Measuring the voltage sag of the battery pack to identify the battery pack and control its performance.

Abstract

To solve the problem of the prior art.SOLUTION: A battery pack power supply device includes: an interface configured to receive a battery pack; a sensing circuit configured to detect voltage of the battery pack; and an electronic controller. The electronic controller is configured to receive a first signal from the sensing circuit indicating no-load voltage of the battery pack, determine threshold voltage based on no-load voltage, generate a control signal for driving en electric motor at a first operation parameter in response to activation of a trigger switch, receive a second signal from the sensing circuit, and update a control signal to drive the electric motor at a second operation parameter less than the first operation parameter in response to the second signal indicating that output voltage is below threshold voltage. The second signal indicates output voltage of the battery pack during operation of the electric motor.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] (Reference to related applications) This application claims the benefit of U.S. Provisional Application No. 63 / 584,773, filed on 22 September 2023. The entire disclosure of the above application is incorporated herein by reference.

[0002] (Technical field) This disclosure relates to power tools, and more particularly to battery-powered tools. [Overview of the Initiative]

[0003] Using a common interface format for power tool battery packs offers various technical and practical advantages. For example, users may be able to easily swap battery packs between different tools without needing a specific battery pack for each tool. If a battery pack fails or becomes undercharged, it can be quickly replaced, for example, with another battery pack from a different tool. Having a common interface format also allows different battery packs from different tools to be charged with the same charger. These improvements to interoperability significantly enhance the flexibility of power tool systems. However, different battery packs may have different capabilities. These differences in capabilities may be due to design differences or the natural degradation of the chemical properties or performance of battery cells over time.

[0004] For example, battery packs of different capacities may have different internal resistances. Some higher-capacity battery packs may have lower internal resistance than some lower-capacity battery packs. Some higher-capacity battery packs may have electrodes with more active material in the electrodes, thicker electrodes, and / or larger electrode surface area, which can reduce the internal resistance of the battery pack. Higher-capacity battery packs may also have more cells arranged in parallel, which can also reduce the internal resistance of the battery pack. Higher-capacity battery packs may also use higher-quality electrolyte, which can also help reduce internal resistance. As a function of lower internal resistance, higher-capacity battery packs may exhibit lower voltage drop (also called voltage sag) than lower-capacity battery packs in response to the same current draw demand.

[0005] This voltage drop V can sometimes be expressed as a function of the current draw I and internal resistance R of the battery pack, according to Ohm's law, i.e., equation (1) below.

number

[0006] As shown by equation (1), The voltage drop across the battery pack in response to the current flow scales linearly as a function of its internal resistance. Therefore, as described herein, a power tool (e.g., an electronic controller included in the tool) is configured to use the voltage drop indicated by the battery pack in response to a given load (e.g., current) to determine the battery pack capacity and optimize the control signals of the power tool based on the battery pack capacity.

[0007] Techniques that use voltage drop to determine the capacity of a battery pack (such as the techniques described herein) can offer advantages over techniques that measure other properties (such as impedance), particularly at low temperatures. For example, the impedance of a battery pack includes and / or is a function of both a resistive component (e.g., resistance) and a reactive component (e.g., chemical reactions within the battery pack). Since chemical reactions within a battery pack may tend to slow down at lower temperatures, the impedance of a battery cell tends to increase at lower temperatures than its impedance at lower temperatures. Because the voltage drop of a battery pack may be a function of the resistance of the battery pack, voltage drop-based techniques (such as the techniques described herein) provide a more accurate assessment of battery pack capacity at lower temperatures than other impedance-based techniques.

[0008] In some examples, a battery pack power supply device, such as a power tool, includes a sensing circuit configured to detect the voltage of the battery pack and an electronic controller. The electronic controller is configured to receive a first signal from the sensing circuit indicating the no-load voltage of the battery pack, determine a threshold voltage based on the no-load voltage, generate a control signal to drive the device's electric motor in response to activation of a trigger switch, receive a second signal from the sensing circuit, and update the control signal in response to the second signal indicating that the output voltage is below the threshold voltage. The second signal indicates the output voltage of the battery pack while the electric motor is operating. The control signal drives the electric motor to operate with a first operating parameter. The updated control signal drives the electric motor to operate with a second operating parameter, which is less than the first operating parameter.

