AU2018201779B2 - An electrical system for driving a pump - Google Patents

Abstract

Provided is an electrical system 10 for operatively driving a pump 18. The system 10 comprises a prime mover 12 having a controllable mechanical output, and an electrical generator 14 mechanically coupled to the prime mover output. The generator 14 operatively generates electrical power and has a controllable excitation system whereby the generator voltage output is controllable. Also included is an electrical induction motor 16 operatively supplied with electrical power from the electrical generator 14, and a pump 18 driven by the induction motor 16 for operatively displacing fluid. A controller 20 of the system 10 is programmed with a speed torque relationship of both the prime mover 12 and induction motor 16, as well as a performance curve of the pump 18. The controller 20 is configured to continuously monitor the operating characteristics of the prime mover 12, the electrical generator 14, the induction motor 16 and the pump 18, and to automatically and dynamically control the prime mover output and excitation system in order to dynamically and continuously match the speed-torque relationship of the prime mover 12 to that of the induction motor 16 and the pump performance curve. In this manner, optimal energy transfer efficiency through the system 10 can be facilitated whilst user-selectable fluid flow rate, fluid pressure and fluid level are maintainable when displacing fluid via the pump 18. CiO II x .2 M: I I * 00 I 'OHz Io D4 0I x CI IL I I i z Ii4cv _0 z w II 0.1r o CcI I* _____ __ __ __ _ _ _ _ 0

Description

AN ELECTRICAL SYSTEM FOR DRIVING A PUMP

TECHNICAL FIELD [0001] This invention relates to the field of electrical engineering, in general, and in particular to an electrical system for operatively driving a pump.

BACKGROUND ART [0002] The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application.

[0003] There are millions of electrical motors in use in industry and offices around the world. Such motors may operate mining dewatering pumps, sewage and irrigation pumps, milking machines and ski lifts, paper machines and power-plant fans, sawmill conveyors and hospital ventilation systems, to name just a few examples. It has been estimated that in the vicinity of sixty-five percent or more of industrial electrical energy is consumed by electrical motors .

[0004] In many cases, these electrical motors operate at a constant speed while fed by static frequency and voltage. In other cases, these electrical motors are required to operate at variable speed fed by dynamic frequency and voltage. The later method uses solid state switching methodologies for starting and controlling such motors, e.g.

pulse width modulation, etc. Such practices are generally inefficient from an energy point of view.

2018201779 13 Mar 2018 [0005] For example, a solid state motor soft starter is a device used with AC electrical motors to temporarily reduce the voltage amplitude which consequently reduce the current applied to the motor during start-up. This can reduce the associated mechanical and electrodynamic stresses and extend the lifespan of the system. In general, starting an induction motor is accompanied by inrush currents up to 7-10 times higher than running current, and starting torque up to 3 times higher than running torque. The increased torque results in sudden mechanical stress on the machine which leads to a reduced service life. Moreover, the high inrush current stresses the power supply, which may lead to voltage dips. As a result, lifespan of sensitive equipment may be reduced.

[0006] Accordingly, solid state devices can be used to control the voltage applied to a motor, but to accommodate the large currents and voltages involved at start-up, these solid state starters must generally be designed with a much higher electrical rating than required for normal operation, and the generator must be much higher rated than a motor which it drives, typically in the order of a 250% rating increase .

[0007] The present invention seeks to propose possible solutions, at least in part, in amelioration of the known shortcomings in the art .

2018201779 13 Mar 2018

SUMMARY OF THE INVENTION [0008] According to an aspect of the invention there is provided an electrical system for operatively driving a pump, said system comprising:

a prime mover having a controllable mechanical output;

an electrical generator mechanically coupled to the prime mover output, said generator operatively generating electrical power and having a controllable excitation system whereby generator voltage output is controllable;

an electrical induction motor operatively supplied vzith electrical power from the electrical generator;

a pump driven by the induction motor for operatively displacing fluid, pump operating characteristics comprising a measurable fluid flow rate, fluid pressure and fluid level; and a controller programmed with a speed-torque relationship of both the prime mover and induction motor and a performance curve of the pump, said controller configured to :

i) continuously monitor operating characteristics of the prime mover, the electrical generator, the induction motor and the pump; and ii) automatically and dynamically control the prime mover output and excitation system in order to dynamically and continuously match the speedtorque relationship of the prime mover to that of the induction motor and the pump performance curve;

so that optimal energy transfer efficiency through the system is facilitated whilst user-selectable fluid flow rate, fluid pressure and fluid level are maintainable when displacing fluid via the pump.

2018201779 13 Mar 2018 [0009] The skilled addressee will appreciate that a speed-torque relationship of either the prime mover or the induction motor may vary depending on prime mover or motor design and is generally indicative of desired operating ranges for a specific prime mover or motor having increased power efficiency. It is also to be appreciated that the performance curve of a pump provides an indication of producible pressure relational to producible fluid flow rate and a desired operating range delivering maximised efficiency for such variables.

[0010] In light hereof, by dynamically matching such speed-torque relationships and performance curves whilst maintaining the user-selectable pump operating characteristics, allows for efficient energy transfer through the system. As an energy source for the system typically comprises a fuel source for the prime mover, such energy efficiency generally allows for minimised fuel use.

