Motor control for gas engine replacement device

Abstract

A gas engine replacement device includes a housing, a battery receptacle coupled to the housing to receive a battery pack, a motor within the housing, a power output shaft receiving torque from the motor and protruding from a side of the housing, a power switch network configured to provide power from the battery pack to the motor, and an electronic processor coupled to the power switch network and configured to control the power switch network to cause the motor to rotate and receive a command speed, determine whether the command speed is within a forbidden zone, set an output speed to the command speed in response to the command speed being outside the forbidden zone, set the output speed to a speed outside the forbidden zone in response to the command speed being within the forbidden zone, and control the power switch network to cause the motor to rotate at the output speed.

Description

[0001] Related Applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 932,711, filed November 8, 2019, and U.S. Provisional Patent Application No. 63 / 009,642, filed April 14, 2020, the entire contents of each of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to gas engine replacement motor units, and more particularly to gas engine replacement motor units for use with power equipment. BACKGROUND

[0004] Small, single-cylinder or multi-cylinder gasoline engines can be installed to power equipment to drive the equipment with a power output shaft. SUMMARY

[0005] In some embodiments, a gas engine replacement device is provided, comprising: a housing; a battery receptacle coupled to the housing and configured to removably receive a battery pack; a motor within the housing; a power output shaft receiving torque from the motor and protruding from a side of the housing; a power switch network configured to selectively provide power from the battery pack to the motor; and an electronic processor. The electronic processor is coupled to the power switch network and configured to control the power switch network to rotate the motor. The electronic processor is configured to: receive a commanded speed for the motor, determine whether the commanded speed is within a forbidden zone, set an output speed of the motor to the commanded speed in response to the commanded speed being outside the forbidden zone, set the output speed to a speed outside the forbidden zone in response to the commanded speed being within the forbidden zone, and control the power switch network to rotate the motor at the output speed set based on determining whether the commanded speed is within the forbidden zone.

[0006] In some embodiments, the electronic processor is configured to set the output speed to an upper limit of the forbidden zone in response to a previous output speed being greater than the forbidden zone. In some embodiments, the electronic processor is configured to set the output speed to a lower limit of the forbidden zone in response to a previous output speed being less than the forbidden zone. In some embodiments, the forbidden zone defines a hysteresis around a resonant frequency of a mechanical system coupled to the motor. In some embodiments, the gas engine replacement device comprises a vibration sensor, and the electronic processor is configured to identify the resonant frequency based on an output of the vibration sensor. In some embodiments, the gas engine replacement device comprises a vibration sensor, and the electronic processor is configured to generate the forbidden zone based on an output of the vibration sensor.

[0007] In some embodiments, a gas engine replacement device is provided that includes a housing, a vibration sensor, a battery receptacle coupled to the housing and configured to removably receive a battery pack, a motor within the housing, a power output shaft receiving torque from the motor and protruding from a side of the housing, a power switch network configured to selectively provide power from the battery pack to the motor, and an electronic processor. The electronic processor is coupled to the power switch network and configured to control the power switch network to rotate the motor. The electronic processor is configured to generate a forbidden zone based on an output of the vibration sensor, receive a commanded speed for the motor, determine an output speed of the motor based on the commanded speed to limit an operating speed to a value outside the forbidden zone, and control the power switch network to rotate the motor at the determined output speed.

[0008] In some embodiments, the electronic processor is configured to set the output speed to an upper limit of the forbidden zone in response to a previous output speed being greater than the forbidden zone. In some embodiments, the electronic processor is configured to set the output speed to a lower limit of the forbidden zone in response to a previous output speed being less than the forbidden zone. In some embodiments, the forbidden zone defines a hysteresis around a resonant frequency of a mechanical system coupled to the motor. In some embodiments, the gas engine replacement device includes a vibration sensor, and the electronic processor is configured to identify the resonant frequency based on an output of the vibration sensor, and the forbidden zone is generated based on the identified resonant frequency.

[0009] In some embodiments, a system including a pump and a gas engine replacement device is provided. The gas engine replacement device includes a housing, a battery receptacle coupled to the housing and configured to removably receive a battery pack, a motor within the housing, a power output shaft receiving torque from the motor and protruding from a side of the housing and coupled to the pump, a power switch network configured to selectively provide power from the battery pack to the motor, and an electronic processor. The electronic processor is coupled to the power switch network and configured to control the power switch network to rotate the motor. The electronic processor is further configured to receive a commanded speed for the motor, determine whether the commanded speed is within a forbidden zone, set an output speed of the motor to the commanded speed in response to the commanded speed being outside the forbidden zone, set the output speed to a speed outside the forbidden zone in response to the commanded speed being within the forbidden zone, and control the power switch network to rotate the motor at the output speed set based on determining whether the commanded speed is within the forbidden zone.

[0010] In some embodiments, the electronic processor is configured to set the output speed to an upper limit of the forbidden zone in response to a previous output speed being greater than the forbidden zone. In some embodiments, the electronic processor is configured to set the output speed to a lower limit of the forbidden zone in response to a previous output speed being less than the forbidden zone. In some embodiments, the forbidden zone defines a hysteresis around a resonant frequency of a mechanical system coupled to the motor. In some embodiments, the gas engine replacement device includes a vibration sensor, and the electronic processor is configured to identify the resonant frequency based on output of the vibration sensor, and the forbidden zone is generated based on the identified resonant frequency.

[0011] In some embodiments, a method is provided that includes an electronic processor of a gas engine replacement device receiving a commanded speed for the motor. The method further includes the electronic processor determining whether the commanded speed is within a forbidden zone. Further, the electronic processor sets an output speed of the motor to the commanded speed in response to the commanded speed being outside the forbidden zone, and to a speed outside the forbidden zone in response to the commanded speed being within the forbidden zone. The method further includes the electronic processor controlling the power switching network to cause the motor of the gas engine replacement device to rotate at the output speed set based on determining whether the commanded speed is within the forbidden zone.

[0012] In some embodiments of the method, the electronic processor sets the output speed to an upper limit of the forbidden zone in response to a previous output speed being greater than the forbidden zone. In some embodiments of the method, the electronic processor sets the output speed to a lower limit of the forbidden zone in response to a previous output speed being less than the forbidden zone. In some embodiments of the method, the forbidden zone defines a hysteresis around a resonant frequency of a mechanical system coupled to the motor. In some embodiments of the method, the gas engine replacement device includes a vibration sensor, and the electronic processor identifies the resonant frequency based on output of the vibration sensor. In some embodiments, the gas engine replacement device includes a vibration sensor, and the electronic processor generates the forbidden zone based on output of the vibration sensor.

[0013] In some embodiments, a gas engine replacement device is provided that includes a housing, a battery receptacle coupled to the housing and configured to removably receive a battery pack, a motor located within the housing, a power output shaft that receives torque from the motor and protrudes from a side of the housing, a power switch network configured to selectively provide power from the battery pack to the motor, and an electronic processor. The electronic processor is coupled to the power switch network and configured to control the power switch network to cause the motor to rotate. The electronic processor is configured to receive a commanded speed for the motor, generate an output speed for the motor based on the commanded speed, detect an out-of-control condition, and mitigate the out-of-control condition.

[0014] In some embodiments, a method for operating a gas engine replacement device is provided, where the gas engine replacement device includes a housing, a battery receptacle coupled to the housing and configured to removably receive a battery pack, a motor located within the housing, a power output shaft that receives torque from the motor and protrudes from a side of the housing, a power switch network configured to selectively provide power from the battery pack to the motor, and an electronic processor. The electronic processor is coupled to the power switch network and configured to control the power switch network to cause the motor to rotate. The method includes the gas engine replacement device receiving a commanded speed for the motor, generating an output speed for the motor based on the commanded speed, detecting an out-of-control condition, and mitigating the out-of-control condition.

[0015] In some embodiments, a gas engine replacement device is provided that includes a housing, a battery receptacle coupled to the housing and configured to removably receive a battery pack, a motor located within the housing, a power output shaft that receives torque from the motor and protrudes from a side of the housing, a power switch network configured to selectively provide power from the battery pack to the motor, and an electronic processor. The electronic processor is coupled to the power switch network and configured to control the power switch network to cause the motor to rotate. The electronic processor is configured to monitor a motor current, estimate a load condition based on the motor current, and set a motor commanded speed based on the load condition.

[0016] In some embodiments, a method for operating a gas engine replacement device is provided, where the gas engine replacement device includes: a housing; a battery receptacle coupled to the housing and configured to removably receive a battery pack; a motor located within the housing; a power output shaft that receives torque from the motor and protrudes from a side of the housing; a power switch network configured to selectively provide power from the battery pack to the motor; and an electronic processor. The electronic processor is coupled to the power switch network and configured to control the power switch network to rotate the motor. The method includes the gas engine replacement device monitoring motor current, estimating a load condition based on the motor current, and setting a motor command speed based on the load condition.

