Method for controlling a genset system

A method for controlling a genset system is provided. The method includes recognizing a communication failure between one or more gensets of a plurality of gensets and a control system and determining an operating state of each of the one or more gensets prior to the communication failure. The method further includes operating the genset system, upon communication failure, according to a load control scheme. The load control scheme includes determining an available power of the genset system based on the determined operating state of each of the one or more gensets and coupling one or more loads to the genset system based on the available power.

TECHNICAL FIELD

The present disclosure relates to a genset system, and more particularly to a method for operating a genset system having a plurality of gensets when a communication failure between one or more of the gensets of the plurality of gensets and a control system of the genset system occurs.

BACKGROUND

A generator set, or genset, generally comprises a primary power source, such as an internal combustion engine, or the like, as well as an electric machine, such as induction generators, switched reluctance generators, or any other suitable electric machine commonly employed to convert mechanical energy, or other forms of energy, into electrical energy. In typical implementations, a plurality of gensets are arranged to communicate generated electrical energy through a shared or common bus that is further supplied to one or more connected loads. The loads may be connected to the common bus, by a central controller, based on total power generated by the gensets.

As, each of the gensets communicates with the central controller, the central controller is aware of the total power generated by the gensets. Therefore, the central controller couple one or more loads to the common bus based on the total power generated by the gensets. However, in an event when communication between one or more gensets and the central controller is lost, the central controller may not be aware of the accurate value of the total power generated by the gensets. Therefore, the central controller may couple one or more loads to the common bus such that total load on the common bus is more or less than the total power generated by the gensets.

In a scenario, when the total load coupled to the common bus is less than the power generated by the gensets, the genset system remains under-utilized which may not be desirable. In another scenario, when the total load coupled to the common bus is more than the total power generated by the gensets, undue stress may come on the common bus, the gensets and/or electrical components associated with the gensets. This may cause electrical failure of the gensets, the common bus, and/or the electrical components associated with gensets.

U.S. Pat. No. 8,301,312 discloses a genset system having a plurality of gensets, which are connected to a local power transmission network by two switches. Further, the plurality of gensets communicate data with each other via a can bus. The patent further discloses controlling the genset according to a droop control based on the position of the two switches, when the genset has lost communication with another gensets. However, the patent does not disclose controlling a genset system when the communication is lost between one or more gensets and a central controller.

SUMMARY OF THE INVENTION

According to an aspect of the disclosure, a method for controlling a genset system is provided. The method includes recognizing a communication failure between one or more gensets of a plurality of gensets and a control system and determining an operating state of each of the one or more gensets prior to the communication failure. The method further includes operating the genset system, upon communication failure, according to a load control scheme. The load control scheme includes determining an available power of the genset system based on the determined operating state of each of the one or more gensets and coupling one or more loads to the genset system based on the available power

According to another aspect of the disclosure, a genset system is provided. The genset system includes a plurality of gensets, a common bus, and a control system. The common bus is configured to be coupled to each of the plurality of gensets. Also, the common bus is configured to communicate electrical power generated by the plurality of gensets to one or more loads. Further, the control system is in communication with the plurality of gensets, the common bus, and the one or more loads. The control system is configured to recognize a communication failure between one or more gensets of the plurality of gensets and determine an operating state of each of the one or more gensets prior to the communication failure. The control system is further configured to operate the genset system, upon communication failure, according to a load control scheme. The load control scheme includes determining an available power of the genset system based on the determined state of each of the one or more gensets and coupling one or more loads to the common bus based on the available power.

According to another aspect of the disclosure, a control system for controlling a genset system is provided. The control system includes a controller. The controller is in communication with a plurality of gensets, a common bus, and one or more loads. The controller is configured to recognize a communication failure between one or more gensets of the plurality of gensets and determine an operating state of each of the one or more gensets prior to the communication failure. The controller is further configured to operate the genset system, upon communication failure, according to a load control scheme. The load control scheme includes determining an available power of the genset system based on the determined state of each of the one or more gensets and coupling one or more loads to the common bus based on the available power.