[0011] Typ ically, the prime mover comprises an internal combustion engine, such as a diesel engine, but other types of engines may also be apposite.

[0012] Typically, the prime mover operating characteristics continuously monitored by the controller are selected from a group consisting of oil pressure, oil temperature, oil level, coolant level, coolant temperature, inlet air pressure, inlet air temperature, fuel level, fuel consumption, fuel pressure, output rotational speed, output torque, cylinder temperature, exhaust temperature, and atmospheric pressure.

2018201779 13 Mar 2018 [0013] Typ ically, the controller is configured to control the mechanical output of the prime mover by varying any of the suitable operating characteristics.

[0014] Typically, the electrical generator comprises a synchronous three-phase AC alternator.

[0015] Typ ically, the synchronous three-phase AC alternator has 2/3 pitch winding configuration and is directly coupled to the prime mover mechanical output. Other winding configurations can be accommodated depending on the numbers of alternators pole.

[0016] Typically, the electrical generator operating characteristics continuously monitored by the controller are selected from a group consisting of voltage output, current output, excitation system voltage, excitation system current, winding temperature, magnetic field status, air intake and air discharge.

[0017] Typ ically, the controller is configured to control the excitation system of the generator by varying any of the suitable operating characteristics of the electrical generator .

[0018] Preferably, the controllable excitation system comprises a voltage regulator whereby the controller is able to control generator voltage output.

[0019] Typ ically, the controller, via the voltage regulator, is configured to control the generator output voltage by controlling the excitation system through pulsewidth modulation.

2018201779 13 Mar 2018 [0020] Typ ically, system includes switchgear electrically coupling the generator and the induction motor, said switchgear having a circuit breaker monitored and controlled by the controller for selectively decoupling the generator and the induction motor, as required, as a safety feature.

[0021] Typ ically, the electrical induction motor comprises a squirrel-cage winding configuration.

[0022] Typ ically, the electrical motor operating characteristics continuously monitored by the controller are selected from a group consisting of nominal voltage, nominal current, a frequency range, lock rotor current, power factor and operating efficiency.

[0023] Typ ically, the pump is selected from a group consisting of a centrifugal pump, a reciprocating pump, a centrifugal fan, a blower and a compressor, but other types of fluid movers may also be used.

[0024] Typically, the pump operating characteristics continuously monitored by the controller are selected from a group consisting of fluid flow rate, fluid pressure, fluid level, pump acceleration and deceleration time, pump frequency, pump rotational speed ranges, and overall pump hydraulic performance.

2018201779 13 Mar 2018 [0025]

Typically the controller comprises any suitable central processing unit having electronic circuitry configured to perform arithmetic, logical, control and/or input/output (I/O) operations as specified by a set of instructions .

[0026]

Typically, the controller logic controller (PLC).

[0027] comprises a programmable

Typically, the controller comprises a remote monitoring interface for remotely monitoring and/or controlling the system.

[0028] According to a further aspect of the invention there is provided a controller for an electrical system for operatively driving a pump, the system having a prime mover with a controllable mechanical output, an electrical generator mechanically coupled to the prime mover output, an electrical induction motor operatively supplied with electrical power from the electrical generator, and the pump driven by the induction motor for operatively displacing fluid, said controller comprising:

an interface for interfacing with a plurality of sensors for operatively monitoring operating characteristics of the prime mover, electrical generator, induction motor and pump; and a memory arrangement operatively programmed with a speed-torque relationship of both the prime mover and induction motor and a performance curve of the pump;

the controller configured to:

i) Continuously monitor the operating characteristics; and

2018201779 13 Mar 2018 ii) automatically and dynamically control the prime mover output and an excitation system of the generator excitation system whereby generator voltage output is controllable, in order to dynamically and continuously match the speedtorque relationship of the prime mover to that of the induction motor and the pump performance curve;

so that optimal energy transfer efficiency through the system is facilitated whilst user-selectable pump fluid flow rate, fluid pressure and fluid level are maintainable when displacing fluid via the pump.

[0029] Typ ically, the prime mover comprises an internal combustion engine, such as a diesel engine, but other types of engines may also be apposite.

[0030] Typ ically, the prime mover operating characteristics continuously monitored by the controller are selected from a group consisting of oil pressure, oil temperature, oil level, coolant level, coolant temperature, inlet air pressure, inlet air temperature, fuel level, fuel consumption, fuel, pressure, output rotational speed, output torque, cylinder temperature, exhaust temperature, and atmospheric pressure.

[0031] Typ ically, the controller is configured to control the mechanical output of the prime mover by varying any of the suitable operating characteristics.

[0032] Typically, the electrical generator comprises a synchronous three-phase AC alternator.

[0033] Typ ically, the synchronous three-phase AC alternator has 2/3 pitch winding configuration and is directly coupled to the prime mover mechanical output. Other winding configurations can be accommodated depending on the numbers of alternators pole.

2018201779 13 Mar 2018 [0034] Typically, the electrical generator operating characteristics continuously monitored by the controller are selected from a group consisting of voltage output, current output, excitation system voltage, excitation system current, winding temperature, magnetic field status, air intake and air discharge.

[0035] Typ ically, the controller is configured to control the excitation system of the generator by varying any of the suitable operating characteristics of the electrical generator .

