Controller for an open power unit

Abstract

In this disclosure, there is provided: a controller for an open power unit, the open power unit comprising a motor configured to output mechanical power to a machine. The controller is configured to: obtain a mechanical power demand from the machine; obtain an operating state of the open power unit; and determine a motor demand to cause the motor to output mechanical power to the machine. The controller is configured to determine the motor demand based on the mechanical power demand, the operating state, and a profile of an internal combustion open power unit such that the output mechanical power of the open power unit mirrors a response of the internal combustion open power unit to the mechanical power demand.

Description

[0001] Description

[0002] CONTROLLER FOR AN OPEN POWER UNIT

[0003] Field of the Disclosure

[0004] The disclosure relates to the field of open power units. In particular, the present disclosure relates to the control of an open power unit.

[0005] Background

[0006] Open power units are used to supply mechanical power to a machine such as a construction machine, agricultural machine, pumping machine, mining machine and / or the like. Open power units may comprise an internal combustion engine configured to output rotational mechanical power. Typically, the internal combustion engine may be a diesel engine. An engine shaft of the internal combustion engine may output rotational mechanical power to one or more components of the machine.

[0007] Against this background, the present disclosure aims to provide an improved controller for an open power unit.

[0008] Summary of the Disclosure

[0009] According to a first aspect, a controller for an open power unit is provided, the open power unit comprising a motor configured to output mechanical power to a machine. The controller is configured to: obtain a mechanical power demand from the machine, obtain an operating state of the open power unit, and determine a motor demand to cause the motor to output mechanical power to the machine. The controller is configured to determine the motor demand based on the mechanical power demand, the operating state, and a profile of an internal combustion open power unit such that the output mechanical power of the open power unit mirrors a response of the internal combustion open power unit to the mechanical power demand.

[0010] According to this disclosure, the open power unit may provide mechanical power to a machine. While an internal combustion engine open power unit comprises an internal combustion engine to provide mechanical power, the open power unit of this disclosure comprises a motor which outputs mechanical power to the machine. As such, the open power unit of this disclosure may be an electric open power unit. That is to say, the open power unit of this disclosure may comprise a motor which is configured to convert electrical power into mechanical power.

[0011] Conventionally, machines utilising open power units have been powered by internal combustion engine open power units. As such, said machines are typically designed to interface with an internal combustion engine open power unit. As the open power unit of this disclosure includes a motor, the behaviour of the motor (e.g. the torque - motor speed response) may be different to the behaviour of an internal combustion engine. The controller of the first aspect allows the open power unit (including a motor) to operate in a similar manner to an internal combustion engine open power unit. As such, the controller of the first aspect may receive a mechanical power demand from the machine (which may be suitable for controlling an internal combustion engine open power unit) and translate the demand into a motor demand. The motor demand is determined by the controller such that the output mechanical power of the open power unit mirrors a response of the internal combustion open power unit to the mechanical power demand.

[0012] Accordingly, the controller of the first aspect may allow a machine manufacturer to substitute an internal combustion engine open power unit for the open power unit including a motor whilst minimising or eliminating any changes to the machine or a controller of the machine. Consequently, the controller of the open power unit makes it possible to provide mechanical power to a machine using an electric motor rather than internal combustion engine, whilst reducing or eliminating the use of any adaptive intermediate systems or modifications to the machine itself.

[0013] According to a second aspect of the disclosure, a method of controlling an open power unit is provided. The open power unit comprises a motor configured to output mechanical power to a machine. The method comprises:

[0014] obtaining a mechanical power demand from the machine; obtaining an operating state of the open power unit; determining a motor demand to cause the motor to output mechanical power to the machine,

[0015] wherein the motor demand is determined based on the mechanical power demand, the operating state, and an internal combustion open power unit profile such that the output mechanical power of the open power unit mirrors a response of the internal combustion open power unit to the mechanical power demand.

[0016] As such, the method of the second aspect may be performed by the controller of the first aspect.

[0017] According to a third aspect of the disclosure, an open power unit configured to supply mechanical power to a machine is provided. The open power unit comprises a motor configured to output mechanical power to the machine, and a controller according to the first aspect. The controller is configured to receive a mechanical power demand from a machine controller of the machine.