[0009] In some embodiments, the threshold voltage is determined as a percentage decrease in the nominal input voltage of the battery pack power supply device. In some embodiments, the percentage decrease is approximately 25%. In some embodiments, the nominal input voltage of the battery pack power supply device is approximately 18 volts, and the threshold voltage is approximately 13.5 volts. In some embodiments, the control signal includes a first pulse-width modulated signal, and the updated control signal includes a second pulse-width modulated signal, with the duty cycle of the first pulse-width modulated signal being greater than the duty cycle of the second pulse-width modulated signal.

[0010] In some embodiments, a first operating parameter is a first power output, a second operating parameter is a second power output, and the first power output is greater than the second power output. In some embodiments, a first operating parameter is a first torque output, a second operating parameter is a second torque output, and the first torque output is greater than the second torque output. In some embodiments, a first operating parameter is a first operating duration, a second operating parameter is a second operating duration, and the first operating duration is greater than the second operating duration.

[0011] Another example is a battery-pack powered device, such as a power tool, which includes an electric motor, an interface configured to receive a battery pack, a sensing circuit configured to detect the voltage of the battery pack, and an electronic controller. The electronic controller is configured to initiate a test current draw from the battery pack, receive a first signal from the sensing circuit, select a first control mode for controlling the electric motor in response to a first signal indicating that the output voltage is not below a threshold, and select a second control mode for controlling the electric motor in response to a first signal indicating that the output voltage is below a threshold. The battery pack powers the electric motor. The first signal indicates the output voltage of the battery pack during the test current draw. The electronic controller is configured to generate a first control signal for controlling the electric motor in the first control mode. The electronic controller is configured to generate a second control signal for controlling the electric motor in the second control mode. The second control signal reduces the operating parameters of the electric motor compared to the first control signal.

[0012] In some embodiments, the threshold is determined as the percentage decrease in the designed output voltage of the battery pack. In some embodiments, the percentage decrease is approximately 25%. In some embodiments, the designed output voltage of the battery pack is approximately 18 volts, and the threshold is approximately 13.5 volts. In some embodiments, the first control signal is a pulse-width modulated signal having a first duty cycle, and the second control signal is a pulse-width modulated signal having a second duty cycle, where the first duty cycle is greater than the second duty cycle.

[0013] In some embodiments, a first control signal controls an electric motor to operate at a first power output, and a second control signal controls an electric motor to operate at a second power output, where the first power output is greater than the second power output. In some embodiments, a first control signal controls an electric motor to operate at a first torque output, and a second control signal controls an electric motor to operate at a second torque output, where the first torque output is greater than the second torque output. In some embodiments, a first control signal controls an electric motor to operate over a first duration, and a second control signal controls an electric motor to operate over a second duration, where the first duration is longer than the second duration.

[0014] Several examples provide a method for operating a battery pack powered device, such as a power tool, which, in response to activation (startup) of a trigger switch, includes using a controller to measure a first voltage of the battery pack electrically connected to the device before the application of a load associated with the activation of the trigger switch, and using the controller to calculate a target voltage based on the first voltage. During the application of a load associated with the activation of the trigger switch, the method includes measuring a second voltage of the battery pack, comparing the second voltage to a target voltage, and correcting the operation of the battery pack powered device in response to the second voltage being less than the target voltage.

[0015] In some embodiments, calculating a target voltage involves reducing a first voltage by a predetermined percentage. In some embodiments, modifying the operation of a battery pack power supply device involves modifying a pulse-width modulated control signal for the electric motor of the battery pack power supply device. In some embodiments, modifying the operation of a battery pack power supply device involves modifying the operation of the battery pack power supply device using a proportional-integral control loop.

[0016] Other examples, embodiments, configurations, and aspects will become apparent by considering the detailed description and accompanying drawings.