[0017] In some embodiments, a gas engine replacement device is provided, where the gas engine replacement device includes: a housing; a battery receptacle coupled to the housing and configured to removably receive a battery pack; a motor located within the housing; a power output shaft that receives torque from the motor and protrudes from a side of the housing; a power switch network configured to selectively provide power from the battery pack to the motor; and an electronic processor. The electronic processor is coupled to the power switch network and configured to control the power switch network to rotate the motor. The electronic processor is configured to receive a position control command, determine a load position, and control the motor based on the load position.

[0018] In some embodiments, a method for operating a gas engine replacement device is provided, where the gas engine replacement device includes: a housing; a battery receptacle coupled to the housing and configured to removably receive a battery pack; a motor located within the housing; a power output shaft that receives torque from the motor and protrudes from a side of the housing; a power switch network configured to selectively provide power from the battery pack to the motor; and an electronic processor. The electronic processor is coupled to the power switch network and configured to control the power switch network to rotate the motor. The method includes the gas engine replacement device receiving a position control command, determining a load position, and controlling the motor based on the load position.

[0019] Before any embodiments are explained in detail, it is to be understood that the embodiments are not limited in their application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. Embodiments described herein are capable of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms "mounted," "connected" and "coupled" are used broadly and encompass both direct and indirect mounting, connecting, and coupling. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings, but can include electrical connections or couplings, whether direct or indirect. Additionally, as used herein, "and / or" refers to a combination or any number of items included in the list, such as "A, B, and / or C" means A; B; C; A and B; B and C; A and C; or A, B, and C.

[0020] It should be noted that the embodiments described herein can be implemented utilizing a plurality of hardware and software-based devices and a plurality of different structural components. Further, and as described in subsequent paragraphs, the particular configurations illustrated in the drawings are intended to be exemplary embodiments, and other alternative configurations are possible. The terms "processor," "central processing unit," and "CPU" are interchangeable. Where the term "processor," "central processing unit," or "CPU" is used as an identifier for a unit that performs a particular function, it is understood that such function can be performed by a single processor or a plurality of processors arranged in any form, including parallel, serial, columnar, or cloud processing configurations / cloud computing configurations, unless otherwise specified.

[0021] Additionally, it is to be understood that the embodiments can include hardware, software, and electronic components or modules that can be arranged to perform various operations described herein. For the sake of brevity, many of the underlying principles of networking and software development are not described in detail herein. Moreover, many hardware and software considerations involved in implementing the embodiments are well known. Accordingly, the embodiments described herein are not limited by the software and hardware illustrated.

[0022] Other features and aspects will become apparent by consideration of the following detailed description and accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 This is a perspective view of a gas engine replacement device according to an embodiment.

[0024] Figure 2 yes Figure 1 A plan view of the gas engine replacement unit.

[0025] Figure 3 yes Figure 1 A schematic diagram of a gas engine replacement device.

[0026] Figure 4 yes Figure 1 A perspective view of the battery pack for a gas engine replacement device.

[0027] Figure 5 yes Figure 4 A cross-sectional view of the battery pack.

[0028] Figure 6 yes Figure 1 A cross-sectional view of the battery socket of the gas engine replacement device.

[0029] Figure 7 yes Figure 1 A cross-sectional view of the motor of the gas engine replacement device.

[0030] Figure 8 yes Figure 1 A schematic diagram of the motor, gear system, and power output shaft of the gas engine replacement device.

[0031] Figure 9 yes Figure 1 A block diagram of a gas engine replacement device.

[0032] Figure 10 It is used for driving Figure 1 A schematic diagram of the power switch network for the motor of a gas engine replacement device.

[0033] Figure 11A This demonstrates the operation of the motor during forward rotation. Figure 10 A diagram illustrating the operation of a power switch network.

[0034] Figure 11B This demonstrates the operation during motor reverse operation. Figure 10 A diagram illustrating the operation of a power switch network.

[0035] Figure 12 yes Figure 1 A simplified block diagram of the motor controller for a gas engine replacement device.

[0036] Figure 13 It is a demonstration Figure 12 A diagram of the speed profile used by the motor controller.

[0037] Figure 14 is an example method for speed control of a motor of a gas engine replacement device. Figure 1

[0038] Figure 15 illustrates a pump system of a gas engine replacement device including Figure 1

[0039] Figure 16 illustrates a speed-torque operating curve of a pump system.

[0040] Figure 17 is a flowchart of a method for runaway detection and control of a motor of a gas engine replacement device. Figure 1

[0041] Figure 18 is a flowchart of a method for load monitoring using a gas engine replacement device. Figure 1

[0042] Figure 19 and Figure 20 are graphs illustrating a disturbance in motor current for identifying a load condition according to some embodiments.

[0043] Figure 21 illustrates a mixing system of a gas engine replacement device including Figure 1

[0044] Figure 22 illustrates a cutting system of a gas engine replacement device including Figure 1

[0045] Figure 23 is a flowchart of an example method for load positioning using a gas engine replacement device. Figure 1

[0046] Figure 24 illustrates a cooling system for one or more electronic components in a gas engine replacement device. Figure 1 DETAILED DESCRIPTION

[0047] as Figure 1 and Figure 2 ​​​​​​​​As shown, a gas engine replacement device 10 for use with a power unit includes a housing 14 having a first side 18, a second side 22 adjacent to the first side 18, a third side 26 opposite to the second side 22, a fourth side 28 opposite to the first side 18, a fifth side 30 extending between the second side 22 and the third side 26, and a sixth side 32 opposite to the fifth side 30. The gas engine replacement device 10 also includes a flange 34 coupled to the housing 14 on the first side 18, an electric motor 36 located within the housing 14, and a power output shaft 38 projecting from the second side 22 and receiving torque from the motor 36. As explained in further detail below, in some embodiments, the power output shaft 38 projects from the first side 18 and from the flange 34. Figure 3 As shown, the gas engine replacement device 10 also includes control electronics 42, which is located within the housing 14 and includes wiring and a controller 46 electrically connected to the motor 36. A similar gas engine replacement device 10 is described and illustrated in U.S. Patent Application No. 16 / 551,197, filed August 26, 2019, the entire contents of which are incorporated herein by reference.

[0048] like Figures 1 to 6 As shown, the gas engine replacement device 10 also includes a battery pack 50, which is removably received in a battery socket 54 within the housing 14 to transmit current from the battery pack 50 to the motor 36 via control electronics 42. (See reference...) Figures 4 to 6 The battery pack 50 includes a battery pack housing 58 having a support portion 62 and a first terminal 66 electrically connected to a plurality of battery cells 68 supported by the housing 58. The support portion 62 provides a sliding arrangement having a complementary protrusion / recess portion 74 to the battery socket 54 (e.g., Figure 6 The protrusions / recesses 70 (as shown in the diagram) correspond to each other. Figures 4 to 6In the embodiments shown in the middle, the raised / recessed portion 70 of the battery pack 50 is a guide rail and the raised / recessed portion 74 of the battery receptacle 54 is a guide recess. A similar battery pack is described and shown in U.S. Patent Publication No. 2019 / 0006980, filed July 2, 2018, which is incorporated by reference herein in its entirety. In some embodiments, the battery cells 68 have a nominal voltage of up to about 80V. In some embodiments, the battery cells 68 have a nominal voltage of up to about 120V. In some embodiments, the battery pack 50 has a weight of up to about 6 lb. In some embodiments, each of the battery cells 68 has a diameter of up to 21 mm and a length of up to about 71 mm. In some embodiments, the battery pack 50 includes up to twenty battery cells 68. In some embodiments, the battery cells 68 are connected in series. In some embodiments, the battery cells 68 are operable to output a continuous run discharge current of between about 40A and about 60A. In some embodiments, each of the battery cells 68 has a capacity of between about 3.0 Ah and about 5.0 Ah.

[0049] Figure 6 A battery receptacle 54 of the gas engine replacement device 10 is shown in accordance with some embodiments. The battery receptacle 54 includes a raised / recessed portion 74, a second terminal 78, a latching mechanism 82, and a power-off switch 86. The raised / recessed portion 74 cooperates with the raised / recessed portion 70 of the battery pack 50 to attach the battery pack 50 to the battery receptacle 54 of the gas engine replacement device 10. When the battery pack 50 is attached to the gas engine replacement device 10, the second terminal 78 and the first terminal 66 are electrically connected to each other. The latching mechanism 82 protrudes from a surface of the battery receptacle 54 and is configured to engage the battery pack 50 to maintain engagement between the battery pack 50 and the battery receptacle 54. Thus, the battery pack 50 can be connected to and supported by the battery receptacle 54 such that the battery pack 50 can be supported by the housing 14 of the gas engine replacement device 10. In some embodiments, the battery pack receptacle 54 is arranged on the housing 14 in a position such that a maximum possible separation distance is created between the motor 36 and the battery pack 50 in order to dampen vibrations transmitted from the motor 36 to the battery pack 50. In some embodiments, an elastomeric member is positioned on the battery pack receptacle 54 in order to dampen vibrations transmitted from the motor 36 to the battery pack 50 via the housing 14.