[0018] As such, the open power unit of the third aspect may be used to perform the method of the second aspect.

[0019] of the

[0020]

[0021] specific embodiment of the disclosure will now be described, by

[0022]

[0023] only, with reference to the accompanying drawings in which:

[0024] Figure 1 is a schematic diagram of an open power unit according to this disclosure;

[0025] Figure 2 is a schematic diagram of a machine according to this disclosure;

[0026] Figure 3 is a flow diagram of a method of controlling the open power unit in response to a mechanical power demand from a machine according to this disclosure;

[0027] Figure 4 is a flow diagram of a further method of controlling the open power unit according to this disclosure;

[0028] Figure 5 is a flow diagram of a method of starting the open power unit according to this disclosure; Figure 6 is a graph of a profile of an internal combustion open power unit;

[0029] Figure 7 shows two schematic graphs showing the relationship between the rotation speed demand and 1) the motor speed demand, and 2) the motor torque demand;

[0030] Figure 8 shows two further schematic graphs showing the relationship between the rotation speed demand and 1) the motor speed demand, and 2) the motor torque demand; and

[0031] Figure 9 is a graph of the showing the response of the motor speed to a step change in the rotation speed demand.

[0032] Detailed Description

[0033] According to an embodiment of this disclosure, an open power unit 10 is provided.

[0034] The open power unit 10 is configured to output mechanical power to a machine 1, such as a construction machine, an agricultural machine, a mining machine, a tracked pipe fuser, a pump, and / or the like. Conventionally, such machines may be configured to receive mechanical power from an internal combustion open power unit. According to this disclosure, the open power unit 10 is provided in place of an internal combustion open power unit, such that the open power unit 10 provides the same functionality as the internal combustion open power unit. As such, the machine 1 may demand mechanical power from the open power unit 10.

[0035] Figure 1 shows a schematic diagram of the open power unit 10 according to this disclosure. Different to an internal combustion open power unit, the open power unit 10 comprises a motor 4 and battery 3. The motor 4 converts electrical power from the battery 3 into mechanical power. The motor 4 is configured to output the mechanical power to the machine 1. As such, the open power unit 10 shown in Figure 1 does not burn fuel using an internal combustion engine to produce mechanical power. As such, the open power unit 10 may be considered to be an electric open power unit 10.

[0036] As shown in Figure 1, the motor 4 may be configured to drive an open power unit shaft 7 at a motor speed, the open power unit shaft 7 being driven at a motor torque. As such, the mechanical power output of the motor 4 may be defined by the product of the motor torque and the shaft speed of the open power unit shaft 7 (i.e. a motor speed).

[0037] As shown in Figure 1, the open power unit 10 may further comprise power electronics 2. The power electronics 2 may comprise a first electric output 2a and a second electric output 2b.

[0038] The first electric output 2a may be configured to supply electrical power to the motor 4. For example, the power electronics 2 may comprise an inverter which is configured to convert DC power provided by the battery to AC power which is output via the first electric output 2a. As such, the inverter may be configured to drive the motor 4.

[0039] The power electronics 2 may also be configured to provide a supply of electrical power to the machine 1. For example, the second electric output 2b may output DC electrical power to the machine 1. Accordingly, the power electronics 2 may include one or more transformers for providing DC power to the machine 1. in some embodiments, the power electronics may also provide a supply of AC power to the machine 1. In the embodiment of Figure 1, the second electric output 2b may be configured to output 12V or 24 V DC to the machine 1. It will be appreciated that such a functionality may mirror the functionality of a battery and / or alternator of an internal combustion open power unit which may also provide e.g. 24 V DC power to a machine 1.

[0040] The power electronics 2 may further comprise a first electric input 2c. The first electric input 2c may be configured to receive electric power from one or more of: an AC or DC power supply 8, and a battery 3. For example, in some embodiments the open power unit 10 may be operated based on electrical power stored in battery 3. Battery 3 may in turn be charged by the AC or DC power supplied from the AC / DC supply 8 via the charging system 6. In some embodiments, the open power unit 10 may be operated based on electrical power supplied directly from the AC or DC power supply 8 (i.e. a tethered open power unit).