[0036] Preferably, the controllable excitation system comprises a voltage regulator whereby the controller is able to control generator voltage output.

[0037] Typ ically, the controller, via the voltage regulator, is configured to control the generator output voltage by controlling the excitation system through pulsewidth modulation.

[0038] Typically, switchgear electrically couples the generator and the induction motor, said switchgear having a circuit breaker monitored and controlled by the controller for selectively decoupling the generator and the induction motor, as required, as a safety feature.

2018201779 13 Mar 2018 [0039] Typ ically, the electrical induction motor comprises a squirrel-cage winding configuration.

[0040] Typ ically, the electrical motor operating characteristics continuously monitored by the controller are selected from a group consisting of nominal voltage, nominal current, a frequency range, lock rotor current, power factor and operating efficiency.

[0041] Typ ically, the pump is selected from a group consisting of a centrifugal pump, a reciprocating pump, a centrifugal fan, a blower and a compressor, but other types of fluid movers may also be used.

[0042] Typically, the pump operating characteristics continuously monitored by the controller are selected from a group consisting of fluid flow rate, fluid pressure, fluid level, pump acceleration and deceleration time, pump frequency, pump rotational speed ranges, and overall pump hydraulic performance.

[0043] Typically, the controller comprises any suitable central processing unit having electronic circuitry configured to perform arithmetic, logical, control and/or input/output (I/O) operations as specified by a set of instructions .

[0044]

Typically, the controller comprises a programmable logic controller (PLC).

[0045] Typ ically, the controller comprises a remote monitoring interface for remotely monitoring and/or controlling the system.

2018201779 13 Mar 2018

BRIEF DESCRIPTION OF THE DRAWINGS

The description will be made with reference to the accompanying drawing in which:

Figure 1 is a diagrammatical representation of one embodiment of an electrical system for operatively driving a pump, in accordance with an aspect of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS [0046] Further features of the present invention are more fully described in the following description of several nonlimiting embodiments thereof. This description is included solely for the purposes of exemplifying the present invention to the skilled addressee. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. In the figures, incorporated to illustrate features of the example embodiment or embodiments, like reference numerals are used to identify like parts throughout.

[0047] Referring now to Figure 1, there is shown one example of an electrical system 10 for operatively driving a pump 18. The system 10 generally comprises a prime mover 12 having a controllable mechanical output, and a synchronous three ¢3) phase alternating current electrical generator 14 mechanically coupled to the prime mover output, as shown.

2018201779 13 Mar 2018

The generator 14 operatively generates electrical power and has a controllable excitation system whereby the generator voltage output is controllable. When combined with a suitable controller 20, described in more detail below, the prime mover 12, generator 14 and controller 20 typically form a generator assembly 34, as shown.

[0048] The system 10 finds typical, yet non-limiting, application in mining water management, particularly dewatering applications, such as in an open pit or an underground mine. Below surface water management is a critical operation, utilised extensively in the mining industry to remove or lower aquifer water levels in a controllable manner, by pumping the water out using purposely build pumps generally driven by three-phase induction motors directly coupled to a pump. Other related application includes injecting an amount of water into the ground into purposely drilled holes called wellbores. Another application is where the pump is above-ground, such as in a transfer station, to maintain a desired flow, pressure, temperature or level.

[0049] These pumps generally require three-phase electrical power to drive them and in typical installation locations, mains grid power is not available. It is known that electrical generators provide electrical power at a frequency of 50Hz or 60Hz, depending on the applicable local regulation. In a steady state operation, at the supplied frequency, a pump will deliver a relatively stable flow, pressure or temperature.

2018201779 13 Mar 2018 [0050] If any of these pump operating characteristics require variation, then at least one of the process parameters, being operating characteristics of the components driving the pump, has to change in a controllable manner. Typically, the most important parameter or characteristic of that pump that needs to be changed is fluid flow rate, and this parameter can be changed in multiple ways: by throttling a flow control valve, by controlling the pump delivery rate via limiting or controlling the power and frequency supplied thereto, etc. In the present invention, by restricting any process parameters, flow or electrical power, the overall system efficiency and reliability are reduced proportional to the type of restriction utilised.

[0051] Accordingly, the system 10 also includes an electrical induction motor 16 operatively supplied with electrical power from the electrical generator 14, and a pump 18 driven by the induction motor 16 for operatively displacing fluid. Operating characteristics of the pump 18 generally comprise a measurable fluid flow rate, fluid pressure and fluid level. As described above, the motor 16 and pump 18 generally form part of a pumping package 36 as a wellbore or transfer station pumping installation. Such an installation typically includes so-called headworks 30 influenced by pump operating characteristics of fluid flow rate, pressure, temperature, etc. These operating characteristics are generally measured or monitored by a controller 20 of the system 10, typically via control feedback into a suitable interface panel, such as a junction box 32, or the like.