DETAILED DESCRIPTION

Reference will now be made in detail to specific embodiments or features, examples of which are illustrated in the accompanying drawings. Generally, corresponding reference numbers will be used throughout the drawings to refer to the same or corresponding parts. Also, wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts.

Referring toFIG. 1, one exemplary embodiment of a system of generator sets, or a genset system100, is diagrammatically illustrated. As shown, the genset system100may generally include a plurality of gensets102which are coupled to a common bus104and configured to supply electrical power to one or more loads106via the common bus104. Each genset102may generally include an engine108and an electric machine110. The engine108may include an internal combustion engine or any other comparable prime mover suitable for supplying mechanical energy, or any other suitable source of energy, to the electric machine110. The electric machine110may employ an induction machine, a switched reluctance machine, or any other suitable electric motor or generator commonly used in the art for converting energy supplied by the engine108into electrical energy.

Gensets102are not limited to the configuration shown inFIG. 1. The gensets102may include components other than engines108and electric machines110for producing electricity. For example, one or more of gensets102may be a fuel cell.

Each genset102may also include various control components. For example, each genset102may have a switch112connected between the output of its electric machine110and the common bus104. Each switch112may have any configuration that allows selectively electrically connecting the output of the associated electric machine110to the common bus104. In an embodiment, the switch112may include a circuit breaker.

In addition to the switches112, the control components of generator sets or gensets102may include one or more information-processing and control devices. For example, each of the genset102may include an associated unit control device114. Unit control device114may include various types of information-processing components, including, but not limited to, hardwired control circuits (not shown) and/or microprocessors (not shown). Additionally, in some embodiments, the unit control device114may include an operator interface (not shown) through which an operator may communicate with the unit control device114. Each genset102may have its unit control device114operatively connected to its engine108, its electric machine110, and its switch112. Accordingly, the unit control device114of each genset102may monitor and/or control one or more aspects of the operation of the engine108, the electric machine110, and the switch112of that genset102. In an embodiment, each of the unit control devices114may operate associated switches112to connect or disconnect associated electric machine110or genset102with the common bus104.

The unit control device114may also connect to various components that supply it with information about various other aspects of the operation of the genset102. The unit control device114may receive information about one or more characteristics of the electricity generated by its genset102, such as the voltage, current, phase, and/or frequency.

Additionally, each of the genset102includes an engine control switch116and a synchronization switch118. Each of the engine control switch116and the synchronization switch118may be in communication with its unit control device114. The engine control switch116may be actuated such as to operate associated engine108in various modes such as a RUN mode, an AUTO mode, and an OFF mode. Upon activation of the RUN mode by appropriately actuating the engine control switch116, associated engine108starts functioning and delivers power to operate associated electric machine110. In the AUTO mode, upon activation, the associated engine108is in standby and starts operating and delivering power to the electric machine110when commanded by the unit control device114. The OFF mode refers to a mode in which the associated engine108is switched off and not delivering power or not ready to deliver power when commanded by the unit control device114. Each of the engine control switches116is in communication with an associated unit control device114and transfers information about activation of the engine control switch116in one of its various positions. In an embodiment, the engine control switch116may be a physical button having three detent positions. In an embodiment, the engine control switch116may be included in the operator interface (not shown) of the associated genset102. In an embodiment, the engine control switch116and the synchronization switch118may be instructions executed by the unit control device114. In such case, the instructions may be stored in a memory (not shown) of the unit control device114.

Further, the synchronization switch118is configured to operate in an AUTO mode and an OFF mode. When the synchronization switch118is positioned in the AUTO mode, the voltage, current, frequency, and any other parameter associated with the electrical output of the associated electric machine110is synchronized with the voltage, current, frequency of the electricity flowing in the common bus104. Each synchronization switch118is communication with an associated unit control device114such that the associated unit control device114receives information regarding a state of the synchronization switch118. The unit control device114may accordingly control its genset102based on the state of the synchronization switch118. Also, each of the unit control device114may store information about the state of the associated engine control switch116and associated synchronization switch118.