[0041] The open power unit 10 further comprises a controller 11 (not shown in Figure 1). The controller 11 is configured to control the various elements of the open power unit 10 such that the motor 4 outputs mechanical power to the machine 1. In particular, the controller 11 controls the open power unit 10 such that it responds (i.e. the output mechanical power) in a manner which mirrors the behaviour of an internal combustion open power unit. As shown in Figure 2, the controller 11 receives communications from a machine controller 13 of the machine 1. The controller 11 may be configured to interface with the machine controller 13 in a manner which is similar to the behaviour of an internal combustion open power unit controller. In this way, the open power unit 10 may be retrofitted to a machine 1 which previously utilised an internal combustion open power unit, as the open power unit 10 mirrors the profile of the internal combustion open power unit. Similarly, machine designs which previously accommodated an internal combustion open power unit may utilise the open power unit 10 according to this disclosure without any updates to the design or control software of the machine 1 which sends power demands to the open power unit 10. As such, the machine 1 may be used interchangeably with the open power unit 10 or the internal combustion engine open power unit without requiring adaptive intermediate systems or modifications to the machine 1 itself.

[0042] The open power unit 10 may comprise one or more sensors (not shown in Figure 2) configured to determine one or more sensor parameters. The controller 11 may obtain the one or more sensor parameters from a respective sensor of the one or more sensors. For example, each sensor may be in communication with the controller 11 of the open power unit 10 by an electrical connection and / or any other connection by which the or each sensor can send information to the controller of the open power unit 10.

[0043] For example, the open power unit 10 may comprise a rotation speed sensor configured to measure the operating speed of the motor 4. The open power unit 10 may comprise a torque sensor configured to measure the operating torque of the motor 4. The motor 4 may comprise a voltmeter configured to measure an operating voltage of the motor 4. The open power unit 10 may comprise an ammeter configured to measure an operating current of the motor 4. In some embodiments, the rotation speed and / or the operating torque of the motor 4 may be determined by the controller 11 based on the operating voltage and / or the operating current of the motor 4. For example, the controller 11 may determine the operating speed and / or the operating torque based on the signals sent to the power electronics 2, e.g. the signals transferred via the first electric output 2a.

[0044] In some embodiments, the open power unit 10 may comprise one or more temperature sensors (not shown in Figures 1 and 2) configured to measure one or more operating temperatures of the open power unit 10. For example, the temperature sensors may measure the temperature of one or more of: the motor 4, the power electronics 2, the charging system 6, the battery 3, and the ambient temperature. In some embodiments, the open power unit 10 may comprise an accelerometer configured to measure a vibration of the open power unit 10. In some embodiments, the open power unit 10 may comprise an atmospheric pressure sensor configured to measure the atmospheric pressure. In some embodiments, the open power unit 10 may comprise a battery sensor configured to measure a state of charge of the battery 3 of the open power unit 10.

[0045] It will be appreciated that a variety of machines may utilise an open power unit 10 according to this disclosure. Figure 2 shows a schematic diagram of the machine 1. As shown in Figure 2, the machine 1 comprises a machine controller 13, a load 15, and the open power unit 10. In Figure 2, the open power unit 10 is shown as part of the machine 1. In other embodiments, the open power unit 10 may be provided separately to the machine 1.

[0046] The load 15 of the machine 1 may be any part of the machine which utilises mechanical power to perform one or more machine functions. For example, the load of the machine 1 may comprise one or more of: a pump (e.g. a pump configured to pump oil to a hydraulic system), and a drivetrain. As shown in Figure 2, mechanical power from the open power unit 7 may be transferred to the load 15 via the open power unit shaft 7. For example, where the load comprises a pump, an impeller of the pump may rotate at a pump rotation speed to create a pumping action. The rotation of the open power unit shaft 7 may cause the impeller to rotate. As such, the open power unit shaft 7 may output a motor rotation speed and / or a motor torque to the impeller. In an event that a pump mechanical demand increases (e.g. the hydraulic system is used to exert a force), the pump may require additional mechanical power from the open power unit 10. In another example, a drivetrain shaft of a drivetrain may rotate at a drivetrain rotation speed to provide mechanical power to the drivetrain. The drivetrain shaft may in turn cause the rotation of one or more wheels or tracks to move the machine 1. In an event that a drivetrain mechanical demand increases (e.g. as the machine 1 moves up an incline or carries a load), the drivetrain may require additional mechanical power from the open power unit 10. Therefore, the machine 1 (e.g. the pump and / or the drivetrain) may require mechanical power from the open power unit 10. Depending on the nature of the operation of the machine 1, the machine 1 may be requesting mechanical power in order to obtain a desired speed (i.e. a desired rotation speed of the open power unit shaft 7, and / or a desired torque provided by the open power unit shaft 7).