2018201779 13 Mar 2018 [0052] The controller 20 of the system 10 is programmed with a speed-torque relationship of both the prime mover 12 and induction motor 16, as well as a performance curve of the pump 18. The controller 20 is then configured to continuously monitor the operating characteristics of the prime mover 12, the electrical generator 14, the induction motor 16 and the pump 18, and to automatically and dynamically control the prime mover output and excitation system in order to dynamically and continuously match the speed-torque relationship of the prime mover 12 to that of the induction motor 16 and the pump performance curve. In this manner, optimal energy transfer efficiency through the system 10 can be facilitated whilst user-selectable fluid flow rate, fluid pressure and fluid level are maintainable when displacing fluid via the pump 18.

[0053] The skilled addressee will appreciate that a speed-torque relationship of either the prime mover 12 or the induction motor 16 may vary depending on prime mover or motor design and is generally indicative of desired operating ranges for a specific prime mover or motor having increased power efficiency. It is also to be appreciated that the performance curve of the pump 18 provides an indication of producible pressure relational to producible fluid flow rate and a desired operating range delivering maximised efficiency for such variables.

[0054] In light hereof, by dynamically matching such speed-torque relationships and performance curves whilst maintaining the user-selectable pump operating characteristics, allows for efficient energy transfer through the system 10. As an energy source for the system 10 typically comprises a fuel source for the prime mover 12, such energy efficiency generally allows for minimised fuel use, resulting in overall cost-saving.

2018201779 13 Mar 2018 [0055] The prime mover 12 typically comprises an internal combustion engine, such as a diesel engine, but other types of engines may also be used. For example, any reciprocating internal combustion engine can be used fuelled by diesel, natural gas, propane, LPG, ethanol, etc. Also, other types of prime movers can be used, such as external combustion engines, diesel and gas turbines, water propelled turbines, wind turbines, solar power, etc. The skilled addressee will appreciate that such alternative prime movers will typically require slightly different controller configurations, as is known in the art .

[0056] Typically, the prime mover operating characteristics continuously monitored by the controller are selected from a group consisting of oil pressure, oil temperature, oil level, coolant level, coolant temperature, inlet air pressure, inlet air temperature, fuel level, fuel consumption, fuel, pressure, output rotational speed, output torque, cylinder temperature, exhaust temperature, and atmospheric pressure.

[0057] The controller 20 is configured to control the mechanical output of the prime mover by varying any of the suitable operating characteristics. In one example, the prime mover 12 comprises a diesel engine with a governor or engine control unit (ECU) 28 which can interface with a large numbers of sensors within the engine 12. In this manner, the controller 20 has the ability to monitor and control the rotational speed, torque and other operating characteristics or parameter set points of the engine via a digital physical communication layer, such as CAN, RS232 or

RS484, as is known in the art.

2018201779 13 Mar 2018 [0058] In one example, communication between ECU 28 and the controller 20 is typically via a CAN bus utilizing various protocols, such as VP, MTU, J1939, J 1850, KWP2000, J1962, etc. To control and monitor the engine, multiple parameters and commands are generally received and sent from the controller 20 at a very high speed, minimizing substantially the wiring requirements, system efficiency, and reliability, and maximizing the uptime. CAN bus communication between controller 20 and engine 12 impose a clear and distinctive advantage in controlling the engine rotational speed, torque and fuel consumption, the ultimate goal being overall system efficiency.

[0059] Appl leant has identified some examples of known engines with which the controller 20 can communicate via CAN or Modbus protocol, as described above, including: Standard 1939, VOLVO EDC3, VOLVO EDC4, VOLVO EMS2, SCANIA, IVECO, IVECO VECTOR, JOHN DEERE HPCR, JOHN DEERE 4045, 6068, CATERPILLAR (series 3000), CATERPILLAR (other series), PERKINS 2300/2800, PERKINS 1100, MTU 304, MTU 303, MTU 302, MTU 201, MTU ADEC, DEUTZ EMR2, CUMMINS, CUMMINS/2, CUMMINS/485.

[0060] The electrical generator 14 typically comprises a synchronous three-phase AC alternator with a 2/3 pitch winding configuration and is directly coupled to the prime mover mechanical output. Other winding configurations can be

2018201779 13 Mar 2018 accommodated depending on the numbers of alternators pole. The electrical generator operating characteristics continuously monitored by the controller 20 are selected from a group consisting of voltage output, current output, excitation system voltage, excitation system current, winding temperature, magnetic field status, air intake and air discharge.

[0061] The controller 20 is generally configured to control the excitation system of the generator 14 by varying any of the suitable operating characteristics of the electrical generator. The controllable excitation system typically comprises a voltage regulator 22 via which the controller 20 is able to control generator voltage output. The controller 20, via the voltage regulator 22, is typically configured to control the generator output voltage by controlling the excitation system through pulse-width modulation, or the like.

[0062] In a preferred embodiment, the system 10 generally includes switchgear 24 electrically coupling the generator 14 and the induction motor 16. The switchgear 24 also has a circuit breaker monitored and controlled by the controller 20 for selectively decoupling the generator 14 and the induction motor 16, as required, as a safety feature.

[0063] In one example, the system 10 uses a synchronous three-phase alternator without sliprings and revolving field brushes, directly coupled to the engine 12. The preferred windings for the alternator are 2/3 pitch optimized for a required voltage and frequency, having insulation class H., rated for a temperature rise of 125°K and an excitation

2018201779 13 Mar 2018 system permanent magnet generator (PMG) which impose a short-circuit capacity of 3 times the nominal current for 10 seconds. Additional temperature sensing elements are utilised to monitor the winding temperature, air intake and discharge as a performance monitoring parameters, as temperature represent one of the critical parameter in the alternator functionality and performance.