[0017] Before describing any embodiment in detail, it should be understood that embodiments are not limited in their application to the details of component arrangement and configuration described below or illustrated in the accompanying drawings. Embodiments can be carried out or performed in a variety of ways. It should also be understood that the usage and terminology used herein are for the purposes of description and should not be considered limiting. The use of “including,” “comprising,” or “having,” and their variations, means to include the items listed thereafter and their equivalents, as well as additional items. Unless otherwise specified or otherwise limited, the terms “mounted,” “connected,” “supported,” and “coupled,” and their variations, are used broadly and include both direct and indirect mounting, connection, support, and coupling.

[0018] Unless the context of use is clearly different, the articles “a,” “an,” and “the” should not be interpreted as meaning “one” or “only one.” Rather, these articles should be interpreted as meaning “at least one” or “one or more.” Similarly, unless the context of use is clearly different, when the terms “the” or “said” are used to refer to a noun previously introduced by the indefinite article “a” or “an,” “the” and “said” mean “at least one” or “one or more.”

[0019] In addition, it should be understood that embodiments may include hardware, software, and electronic components or modules, which may be illustrated and described for the purposes of discussion as if the majority of the components were implemented solely in hardware. However, those skilled in the art will recognize, based on reading this detailed description, that in at least one embodiment, the electronic-based aspect may be implemented in software (e.g., stored on a non-temporary computer-readable medium) executable by one or more processing units, such as a microprocessor and / or application-specific integrated circuit ("ASIC"). Thus, it should be noted that multiple hardware and software-based devices, as well as multiple different structural components, may be used to implement the embodiments. For example, “server,” “computing device,” “controller,” “processor,” etc., as described herein may include one or more processing units, one or more computer-readable medium modules, one or more input / output interfaces, and various connections (e.g., system buses) for connecting components.

[0020] For example, relative terms such as “about,” “approximately,” and “substantially,” used in relation to quantity or state, are understood by those skilled in the art to include the described value and have meanings indicated by the context (e.g., the term includes at least the degree of error related to the measurement precision, tolerance [e.g., manufacturing, assembly, use, etc.] associated with a particular value). Such terms should also be considered as disclosing a range defined by the absolute values ​​of two endpoints. For example, the expression “about 2 to about 4” also discloses the range “2 to 4.” Relative terms may refer to a percentage (e.g., 1%, 5%, 10%) of the indicated value, either plus or minus.

[0021] While certain drawings illustrate hardware and software located within a particular device, it should be understood that these depictions are for illustrative purposes only. Functionality described herein as being performed by a single component may be performed by multiple components in a distributed manner. Similarly, functionality performed by multiple components may be integrated and performed by a single component. In some embodiments, the illustrated components may be combined or divided into separate software, firmware, and / or hardware. For example, logic and processing may be distributed across multiple electronic processors instead of being located and executed within a single electronic processor. Regardless of how they are combined or divided, hardware and software components may be located on the same computing device or distributed across different computing devices connected by one or more networks or other appropriate communication links. Similarly, a component described as performing a particular functionality may perform additional functionality not described herein. For example, a device or structure “configured” in a particular manner may be configured in at least that manner, but may be configured in ways not explicitly enumerated.

[0022] Accordingly, if a claim is made that an apparatus, method, or system includes, for example, a controller, control unit, electronic processor, computing device, logic element, module, memory module, communication channel or network, or other elements configured in a particular manner to perform a plurality of functions, then the claim or the inventive features of the claim should be interpreted as meaning one or more such elements, in which case one or more elements are configured to perform a plurality of functions collectively, or any one of the one or more elements is configured to perform, for example, one or more of the enumerated functions, as claimed.

Brief Description of the Drawings

[0023] [Figure 1A] Shows a battery pack according to some embodiments described herein.

[0024] [Figure 1B] Shows a group of battery cells according to some embodiments described herein.

[0025] [Figure 2A] Shows a battery pack according to some embodiments described herein.

[0026] [Figure 2B] Shows a group of battery cells according to some embodiments described herein.

