AU2019203914A1 - Conductor loss optimisation in an electrical system for driving a pump - Google Patents

Abstract

Provided is an electrical system 10 for operatively driving a pump 18 which includes automatic conductor loss optimisation and related efficiency improvements. The system 10 generally comprises a prime mover 12 having a controllable mechanical output, and a synchronous three phase alternating current 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. When combined with a suitable controller 20, the prime mover 12, generator 14 and controller 20 typically form a generator assembly 34. 0 C) ce) cv C/) cc $ 0 -w en o z w 0- IL cr- I* co 0I I- I wI I -I 0 _ z ii wO wO II I w C-4 LL o LLLf -3. 1Ir 04w 1~ 0 04 '0 CN I IiI z z -0 0 0 <10 cc 04 x D c'. ____ _____ W_ _ _ _ _ _

Description

CONDUCTOR LOSS OPTIMISATION IN 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 conductor loss optimisation in 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] Applicant has developed an electrical system and associated controller for operatively driving a pump which are described in Australian Patent Application No. 2017213531, the contents of which are incorporated herein by reference .

[0004] Winding, conductor or copper loss is well-known in the art of electrical engineering and is typically the term given to heat produced by electrical currents in the conductors and/or windings of electrical machines or devices. Such heat production is 'lost' electrical energy and is determined by the electrical resistance of the conductor, the current in the conductor, as well as the

2019203914 04 Jun 2019 period of time the current is maintained. As the time period is relevant, a frequency of electrical current in alternating current, or AC, systems is relevant to calculating conductor losses.

[0005] Accordingly, given the relationship between voltage, current and resistance, it has been practically observed that a voltage loss or potential difference over a length of a conductor is significantly higher at low frequencies in comparison with voltage losses at high frequencies in AC systems.

[0006] In applications where such conductor losses have an appreciable impact on system efficiency, such as in Applicant's electrical system described in Australian Patent Application No. 2017213531, optimising for conductor loss may lead to significant savings.

[0007] For example, where Applicant's electrical system is used to drive a pump in industrial pumping arrangements, such as mining water management, particularly dewatering applications such as in an open pit or an underground mine where below-surface water management is a critical operation, a prime mover and electrical generator is often geographically distant from an induction motor driving a pump. As such, conductors arranging such electrical generator in electrical communication with the induction motor have appreciable resistance given their length, where variable frequency operation plays a further role in conductor loss.

2019203914 04 Jun 2019 [0008] Typically, in such application, an internal combustion engine functions as prime mover and even a relatively small efficiency increase can mean thousands of dollars in fuel savings over a lifetime of the system.

[0009] The present invention was conceived with these shortcomings in mind in an attempt to ameliorate such shortcomings in the prior art.

SUMMARY OF THE INVENTION [0010] 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 with electrical power from the electrical generator via conductors;

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, as well as physical characteristics of the conductors, said controller configured to:

2019203914 04 Jun 2019

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

ii) automatically and continuously calculate conductor loss based on the physical characteristics of the conductors relative to said monitored operating characteristics; and iii) automatically and dynamically control the prime mover output and/or 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 whilst automatically compensating for calculated conductor loss;

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

[0011] 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 in light of increased power efficiency, e.g. to reduce energy losses. 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 .

2019203914 04 Jun 2019 [0012] In light hereof, by dynamically matching such speed-torque relationships and performance curves as described 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 whilst delivering the user-selectable fluid flow rate, fluid pressure and/or fluid level.

[0013] Typically, the prime mover comprises an internal combustion engine, such as a diesel engine, but other types of engines may also be apposite.

[0014] Typically, the prime mover operating characteristics continuously monitored by the controller are selected from a non-exhaustive 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.

[0015] Typically, the controller is configured to control the mechanical output of the prime mover by varying any of the suitable operating characteristics. The skilled addressee is to appreciate that such operating characteristics may vary, depending on requirements.

[0016] Typically, the electrical generator comprises a synchronous three-phase AC alternator.

2019203914 04 Jun 2019 [0017] Typically, 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.

[0018] Typically, the electrical generator operating characteristics continuously monitored by the controller are selected from a non-exhaustive group consisting of voltage output, current output, frequency, excitation system voltage, excitation system current, winding temperature, magnetic field status, air intake and air discharge.