[0047] The machine 1 may further comprise a machine controller 13. The machine controller 13 may be in communication with the controller 11 of the open power unit 10 by an electrical connection and / or any other connection by which the machine controller 13 can send information to the controller of the open power unit 10. The machine controller 13 may be configured to determine a mechanical power demand from the load 15 of the machine 1. Often, the mechanical power demand from the load of the machine 15 may be expressed by the machine controller in terms of a desired rotation speed (a rotation speed demand) for the open power unit shaft 7, or a desired torque (a torque demand) to be applied to the open power unit shaft 7. The machine controller 13 may determine the rotation speed demand and / or the desired torque based on the current operating state of the machine and any operator inputs. It will be appreciated that various parameters and sensors of the machine 1 may influence the rotation speed demand / torque demand determined by the machine controller 13. Once determined, the machine controller 13 communicates the rotation speed demand / torque demand to the controller 11 of the open power unit 10.

[0048] Figure 3 shows a method 100 of controlling the open power unit in response to a mechanical power demand received from the machine controller 13. The controller 11 of the open power unit 10 may be configured to perform the steps shown in the method 100 of Figure 3. As shown in step 101 of Figure 3, the controller 11 obtains the mechanical power demand from the machine 1. For the embodiment of Figure 2, the controller 11 obtains the mechanical power demand from the machine controller 13. In some embodiments, the mechanical power demand may be expressed as a rotation speed demand and / or a torque demand. The mechanical power demand may be for mechanical power from the engine. For example, the rotation speed demand may be for rotation speed from the engine. As another example, the torque demand may be for torque from the engine.

[0049] As shown in step 102 of Figure 3, the controller 11 also obtains an operating state of the open power unit 10 from the open power unit 10. The operating state of the open power unit 10 may comprise an operating speed of the motor 4 / open power unit shaft 7. The operating state of the open power unit 10 may comprise an operating torque of the motor 4. In some embodiments, the operating torque and / or the operating speed of the motor 4 may be obtained from the rotation speed sensor and / or the torque sensor respectively or otherwise be determined by the controller 11 as discussed above. As part of obtaining the operating of the open power unit 10, the controller 11 may also determine an operating state of one or more sensors of the open power unit 10 (e.g. one or more temperature sensors, a battery sensor, an atmospheric pressure sensor and the like). As such, the operating state of the open power unit 10 may comprise one or more sensor parameters.

[0050] As shown in step 103 of Figure 3, the controller 11 determines a motor demand, based on the mechanical power demand, the operating state, and a profile of an internal combustion open power unit. In effect, the controller 11 translates the mechanical power demand from the machine controller 13 (which may be suitable for an internal combustion engine) to a motor demand for controlling the motor 4 of the open power unit 10. In particular, it will be appreciated that the response of a motor 4 to e.g. a torque demand is different to the response of an internal combustion engine. So, according to this disclosure, the controller 11 determines the motor demand based on a profile of an internal combustion open power unit. As such, the controller 11 may translate a rotation speed demand and / or a torque demand into a motor demand such that the motor 4 behaves in a similar manner to an internal combustion engine. The motor demand determined by the controller 11 may comprise a motor speed demand and a motor torque demand. In some embodiments, the motor speed demand and the motor torque demand may be constrained based on the profile of the internal combustion open power unit. As such, the profile of the internal combustion open power unit may prevent the motor 4 from operating at a motor torque / motor speed combination which is unexpected by the machine 1 (i.e. a torque / speed which is outside the usual operating range of the equivalent internal combustion open power unit). The profile of the internal combustion open power unit may comprise a relationship between the engine torque and the engine speed. An example of such a relationship is shown in the graph of Figure 6. For example, for a particular engine speed, the internal combustion engine of the internal combustion open power unit may have a maximum engine torque. The controller 11 may be configured to determine the motor torque demand such that the motor torque demand does not exceed the maximum engine torque. Similarly, for a particular engine torque, the internal combustion engine may have a minimum engine speed. The controller 11 may be configured to determine the motor speed demand such that the motor speed demand is above the minimum engine speed. In some embodiments, for a particular engine torque, the internal combustion engine may have a maximum engine speed. The controller 11 may be configured to determine the motor speed demand such that the motor speed demand is no greater than the maximum engine speed. In some embodiments, the internal combustion engine profile may define, for a particular engine torque, a range of allowable engine speeds. Accordingly, the controller 11 may be configured to determine the motor speed demand such that the motor speed demand does causes the motor 4 to behave in a similar manner to the corresponding internal combustion open power unit.