[0027] [Figure 3] Shows a device for determining the impedance of a battery pack, such as the battery pack of FIG. 1A or FIG. 2A, according to some embodiments described herein.

[0028] [Figure 4] Shows a control system for a device, such as the device of FIG. 3, according to some embodiments described herein.

[0029] [Figure 5] Shows a circuit diagram for the field effect transistor (FET) switching module of the device of FIG. 4, according to some embodiments described herein.

[0030] [Figure 6A] Shows a circuit diagram showing the flow of current in a circuit, such as the circuit of FIG. 5, according to some embodiments described herein. [Figure 6B] Shows a circuit diagram showing the flow of current in a circuit, such as the circuit of FIG. 5, according to some embodiments described herein. [Figure 6C] The following are circuit diagrams showing the flow of current in a circuit, such as the circuit in Figure 5, according to some embodiments described herein. [Figure 6D] The following are circuit diagrams showing the flow of current in a circuit, such as the circuit in Figure 5, according to some embodiments described herein.

[0031] [Figure 7] This block diagram shows a power input module of the device shown in Figure 4, according to some embodiments described herein.

[0032] [Figure 8] This is a circuit diagram showing a voltage divider circuit for the power input module of Figure 7, according to some embodiments described herein.

[0033] [Figure 9A] This is a flowchart of a process for controlling the operating sequence of a battery-powered device, such as the device in Figure 3, according to some embodiments described herein. [Figure 9B] This is a flowchart of a process for controlling the operating sequence of a battery-powered device, such as the device in Figure 3, according to some embodiments described herein. [Figure 10A] This is a flowchart of a process for controlling the operating sequence of a battery-powered device, such as the device in Figure 3, according to some embodiments described herein. [Figure 10B] This is a flowchart of a process for controlling the operating sequence of a battery-powered device, such as the device in Figure 3, according to some embodiments described herein.

[0034] [Figure 11] This specification shows block diagrams of processes for implementing control schemes according to several embodiments described herein, and graphs showing the measured voltage of the battery pack as a function of time.

[0035] [Figure 12] This block diagram shows a feedback loop that may be used to implement control schemes according to some embodiments described herein.

[0036] [Figure 13] This graph shows the voltage drop of an exemplary first battery pack in response to a current load as a function of time.

[0037] [Figure 14] This graph shows the voltage drop of an exemplary second battery pack (having a lower capacity than the first battery pack in Figure 13) in response to the same current load as a function of time.

[0038] [Figure 15] This graph shows the voltage of the battery pack as a function of the load and the region in which the controller generates an updated control signal (under the target voltage), according to some embodiments described herein.

[0039] [Figure 16] This graph shows the power output of a battery-powered device's motor during an operating cycle implemented using a dynamic threshold update process, and the operating cycle implemented without using a dynamic threshold update process.

[0040] [Figure 17] This block diagram shows measurement and calculation methods that may be used to implement a control scheme according to a dynamic threshold update process in several embodiments.

[0041] In drawings, reference numbers may be reused to identify similar and / or identical elements. [Modes for carrying out the invention]

[0042] Figure 1A shows a battery pack 100. The battery pack 100 includes a housing 105, an optional user interface portion 110 for displaying the charge status of the battery pack 100, and a device interface portion 115 for connecting the battery pack 100 to a device (e.g., a power tool) (e.g., mechanically and electrically). The battery pack 100 contains a plurality of battery cells within the housing 105.

[0043] Figure 1B shows a group 125 of battery cells 120, for example, containing 10 individual battery cells 120. The battery cells 120 can be arranged within the housing 105 of the battery pack 100. In some embodiments, the battery pack 100 contains more or fewer than 10 battery cells within the housing 105.

[0044] Figure 2A shows a battery pack 200 for supplying power to a device (e.g., a power tool). The battery pack 200 includes a battery housing 230 and, referring to Figure 2B, includes a number of battery cells 290.

