immediately to optimize the performance of entire ESP without any central/distributed controller. 2. An enhance controller to control and monitor the operation of electrostatic precipitation a substantially described and illustrated herein with reference to the accompanying drawing. The invention relates to an enhanced controller to control and monitor the operation of electrostatic precipitator adaptable to industrial plants. The precipitator (04) comprising a plurality of fields with collecting and emitting electrodes, each field being energized with atleast one high-voltage transformer (03) via a firing circuit (02) including a thyristor circuit (01), and a plurality of electrical rapping motors being controlled through a rapping circuit (05), a plurality of micro-controller based controllers controlling the plurality of fields, the plurality of microbased controllers connected through a communication area network (CAN) via a bus. The enhanced controller (06) comprising a monitoring device (07) capturing field signals from the electrostatic precipitator (04), a control device (08) controlling ON/OFF operation of the plurality of rapping motors, a communication device (09) providing communication interface between the other precipitator controllers including the remote controllers and the distributed controllers over the communication area network (CAN), and a micro controller (15) having an embedded memory device (10) stored with an inbuilt optimization algorithm enabling the peripheral devices (07,08,09) measuring the field parameters including sharing of the parameters among the plurality of other micro controllers so as to effect a coordinated control for optimum performance of the precipitator (04).

Documents:

491-KOL-2005-FORM 27.pdf

491-KOL-2005-FORM-27.pdf

491-kol-2005-granted-abstract.pdf

491-kol-2005-granted-claims.pdf

491-kol-2005-granted-correspondence.pdf

491-kol-2005-granted-description (complete).pdf

491-kol-2005-granted-drawings.pdf

491-kol-2005-granted-examination report.pdf

491-kol-2005-granted-form 1.pdf

491-kol-2005-granted-form 18.pdf

491-kol-2005-granted-form 2.pdf

491-kol-2005-granted-form 3.pdf

491-kol-2005-granted-form 5.pdf

491-kol-2005-granted-gpa.pdf

491-kol-2005-granted-reply to examination report.pdf

491-kol-2005-granted-specification.pdf