[0050] In other embodiments (not shown), the latching mechanism 82 may be located at different positions (e.g., on the side wall, end wall, top end wall, etc. of the battery socket 54) such that the latching mechanism 82 engages a corresponding structure on the battery pack 50 to maintain engagement between the battery pack 50 and the battery socket 54. The latching mechanism 82 includes a pivotable actuator or handle 90 that operatively engages a latching member 94. The latching member 94 is slidably disposed in a hole 98 in the socket 54 and biased toward a latched position by a biasing member 102 (e.g., a spring) to protrude through the surface of the battery socket 54 and into the cavity of the battery pack 50.

[0051] The latching mechanism 82 also includes a power-off switch 86 (e.g., a microswitch) that facilitates electrically connecting / disconnecting the battery pack 50 from the battery socket 54 during actuation of the handle 90 to remove the latching member 94 from the battery pack 50. The power-off switch 86 can be used to electrically disconnect the battery pack 50 from the gas engine replacement device 10 before removing it from the battery socket 54. The power-off switch 86 is actuated when the latching member 94 moves from the latched position (i.e., when the latching member 94 is fully within the cavity of the battery pack 50) to an intermediate position. The power-off switch 86 is electrically connected to the controller 46 and can generate an interrupt to indicate that the battery pack 50 is being disconnected from the gas engine replacement device 10. When the controller 46 receives the interrupt, the controller 46 initiates power-down operation to safely de-energize the control electronics 42 of the gas engine replacement device 10. A similar latching mechanism and disconnecting switch are described and illustrated in U.S. Patent Publication No. 2019 / 0006980, the entire contents of which are incorporated herein by reference.

[0052] like Figure 7 As shown, motor 36 includes a motor housing 96 having an outer diameter 97, a stator 99 having a nominal outer diameter 103 of at least 80 mm, a rotor 104 having an output shaft 106 and supported for rotation within the stator 99, and a fan 108. A similar motor is described and illustrated in U.S. Patent Publication No. 2019 / 0006980, which is incorporated herein by reference. In some embodiments, motor 36 is a brushless DC motor. In some embodiments, motor 36 has a power output of at least about 2760 W. In some embodiments, the power output of motor 36 may drop below 2760 W during operation. In some embodiments, the diameter 109 of fan 108 is the larger diameter 97 of motor housing 96. In some embodiments, motor 36 can be stopped with an electronic clutch (not shown) for rapid overload control. In some embodiments, motor 36 has at least 443,619 mm². 3The volume. In some embodiments, the motor has a weight of approximately 4.6 lb. The housing 14 includes an inlet vent and an outlet vent, such that the motor fan 108 draws air through the inlet vent and along the control electronics 42 to cool the control electronics 42 before the air is exhausted through the outlet vent. Figure 7 In the embodiment shown, motor 36 is an internal rotor motor, but in other embodiments, motor 36 may be an external rotor motor with a nominal outer diameter (i.e., the nominal outer diameter of the rotor) of up to about 80 mm.

[0053] Reference Figure 8 Motor 36 can transmit torque to power output shaft 38 in various configurations. In some embodiments, output shaft 106 is also power output shaft 38, allowing motor 36 to directly drive power output shaft 38 without any intermediate gear system. For example, motor 36 can directly drive a high-pole motor. Figure 8 As shown, in other embodiments, the gas engine replacement device 10 includes a gear train 110 that transmits torque from the motor 36 to the power output shaft 38. In some embodiments, the gear train 110 may include a mechanical clutch (not shown) to interrupt torque transmission from the motor 36 to the power output shaft 38. In some embodiments, the gear train 110 may include a planetary gearbox that transmits torque from the output shaft 106 to the power output shaft 38, and the axis of rotation of the output shaft 106 is coaxial with the axis of rotation of the power output shaft 38. In some embodiments, the gear train 110 includes a spur gear that engages with the output shaft 106 of the rotor such that the axis of rotation of the output shaft 106 is offset from and parallel to the axis of rotation of the power output shaft 38. In some embodiments, the gear train 110 includes a bevel gear such that the axis of rotation of the output shaft 106 is perpendicular to the axis of rotation of the power output shaft 38. In other embodiments utilizing bevel gears, the axis of rotation of the output shaft 106 is not perpendicular to, parallel to, or coaxial with the axis of rotation of the power output shaft 38, and the power output shaft 38 protrudes from the flange 34.

[0054] In some embodiments, the gas engine replacement device 10 includes an on / off indicator (not shown). In some embodiments, the gas engine replacement device 10 includes a filter (not shown) to block unloaded debris from the motor 36 and control electronics 42. In some embodiments, the filter includes a dirty filter sensor (not shown) and a self-cleaning mechanism (not shown). In some embodiments, the motor 36 will simulate a gas engine response when encountering resistance (such as slowing down or stopping). In some embodiments, the gas engine replacement device 10 includes a heat sink 202 in the housing 14 for air cooling of the control electronics 42. Figure 1 and Figure 2 In some embodiments, the gas engine replacement device 10 is liquid-cooled.

[0055] In some embodiments, the output shaft 106 of the rotor 104 has forward and reverse capability, as described further below. In some embodiments, the forward and reverse capability is controllable without shifting the gear train 110, as compared to gas engines that do not enable forward / reverse capability without additional gearing and time delay. Thus, the gas engine replacement 10 provides increased speed, lighter weight, and lower cost. Because the gas engine replacement 10 has fewer moving parts and no combustion system as compared to a gas engine, the gas engine replacement also provides additional speed, weight, and cost advantages.

[0056] The gas engine replacement 10 is capable of operating for long periods of time in any orientation (vertical, horizontal, inverted) relative to the ground surface, which makes it superior to four-cycle gas engines that can only operate in one orientation and for a short period of time with slight tilting. Because the gas engine replacement 10 does not require gas, oil, or other fluids, the gas engine replacement can be inverted or run on any given side, shipped, and stored without leaking or spilling.

[0057] In operation, the gas engine replacement 10 can be used to replace a gas engine system. Specifically, by aligning a first bolt pattern defined by a plurality of apertures in the flange 34 with a second bolt pattern, the gas engine replacement 10 can be installed onto a power equipment having the second bolt pattern. In some embodiments, the flange 34 can include one or more intermediate mounting members or adapters arranged between the flange 34 itself and a flange of the power equipment having the second bolt pattern, such that the adapter(s) couple the flange 34 to the power equipment. In these embodiments, the adapters include both the second bolt pattern and the first bolt pattern, such that the first bolt pattern of the flange 34 is aligned with the first bolt pattern of the adapters, and the second bolt pattern of the adapters is aligned with the second bolt pattern defined in the power equipment, thereby allowing the flange 34 of the gas engine replacement 10 to be coupled to the power equipment.

[0058] Alternatively, the gas engine replacement 10 can be connected to a power equipment using a belt system by providing a belt that is operably connected to the power output shaft and an equipment bit. Thus, the power output shaft 38 of the gas engine replacement 10 can be used to drive the equipment.

[0059] During operation, the housing 14 of the gas engine replacement unit 10 can be much cooler than the housing of the internal combustion unit because there is no combustion in the gas engine replacement unit 10. Specifically, when the gas engine unit is operating, the housing of the gas engine unit is 220 degrees Celsius or higher. In contrast, when the gas engine replacement unit 10 is operating, all outer surfaces of the housing 14 are below 95 degrees Celsius. Tables 1 and 2 below list in more detail the temperature limits of different components on the housing 14 of the gas engine replacement unit 10.

[0060] Table 1 below lists the Underwriters Laboratories (UL) temperature limits for different components typically used in power tools, whether they are made of metal, plastic, rubber, wood, ceramic, or glass. For example, in at least some embodiments, the gas engine replacement unit 10 will never exceed the rated temperature for plastics.

[0061] Table 1

[0062] Metal Plastic / rubber / wood Porcelain / glassy Accidental contact 85℃ 85℃ 85℃ Handles and knobs that are held continuously 55℃ 75℃ 65℃ Handles and knobs that are held only briefly (i.e. switches) 60℃ 80℃ 70℃

[0063] Table 2 below lists the UL temperature limits of the different components of the battery pack housing 58 of the battery pack 50, regarding whether these components are made of metal, plastic, or rubber. For example, in at least some embodiments, the gas engine replacement device 10 will never exceed the rated temperature for plastic.