[0051] By way of example, Figure 7 includes two graphs which show, schematically, the relationship between the rotation speed demand obtained from the machine controller 13 and the motor speed demand and the motor torque demand determined by the controller. As shown in the first graph (labelled 1 in Figure 7) the controller determines the motor speed demand based on the obtained rotation speed demand. As shown in the first graph, the relationship between the motor speed demand and the rotation speed demand may be a linear relationship, for example 1:1. Other relationships between the obtained rotation speed demand and the motor speed demand may also be used, as further explained below. For example, the relationship may be adjusted to account for any gearing of the motor 4 relative to the open power unit shaft 7. As such, the first graph, may form part of a profile of an internal combustion open power unit for the motor 4 of the open power unit 10.

[0052] As shown in the second graph (labelled 2) in Figure 7), the motor torque demand may be determined based on the obtained rotation speed demand and the second graph. As such, the second graph may also form part of the profile of an internal combustion open power unit. For example, as shown in the second graph, the controller 4 may determine a maximum motor torque based on the relationship between torque and engine speed of the profile of the internal combustion open power unit. The maximum motor torque may be used to constrain the response of the motor 4 by the controller 11. In some embodiments (not shown in the second graph) the second graph may also provide a minimum motor torque for a given rotation speed demand. As such, the controller 4 may determine a maximum motor torque and a minimum motor torque (or an operating torque range) based on the profile of the internal combustion open power unit.

[0053] While the graphs of Figure 7 showed a linear relationship between the obtained rotation speed demand and the determined motor speed, Figure 8 shows an embodiment where the relationship may be non-linear. A non-linear relationship between the obtained rotation speed demand and the determined motor speed may be provided to account for non-linearities in the response of the motor 4 to a change in demanded speed.

[0054] Figure 9 shows a schematic graph showing the response of the motor 4 to a step change in the rotation speed demand obtained from the machine 1. As shown in Figure 9 (solid line), the motor speed adjusts to the demanded motor speed over time. As indicated by the dashed high torque limit line and the dashed low torque limit line in Figure 9, it will be appreciated that the step response may be shaped by the constraints of the maximum (and optionally minimum) motor torques determined by the controller 11. Once the motor speed demand and the motor torque demand is determined by the controller 11, the controller 11 may cause the motor 4 to rotate at the desired motor speed demand. For example, in the embodiment of Figures 1 and 2, the power electronics 2 may be configured to cause the motor 4 to rotate at the desired motor speed, as further described below. Figure 4 shows a method 200 of outputting the motor demand to the motor in more detail.

[0055] Steps 201, 202, and 203 of the method 200 of Figure 4 are similar to steps 101, 102, 103 of the method 100 of Figure 3 respectively, except that the method 200 is directed to the embodiment wherein the mechanical power demand is expressed as a rotation speed demand. Therefore, as shown in step 201 of Figure 4, the controller 11 obtains the rotation speed demand from the machine 1. In some embodiments (not shown in Figure 4), the mechanical power demand may be expressed as a torque demand.

[0056] Steps 204 to 207 of the method 200 exemplify how the controller 11 may output the motor speed demand and the motor torque demand to the motor 4.

[0057] As shown in step 204 of Figure 4, the controller 11 may send the motor speed demand to the power electronics 2. The controller 11 may also send the motor torque demand to the power electronics. In some embodiments, the controller 11 may also send the maximum motor torque to the power electronics 2. In some embodiments, the controller 11 may also send a minimum motor torque to the power electronics 2.