Additionally, each of the unit control devices114may store information regarding one or more warning events related to its genset102. The one or more warning events may be generated during the current operation or previous operation of the gensets102. One of the warning events may be associated with the readiness of the genset102to automatically parallel with the common bus104. The readiness of a genset102to automatically parallel to the common bus104refers to readiness of the genset102for connection to the common bus104. The connection of the genset102may be achieved with the common bus104when the parameters of the electricity produced by the genset102such as voltage and frequency are in synchronization with the electricity present in the common bus104before the connection occurs.

Further, the warning events may also be associated with a failure of a synchronization of the genset102with the common bus104. Also, each of the unit control devices114stores information about the state of each of the warning events for its genset102. The state information may be stored as true or false.

Also, the unit control device114may receive and store information regarding the operation of an associated engine108at idle or at a rated power. Further, the unit control device114may also receive and store information regarding any active engine shutdown events of the engine108and/or the electric machine110of its genset102.

The genset system100further includes a control system120in communication with each of the gensets102, the common bus104, and the loads106. The control system120includes one or more controllers122configured to, among other things, operate the genset system100according to a load control scheme in the event communication with one or more gensets102of the genset system100is lost, during normal operation. The controller122may be in communication with each of the gensets102via a communication link123such as an Ethernet based communication link. Although an Ethernet based communication link is contemplated, any other suitable communication link known in the art would also apply.

In an embodiment, the controller122may be in communication with the associated unit control device114of each of the gensets102to receive information related to an operating state of the each of the gensets102. The operating state of the genset102may include such as, but not limited to, a state of the engine control switch116, a state of the synchronization switch118, a state of an engine power output. The controller122may be configured to continuously record and store the operating state of each of the gensets102. The stored information regarding the operating state of each of the gensets102may be available for retrieval by the controller122. In an exemplary embodiment, the controller122may store information regarding current and past operating states of each of the gensets102.

In an embodiment, the controller122may independently communicate with each of the components of the genset102such as the engine108, the electric machine110, switch112, unit control device114, the engine control switch116, synchronization switch118etc. and receive and store various information related to operating mode or states of each of the components. Further, the controller122may control the gensets102or the associated components based on the received operating state. Additionally or optionally, the controller122may also be in communication with each of the switches112to control and manipulate coupling of associated gensets102to the common bus104. In the illustrated embodiment, when the switches112are controlled by the associated unit control devices114, the information related to actuation of the switches112is communicated to the controller122by the associated unit control devices114.

Further, the control system120may include an operator interface (not shown) through which an operator may communicate with the controller122. The operator may input a priority order or sequence for the each of the loads106according to which the loads106are to be connected with the common bus104. Further, each of the loads106may be coupled to the common bus104by actuating their associated switches124. The controller122may be in communication with each of the switches124via communication link125to selectively connect or disconnect each of the loads106to the common bus104. The controller122operates each of the switches124to connect each of the loads106according to the priority sequence and an available power from the gensets102. In an embodiment, the switch124may be a circuit breaker.

Turning toFIG. 2, one exemplary algorithm or method200by which the controller122of the control system120may be programmed to control and operate the genset system100is provided. Such an algorithm or set of instructions may be preprogrammed or incorporated into a memory126that is disposed within the controller122or is otherwise accessible by the controller122. Furthermore, the controller122may be implemented using one or more of a processor, a microprocessor, a microcontroller, a digital signal processor (DSP), a field-programmable gate array (FPGA), an electronic control module (ECM), an electronic control unit (ECU), or any other suitable means for electronically engaging one or more tasks of the control system120.