[0064] Table 2

[0065] Metal Plastic / rubber Accidental contact 70℃ 95℃ Handles and knobs that are held continuously 55℃ 75℃ Handles and knobs that are held only briefly (i.e. switches) 60℃ 85℃

[0066] Figure 9 A simplified block diagram of a gas engine replacement device 10 according to an example embodiment is shown. Figure 9 As shown, the gas engine replacement device 10 includes an electronic processor 302, a memory 306, a battery pack 50, a power switch network 310, a motor 36, a rotor position sensor 314, a current sensor 318, a user input device 322 (e.g., a throttle, trigger, or power button), a transceiver 326, an indicator 330 (e.g., a light-emitting diode), and a vibration sensor 320. In some embodiments, the gas engine replacement device 10 includes a... Figure 9 The components shown may be fewer or additional. For example, the gas engine replacement device 10 may include a battery pack fuel gauge, work lights, additional sensors, a cut-off switch, a power-off switch 86, etc. In some embodiments, Figure 9The elements of the gas engine replacement device 10 shown in FIG. 1 include one or more of an electronic processor 302, a memory 306, a power switch network 310, a rotor position sensor 314, a current sensor 318, a user input device 322, a transceiver 326, an indicator 330, and a vibration sensor 320 Figure 3 The at least a portion of the control electronics 42 shown in FIG. 1, where the electronic processor 302 and the memory 306 form Figure 3 The at least a portion of the controller 46 shown in FIG. 1.

[0067] The memory 306 includes read-only memory (ROM), random access memory (RAM), other non-transitory computer-readable media, or a combination thereof. The electronic processor 302 is configured to communicate with the memory 306 to store data and retrieve stored data. The electronic processor 302 is configured to receive instructions and data from the memory 306 and execute the instructions, among other things. In particular, the electronic processor 302 executes instructions stored in the memory 306 to perform the methods described herein.

[0068] As described above, in some embodiments, the battery pack 50 is removably attached to the housing of the gas engine replacement device 10, such that different battery packs 50 can be attached to and removed from the gas engine replacement device 10 to provide different amounts of power to the gas engine replacement device 10. Further descriptions of the battery pack 50 (e.g., nominal voltage, continuous operating discharge current, size, number of battery cells, operation, etc.) and further descriptions of the motor 36 (e.g., power output, size, operation, etc.) are described above with respect to Figures 1 to 8 Provided.

[0069] The power switch network 310 enables the electronic processor 302 to control the operation of the motor 36. Generally, when the user input device 322 is depressed (or otherwise actuated), current is supplied from the battery pack 50 to the motor 36 via the power switch network 310. When the user input device 322 is not depressed (or otherwise actuated), current is not supplied from the battery pack 50 to the motor 36. In some embodiments, the amount that the user input device 322 is depressed is related to or corresponds to a desired rotational speed of the motor 36. In other embodiments, the amount that the user input device 322 is depressed is related to or corresponds to a desired torque. In other embodiments, a separate input device (e.g., a slider, a dial, etc.) is included on the gas engine replacement device 10 that is in communication with the electronic processor 302 to provide a desired rotational speed or torque to the motor 36.

[0070] In response to the electronic processor 302 receiving a drive request signal from the user input device 322, the electronic processor 302 activates the power switching network 310 to provide power to the motor 36. Through the power switching network 310, the electronic processor 302 controls the amount of current available to the motor 36, thereby controlling the speed and torque output of the motor 36. The power switching network 310 can include a number of field effect transistors (FETs), bipolar transistors, or other types of electrical switches. For example, the power switching network 310 can include a six-FET bridge (see Figure 10 ) that receives pulse width modulated (PWM) signals from the electronic processor 302 to drive the motor 36.

[0071] The rotor position sensor 314 and the current sensor 318 are coupled to the electronic processor 302 and communicate various control signals to the electronic processor 302 indicative of different parameters of the gas engine replacement device 10 or the motor 36. In some embodiments, the rotor position sensor 314 includes one Hall sensor or a plurality of Hall sensors. In other embodiments, the rotor position sensor 314 includes a quadrature encoder attached to the motor 36. The rotor position sensor 314 outputs motor feedback information to the electronic processor 302, such as an indication (e.g., a pulse) when a magnet of a rotor of the motor 36 rotates past a surface of a Hall sensor. In other embodiments, the rotor position sensor 314 includes a voltage or current sensor, for example, that provides an indication of back electromotive force (back emf) generated in a motor coil. The electronic processor 302 can determine rotor position, rotor speed, and rotor acceleration based on the back emf signal received from the rotor position sensor 314 (i.e., voltage or current sensor). The rotor position sensor 314 can be combined with the current sensor 318 to form a combined current and rotor position sensor. In this example, the combined sensor provides current to the active phase coil(s) of the motor 36 and also provides current in one or more of the inactive phase coil(s) of the motor 36. The electronic processor 302 measures current flow to the motor based on the current to the active phase coil and measures motor speed based on the current in the inactive phase coil.

[0072] Based on motor feedback information from the rotor position sensor 314, the electronic processor 302 can determine the position, velocity, and acceleration of the rotor. In response to the motor feedback information and signals from the user input device 322, the electronic processor 302 transmits control signals to control the power switch network 310 to drive the motor 36. For example, by selectively enabling and disabling the FETs of the power switch network 310, power received from the battery pack 50 is selectively applied to the stator windings of the motor 36 in a cyclical manner to cause the rotor of the motor 36 to rotate. The electronic processor 302 uses the motor feedback information to ensure proper timing of the control signals to the power switch network 310, and in some cases, provides closed loop feedback to control the velocity of the motor 36 at a desired level. For example, to drive the motor 36, using motor positioning information from the rotor position sensor 314, the electronic processor 302 determines the position of the rotor magnet relative to the stator windings and (a) energizes the next stator winding pair (or stator winding pairs) in a predetermined pattern to provide a magnetic force to the rotor magnet in a desired direction of rotation, and (b) de-energizes the previously energized stator winding pair (or stator winding pairs) to prevent the application of a magnetic force on the rotor magnet in the opposite direction of rotation of the rotor.

[0073] The current sensor 318 monitors or detects the current level of the motor 36 during operation of the gas engine replacement device 10 and provides control signals to the electronic processor 302 indicative of the detected current level. The electronic processor 302 can use the detected current level to control the power switch network 310, as explained in more detail below.

[0074] The transceiver 326 allows the electronic processor 302 to communicate with an external device 338 (e.g., a smartphone, tablet, or laptop computer) through a wired or wireless communication network 334. In some embodiments, the transceiver 326 can include separate transmitting and receiving components. In some embodiments, the transceiver 326 can include a wireless adapter attached to the gas engine replacement device 10. In some embodiments, the transceiver 326 is a wireless transceiver that encodes information received from the electronic processor 302 into a carrier wireless signal and transmits the encoded wireless signal through the communication network 334 to the external device 338. The transceiver 326 also decodes information from wireless signals received through the communication network 334 from the external device 338 and provides the decoded information to the electronic processor 302. In some embodiments, the transceiver 326 communicates with one or more external sensors 340 through the communication network 334. For example, the external sensors 340 can be associated with equipment in which the gas engine replacement device 10 is installed. In some embodiments, the external sensors 340 are velocity sensors, position sensors, or the like.

[0075] The communication network 334 provides wired or wireless connectivity between the gas engine replacement device 10, the external device 338, and the external sensor 340. The communication network 334 may include short-range networks, such as Bluetooth networks, Wi-Fi networks, etc., or long-range networks, such as the Internet, cellular networks, etc.

[0076] like Figure 9 As shown, indicator 330 is also connected to electronic processor 302 and receives control signals from electronic processor 302 to turn the gas engine replacement device 10 on and off based on different states or otherwise transmit information. Indicator 330 includes, for example, one or more light-emitting diodes (“LEDs”) or a display screen. Indicator 330 can be configured to display the status of gas engine replacement device 10 or information associated with gas engine replacement device. For example, indicator 330 is configured to indicate measured electrical characteristics of gas engine replacement device 10, status of gas engine replacement device 10, mode of gas engine replacement device 10, etc. Indicator 330 may also include elements that transmit information to a user via auditory or tactile output. In some embodiments, indicator 330 includes an eco indicator that indicates the electrical force used by the load during operation.

[0077] Figure 9 The connections between the components of the gas engine replacement device 10 are simplified in the diagram. In reality, the wiring of the gas engine replacement device 10 is more complex because the components are interconnected via several lines for power and control signals. For example, each FET of the power switch network 310 is connected to the electronic processor 302 via a control line; each FET of the power switch network 310 is connected to a terminal of the motor 36; the power lines from the battery pack 50 to the power switch network 310 include a positive line and a negative / ground line; and so on. Additionally, the power lines may have a large gauge / diameter to handle increased current. Furthermore, although not shown, additional control signal lines and power lines are used to interconnect additional components of the gas engine replacement device 10.

[0078] Figure 10 An example of a power switch network 310 for driving a motor 36 of a gas engine replacement device 10 is shown. The power switch network 310 includes three high-side FETs H1, H2, and H3 and three low-side FETs L1, L2, and L3, each having a first or on state and a second or off state. The power switch network 310 is used to selectively apply power from a battery pack 50 to the motor 36. An example of how the high-side and low-side switches are controlled to operate the motor 36 in forward and reverse directions is described below.