[0064] The alternator voltage can be adjusted via the excitation system closely controlled by the voltage regulator (VR) with a closed control loop an external controller voltage set point from the controller 21. Depending on requirements, the rated output voltage can be 400VAC, 480VAC, 690VAC, 2600VAC, 3300VAC, 4100VAC, 4800VAC, etc. For example, the engine 12 and alternator can be coupled directly or via a transfer gearbox to a variety of

synchronous	alternators, some	manufacturers	including
LeroySomer, etc .	AVK, TOYO, MeccAlte,	Stamford, WEG,	LINZ, ABB,

[0065] It is to be appreciated that the primary function of the voltage regulator 22 is to maintain a constant voltage at the alternator terminals by precisely controlling the excitation utilising PWM as the most effective control system. The voltage regulator 22 is generally able to monitor the alternator exciter inductor field, exciter armature, EMC varistor status, diode block and main field performance. An important control parameter in the system 10 is the ability to precisely control the excitation level which directly controls the alternator voltage output which influences the induction motor speed and torque characteristics which further influence the controlled

2018201779 13 Mar 2018 process value. Examples of voltage regulator manufacturers include Basler DECS-150, DECS-200, DEIF DVC 310, Leroy-Somer

D510, etc.

[0066] The electrical switchgear 24 are utilised to protect the load and power source (alternator) by disconnecting them form each other, using a circuit breaker, manual operated or automatic with motor mechanism, air or vacuum type, magnetic and/or thermal, or electronic, with protection setting for rated voltage, rated current, tripping current level and overload and short-circuit current breaking characteristics, along with current imbalance, earth fault level, etc. The circuit breaker is externally monitored and controlled by the controller 20 to connect or disconnect the induction motor load in accordance with a desired operating condition.

[0067] The electrical induction motor 16 generally comprises a squirrel-cage winding configuration. The electrical motor operating characteristics continuously monitored by the controller are selected from a group consisting of nominal voltage, nominal current, a frequency range, lock rotor current, power factor and operating efficiency .

[0068] The pump can be selected from a group consisting of a centrifugal pump, a reciprocating pump, a centrifugal fan, a blower and a compressor, but other types of fluid movers may also be used. Typically, the pump operating characteristics continuously monitored by the controller are selected from a group consisting of fluid flow rate, fluid pressure, fluid level, pump acceleration and deceleration

2018201779 13 Mar 2018 time, pump frequency, pump rotational speed ranges, and overall pump hydraulic performance. The controller 20 generally takes into consideration the acceleration and deceleration time, pump process values, frequency or rotational speed ranges and the overall pump hydraulic performance .

[0069] The controller 20 can comprise any suitable central processing unit having electronic circuitry configured to perform arithmetic, logical, control and/or input/output (I/O) operations as specified by a set of instructions. Typically, the controller comprises a programmable logic controller (PLC). The controller 20 generally also comprises a remote monitoring interface 26 for remotely monitoring and/or controlling the system 10.

[0070] In one example, the controller 20 is based on a SICES generator controller DST4602 Evolution with colour screen human machine interface (HMI) with programmable logic control logic (PLC) included. There are also additional RTD, thermocouple, voltage and current inputs via additional CAN bus modules. The controller 20 has the native ability to be remote controlled for extra flexibility via ModBus communication protocol over RS232, rs485 and TCP/IP physical layer, where it can be integrated into a SCADA, as is known in the art.

[0071] Based on Applicant's experimental data, the avoidable frequencies using a Volvo TAD754GE diesel engine and LeroySomer LSA 46.2L6 J6/4 alternator are below 28 Hz, with other engine-alternators combinations having similar limitations. As such, the controller 20 is generally

2018201779 13 Mar 2018 programmed to control the operating characteristics to operate between 30 to 60Hz . This frequency limitation defines the functional frequency range of the system 10 from an electrical power perspective. Also, it restricts the induction motor 16 coupled pump 18 to run at speeds less than minimum functional speed typically imposed by pump manufacturers .

[0072] Another power limitation is the voltage output of the generator 14 which is precisely controlled to deliver the desired electrical power and protect the engine 14 from stall, in the event of load being more than the maximum deliverable power from the alternator 14. This closed control loop system is one of the two dynamically controlled parameter used by the controller 20. The controller 20 controls the engine parameters and its performance by continually adjusting the rotational speed based on the primary control parameter of the headworks 30 (level, flow, pressure or frequency) and is achieved, depending on the selected engine, by adjusting the throttle on mechanical engine or by requesting a particular speed or torque, on electronic engines, as a command over the CANbus to the ECU 28 .

[0073] An important feature of the system 10, being a clear and distinct difference between conventional variable speed or soft start systems, are at start-up. When the system 10 is required to start, the engine 12 generally starts with the load 36 connected and circuit breaker closed, without excitation (starting); after the system 10 is started, it runs for a period of time at a desired engine idle speed, typically between 750 to 900rpm, for a warmup

2018201779 13 Mar 2018 (idle run); after the idle run time, the alternator excitation is engaged and output voltage is increased proportional to the rotational speed of the load, without exceeding the maximum power delivered by the engine in accordance with its power curve and without exceeding the synchronous alternator overcurrent level, as the current level.