Also, the control system120utilizes the memory126for storing various instruction associated with the exemplary algorithm of method200. Also, the memory126may record and store information about the operating state of each of the genset102received from each of the unit control device114. Further, the memory126may store the priority order of connecting the loads106to the common bus104. The memory126may be implemented using one or more of a volatile memory or a non-volatile memory. The memory126may include one or more of a read only memory (ROM), random access memory (RAM), a flash memory, an electronic erasable program read only memory (EEPROM), or other type of memory. The memory126may be removable from the network device, such as a secure digital (SD) memory card.

Specifically, as shown inFIG. 2, the controller122during an initial step202may be configured to determine whether a fail-safe condition should be triggered based on various operating characteristics of the genset system100. For example, the controller122may be configured to recognize any loss of communication from one or more of the gensets102of the plurality of gensets102ofFIG. 1. The controller122may periodically ping each of the gensets102in order to determine active communication between the controller122and each of the gensets102. The controller122may recognize loss of communication with one or more gensets102when the controller122does not receive reply of the ping. Although, a ping message is used for recognizing the communication loss between the controller122and the gensets102, it may be contemplated that other known techniques of identifying or recognizing a loss of communication may be utilized.

If no loss of communication is recognized during the step202, the controller122may continue monitoring for such satisfying conditions and maintain normal operation of the genset system100. If, however, a loss of communication is recognized, the controller122is configured to determine the operating state of each of those gensets102prior to the loss of communication, at a step204.

Further, at the step204, the controller122may determine the state of the engine control switch116, the state of the synchronization switch118, the state of the engine power output, the state of the warning events, the state of the engine shutdown event prior to the loss of communication from each of those gensets102. Further, the controller122may compare the operating state of each of those gensets102with which communication is lost to a predefined state. In an exemplary embodiment, the predefined state corresponds to an operating state in which the engine control switch116is in the AUTO mode, the synchronization switch118is in the AUTO mode, the engine power output is at the rated power, the absence of the engine shutdown event, and the state of the one or more warning events is False i. e. there is absence of the warning events.

Further, at a step206, the controller122automatically operate the genset system100according to a load control scheme based on the operating status of those gensets102with which communication is lost. The controller122calculates the available power of genset system100by adding power of the gensets102with which communication was not lost and the power of those gensets102with which the communication was lost and the operating state of those gensets102, prior to communication failure, matches the predefined state. The genset102which has lost communication with the controller122and has the operating state corresponding to the predefined state may be referred as assumed to be online genset102. Further, the gensets102with which communication is not lost may be referred as online gensets102. In an embodiment, the controller122may utilize rated power of those online gensets102which are running (RUN mode) and connected to the common bus104to determine the available power of the genset system100. In an embodiment, the controller122may utilize rated power of the online gensets102to determine the available power when the online gensets102are either running (RUN mode) or ready for operation (AUTO mode).

In an exemplary embodiment, when communication to all the gensets102has failed, the controller122may determine the available power based on rated power of those gensets102whose operating states corresponds to the predefined state. For example, out of the five gensets102shown inFIG. 2, only three gensets102have their operating state as the predefined state, the controller122adds the rated power of the three gensets102to calculate the available power from the genset system100.

In another exemplary embodiment, the controller122may have lost communication with three of the five gensets102. In such case, the controller122may determine the operating state of each of the three gensets102and determine the available power by adding the rated power of only those gensets102out of three gensets102whose operating state corresponds to the predefined state. Further, the controller122may add the rated power of the remaining two gensets102with which the controller122has not lost communication, in the total power of the assumed to be online genset102to calculate the available power of the genset system100. The rated power of only those gensets102out of the remaining two online gensets102are added to the total power of the assumed to be online gensets102, which are connected to the common bus104and running i. e. in the RUN mode.

Additionally or optionally, the controller122may determine the genset102having the highest rated power among the assumed to be online gensets102. The controller122may subtract a value corresponding to the highest rated power from the available power calculated based on the rated power of the online gensets102and/or the assumed to be online gensets102to obtain the available power of the genset system100. In an embodiment, the rated power of the all the gensets102may be equal. In such case, the available power may be calculated by subtracting the rated power of any of the genset102from the summation of the rated power i.e. a total rated power of the assumed to be online gensets102and/or the online gensets102.