[0079] High-side and low-side switches can be controlled using (pulse width modulation) commutation, centerline commutation, or other commutation schemes. Figure 11A A simple PWM commutation method is demonstrated for controlling the rotation of motor 36 in the positive direction. For example... Figure 11A As shown, each high-side FET H1, H2, and H3 is periodically turned on throughout the commutation phase. When one of FETs H1, H2, and H3 stops conducting, the next high-side FET begins conducting. Similarly, each low-side FET L1, L2, and L3 is periodically turned on throughout the commutation phase. When one of FETs L1, L2, and L3 stops conducting, the next low-side FET begins conducting. However, one or both of the high-side or low-side FETs may be activated only for a certain period of the commutation phase based on the desired speed of motor 36 or the load on motor 36 (e.g., with a PWM signal having 75%, 50%, 25%, or another duty cycle). In the example shown, to drive motor 36 in the positive direction, the high-side and low-side FETs are activated in a predetermined pair and in a predetermined order. Figure 11A In the example shown, H1 and L2 are activated first, then H2 and L3, and then H3 and L1. In forward operation, this sequence continues during the operation of motor 36. Figure 11B A simple PWM commutation method is demonstrated for controlling motor 36 to rotate in the opposite direction. Figure 11B In the example shown, H1 and L3 are activated first, then H3 and L2, and then H2 and L1. In reverse operation, this sequence continues during the operation of motor 36. In some embodiments, one or more variations of this sequence can be performed based on desired motor operation. For example, one or both of the high-side and low-side FETs can switch at a certain frequency during their activation phase to control the speed of the motor. Alternatively, the activation phases of the high-side and low-side FETs can be shifted to overlap with other activations, thereby achieving different controls (e.g., field-oriented control).

[0080] Figure 12 This is a simplified block diagram of a motor controller 400, which in some embodiments is implemented by software stored in memory 306 and executed by electronic processor 302. The motor controller 400 includes a profile generator 405, a speed controller 410, a torque controller 415, a brushless controller 420, and a D / DT unit 425. In some embodiments, the D / DT unit 425 calculates the derivative of the shaft angle to determine the shaft speed. The profile generator 405 receives speed control settings (e.g., from user input device 322) and system settings. The profile generator 405 generates a speed reference for the speed controller 410 and a torque reference for the torque controller 415. The profile generator 405 aligns the speed and torque control with specific characteristics of the mechanical system coupled to the motor 36.

[0081] The torque controller 415 receives shaft angle feedback from the rotor position sensor 314, and the speed controller 410 receives shaft speed feedback from the D / DT unit 425. The brushless controller 420 receives the speed output of the speed controller 410 and the torque output of the torque controller 415, and generates control signals for the power switch network 310 as described above. For example, the brushless controller 420 can generate a sequence of PWM signals for each power switch element of the power switch network 310 to drive the motor 36. The motor controller 400 provides independent speed and torque control over a wide operating range. The motor controller 400 allows operation over a wide speed range that exceeds the typical speed range of internal combustion engines. For example, while reciprocating engines are limited to a small operating speed and torque delivery range, the motor controller 400 provides an almost infinite speed range with full torque control without the need for complex gearboxes or reducers that are common in systems driven by internal combustion engines. Since the motor controller 400 can produce rated torque at or slightly above the stall speed, low speed operation is supported for creep and inching applications.

[0082] The profile generator 405 allows the use of speed profiles that conform to the mechanical system, enabling features such as detection of pump cavitation or water hammer in pumping applications, nonlinear speed and torque relationships for fans and pumps, torque limits and control for lifting and tension winding applications. In some embodiments, to mitigate damage to the mechanical system, the motor controller 400 detects stall or stalling and limits the torque output of the torque controller 415. The motor controller 400 allows smooth acceleration and closed loop speed regulation compared to mechanical systems operated by internal combustion engines that require imprecise mechanical governors. The motor controller 400 provides load independent speed control, allowing constant speed operation under load (e.g., for cutting or finishing applications). In some embodiments, the profile generator 405 receives shaft speed, shaft angle, or both.

[0083] Referring to Figure 13 and Figure 14 , the motor controller 400 employs a skip speed technique to avoid mechanical resonances inherent in the mechanical system coupled to the motor 36. Figure 13 is a graph 450 illustrating a speed profile used by the profile generator 405 according to some embodiments. Figure 14 is a flowchart 500 of an example method for speed control of the motor 36.

[0084] Mechanical systems often have rotational speeds that are related to the natural resonant frequencies of the mechanical system. Operating at these speeds can cause excessive wear and failure of the mechanical system. In typical internal combustion engine applications, dampers or other methods can be used to prevent damage from mechanical vibrations. In some embodiments, the motor controller 400 is programmed to avoid speeds that cause mechanical resonance and to mitigate the need for damping equipment. The profile generator 405 provides a speed profile that avoids a predetermined programmed speed range. In one embodiment, the profile generator 405 provides a speed command with hysteresis.

[0085] The profile generator 405 receives a command speed (e.g., determined by a governor setting or a system setting) and generates an output speed for the speed controller 410. As Figure 13 shown, the command speed and the output speed follow until the command speed approaches the jump speed. A forbidden zone 455 is defined that corresponds to the programmed speed range (e.g., bounding the jump speed or resonant frequency defined for the mechanical system). For example, the forbidden zone 455 is defined by an upper speed limit 460 and a lower speed limit 465. The profile generator 405 maintains the output speed at a first (lower) speed value 470 even as the command speed continues to increase until the command speed exceeds the upper limit 460 of the forbidden zone 455. The first (lower) speed value 470 is the speed value associated with the command speed at the lower speed limit 465. After the command speed exceeds the forbidden zone 455, the output speed increases to match the command speed. The profile generator 405 implements a forbidden zone for both increasing and decreasing command speeds. For example, when the command speed decreases to the upper limit 460 and below, the profile generator 405 maintains the output speed at a second (higher) speed value 475 until the command speed decreases below the lower limit 465 of the forbidden zone 455. The second (higher) speed value 470 is the speed value associated with the command speed at the upper speed limit 460. After the command speed decreases below the forbidden zone 455, the output speed decreases to match the command speed. In some embodiments, multiple forbidden zones can be implemented by the profile generator 405.

[0086] In some embodiments, the forbidden zone 455 is preprogrammed into the profile generator 405. For example, the upper and lower limits of the forbidden zone can be determined based on vibration testing of the particular mechanical system in which the gas engine replacement device 10 is to be included, and these limits can be saved into the memory 306. In other embodiments, the profile generator 405 employs the vibration sensor 320 (see Figure 9 ) to measure the vibrations of the mechanical system. In some embodiments, the profile generator 405 employs the forbidden zone 455 in response to the output of the vibration sensor 320 exceeding a vibration limit. In some embodiments, the profile generator 405 uses a learning technique that dynamically sets the forbidden zone 455 as the vibration sensor 320 collects data over time about the vibration characteristics of the mechanical system.

[0087] In some embodiments, the profile generator 405 dynamically determines the restricted area 455 based on the real-time output of the vibration sensor 320. If the vibration sensor 320 measures vibration above a first threshold, the profile generator 405 limits the output speed to a first value, thereby setting a first limit for the restricted area 455 (i.e., an upper limit if the command speed is decreasing, or a lower limit if the command speed is increasing). As the command speed continues to change, the profile generator 405 sets the output speed to a temporary command speed and determines whether the vibration sensor 320 measures vibration below the first threshold. If the vibration level does not drop below the first threshold at the temporary command speed, the profile generator 405 determines that the gas engine replacement device 10 is still within the restricted area 455 and returns the output speed to the first value. If the vibration level drops below the first threshold at the temporary command speed, the profile generator 405 determines that a second limit of the restricted area has been passed and allows continued operation at the temporary command speed. In some embodiments, the profile generator 405 sets the temporary command speed in predetermined increments of the command speed until the second limit is passed.

[0088] As pointed out, Figure 14 Flowchart 500 describes a speed control method for motor 36. Flowchart 500 relates to its implementation on the gas engine replacement device 10. Figure 12 Motor controller 400 and such Figure 13 The flowchart 500 is generally described in terms of the restricted areas. However, in some embodiments, the method of flowchart 500 is implemented by other devices or variations of motor controller 400, and in some embodiments, the flowchart is implemented using a form that is similar to... Figure 13 This is achieved through different types of restricted areas, as shown. (See reference) Figure 14 In block 505, profile generator 405 receives a commanded speed for motor 36 (e.g., indicated by a speed regulator setting or system setting, as previously described). For example, in some embodiments, the speed regulator setting and system setting are values ​​representing the desired speed of motor 36.