[0074] The induction motor 16 coupled to the pump 18 achieves minimum speed typically less than three seconds under full operational load. This starting phase is operationally similar to conventional soft starter systems, with the exception that the delivered power in the system 10 is at variable speed and is identical with an external variable speed drive or variable frequency drive which delivers power to the load at variable frequency and voltage, with the exception the power system is not affected by the harmonics generated by Soft Starter or VSD, resulting into a much smoother operation, reduces copper loses, reduces cable temperature; as the power supplied to the induction motor is a pure sine-ware without any distortions. The final speed is then determined by the functional mode selected.

[0075] From a process perspective, the pump temperature is monitored and if above a typical 60°C, the system 10 will initiate a warning and above 70°C will initiate an alarm. The difference between warning and alarm is that the system 10 will signal a warning if a parameter is outside of normal operation value but the system will continue to function; and an alarm is a situation where the system 10 will signal an outside warning limit value and will shut down the

2018201779 13 Mar 2018 system. As designed, there are two types of alarm use in system 10: one which will trip the system e.g. low bore level, electrical faults, pump temperature and critical mechanical faults; and process alarms which will not trip the system 10 but will inhibit operation e.g. stop bore level, low flow, high flow, pump low pressure, pump high pressure, discharge low pressure, discharge high pressure and remote inhibit.

[0076] The controller 20 generally monitors and displays the following process instruments: pump temperature, Input: RTD (PTC, NTC), slope indicator (level transmitter), Input: 4-20mA, flow transmitter; Input: 4-20mA, pulse, PWM, pump discharge pressure, Input: 4-20mA, PNP, NPN, discharge pressure, Input: 4-20mA, PNP, NPN, instrument failure. It also control includes user defined operation parameters: level start (m) — System starts, Level Stop (m) — System stops, Minimum bore level (m) — System trips due dangerously low bore level, Pump temperature warning and alarm(°C) — pump protection, Flow Levels, minimum and maximum (Vs) — pump cooling and pipework protection, Pump pressure (kPa) — pump protection and efficiency, pipework protection, Starting interval — pump and generator protection.

[0077] The system 10 can also display the system efficiency: fuel consumption, 1/hr, water pumped per litre of diesel consumed, kL/L, water totalizer, m³ and able to monitor and control optional equipment: pipework water temperature, Input: RTD (PTC, NTC), external fuel tank monitoring and protections, pump type automatic detection, additional 4-20mA input and outputs, alarm beacon, user selectable colour, radio communication equipment, etc.

2018201779 13 Mar 2018 [0078] The system 10 generally includes a number of selectable operational modes, such as: Generator - This mode of operation includes all the details specified and functions as generic power generator suppling desired frequency, 50 or 60Hz. In this mode all the process conditions are ignored and if the induction motor is connected to the system, prohibits the generator starting and trips the circuit breaker.

[0079] Operational mode soft starter - This mode of operation controls the pump power by applying the voltage gradually to the desired frequency (from 30 to 60Hz), Start/Stop manually or automatic by the level transmitter, monitors the pump connection, monitors earth continuity, monitors alternator.

[0080] Operational mode level control - This mode of operation controls the bore water level, controls the pump power by varying the frequency (30 to 60Hz) to maintain a desired water level, Start/Stop manually or automatic by the level transmitter, monitors the pump connection, monitors earth continuity, monitors alternator winding temperature, monitors the pump temperature, monitors flow, monitors pump pressure upstream and downstream.

[0081] Op erational mode flow control - This mode of operation controls the bore water flow, controls the pump power by varying the frequency (30 to 60Hz) to maintain a desired water flow, Start/Stop manually or automatic by the level transmitter, monitors the pump connection, monitors earth continuity, monitors alternator winding temperature,

2018201779 13 Mar 2018 monitors the pump temperature, monitors pump pressure upstream and downstream.

[0082] Op erational mode pressure mode - This mode of operation controls the pressure, controls the pump power by varying the frequency (30 to 60Hz) to maintain a desired water pressure, Start/Stop manually or automatic by the level transmitter, monitors the pump connection, monitors earth continuity, monitors alternator winding temperature, monitors the pump temperature, monitors flow.

[0083] Appl leant believes it particularly advantageous that, the system 10 carries multiple distinctive advantages over conventional variable speed drive (VSD) or soft starter (SS) system, by eliminating the harmonics induced by the VSD, less copper losses due to harmonics, less operational temperature for engine, alternator, switchgear, cables, induction motor and pump; eliminating the requirements for VSD, transformers, associated filters, special cables, external switchgear and electrical cabinets; smaller foot print, decreased weight, increased reliability and fuel efficiency. Oversizing is eliminated in comparison with the traditional systems as the pumping system at full load is at 75% of the maximum power level provided by the power generator. This load level coincides with the maximum fuel efficiency of the engine.

[0084] As the system 10 is revolving at reduced speed the mechanical wear is also reduced, via reduced vibration, reduces friction and reduces rotational speed. The controller 10 is reduced to a single box with latest control technology, extended temperature range and increased

2018201779 13 Mar 2018 vibration resistance. Less electrical and mechanical stress due to a smoother starting and running operation; consequently longer asset operation. Capital investment is reduced to 60 - 70% of the traditional system and operation cost is reduced with 7-15% based on the fuel consumption alone .