[0019] Typically, the controller is configured to control the excitation system of the generator by varying any of the suitable operating characteristics of the electrical generator. Again, the skilled addressee is to appreciate that such operating characteristics may vary, depending on requirements .

[0020] Preferably, the controllable excitation system comprises a voltage regulator whereby the controller is able to control generator voltage output.

[0021] Typically, the controller, via the voltage regulator, is configured to control the generator output voltage by controlling the excitation system through pulsewidth modulation.

[0022] Typically, the system includes switchgear and the associated conductors electrically coupling the generator and the induction motor, said switchgear having a circuit

2019203914 04 Jun 2019 breaker monitored and controlled by the controller for selectively decoupling the generator and the induction motor, as required, as a safety feature.

[0023] Typically, the electrical induction motor comprises a squirrel-cage winding configuration.

[0024] Typically, the electrical motor operating characteristics continuously monitored by the controller are selected from a non-exhaustive group consisting of nominal voltage, nominal current, a frequency range, lock rotor current, power factor and operating efficiency.

[0025] Typically, the controller is programmed with the physical characteristics of the conductors to facilitate operative calculation of conductor loss.

[0026] Typically, the physical characteristics of the conductors are selected from a group consisting of impedance per unit length, an impedance-frequency relationship, and an impedance-temperature relationship .

[0027] Typically, the controller is configured to calculate conductor loss according to an operating frequency characteristic relative to an impedance-frequency relationship of the conductor.

[0028] In one embodiment, the controller is configured to sense a voltage output from the electrical generator and a voltage input to the induction motor to calculate conductor loss .

2019203914 04 Jun 2019 [0029] In an embodiment, the controller includes a conductor temperature sensor for sensing a temperature of the conductors to calculate conductor loss according to an impedance-temperature relationship of the conductors.

[0030] Typically, the pump is selected from a nonexhaustive 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.

[0031] Typically, the pump operating characteristics continuously monitored by the controller are selected from a non-exhaustive 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.

[0032] 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 .

[0033] Typically, the controller comprises a programmable logic controller (PLC).

[0034] Typically, the controller comprises a remote monitoring interface for remotely monitoring and/or controlling the system.

2019203914 04 Jun 2019 [0035] 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 via conductors, 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, as well as physical characteristics of the conductors;

the controller configured to:

i) continuously monitor the operating characteristics ;

ii) automatically and continuously calculate conductor loss based on the physical characteristics of the conductors relative to said monitored operating characteristics; and iii) automatically and dynamically control the prime mover output and/or 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

2019203914 04 Jun 2019 whilst automatically compensating for calculated conductor loss;

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

[0036] Typically, the prime mover comprises an internal combustion engine, such as a diesel engine, but other types of engines may also be apposite.

[0037] Typically, the prime mover operating characteristics continuously monitored by the controller are selected from a non-exhaustive 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.

[0038] Typically, the controller is configured to control the mechanical output of the prime mover by varying any of the suitable operating characteristics.

[0039] Typically, the electrical generator comprises a synchronous three-phase AC alternator.

[0040] Typically, 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.

2019203914 04 Jun 2019 [0041] Typically, the electrical generator operating characteristics continuously monitored by the controller are selected from a non-exhaustive group consisting of voltage output, current output, frequency, excitation system voltage, excitation system current, winding temperature, magnetic field status, air intake and air discharge.

[0042] Typically, the controller is configured to control the excitation system of the generator by varying any of the suitable operating characteristics of the electrical generator .

[0043]

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

[0044] Typically, the controller, via the voltage regulator, is configured to control the generator output voltage by controlling the excitation system through pulsewidth modulation.

[0045] Typically, switchgear and the associated conductors electrically couple 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.

[0046] Typically, the electrical induction motor comprises a squirrel-cage winding configuration.

2019203914 04 Jun 2019 [0047] Typically, the electrical motor operating characteristics continuously monitored by the controller are selected from a non-exhaustive group consisting of nominal voltage, nominal current, a frequency range, lock rotor current, power factor and operating efficiency.

[0048] Typically, the controller is programmed with the physical characteristics of the conductors to facilitate operative calculation of conductor loss.