[0089] In box 510, profile generator 405 determines whether the commanded speed is within the restricted area (in box 510). For example, profile generator 405 compares the commanded speed received in box 505 with the restricted area defined by a speed upper limit 460 and a speed lower limit 465. When profile generator 405 determines, based on the comparison result, that the commanded speed is greater than the speed lower limit 465 and less than the speed upper limit 460, the profile generator determines that the commanded speed is within the restricted area. In response to determining that the commanded speed is not within the restricted area, profile generator 405 sets the output speed to the commanded speed (in box 515).

[0090] In response to determining that the command speed is within the restricted area, profile generator 405 determines whether the previous output speed was below the restricted area (in box 520) (i.e., approaching from below). In response to determining that the previous output speed was below the restricted area, the profile generator sets the command speed to a lower limit 465, thereby setting the output speed to a first (lower) speed 470 associated with the lower limit 465 (in box 525). In other words, in box 525, the profile generator sets the output speed to the lower limit of the restricted area. If the previous output speed was not below the restricted area (i.e., approaching from above), the profile generator sets the command speed to an upper limit 460, thereby setting the output speed to a second (higher) speed 475 of the restricted area (in box 530). In other words, in box 530, the profile generator sets the output speed to the upper limit of the restricted area.

[0091] Profile generator 405 receives the next command speed (at box 505) and repeats the speed limit until the command speed is no longer within the restricted area (at box 515).

[0092] As noted above, in some embodiments, flowchart 500 is used to take and Figure 13 The restricted zones are implemented in different forms as shown. For example, in some embodiments, multiple restricted zones are implemented, each with its own upper and lower speed limits and associated first and second speeds. In such an embodiment, in block 510, profile generator 405 uses a comparison function similar to that noted above regarding determining whether the command speed is within restricted zone 455 to determine whether the command speed is within any of these restricted zones, although each restricted zone has different limits. Furthermore, in blocks 525 and 530, the output speed is respectively set to the first or second speed associated with the restricted zone where the command speed is determined to be.

[0093] Figure 15 A pump system 620 is shown, comprising a frame 624 supporting a gas engine replacement device 10 and a pump 628, wherein the gas engine replacement device 10 is operable to drive the pump 628. The pump 628 shown is a centrifugal pump having an impeller positioned within a housing 632 of the pump 628, the impeller being rotatable about an axis to move material from an inlet 636 of the pump 628 to an outlet 640 of the pump 628. In some embodiments, the gas engine replacement device 10 of the pump system 620 implements the above-described... Figures 12 to 14 The motor control described.

[0094] Figure 16 The speed-torque operating curve 700 of the pump system 620 is shown. The profile generator 405 in the motor controller 400 provides speed and torque control over the entire operating range, closely matching the theoretical operating curve 705.

[0095] Figure 17 is a flowchart 800 of an example method for runaway detection and control of the motor 36 according to some embodiments. The motor controller 400 employs a runaway detection technique to identify and respond to potential runaway conditions. For example, in embodiments where the gas engine replacement device 10 provides power to move a vehicle, such as a lawn mower, garden tractor, etc., the vehicle can be operated on a hill such that the speed of the vehicle increases without a signal to increase the commanded speed of the motor (e.g., using the user input device 322). The flowchart 800 is described with respect to the motor controller 400 of the gas engine replacement device 10 of Figure 12 However, in some embodiments, the method of the flowchart 800 is implemented by other devices or variations of the motor controller 400.

[0096] Referring to FIG. 8A, Figure 17 At block 805, the profile generator 405 of the motor controller 400 receives a commanded speed for the motor 36 (e.g., indicated by a throttle setting or a system setting, as previously described). For example, in some embodiments, the throttle setting and the system setting are values representative of a desired speed of the motor 36. At block 810, the motor controller 400 generates a commanded speed for the motor 36. For example, in some embodiments, the profile generator 405 generates the commanded speed based on a profile of the device powered by the gas engine replacement device 10, and the brushless controller 420 generates drive parameters (e.g., PWM duty cycles) for the motor 36 based on the commanded speed. In some embodiments, the speed controller employs a closed loop control process, in which shaft speed feedback is employed to adjust the drive parameters employed by the brushless controller 420. In some embodiments, the speed controller employs an open loop control process, in which the drive parameters generated by the brushless controller 420 are set (e.g., by a fixed PWM duty cycle) according to the throttle setting and the system setting received by the profile generator 405.

[0097] At block 815, the motor controller 400 detects an out-of-control condition. In some embodiments, the speed controller 410 monitors the shaft speed of, for example, the motor 36 or the power take-off shaft 140 to identify an out-of-control condition. In one example, the speed controller 410 identifies an out-of-control condition when the shaft speed increases by a predetermined value within a predetermined time interval. For example, the motor controller 400 can detect the shaft speed periodically (e.g., every 100 ms, 10 ms, or 1 ms) using output from the rotor position sensor 314 and detect the change in shaft speed relative to a previous reading (e.g., 100 ms or 1 second ago) at the same frequency. The motor controller 400 can further compare the change in shaft speed to a threshold value and identify an out-of-control condition when the detected change in shaft speed exceeds the threshold value. Because the speed of the motor 36 is proportional to the speed of the vehicle powered by the gas engine replacement device 10, an unexpected increase in shaft speed indicates an out-of-control condition. In some embodiments, the speed controller 410 employs information from the external sensor 340 to identify an out-of-control condition. For example, the external sensor 340 can be a sensor that measures the ground speed of the vehicle powered by the gas engine replacement device 10. Rather than (or in addition to) determining whether the shaft speed increases by a predetermined value within a predetermined time interval, the motor controller determines whether the vehicle ground speed increases by a predetermined value within a predetermined time interval. This determination can be accomplished using similar techniques as for the shaft speed but using the sensed vehicle ground speed instead. In some embodiments, the threshold value is set based in part on the desired throttle setting so as to account for user requests for speed increases. For example, the threshold value can increase when the user requests an increase in vehicle speed as indicated by the throttle setting signal and decrease when the user requests a decrease in vehicle speed as indicated by the throttle setting signal. In this way, typical requests for an increase in vehicle speed are less likely to be detected as an out-of-control condition.

[0098] At block 820, in response to detecting a runaway condition, motor controller 400 mitigates the runaway condition. In some embodiments, motor controller 400 reduces the command speed in response to detecting a runaway condition. In some embodiments, motor controller 400 generates a braking signal in response to detecting a runaway condition. In one example, motor controller 400 shuts down power switching network 310 by controlling all high-side and low-side FETs to turn off, allowing motor 36 to stop due to inertia. Since no current is supplied to the motor when the FETs are off, motor 36 stops due to friction or load acting on motor 36. In other examples, passive or active braking can be used to stop motor 36. During passive braking, motor controller 400 may provide control signals to the high-side and low-side FETs to connect the motor to a braking load (e.g., a braking coil or braking resistor connected between one or more stator coils and ground) to rapidly dissipate energy in motor 36 and brake motor 36. During active braking, motor controller 400 may control the high-side FETs to turn off and the low-side FETs to turn on, short-circuiting the motor coils to ground and dissipating any remaining energy in the coils to ground. In other examples, the motor controller 400 can provide control signals to the high-side and low-side FETs to perform regenerative braking and to supply energy from the motor 36 back to the battery pack 50 via the power switching network 310. In yet another example, dynamic pulses can be used to brake the motor 36. The motor controller 400 can provide control signals to the high-side and low-side FETs to provide electrical braking force on the rotor of the motor 36. The motor controller 400 can monitor the rotor position sensor 314 to activate the phase when the rotor has just passed a phase (i.e., the corresponding pair of high-side and low-side FETs). For example, the rotor position sensor 314 indicates that the rotor has just passed the phase corresponding to FETs H1 and L2. In response, the motor controller 400 can activate FETs H1 and L2 to drive current through the stator coils to generate a magnetic field that provides braking force to the rotor in the opposite direction to the rotor's rotation direction, thereby stopping the rotation. The motor controller 400 can continue to operate in a similar manner... Figure 11A The FET pairs are activated sequentially, but with timing based on rotor position information from rotor position sensor 314, such that the resulting magnetic field generated by the coupled stator coils continues to provide braking force to stop rotation. In some embodiments, motor controller 400 sends a signal to the electronically controlled mechanical brake of the vehicle powered by replacement device 10.