[0085] Opt ional embodiments of the present invention may also be said to broadly consist in the parts, elements and features referred to or indicated herein, individually or collectively, in any or all combinations of two or more of the parts, elements or features, and wherein specific integers are mentioned herein which have known equivalents

in the art	to	which	the	invention relates, such	known
equivalent s	are	deemed	to	be incorporated herein	as if
individually	set	forth .	In	the example embodiments,	well-
known proce	sses,	well-	known	device structures, and	well

known technologies are not described in detail, as such will be readily understood by the skilled addressee.

[0086] The use of the terms a, an, said, the, and/or similar referents in the context of describing various embodiments (especially in the context of the claimed subject matter) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms comprising, having, including, and containing are to be construed as open-ended terms (i.e., meaning including, but not limited to,) unless otherwise noted. As used herein, the term and/or includes any and all combinations of one or more of the associated listed items. No language in the specification should be construed as indicating any non-claimed subject matter as essential to the practice of the claimed subject matter.

2018201779 13 Mar 2018 [0087] It is to be appreciated that reference to one example or an example of the invention, or similar exemplary language (e.g., such as) herein, is not made in an exclusive sense. Various substantially and specifically practical and useful exemplary embodiments of the claimed subject matter are described herein, textually and/or graphically, for carrying out the claimed subject matter.

[0088] Accordingly, one example may exemplify certain aspects of the invention, whilst other aspects are exemplified in a different example. These examples are intended to assist the skilled person in performing the invention and are not intended to limit the overall scope of the invention in any way unless the context clearly indicates otherwise. Variations (e.g. modifications and/or enhancements) of one or more embodiments described herein might become apparent to those of ordinary skill in the art upon reading this application. The inventor(s) expects skilled artisans to employ such variations as appropriate, and the inventor(s) intends for the claimed subject matter to be practiced other than as specifically described herein.

[0089] Any method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

Claims (36)

1. An electrical system for operatively driving a pump, said system comprising:

a prime mover having a controllable mechanical output;

an electrical generator mechanically coupled to the prime mover output, said generator operatively generating electrical power and having a controllable excitation system whereby generator voltage output is controllable;

an electrical induction motor operatively supplied with electrical power from the electrical generator;

a pump driven by the induction motor for operatively displacing fluid, pump operating characteristics comprising a measurable fluid flow rate, fluid pressure and/or fluid level; and a controller programmed with a speed-torque relationship of both the prime mover and induction motor and a performance curve of the pump, said controller configured to:

i) continuously monitor operating characteristics of the prime mover, the electrical generator, the induction motor and the pump;

ii) monitor a temperature of the pump and raise an alarm and/or inhibit operation of the prime mover and/or excitation system at a predetermined pump temperature; and iii) automatically and dynamically control the prime mover output and excitation system in order to dynamically and continuously match the speed-torque relationship of the prime mover to that of the induction motor and the pump performance curve;

so that optimal energy transfer efficiency through the system is facilitated whilst user-selectable fluid flow rate, fluid

2018201779 24 Apr 2020 pressure and/or fluid level are maintainable when displacing fluid via the pump, the controller further providing thermal protection for the pump.

2. The electrical system of claim 1, wherein the prime mover comprises an internal combustion engine.

3. The electrical system of claim 1, wherein the prime mover operating characteristics continuously monitored by the controller are selected from a group consisting of oil pressure, oil temperature, oil level, coolant level, coolant temperature, inlet air pressure, inlet air temperature, fuel level, fuel consumption, fuel, pressure, output rotational speed, output torque, cylinder temperature, exhaust temperature, and atmospheric pressure.

4. The electrical system of claim 3, wherein the controller is configured to control the mechanical output of the prime mover by varying any of the suitable operating characteristics .

5. The electrical system of claim 1, wherein the electrical generator comprises a synchronous three-phase AC alternator.

6. The electrical system of claim 5, wherein the synchronous three-phase AC alternator has 2/3 pitch winding configuration and is directly coupled to the prime mover mechanical output.

7. The electrical system of claim 1, wherein the electrical generator operating characteristics continuously monitored by the controller are selected from a group consisting of voltage output, current output, excitation system voltage,

2018201779 24 Apr 2020 excitation system current, winding temperature, magnetic field status, air intake and air discharge.

8. The electrical system of claim 7, wherein the controller is configured to control generator by varying any of the suitable operating characteristics of the electrical generator .

9. The electrical system of claim 1, wherein the controllable excitation system comprises a voltage regulator whereby the controller is able to control generator voltage output.

10. The electrical system of claim 9, wherein the controller, via the voltage regulator, is configured to control the generator output voltage by controlling the excitation system through pulse-width modulation.

11. The electrical system of claim 1, wherein system includes switchgear electrically coupling the generator and the induction motor, said switchgear having a circuit breaker monitored and controlled by the controller for selectively decoupling the generator and the induction motor, as required, as a safety feature.

12. The electrical system of claim 1, wherein the electrical induction motor comprises a squirrel-cage winding configuration.