[0049] Typically, the physical characteristics of the conductors are selected from a non-exhaustive group consisting of impedance per unit length, an impedancefrequency relationship, and an impedance-temperature relationship .

[0050] Typically, the controller is configured to calculate conductor loss according to an operating frequency characteristic relative to an impedance-frequency relationship of the conductor.

[0051] In one embodiment, the controller is configured to sense a voltage output from the electrical generator and a voltage input to the induction motor to calculate conductor loss .

[0052] In an embodiment, the controller includes a conductor temperature sensor for sensing a temperature of the conductors to calculate conductor loss according to an impedance-temperature relationship of the conductors.

2019203914 04 Jun 2019 [0053] Typically, the pump is selected from a nonexhaustive 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.

[0054] Typically, the pump operating characteristics continuously monitored by the controller are selected from a non-exhaustive 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.

[0055] 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 .

[0056] Typically, the controller comprises a programmable logic controller (PLC).

[0057] Typically, the controller comprises a remote monitoring interface for remotely monitoring and/or controlling the system.

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 conductor loss optimisation in an electrical

2019203914 04 Jun 2019 system for operatively driving a pump, in accordance with an aspect of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS [0058] 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.

[0059] Referring now to Figure 1, there is shown one example of an electrical system 10 for operatively driving a pump 18 which includes automatic conductor loss optimisation and related efficiency improvements. 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. 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 .

2019203914 04 Jun 2019 [0060] It will be readily apparent to a person sufficiently skilled in the art that reference herein to an electrical system also includes suitable reference to mechanical components within such system, i.e. an electromechanical system. Such broad reference to an electrical system is not to be construed as exclusive of any mechanical components.

[0061] 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 aguifer 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.

[0062] These pumps generally reguire 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 freguency of 50Hz or 60Hz, depending on the applicable local regulation. In a steady state operation, at the supplied freguency, a pump will deliver a relatively stable flow, pressure or temperature.

2019203914 04 Jun 2019 [0063] 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.

[0064] Accordingly, the system 10 also includes an electrical induction motor 16 operatively supplied with electrical power from the electrical generator 14 via suitable electrical conductors, 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.

2019203914 04 Jun 2019 [0065] 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 and physical characteristics of the conductors. 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. The controller 20 is also configured to automatically and continuously calculate conductor loss based on the physical characteristics of the conductors relative to said monitored operating characteristics, typically system electrical frequency, i.e. a frequency of voltage and current supplied to the induction motor 16. The controller 20 then automatically and dynamically controls 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 whilst automatically compensating for calculated conductor loss. 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.

[0066] Reference herein to 'continuous' is to be construed as 'at an appropriate and ongoing rate, requirements depending' , or the like, as will be apparent to the skilled addressee.

[0067] 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

2019203914 04 Jun 2019 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.

[0068] 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.

[0069] 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.

[0070] Typically, the prime mover operating characteristics continuously monitored by the controller are selected from a non-exhaustive group consisting of oil

2019203914 04 Jun 2019 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.

[0071] The controller 20 is configured to control the mechanical output of the prime mover by varying any of the suitable operating characteristics. Of course, such varying of operating characteristics will be within reason, as understood by the skilled addressee e.g. although possible, it is less likely that an inlet air temperature or atmospheric pressure will be varied, unless required. 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 number 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.

[0072] 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

2019203914 04 Jun 2019 rotational speed, torque and fuel consumption, the ultimate goal being overall system efficiency.

[0073] 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.

[0074] 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 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, frequency, excitation system voltage, excitation system current, winding temperature, magnetic field status, air intake and air discharge.

[0075] 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. As above, such operating characteristics are typically varied within engineering reason, e.g. winding temperature is less likely to be varied directly, unless required. The controllable excitation

2019203914 04 Jun 2019 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.

[0076] 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.

[0077] 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 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 performance monitoring parameters, as temperature represent one of the critical parameters in the alternator functionality and performance.

[0078] 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.

2019203914 04 Jun 2019

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, AVK, TOYO, MeccAlte, Stamford, WEG, LINZ, ABB, etc .

[0079] 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 process value. Examples of voltage regulator manufacturers include Basler DECS-150, DECS-200, DEIF DVC 310, Leroy-Somer D510, etc.