[0045] Figure 2B shows an internal view 245 of the battery housing 230. As shown in Figure 2B, the battery housing 230 includes a wall 265 having an inner surface 280 and an outer surface 275. The inner surface 280 defines an internal cavity 270. The outer surface 275 includes a top portion 215 (Figure 2A) and a bottom portion 285. Referring to Figure 2B, the battery cells 290 located within the cavity 270 are connected in series to the battery contacts 205 (battery contacts). Referring to Figure 2A, a number of contacts 250 (Figure 2B) are located on the top portion 215 within the battery contact housing extension 210. The housing extension 210 is configured to matingly engage with one or more power tools or powered accessories. A battery charge level indicator 220 may also be located on the housing (Figure 2A), and additional battery charging, monitoring, and display components 255 may be located within the cavity 270 (Figure 2B). As shown in Figure 2A, two tabs 235 are coupled to the housing 230 to secure the housing 230 to the power tool in a releasable manner. Configurations corresponding to those described above with respect to the battery pack 200 may also be included in the battery pack 100. Battery packs 100 and 200 are provided as illustrative illustrations of battery packs, and it should be understood that battery packs used as part of the embodiments described herein may take on various sizes and shapes and may include various numbers and types of battery cells as well as other connection mechanisms for providing various numbers and types of tabs or devices (e.g., power tools). It should also be understood that battery packs used as part of the embodiments described herein may include additional or fewer components in various configurations, and the illustrated packs 100 and 200 are not limiting.

[0046] Figure 3 shows device 300. In the embodiment shown in Figure 3, device 300 is a power tool (e.g., a drill / driver). In other embodiments, device 300 is a different type of power tool (e.g., an impact wrench, ratchet, saw, hammer drill, impact driver, rotary hammer, grinder, blower, trimmer, etc.) or a different type of device (e.g., a light, a non-electric sensing tool, etc.). Device 300 includes a housing 305 and an interface portion 310 for connecting device 300 to, for example, battery packs 100 and 200.

[0047] Figure 4 shows the control system for device 300. The control system includes a controller 400. The controller 400 is electrically and / or communicatively connected to various modules or components of device 300. For example, the illustrated controller 400 is electrically connected to a motor 405 (e.g., an electric motor), a battery pack interface 410, a trigger switch 415 (connected to a trigger 420), one or more sensors or sensing circuits 425, one or more indicators 430, a user input module 435, a power input module 440, and an FET switching module 450 (e.g., including multiple switching FETs). The controller 400 includes a combination of hardware and software that can, among other things, control the operation of device 300 (e.g., control the operation of the motor 405), monitor the operation of device 300, activate one or more indicators 430 (e.g., LEDs), etc.

[0048] The controller 400 includes several electrical and electronic components that provide power, operational control, and protection to the components and modules within the controller 400 and / or device 300. For example, the controller 400 includes, among other things, a processing unit 455 (e.g., a microprocessor, microcontroller, electronic processor, electronic controller, or another suitable programmable device), memory 460, input unit 465, and output unit 470. The processing unit 455 includes, among other things, a control unit 475, an ALU 480, and several registers 485 (shown as a group of registers in Figure 4), and is implemented using a known computer architecture (e.g., a modified Harvard architecture, a von Neumann architecture, etc.). The processing unit 455, memory 460, input unit 465, and output unit 470, as well as various modules or circuits connected to the controller 400, are connected by one or more control buses and / or data buses (e.g., a common bus 490). The control buses and / or data buses are generally shown in Figure 4 for illustrative purposes. The use of one or more control buses and / or data buses for interconnection and communication between various modules, circuits, and components will be known to those skilled in the art in view of the embodiments described herein.

[0049] Memory 460 is a non-temporary computer-readable medium and includes, for example, a program storage area and a data storage area. The program storage area and data storage area may include a combination of different types of memory, such as ROM, RAM (e.g., DRAM, SDRAM, etc.), EEPROM, flash memory, hard disk, SD card, or other suitable magnetic, optical, physical, or electronic memory devices. Processing unit 455 is connected to memory 460 and executes software instructions that can be stored (e.g., during execution) in the RAM of memory 460, (e.g., on a near-permanent basis) in the ROM of memory 460, or in another non-temporary computer-readable medium such as another memory or disk. Software included in the implementation of device 300 may be stored in memory 460 of controller 400. The software includes, for example, firmware, one or more applications, program data, filters, rules, one or more program modules, and other executable instructions. Controller 400 is configured to retrieve from memory 460 and, among other things, execute instructions related to the control processes and methods described herein. In other configurations, the controller 400 may include additional components, fewer components, or different components.