[0058] In step 205 of Figure 4, the power electronics 2 determines suitable signals for the first electric output 2a in order to drive the motor 4. For example, in step 205, the power electronics 2 may determine, a current / voltage pattern based on the motor speed demand (and optionally motor torque demand). The signals may cause the motor 4 to rotate in accordance with the motor speed demand and the motor torque demand. The signals may also take into account the maximum motor torque and / or the minimum motor torque, if provided by the controller 4.

[0059] In step 205, the power electronics 2 may determine signals to be output as the first electric output 2a to drive the motor 4. For example, the power electronics may determine an AC current magnitude and frequency to be output to the motor 4 in order to drive the motor at the motor speed demand and an associated motor torque. The power electronics may determine the signal to be output via the first electric output 2a using a motor point model. The motor point model may comprise a mathematical model within the power electronics 2 which determines an AC current magnitude for each phase of three current phases based on an angle of the open power unit shaft 7, the motor speed demand, and the motor torque demand.

[0060] In some embodiments, the power electronics 2 may also implement the maximum motor torque (if provided) as a maximum AC current limit to be applied to the motor point model. The relationship between maximum torque and a corresponding maximum AC current may be provided / specified by the power electronics 2 / motor 4 or a torque / current relationship may be determined through calibration measurements of the motor 4 / power electronics 2 (e.g. using a dynamometer). The minimum motor torque may also be implemented by the power electronics 2 using a similar minimum AC current.

[0061] In step 206 of Figure 4 the power electronics 2 outputs an AC current to the motor 4 via the first electric output 2a in order to drive the motor in accordance with the motor demand.

[0062] As such, it will be appreciated from Figures 3 and 4 that the controller 11 of the open power unit 10 may control the motor 4 to mirror the behaviour of an internal combustion open power unit during normal operation.

[0063] In addition, in some embodiments the open power unit 10 may also be controlled to mirror the response of the internal combustion open power unit during a start up procedure. As such, the motor 4 may mirror the behaviour of an internal combustion engine as it warms up from zero engine speed to an idle engine speed. The motor idle speed may be the same as the engine idle speed. In an event that there is a rotation speed demand from the machine 1 to the motor 4, the controller 11 then may cause the open power unit shaft 7 to increase the motor speed from the motor idle speed to the rotation speed demand. In this way, the open power unit 10 mirrors the response to the internal combustion open power unit. A flow diagram of a start-up procedure 300 is shown in Figure 5, wherein the controller 11 may be configured to carry out the start-up procedure 300. As shown in Figure 5, the start-up procedure 300 may be similar to the method 200, wherein the rotation speed demand is an idle speed demand. As such, steps 301, 302, 303, 304, 305, 306, of method 300 may be similar to steps 201, 202, 203, 204, 205, and 206 of method 200 respectively, but for an idle speed demand. The controller 11 may be configured to carry out one or more of the steps shown in the method 300 of Figure 5.

[0064] As shown in step 321 of Figure 5, the start-up procedure may further comprise obtaining an ignition on signal (e.g. a signal indicative of a key-on by a user, or a user pushing a start button). In response to obtaining the ignition on signal, the controller 11 may carry out the start up-procedure 300. As shown in step 323 of Figure 5, the start-up procedure may further comprise sending a first on signal to a low voltage system. The low voltage system may comprise the second output 2b of the power electronics 2. As shown in step 325 of Figure 4, the start-up procedure may further comprise sending a second on signal to a high voltage system. The high voltage system may comprise the first output 2a of the power electronics 2. The first on signal may be sent before the second on signal such that the low voltage system is switched on before the high voltage system. Once the low voltage system and the high voltage system of the open power unit 10 are initialised, the method 300 may proceed to step 301, wherein the controller 11 obtains an idle speed demand.

[0065] As such, it will be appreciated that the controller 1 may implement method 300 in order to start-up the open power unit in a similar manner to an internal combustion open power unit. As part of the start-up routine, the controller 11 may also communicate with the machine controller 13 to confirm that start-up routine is completed, in a similar manner to an internal combustion open power unit.