[0080] 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

2019203914 04 Jun 2019 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.

[0081] The electrical induction motor 16 generally comprises a squirrel-cage electrical motor operating monitored by the controller consisting of nominal voltage, range, lock rotor current, efficiency.

winding configuration. The characteristics continuously are selected from a group nominal current, a frequency power factor and operating [0082] As mentioned above, the controller 20 is programmed with the physical characteristics of the conductors to facilitate operative calculation of conductor loss. Such physical characteristics of the conductors are well-known in the art and typically selected from a nonlimiting group consisting of impedance per unit length, an impedance-frequency relationship, and an impedancetemperature relationship.

[0083] The controller 20 typically is configured to calculate conductor loss according to an operating frequency characteristic relative to an impedance-frequency relationship of the conductor, i.e. impedance depends on electrical frequency. In a further embodiment, the controller 20 is configured to sense a voltage output from the electrical generator 14 and a voltage input to the induction motor 16 to calculate conductor loss, as indicated by reference numeral 23.

2019203914 04 Jun 2019 [0084]

The controller 20 may also include a conductor temperature sensor 25 for sensing a temperature of the conductors to calculate conductor loss according to an impedance-temperature relationship of the conductors, or the like .

[0085]

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 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 .

[0086] 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.

[0087] 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

2019203914 04 Jun 2019 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.

[0088] 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 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 .

[0089] 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

2019203914 04 Jun 2019 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 .

[0090] 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 (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.

[0091] 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,

2019203914 04 Jun 2019 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.

[0092] 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 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.

[0093] 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 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

2019203914 04 Jun 2019 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] Operational mode level control - This mode of operation controls the bore water level, controls the pump

2019203914 04 Jun 2019 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.

[0098] Operational 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, monitors the pump temperature, monitors pump pressure upstream and downstream.

[0099] Operational 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.

[00100] Applicant believes it particularly advantageous that the system 10 is able to calculate conductor loss as described herein in order to improve electrical efficiency and associated fuel efficiency where the prime mover is an internal combustion engine.

[00101] 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 vibration resistance. Less electrical and mechanical stress due to a smoother starting and running operation, and conseguently 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 .

[00102] 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 eguivalents

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

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

[00103] 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

2019203914 04 Jun 2019 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.

[00104] 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.

[00105] 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.

[00106] 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

2019203914 04 Jun 2019 an order of performance. It is also to be understood that additional or alternative steps may be employed.

Claims (32)

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 via conductors;

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, as well as physical characteristics of the conductors, said controller configured to:

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

ii) automatically and continuously calculate conductor loss based on the physical characteristics of the conductors relative to said monitored operating characteristics; and iii) automatically and dynamically control the prime mover output and/or excitation system in order to dynamically and continuously match the speedtorque relationship of the prime mover to that of

2019203914 04 Jun 2019 the induction motor and the pump performance curve whilst automatically compensating for calculated conductor loss;

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

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

3. The system of either of claims 1 or 2, wherein the prime mover operating characteristics continuously monitored by the controller are selected from a non-exhaustive 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 system of any of claims 1 to 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 system of any of claims 1 to 4, wherein the electrical generator operating characteristics continuously monitored by the controller are selected from a nonexhaustive group consisting of voltage output, current output, frequency, excitation system voltage, excitation system current, winding temperature, magnetic field status, air intake and air discharge.

2019203914 04 Jun 2019

6. The system of claim 5, 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.

7. The system of any of claims 1 to 6, wherein the controllable excitation system comprises a voltage regulator whereby the controller is able to control generator voltage output.

8. The system of claim 7, wherein the controller, via the voltage regulator, is configured to control the generator output voltage by controlling the excitation system through pulse-width modulation.

9. The system of any of claims 1 to 8, which includes switchgear and the associated conductors 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.

10. The system of any of claims 1 to 9, wherein the electrical motor operating characteristics continuously monitored by the controller are selected from a nonexhaustive group consisting of nominal voltage, nominal current, a frequency range, lock rotor current, power factor and operating efficiency.

11. The system of any of claims 1 to 10, wherein the controller is programmed with the physical characteristics

2019203914 04 Jun 2019 of the conductors to facilitate operative calculation of conductor loss.