13. The electrical system of claim 1, wherein the electrical motor operating characteristics continuously monitored by the controller are selected from a group consisting of nominal

2018201779 24 Apr 2020 voltage, nominal current, a frequency range, lock rotor current, power factor and operating efficiency.

14. The electrical system of claim 1, wherein the pump is selected from a group consisting of a centrifugal pump, a reciprocating pump, a centrifugal fan, a blower and a compressor .

15. The electrical system of claim 1, wherein the pump operating characteristics continuously monitored by the controller are selected from a group consisting of fluid flow rate, fluid pressure, fluid level, pump acceleration and deceleration time, pump frequency, pump rotational speed ranges, and overall pump hydraulic performance.

16. The electrical system of claim 1, wherein the controller comprises any suitable central processing unit having electronic circuitry configured to perform arithmetic, logical, control and/or input/output (I/O) operations as specified by a set of instructions.

17. The electrical system of claim 1, wherein the controller comprises a programmable logic controller (PLC).

18. The electrical system of claim 1, wherein the controller comprises a remote monitoring interface for remotely monitoring and/or controlling the system.

19. A controller for an electrical system for operatively driving a pump, the system having a prime mover with a controllable mechanical output, an electrical generator mechanically coupled to the prime mover output and having an

2018201779 24 Apr 2020 excitation system whereby generator voltage output is controllable, an electrical induction motor operatively supplied with electrical power from the electrical generator, and the pump driven by the induction motor for operatively displacing fluid, said controller comprising:

an interface for interfacing with a plurality of sensors for operatively monitoring operating characteristics of the prime mover, electrical generator, induction motor and pump; and a memory arrangement operatively programmed with a speed-torque relationship of both the prime mover and induction motor and a performance curve of the pump;

the controller configured to:

i) continuously monitor the operating characteristics;

ii) monitor a temperature of the pump and raise an alarm and/or inhibit operation of the prime mover and/or excitation system at a predetermined pump temperature; and iii) automatically and dynamically control the prime mover output and excitation system in order to dynamically and continuously match the speed-torque relationship of the prime mover to that of the induction motor and the pump performance curve;

so that optimal energy transfer efficiency through the system is facilitated whilst user-selectable pump fluid flow rate, fluid pressure and fluid level are maintainable when displacing fluid via the pump, the controller further providing thermal protection for the pump.

20. The controller of claim 19, wherein the prime mover comprises an internal combustion engine.

2018201779 24 Apr 2020

21. The controller of claim 19, wherein the prime mover operating characteristics continuously monitored by the controller are selected from a group consisting of oil pressure, oil temperature, oil level, coolant level, coolant temperature, inlet air pressure, inlet air temperature, fuel level, fuel consumption, fuel, pressure, output rotational speed, output torque, cylinder temperature, exhaust temperature, and atmospheric pressure.

22. The controller of claim 21, wherein the controller is configured to control the mechanical output of the prime mover by varying any of the suitable operating characteristics .

23. The controller of claim 19, wherein the electrical generator comprises a synchronous three-phase AC alternator.

24. The controller of claim 23, wherein the synchronous three-phase AC alternator has 2/3 pitch winding configuration and is directly coupled to the prime mover mechanical output.

25. The controller of claim 19, wherein the electrical generator operating characteristics continuously monitored by the controller are selected from a group consisting of voltage output, current output, excitation system voltage, excitation system current, winding temperature, magnetic field status, air intake and air discharge.

26. The controller of claim 25, wherein the controller is configured to control the excitation system of the generator by varying any of the suitable operating characteristics of the electrical generator.

2018201779 24 Apr 2020

27. The controller of claim 19, wherein the controllable excitation system comprises a voltage regulator whereby the controller is able to control generator voltage output.

28. The controller of claim 27, wherein the controller, via the voltage regulator, is configured to control the generator output voltage by controlling the excitation system through pulse-width modulation.

29. The controller of claim 19, wherein switchgear electrically couples the generator and the induction motor, said switchgear having a circuit breaker monitored and controlled by the controller for selectively decoupling the generator and the induction motor, as required, as a safety feature .

30. The controller of claim 19, wherein the electrical induction motor comprises a squirrel-cage winding configuration.

31. The controller of claim 19, wherein the electrical motor operating characteristics continuously monitored by the controller are selected from a group consisting of nominal voltage, nominal current, a frequency range, lock rotor current, power factor and operating efficiency.

32. The controller of claim 19, wherein the pump is selected from a group consisting of a centrifugal pump, a reciprocating pump, a centrifugal fan, a blower and a compressor .

2018201779 24 Apr 2020

33. The controller of claim 19, wherein the pump operating characteristics continuously monitored by the controller are selected from a group consisting of fluid flow rate, fluid pressure, fluid level, pump acceleration and deceleration time, pump frequency, pump rotational speed ranges, and overall pump hydraulic performance.

34. The controller of claim 19, which comprises any suitable central processing unit having electronic circuitry configured to perform arithmetic, logical, control and/or input/output (I/O) operations as specified by a set of instructions .

35. The controller of claim 19, which comprises a programmable logic controller (PLC).

36. The controller of claim 19, which comprises a remote monitoring interface for remotely monitoring and/or controlling the system.