[0050] The battery pack interface 410 includes a combination of mechanical components (e.g., rails, grooves, latches, etc.) and electrical components (e.g., one or more terminals) configured and operable to interface (e.g., mechanically, electrically, and optionally communicatively) the device 300 with a battery pack (e.g., battery packs 100, 200). For example, power supplied to the device 300 by battery pack 100 is supplied to the power input module 440 through the battery pack interface 410. The power input module 440 includes a combination of active and passive components for adjusting or controlling the power received from battery pack 100 before it is supplied to the controller 400. The battery pack interface 410 also supplies power to the FET switching module 450 to supply power to the motor 405. The battery pack interface 410 may also include a communication line 495 for providing a communication link between the controller 400 and the battery pack 100.

[0051] The indicator 430 may include, for example, one or more light-emitting diodes ("LEDs"). The indicator 430 may be configured to display the status of device 300 or information related to device 300. For example, in some embodiments, the indicator 430 may be configured to show the measured electrical characteristics of device 300, the status of device 300, and so on.

[0052] The user input module 435 is operably coupled to the controller 400 to select, for example, a forward or reverse operating mode, torque and / or speed settings for device 300 (e.g., using torque and / or speed switches), or other operation of device 300. In some embodiments, the user input module 435 includes one or more digital input devices, one or more digital output devices, one or more analog input devices, one or more analog output devices, or a combination such as one or more knobs, one or more dials, one or more switches, one or more buttons, etc. In some embodiments, the user input module 435 includes a touchscreen that can be used as an input device, an output device, or a combination thereof.

[0053] In some embodiments, the controller 400 is configured to determine whether a fault condition exists in the device 300 and to generate one or more control signals associated with the fault condition. For example, the sensing circuit 425 may include one or more current sensors, one or more speed sensors, one or more Hall effect sensors, one or more temperature sensors, or a combination thereof, and the controller 400 is configured to process the data received from the sensing circuit 425 to determine whether a fault condition exists. For example, the controller 400 may be configured to compare the data received by the sensing circuit 425 (e.g., in raw form, processed form, or a combination thereof) with one or more predetermined operating thresholds or limits that the controller 400 may calculate or access (e.g., in memory 460). For example, when a potential thermal failure (e.g., FET, motor 405) is detected or predicted by the controller 400, the controller 400 may be configured to limit or interrupt the power supplied to the motor 405 from the interfaced battery pack until the device 300 is reset, for example, until the likelihood of the thermal failure is reduced. In some embodiments, the controller 400 is configured to provide information and / or control signals to another component of the device 300 (e.g., indicator 430), to the battery pack 100 or 200 (e.g., via the battery pack interface 410), or a combination thereof, in response to detecting one or more such fault conditions of the device 300 or determining that no fault conditions of the device 300 exist anymore. In some embodiments, as described in more detail with respect to Figures 9A, 9B, 10A, and 10B, the controller 400 uses the sensing circuit 425 to determine the capacity (e.g., internal impedance) of the main pack interfaced with the device 300, in addition to or instead of using the sensing circuit 425 to detect fault conditions.

[0054] In various implementations, the FET switching module 450 may be connected to, or part of, an inverter 451 that provides alternating current (AC) power to the motor 405. For example, the battery pack interface 410 may be connected to a direct current (DC) bus 452, which may be connected to the inverter 451 and / or the FET switching module 450. The battery pack interface 410 may provide DC power to the DC bus 452. The DC bus 452 may provide DC power to the inverter 451. The inverter 451 may include a switching device such as the FET switching module 450, which may be controlled to generate an AC waveform from source DC power. The inverter 451 may provide the AC waveform as AC power to drive the motor 405. As shown in Figure 4, in some examples, a controller 400 may be connected to the inverter 451 and / or the DC bus 452 to monitor and / or control the inverter 451 and / or the DC bus 452.