12. The system of claim 12, wherein the physical characteristics of the conductors are selected from a nonexhaustive group consisting of impedance per unit length, an impedance-frequency relationship, and an impedancetemperature relationship.

13. The system of claim 12, wherein the controller is configured to calculate conductor loss according to an operating frequency characteristic relative to an impedancefrequency relationship of the conductor.

14. The system of any controller is configured to electrical generator and a motor to calculate conductor of claims 1 to 13, wherein the sense a voltage output from the voltage input to the induction loss .

15. The system of claim 12, wherein the controller includes a conductor temperature sensor for sensing a temperature of the conductors to calculate conductor loss according to an impedance-temperature relationship of the conductors .

16. The system of any of claims 1 to 15, wherein the pump operating characteristics continuously monitored by the controller are selected from a non-exhaustive 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 .

2019203914 04 Jun 2019

17. The system of any of claims 1 to 16, wherein the controller comprises a remote monitoring interface for remotely monitoring and/or controlling the system.

18. 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 via conductors, 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, as well as physical characteristics of the conductors;

the controller configured to:

i) continuously monitor the operating characteristics;

ii) automatically and continuously calculate conductor loss based on the physical characteristics of the conductors relative to said monitored operating characteristics; and iii) automatically and dynamically control the prime mover output and/or an excitation system of the generator excitation system whereby generator voltage output is controllable, in order to

2019203914 04 Jun 2019 dynamically and continuously match the speedtorque relationship of the prime mover to that of the induction motor and the pump performance curve whilst automatically compensating for calculated conductor loss;

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

19. The controller of claim 18, wherein the prime mover comprises an internal combustion engine.

20. The controller of either of claims 18 or 19, wherein the prime mover operating characteristics continuously monitored by the controller are selected from a non-exhaustive 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.

21. The controller of claim 20, which is configured to control the mechanical output of the prime mover by varying any of the suitable operating characteristics.

22. The controller of any of claims 18 to 21, wherein the electrical generator operating characteristics continuously monitored by the controller are selected from a non-exhaustive group consisting of voltage output, current output, frequency, excitation system voltage, excitation

2019203914 04 Jun 2019 system current, winding temperature, magnetic field status, air intake and air discharge.

23. The controller of claim 22, which is configured to control the excitation system of the generator by varying any of the suitable operating characteristics of the electrical generator.

24 . The controller of any of claims 18 to 21, wherein the controllable excitation system comprises a voltage regulator whereby the controller is able to control generator voltage output. 25. The controller of claim 24, which, via the voltage

regulator, is configured to control the generator output voltage by controlling the excitation system through pulsewidth modulation.

26. The controller of any of claims 18 to 25, wherein the system includes switchgear and the associated conductors 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 .

27. The controller of any of claims 18 to 26, wherein the electrical motor operating characteristics continuously monitored by the controller are selected from a nonexhaustive group consisting of nominal voltage, nominal current, a frequency range, lock rotor current, power factor and operating efficiency.

2019203914 04 Jun 2019

28. The controller of any of claims 18 to 27, which is programmed with the physical characteristics of the conductors to facilitate operative calculation of conductor loss .

29. The controller of any of claims 18 to 28, wherein the physical characteristics of the conductors are selected from a non-exhaustive group consisting of impedance per unit length, an impedance-frequency relationship, and an impedance-temperature relationship .

30. The controller of claim 29, which is configured to calculate conductor loss according to an operating frequency characteristic relative to an impedance-frequency relationship of the conductor.

31. The controller of any of claims 18 to 30, which is configured to sense a voltage output from the electrical generator and a voltage input to the induction motor to calculate conductor loss.

32 .

The controller of claim 29, which includes a conductor temperature sensor for sensing a temperature of the conductors to calculate conductor loss according to an impedance-temperature relationship of the conductors.

33. The controller of any of claims 18 to 23, wherein the pump operating characteristics continuously monitored by the controller are selected from a non-exhaustive group consisting of fluid flow rate, fluid pressure, fluid level, pump acceleration and deceleration time, pump frequency,

2019203914 04 Jun 2019 pump rotational speed ranges, and overall pump hydraulic performance .

34. The controller of any of claims 18 to 22, which comprises a remote monitoring interface for remotely monitoring and/or controlling the system.