[0066] Indeed, in some embodiments, the controller 11 may send various signals to the machine controller 13 which provide the machine controller 13 with operational information concerning the open power unit 10. For example sensor data determined from one or more sensors of the open power unit 10 may be communicated to the machine controller 13.

[0067] For example, in some embodiments, the controller 11 may be further configured to determine a diagnostic output of the open power unit 10. The diagnostic output may be output to a user interface of the open power unit 10, or a machine user interface of the machine 1. The controller 11 may determine the diagnostic output based on the operating state of the open power unit 10. For example, in an event that the sensor parameter is different to a predefined value, the controller 11 may output the diagnostic output to indicate that the sensor parameter is different to the predefined value.

[0068] In some embodiments, the controller 11 may determine an internal combustion parameter based on the sensor parameter. For example, the internal combustion parameter may comprise a fuel level. The controller 11 may determine the fuel level based on the operating state of charge of the battery 3. In some embodiments, a minimum state of charge may correspond to a minimum fuel level and a maximum state of charge may correspond with a maximum fuel level.

[0069] The controller 11 may determine the diagnostic output based on the mechanical power demand from the machine 1 and the profile of the internal combustion open power unit. For example, the rotation speed demand may be greater than the maximum rotation speed of the internal combustion engine, or the torque demand may be greater than the maximum torque of the internal combustion engine, in an event that the rotation speed demand is greater than the maximum rotation speed of the internal combustion engine, or the torque demand is greater than the maximum torque of the internal combustion engine, the controller 11 may output the diagnostic output to indicate that the mechanical power demand cannot be fulfilled.

[0070] Industrial Applicability

[0071] The open power unit 10 may provide mechanical power to the machine 1. While a conventional internal combustion open power unit utilises an internal combustion engine to provide mechanical power, the open power unit 0 of this disclosure comprises a motor 4 which outputs mechanical power to the machine 1. As such, the open power unit 10 of this disclosure may be an electric open power unit. That is to say, the open power unit 10 of this disclosure may comprise the motor 4 which is configured to convert electrical power into mechanical power. Conventionally, machines 1 utilising open power units have been powered by internal combustion open power units. As such, said machines 1 are typically designed to interface with an internal combustion open power unit. As the open power unit 10 of this disclosure includes the motor 4, the behaviour of the motor 4 (e.g. the torque - motor speed response) may be different to the behaviour of the internal combustion engine. The controller 11 allows the open power unit 10 (including a motor 4) to operate in a similar manner to the internal combustion open power unit. As such, the controller 11 may receive the mechanical power demand from the machine 1 (which may be suitable for controlling the internal combustion open power unit) and translate the demand into the motor demand. The motor demand is determined by the controller 11 such that the output mechanical power of the open power unit 10 mirrors the response of the internal combustion open power unit to the mechanical power demand.

[0072] Accordingly, the controller 11 of the first aspect may allow the machine manufacturer to substitute the internal combustion open power unit for the open power unit 10 including the motor 4 and vice versa whilst minimising or eliminating any changes to the machine 1 or the machine controller 13.

[0073] Consequently, the controller 11 of the open power unit 10 makes it possible to provide mechanical power to the machine 1 using the motor 4 rather than internal combustion engine, whilst reducing or eliminating the use any adaptive intermediate systems or modifications to the machine 1 itself.

[0074] Figure 6 shows an example of the profile of the internal combustion open power unit. As shown in Figure 6, the engine torque increases with engine speed between 1200 and 1500 rev / min, and then decreases with engine speed between 1500 rev / min and 2400 rev / min. Below 1200 rev / min, the engine may stall, and therefore the engine torque below 1200 rev / min may be zero. The motor torque and motor speed may, in the absence of the controller 11 according to claim 1, follow a motor profile which is different to the profile of the internal combustion open power unit. The motor profile may comprise the relationship between the motor torque and the motor speed.

[0075] The motor profile may be different to the profile of the internal combustion open power unit in that the motor torque is greater than zero when the motor speed is zero, whereas the engine torque may be zero when the engine speed is zero (not shown in Figure 6). Using the controller 11 according to claim 1, the motor profile mirrors the profile of the internal combustion open power unit (e.g. the start-up procedure 300 is used such that the open power unit shaft 7 rotates at the motor idle speed).