[0055] Figure 5 shows a circuit diagram 500 of the FET switching module 450. The FET switching module 450 includes a plurality of high-side power switching elements 502 and a plurality of low-side power switching elements 504. In some embodiments, the controller 400 provides control signals to control the high-side FETs 502 and low-side FETs 504 in order to drive the motor 405. For example, in response to detecting the activation of a trigger 420, the controller 400 provides one or more control signals to selectively enable and disable the FETs 502 and 504 (e.g., sequentially, in pairs) to generate power from a power supply 510 (e.g., one of the battery packs 100 and 200 interfaced with device 300) which is to be selectively applied to the stator coil of the motor 405 to cause the rotor to rotate. More specifically, in order to drive the motor 405, the controller 400 activates the first high-side FET 502 and first low-side FET 504 pair over a first time period (for example, by providing voltage at the gate terminals of the FETs). In response to determining that the rotor of the motor 405 has rotated based on pulses from the sensing circuit 425, the controller 400 deactivates the first FET pair and activates the second high-side FET 502 and second low-side FET 504. In response to determining that the rotor of the motor 405 has rotated (for example, based on pulses from the sensing circuit 425), the controller 400 deactivates the second FET pair and activates the third high-side FET 502 and third low-side FET 504. This sequence of periodically activating the high-side FET 502 and low-side FET 504 pair is repeated to drive the motor 405. Furthermore, in some embodiments, the control signal includes a pulse-width modulation (PWM) signal having a duty cycle set proportionally to the amount of trigger pull (attraction) of the trigger 420, thereby controlling the speed or torque of the motor 405. The device 300 may include different configurations for controlling the power from the power supply 510 to the motor 405, and it should be understood that the FET 504 and associated components are provided as one non-limiting example.

[0056] For example, Figure 6A shows a current flow diagram 600 of the FET switching module 450. The FET switching module 450 includes a plurality of high-side power switching elements 502 and a plurality of low-side power switching elements 504, as described above. For example, in response to detecting a pull of trigger 420, controller 400 provides one or more control signals to selectively enable and disable FETs 502 and 504 (e.g., sequentially, in pairs), bringing power from power supply 510 (e.g., battery packs 100, 200). The current 610 travels from power supply 510 through one of the high-side power switching elements 502 to the stator coil of motor 405. The current 610 then travels from motor 405 to one of the low-side power switching elements 504 before completing the connection path 615 of power supply 510.

[0057] Figure 6B shows another current flow diagram 620 of the FET switching module 450. The FET switching module 450 includes a plurality of high-side power switching elements 502 and a plurality of low-side power switching elements 504, as described above. For example, in response to detecting a pull of trigger 420, controller 400 provides one or more control signals to selectively enable and disable FETs 502 and 504 (e.g., sequentially, in pairs) to bring power supplied from power supply 510 (e.g., battery packs 100, 200). The current 610 proceeds from power supply 510 through one high-side power switching element 502 to one low-side power switching element 504. The current 610 then closes the circuit by returning to power supply 510. This reduced current 610 path proceeds through only the two switching FETs and completes a short portion of the connection path 615 of power supply 510. In some embodiments, one or more high-side power switching elements 502 and / or one or more low-side power switching elements 504 are enabled simultaneously. Such control can reduce the overall resistance of the system, allow for higher current flow, and distribute the system load through FETs 502 and 504, thereby reducing the burnup of FETs 502 and 504.

[0058] Figure 6C also shows another current flow diagram 625 for the FET switching module 450. In this example, an additional switching module 630 is connected to the connection path 615. In addition to the additional switching module 630, an additional resistor is connected to the connection path 615. For example, in response to detecting a pull on the trigger 420, the controller 400 provides one or more control signals to selectively enable and disable the switching module 630, bringing power from the power supply 510 (e.g., battery packs 100, 200). The current 610 flows from the power supply 510 through the additional resistor and then through the additional switching module 630. In this example, the current 610 only flows through the additional resistor and the additional switching module 630 before returning to the power supply 510 to close the circuit. In other embodiments, an inductor can be used for a similar purpose as the additional resistor. In addition, other circuit configurations may be configured in a manner that allows the use of other components (e.g., capacitors).