[0099] refer to Figure 18 , Figure 19 and Figure 20 The motor controller 400 uses load monitoring technology to estimate the load condition and adjust the load speed according to the load parameters. Figure 18 This is a flowchart 900 of an example method for load monitoring according to some embodiments. Figure 19 andFigure 20 is a graph 450 illustrating identifying a disturbance in motor current for a load condition according to some embodiments. For example, in a gas engine replacement device 10 powering a concrete mixer embodiment, the viscosity of the load is variable based on the contents of the mixer and the rotational speed. Increasing the rotational speed of the mixer generally decreases the viscosity, while decreasing the rotational speed of the mixer generally increases the viscosity. In another embodiment of the gas engine replacement device 10 powering a cutting blade such as a lawnmower or saw, the density of the material being cut is variable (e.g., based on the length and thickness of the grass or material composition). Increasing the rotational speed of the cutting blade is useful for thick grass or dense material, while decreasing the rotational speed of the cutting blade is useful for less dense grass or material, which can reduce power consumption. The flowchart 900 is described with respect to the motor controller 400 implemented on the gas engine replacement device 10. However, in some embodiments, the method of the flowchart 900 is implemented by other devices or variants of the motor controller 400. Figure 12

[0100] Referring to Figure 18 , at block 905, the motor controller 400 monitors a current parameter of the motor 36. In some embodiments, the motor controller 400 identifies an overshoot condition in the motor current. For example, in a concrete mixer embodiment, when the mixer is first rotated, material adheres to the walls of the mixer. At some rotational position depending on the viscosity of the material, the material falls to the bottom of the mixer, causing a sudden decrease in the load on the mixer. As shown in Figure 19 , this load reduction is indicated by an overshoot 1000 in the motor current curve 1010. As shown in Figure 20 , in a cutting blade embodiment, an increase in the density of the material being cut is indicated by a ramp 1100 in the motor current curve 1110.

[0101] At block 910, the motor controller 400 estimates a load condition. For example, the motor controller estimates a load viscosity or density parameter as the load condition. In the mixing embodiment, the rotational position and the amplitude of the overshoot 1000 are a function of the viscosity of the material. In some embodiments, the motor controller 400 uses the rotor position sensor 314 to determine the rotational position. In some embodiments, the external sensor 340 is a position sensor that provides the rotational position of the mixer. In the cutting example, the amplitude and slope of the ramp 1100 are a function of the density of the material. In some embodiments, the profile generator 405 stores a profile of the device powered by the gas engine replacement device 10 that relates the load condition to the sensed motor parameter. In some embodiments, the profile includes a lookup table, an equation model, or a deep learning model.

[0102] ​At block 915, the motor controller 400 sets a motor command speed based on the load condition. In some embodiments, the motor controller 400 (e.g., the profile generator 405) is programmed with a viscosity target value and adjusts the command speed of the motor 36 in response to the estimated viscosity load condition to drive the estimated viscosity load condition closer to or maintain it close to the viscosity target value. In some embodiments, for a cutting application, the motor controller 400 changes the command speed in proportion to changes in the estimated density. In some embodiments, the motor controller 400 increases the command speed of the cutting blade as the density increases and decreases the command speed as the density decreases. In some embodiments, the motor controller 400 stores a model or lookup table as a function of the estimated load condition that specifies an adjustment factor for the command speed.

[0103] Figure 21 A mixing system 1200 is shown that includes a frame 1205 that supports a gas engine replacement device 10, and a mixing drum 1210, where the gas engine replacement device 10 is operable to rotate the mixing drum 1210. In some embodiments, the gas engine replacement device 10 of the mixing system 1200 implements the motor control described above with respect to Figure 18 and Figure 19 .

[0104] Figure 22 A cutting system 1300 is shown that, in the embodiment shown, is a cutoff saw. The cutting system 1300 includes a housing 1305, a support arm 1310 coupled to and extending from the housing 1305, a cutting wheel 1315 carried by the support arm 1310, and a guard 1320 covering a portion of the circumference of the cutting wheel 1315. The cutting wheel 1315 can be a blade, a grinding disc, or any other rotatable element capable of removing material from a workpiece. A first or rear handle 1325 extends from a rear portion of the housing 1305 in a direction generally opposite the support arm 1310. A trigger 1330 for operating the cutting system 1300 is located on the rear handle 1325. In the embodiment shown, the cutting system 1300 also includes a second or front handle 1335 that encircles an upper portion of the housing 1305. The front handle 1335 and the rear handle 1325 provide gripping areas to facilitate two-handed operation of the cutting system 1300. The cutting system 1300 shown is a cordless electric saw and includes a gas engine replacement device 10. In some embodiments, the gas engine replacement device 10 of the cutting system 1300 implements the motor control described above with respect to Figure 18 and Figure 20 .

[0105] Figure 23is a flowchart 1400 of an example method for load positioning according to some embodiments. For example, in embodiments where the gas engine replacement device 10 powers a concrete mixer, material can be loaded into the mixing drum when the mixing drum is positioned in a first rotational position, and material can be unloaded from the mixing drum when the mixing drum is positioned in a second rotational position.

[0106] Referring to Figure 23 At block 1405, the motor controller receives a position control command. In some embodiments, the user inputs the position control command using the external device 338 (see Figure 9 ). For example, the user can select a load position or an unload position by selecting a control displayed on the external device 338 or a user input device 322 (e.g., a button). In some embodiments, the external device 338 is a wired device or a wireless remote control device associated with the equipment driven by the gas engine replacement device 10. The position control command instructs the motor controller 400 to rotate the load to a particular position (e.g., a particular rotational position of the mixing drum of the concrete mixer 1200).

[0107] At block 1410, the motor controller 400 determines the load position. In some embodiments, the motor controller 400 uses the rotor position sensor 314 to determine the position of the load. In some embodiments, the external sensor 340 is a position sensor that provides the position of the load (e.g., the rotational position of the mixing drum).

[0108] At block 1415, the motor controller 400 controls the motor 36 based on the load position. In some embodiments, the profile stored by the profile generator 405 includes position data, such as the load position for a load or unload position, or for other positions associated with the equipment. In response to the position control command received at block 1405 and the load position determined at block 1410, the motor controller 400 stops the motor 36 in response to the load position corresponding to the position control command. For example, the motor controller 400 can control the motor 36 to rotate until a particular rotational position of the mixing drum is reached, at which point the motor 36 stops. The motor 36 can decelerate to reduce position overshoot before reaching the desired position of the load.

[0109] In some embodiments, the load position corresponding to the position control command is set by the manufacturer or user of the gas engine replacement device 10 that sets up the device. For example, an external device 338 or user input device 322 can be employed to specify the load position corresponding to the position control command. For example, in response to user input via the external device 338 or user input device 322, the current load position can be stored as the load position target corresponding to the position control command. In some embodiments, multiple position control commands can be provided corresponding to multiple load position targets (e.g., a load position and an unload position), and each position control command can be associated with a different desired load position of the load, which can be set using similar techniques (e.g., by the manufacturer or by the user using the external device 338 or user input device 322) by the motor controller 400. For example, the user input device 322 can include a set load position button and a set unload position button that provide input to the motor controller 400 to store the current load position as the desired load position and the desired unload position, respectively. The stored desired load position and desired unload position can then be used by the motor controller 400 in block 1415, where one of the two stored positions is selected depending on whether the load is requested to be rotated to the load position or the unload position according to the position control command.

[0110] Power tools can potentially be affected by intrusion, vibration, and hot components, and the electronics of the power tool can be sensitive to these components. Various techniques can be used to protect one or more electronic components of the gas engine replacement device 10 from extreme environments. In one example, extreme temperatures can damage electronics. In some embodiments, a protection technique for improving tool performance in extreme hot environments includes the use of thermally conductive potting. Another technique includes placing one or more electronic components in a pressurized mineral oil pocket with cooling to provide heat dissipation and allow for improved performance. These techniques can also provide protection from environmental hazards such as intrusion of water or other substances. Also, open contacts can be covered with glue or low pressure injection molding for live or sensitive components to extend tool life in extreme conditions. In some applications, these techniques can also be effective in reducing the risk of vibration and help to mitigate strain on components soldered to the circuit board.

[0111] Figure 24 A cooling system 1500 for one or more electronic components in a gas engine replacement device of Figure 1 The cooling system 1500 includes an electronics enclosure 1510, a pump 1520, and a heat exchanger 1530. Sensitive components of the gas engine replacement device 10, such as the motor controller 400, the motor 420, and the battery 430, can be placed in the electronics enclosure 1510. The pump 1520 can be used to circulate a coolant through the electronics enclosure 1510 and the heat exchanger 1530. The heat exchanger 1530 can be used to cool the coolant, and the cooled coolant can be recirculated through the electronics enclosure 1510. In some embodiments, the pump 1520 and the heat exchanger 1530 can be placed in the electronics enclosure 1510. In some embodiments, the pump 1520 and the heat exchanger 1530 can be placed outside of the electronics enclosure 1510. Figure 9The electronic processor 302 and memory 306 in the electronic processing unit 300 can be disposed in the electronic enclosure 1510. A pump 1520 circulates an inert fluid, such as mineral oil, through the electronic enclosure 1510 to remove heat. A heat exchanger 130 cools the inert fluid to remove heat from the cooling system 1500. In some embodiments, the heat exchanger can be a radiative exchanger, such as a fin-based heat sink, that radiates heat to the external environment. Air in the surrounding environment can circulate over the fins to remove heat. The electronic enclosure 1510 also serves to provide protection from intrusion, vibration, strain, and the like.