[0076] Another difference between the motor profile and the profile of the internal combustion open power unit may be that the motor torque at a first speed is greater than the engine torque at the first speed. Using the controller 11 according to claim 1, the motor profile mirrors the profile of the internal combustion open power unit (e.g. the motor torque is constrained such that the motor torque at the first speed is the same as the engine torque at the first speed).

[0077] The controller 11 of the open power unit may also be configured to output control signals to the machine controller 13 in a similar format as the corresponding internal combustion open power unit. For example, the controller may be configured to output the operating state of the open power unit to the machine controller 13 of the machine 1. Furthermore, some signals of the controller 4, for example battery state of charge, may be translated to a relevant, corresponding signal for use by the machine controller 13. As such, a machine controller 13 may utilise a display / output a battery state of charge signal from the controller 11 in place of a fuel level signal from a corresponding internal combustion open power unit.

[0078] Thus, according to this disclosure, an open power unit 10 and a controller 11 for the open power unit 10 are provided which can be used to power a machine 1 in place of a corresponding Internal combustion open power unit.

Claims

Claims1. A controller for an open power unit, the open power unit comprising a motor configured to output mechanical power to a machine, wherein the controller is configured to:obtain a mechanical power demand from the machine; obtain an operating state of the open power unit;determine a motor demand to cause the motor to output mechanical power to the machine,wherein the controller is configured to determine the motor demand based on the mechanical power demand, the operating state, and a profile of an internal combustion open power unit such that the output mechanical power of the open power unit mirrors a response of the internal combustion open power unit to the mechanical power demand.

2. The controller of claim 1, whereinthe mechanical power demand comprises a rotation speed demand and the motor demand comprises a motor speed demand and a motor torque demand.

3. The controller of claim 1, wherein the mechanical power demand comprises a torque demand and the motor demand comprises a motor torque demand and a motor speed demand.

4. The controller of claim 2 or claim 3, wherein the profile of the internal combustion open power unit comprises a relationship between a torque and an engine speed for the internal combustion open power unit.

5. The controller of claim 4, whereinthe motor speed demand and / or the motor torque demand are constrained based on the relationship between the torque and the engine speed for the internal combustion open power unit.

6. The controller of any preceding claim, wherein the operating state of the open power unit comprises:an operating speed of the motor and / or an operating torque of the motor.

7. The controller of any preceding claims wherein the operating state of the open power unit comprises a sensor parameter obtained from a sensor of the open power unit.

8. The controller of claim 7, whereinthe sensor of the open power unit comprises one or more of: a temperature sensor, an accelerometer, an atmospheric pressure sensor, a battery sensor.

9. The controller of any of claims 1 to 8, wherein the motor demand comprises a maximum torque demand.

10. The controller of claim 10, whereinthe maximum torque demand is determined based on the mechanical power demand and the profile of the internal combustion open power unit.

11. The controller of any of claims 1 to 10, wherein the motor demand comprises a minimum torque demand.

12. The controller of claim 11, whereinthe minimum torque demand is determined based on the mechanical power demand and the profile of the internal combustion open power unit.

13. The controller of any of claims 1 to 12, wherein the mechanical power demand comprises a rotation speed demand and the motor demand comprises a motor speed demand, andthe motor speed demand is determined based on the rotation speed demand anda relationship between the rotation speed demand the motor speed demand defined by the profile of the internal combustion open power unit.

14. The controller of any of claims 1 to 13, whereinthe controller is configured to output the operating state of the open power unit to a machine controller of the machine.

15. A method of controlling an open power unit, the open power unit comprising a motor configured to output mechanical power to a machine, the method comprising:obtaining a mechanical power demand from the machine; obtaining an operating state of the open power unit; determining a motor demand to cause the motor to output mechanical power to the machine,wherein the motor demand is determined based on the mechanical power demand, the operating state, and an internal combustion open power unit profile such that the output mechanical power of the open power unit mirrors a response of the internal combustion open power unit to the mechanical power demand.

16. An open power unit configured to supply mechanical power to a machine, the open power unit comprising:a motor configured to output mechanical power to the machine; anda controller according to any of claims 1 to 14, the controller configured to receive a mechanical power demand from a machine controller of the machine.

Images