In another embodiment, an operator may select the genset102among the assumed to be online gensets102. The rated power of the selected genset102is subtracted from the summation of the rated power i.e. the total rated power of the assumed to be online gensets102and/or the online gensets102to calculate the available power of the genset system100. In an exemplary embodiment, the operator may select the genset102having second highest rated power among the assumed to be online gensets102to determine the available power of the genset system100. In such a case, the controller122determines the available power by subtracting a value corresponding of the second highest rated power from the summation of rated power of the assumed to be online gensets102and/or the online gensets102.

Further, at the step206, the controller122connects the one or more loads106to the common bus104based on the available power of the genset system100. The controller122may determine the available power of the genset system100by subtracting the operating power of the loads106already coupled to the common bus104before initiating coupling of additional loads106to the common bus104.

The controller122may actuate the switch124associated with its load106for coupling the load106to the common bus104. Each of the loads106may be sequentially connected with the common bus104according to the predefined priority sequence. The predefined priority sequence may be defined by the operator and stored in the memory126. In an embodiment, the predefined priority sequence for connecting the loads106to the common bus104may be defined automatically by the controller122. The controller122may define the priority sequence based on the type of loads and operation of the genset system100.

Further, the loads106may be coupled to the common bus104based on the assumption that the first assumed to be online genset102is connected to the common bus104after a predetermined time of the communication failure with the controller122. Thereafter each of the assumed to be online genset102is assumed to be connected to the common bus104sequentially after the predetermined time of coupling of the previous assumed to be online genset102. The controller122may assume the connection of the assumed to be online gensets102is sequentially based on the rated power of those gensets102. In an embodiment, the controller122may assume the connection of the assumed to be online gensets102sequentially starting from the genset102which e lowest rated power among the assumed to be online gensets102.

In an exemplary embodiment, the predetermined time may be 10 seconds. In such case, the first assumed to be online genset102is assumed to be coupled to the common bus104after loss of communication of one or more gensets102with the controller122. Thereafter, the controller122may connect the load106which is first in the priority sequence, according to the predefined priority sequence, based on the available power, determined using the rated powers of the online gensets102and the first assumed to be online genset102, and the power needed to operate the load106. Second assumed to be online genset102is assumed to be coupled to the common bus104after 10 seconds of assumed coupling of the first assumed to be online genset102. The loads106may be coupled to the common bus104, in the predefined priority sequence, based on the rated power of the online gensets102and first and second assumed to be online gensets102, and the power needed to operate the loads106. The connection to the remaining loads106proceeds in similar manner by assuming coupling of each of the additional assumed to be online gensets102after every 10 seconds. Also, the controller122may determine the available power of the genset system100by subtracting the operating power of the loads106already coupled to the common bus104before initiating coupling additional loads106to the common bus104.

INDUSTRIAL APPLICABILITY

In general, the foregoing disclosure finds utility in any one of a variety of applications, which may benefit from improved balancing and connections of loads in the absence of discrete communications between particular components, modules, or subparts thereof. More specifically, the disclosed systems and methods may be used to automatically and adaptively aid in connecting loads, according a load control scheme, to a common bus of a genset system having two or more generator sets or gensets upon loss of communication between gensets and a controller of the genset system.

In particular, the disclosed control system and methods for controlling a genset system to provide better load connection to common bus in the absence of communications between the gensets of the genset system and the control system by adapting the load control scheme. More particularly, the load control scheme automatically manage the number of loads connected to the common bus, upon communication failure between one or more gensets and the control system, according to the operating state of those gensets prior to communication failure. The loads are connected or disconnected from the common bus based on the total available power of the genset system and the operating power of the loads according to the load control scheme. The present disclosure, thus, not only enables more effective use of the gensets during communication failures, but also enables the otherwise fixed operating nature of the gensets and also prevents overloading of the gensets and thereby preventing an impending failure of the genset system.