[0112] The mechanical systems described above that are driven by the gas engine replacement device 10 include a number of advantages over conventional equipment driven by internal combustion engines, some of which will be discussed below.

[0113] In some embodiments, the gas engine replacement device 10 can be mated with a new piece of equipment, and the memory 306 can be reprogrammed to optimize the gas engine replacement device 10 for operation with the new equipment. In some embodiments, the electronic processor 302 automatically identifies the type of new equipment that the gas engine replacement device 10 has been mated with, and governs the operation of the gas engine replacement device 10 accordingly. In some embodiments, the electronic processor 302 can automatically detect which equipment the gas engine replacement device 10 has been mated with via radio frequency identification (RFID) communication with the new equipment.

[0114] In some embodiments, the memory 306 is reprogrammable via BLUETOOTH or Wi-Fi communication protocols. In some embodiments, the electronic processor 302 has control modes for different uses of the same equipment. The control modes can be preset or user programmable, and can be programmed remotely via BLUETOOTH or Wi-Fi. In some embodiments, the electronic processor 302 utilizes master / slave device-to-device communication and coordination, such that the gas engine replacement device 10 can exert unidirectional control over the equipment, or an operator can exert unidirectional control over the gas engine replacement device 10 using a smartphone app.

[0115] In some embodiments, the operator or original equipment manufacturer (OEM) is allowed to limit control of the speed of the gas engine replacement device 10 through the electronic processor 302 via an interface such as a controller area network (CAN) like interface. In some embodiments, the electronic processor 302 is able to utilize a single gear set in the gear train 110 for a wider range of speed selection compared to a gasoline engine. For example, the control electronics 42 are configured to drive the motor 36 at less than 2,000 RPM, which is lower than any speed that a gasoline engine is capable of reaching, allowing the associated equipment to have a longer total run time when the battery pack 50 is fully discharged compared to a gasoline engine. In addition, the control electronics 42 are configured to drive the motor at more than 3,600 RPM, which is higher than any speed that a gasoline engine is capable of reaching, and have the ability to deliver greater torque. The wider range of speeds of the motor 36 provides higher efficiency and capability compared to a gasoline engine. In some embodiments, in addition to speed, the operator can also control the current drawn by the motor 36.

[0116] In some embodiments, the electronic processor 302 is configured to record and report data. For example, the electronic processor 302 is configured to provide wired or wireless diagnostics for monitoring and reading the status of the gas engine replacement device 10. For example, the electronic processor 302 can monitor and record the run time of the gas engine replacement device 10, for example in the case of a lease. In some embodiments, the motor 36 and the electronic processor 302 use regenerative braking to charge the battery pack 50. In some embodiments, the gas engine replacement device 10 includes a DC output (not shown) for lights or accessories. In some embodiments, the electronic processor 302 can detect abnormalities or malfunctions of the gas engine replacement device 10 via voltage, current, motion, speed, and / or thermocouples. In some embodiments, the electronic processor 302 can detect unintended use or stopping of the gas engine replacement device 10. If the equipment driven by the gas engine replacement device 10 is not operating with expected characteristics or is not being used properly or safely, the electronic processor 302 can detect the abnormality and disable the gas engine replacement device 10. For example, the gas engine replacement device 10 can include one or more accelerometers to sense whether the gas engine replacement device 10 and equipment are in an expected orientation. Also, if the electronic processor 302 determines that the gas engine replacement device 10 is not in an expected orientation (i.e., the equipment has been tipped over), the electronic processor 302 can disable the gas engine replacement device 10.

[0117] In some embodiments, the gas engine replacement device 10 includes an accessible sensor port (not shown) to electrically connect with a user-selected sensor (such as an accelerometer, gyroscope, GPS unit, or real-time clock) for use with the power equipment, allowing the operator to customize the variables sensed and detected by the electronic processor 302. In some embodiments, the electronic processor 302 can indicate the status of the battery pack 50 to the operator via visual, audible, or tactile notifications, such as when the battery charge is low. In some embodiments, the electronic processor 302 can operate an auxiliary motor separate from the motor 36 to drive an auxiliary device, such as a winch. The auxiliary motor can be internal or external to the gas engine replacement device 10.

[0118] In some embodiments, the gas engine replacement device 10 can include digital controls on a customizable user interface, such as a touch display, or a combination of knobs and buttons. In contrast, analog gasoline engines do not include such digital controls. In some embodiments, the user interface of the gas engine replacement device 10 can be modular, wired, or wireless, and can be attachable to the gas engine replacement device 10 or handheld. In some embodiments, the gas engine replacement device 10 can be controlled with a remote control that includes status indicators for certain characteristics of the gas engine replacement device 10, such as the state of charge of the battery pack 50, as well as temperature. In some embodiments, the gas engine replacement device 10 can provide status indications with a remote programmable device.

Claims

1. A gas engine replacement device, comprising: a housing; a battery receptacle coupled to the housing and configured to removably receive a battery pack; a motor within the housing; a power output shaft receiving torque from the motor and protruding from a side of the housing; a power switch network configured to selectively provide power from the battery pack to the motor; and an electronic processor coupled to the power switch network and configured to control the power switch network to rotate the motor, the electronic processor configured to: receive a commanded speed for the motor, determine whether the commanded speed is within a first exclusion zone, the first exclusion zone being a first speed exclusion zone, determine whether the commanded speed is within a second exclusion zone, the second exclusion zone being a second speed exclusion zone, set an output speed of the motor to the commanded speed in response to the commanded speed being outside the first exclusion zone and the second exclusion zone, set the output speed to a speed outside the first exclusion zone in response to the commanded speed being within the first exclusion zone, set the output speed to a speed outside the second exclusion zone in response to the commanded speed being within the second exclusion zone, and control the power switch network to rotate the motor at the output speed set based on determining whether the commanded speed is within the first exclusion zone or the second exclusion zone. the electronic processor configured to set the output speed to an upper limit of the first exclusion zone in response to a previous output speed being greater than the first exclusion zone.

2. The gas engine replacement device of claim 1, wherein, the electronic processor configured to set the output speed to a lower limit of the first exclusion zone in response to a previous output speed being less than the first exclusion zone.

3. The gas engine replacement device of claim 1, wherein, the first exclusion zone defining a hysteresis range around a resonant frequency of a mechanical system coupled with the motor.

4. The gas engine replacement device of claim 1, wherein, the electronic processor configured to identify the resonant frequency based on an output of a vibration sensor.

5. The gas engine replacement device of claim 4, further comprising a vibration sensor, wherein, the electronic processor configured to generate the first exclusion zone based on an output of a vibration sensor.

6. The gas engine replacement device of claim 1, comprising a vibration sensor, wherein, 7. The gas engine replacement device of claim 1, comprising: a pump coupled to the power output shaft.

8. The gas engine replacement device of claim 1, comprising: a housing surrounding the electronic processor and comprising an inert fluid; a pump configured to circulate the inert fluid in the housing; and a heat exchanger coupled to the housing. a housing; a battery receptacle coupled to the housing and configured to removably receive a battery pack; 9. A method for operating a gas engine replacement device, the gas engine replacement device comprising: a motor within the housing; a power output shaft receiving torque from the motor and protruding from a side of the housing; a power switch network configured to selectively provide power from the battery pack to the motor; and an electronic processor coupled to the power switch network and configured to control the power switch network to rotate the motor, the method comprising: the electronic processor receiving a commanded speed for the motor; the electronic processor determining whether the commanded speed is within a first exclusion zone, the first exclusion zone being a first speed exclusion zone; the electronic processor determining whether the commanded speed is within a second exclusion zone, the second exclusion zone being a second speed exclusion zone; ​ ​ the electronic processor sets the output speed of the motor to the command speed in response to the command speed being outside the first and second exclusion zones; the electronic processor sets the output speed to a speed outside the first exclusion zone in response to the command speed being within the first exclusion zone; the electronic processor sets the output speed to a speed outside the second exclusion zone in response to the command speed being within the second exclusion zone; and the electronic processor controls the power switching network to cause the motor to rotate at the output speed set based on determining whether the command speed is within the first or second exclusion zones.

10. The method of claim 9, further comprising: the electronic processor sets the output speed to an upper limit of the first exclusion zone in response to a previous output speed being greater than the first exclusion zone.

11. The method of claim 10, further comprising: the electronic processor sets the output speed to a lower limit of the first exclusion zone in response to a previous output speed being less than the first exclusion zone.

12. The method of claim 9, wherein, the first exclusion zone defines a hysteresis range around a resonant frequency of a mechanical system coupled with the motor.

13. The method of claim 12, further comprising: the electronic processor identifies the resonant frequency based on an output of a vibration sensor.

14. The method of claim 9, wherein, the gas engine replacement device includes a vibration sensor, the method further comprising: the electronic processor generates the first and second exclusion zones based on an output of the vibration sensor.

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