[0059] Figure 6D shows yet another current flow diagram 635 for the FET switching module 450. In this example, only one power switching module 504 is used. For example, in response to detecting a pull of trigger 420, controller 400 provides one or more control signals to selectively enable and disable the power switching element 504, bringing power supplied from power supply 510 (e.g., battery packs 100, 200). The current 610 flows from power supply 510 to motor 405 (e.g., brushed motor) and power switching element 504 before closing the connection path 615.

[0060] Again, the embodiments described herein may be used with various types of battery packs and battery-powered devices, and the details provided in Figures 1 to 6D are provided as non-limiting exemplary embodiments.

[0061] Figure 7 is a block diagram showing a power input module 440 according to several embodiments. In various embodiments, the power input module 440 includes a voltage divider circuit 702 and an analog-to-digital converter 704. The inputs of the voltage divider circuit 702 may be coupled to the positive and negative terminals of the battery pack interface 410. The voltage divider circuit 702 may step down the output voltage of a battery pack connected to the battery pack interface 410 (such as battery pack 100 or battery pack 200) and output the stepped-down voltage to the analog-to-digital converter 704. The analog-to-digital converter 704 converts the analog step-down voltage signal into a digital signal and outputs the digital signal to the controller 400. As described in more detail with respect to Figure 8, the controller 400 may determine the output voltage of the battery pack connected to the battery pack interface 410 based on the digital signal output from the analog-to-digital converter 704. For example, in an example where the power input module 440 includes a voltage divider circuit 702, the controller 400 may determine the actual voltage of the battery pack based on the step-down voltage output from the voltage divider circuit 702 to the analog-to-digital converter 704, according to a voltage divider formula suitable for the voltage divider circuit 702.

[0062] Figure 8 is a circuit diagram showing a voltage divider circuit 702 according to several embodiments. As shown in Figure 8, several implementations of the voltage divider circuit 702 include a first input terminal 802 and a second input terminal 804, and a first resistor 806 and a second resistor 808 arranged in series between the first input terminal 802 and the second input terminal 804. A first output terminal 810 may be connected to a first node between the first resistor 806 and the second resistor 808, and a second output terminal 812 may be connected to a second node between the second input terminal 804 and the second resistor 808. In some embodiments, a battery pack (represented by battery 814 in Figure 8, which may include a battery pack 100 or 200 as described herein) may be connected to the first input terminal 802 and the second input terminal 804. For example, the positive terminal of battery 814 may be connected to the first input terminal 802, and the negative terminal of battery 814 may be connected to the second input terminal 804. Therefore, the input voltage V from battery 814 in However, it may be applied across the first resistor 806 and the second resistor 808. Since the first resistor 806 and the second resistor 808 may be connected in series, the input voltage V in The current may be divided between the first resistor 806 and the second resistor 808 according to the resistance R1 of the first resistor 806 and the resistance R2 of the second resistor 808.

[0063] In an example where the first output terminal 810 and the second output terminal 812 are connected across the second resistor 808, the output voltage V of the voltage divider circuit 702 (measured across the first output terminal 810 and the second output terminal 812) out This can be expressed according to the following voltage divider equation (2), which is derived from Ohm's law and the principle of pressure division.

number

[0064] The relationship between the resistors in the above voltage divider equation (2) can sometimes be expressed as the transfer function H shown in equation (3) below.

number

[0065] Therefore, as will be described in more detail with respect to Figure 8, the controller 400 operates according to the following equation (4), (V out Based on the voltage output from the voltage divider circuit 702 (represented by) and the transfer function H of the voltage divider circuit 702, (V in Sometimes the voltage of battery 814 (represented by) is calculated.

number

[0066] Although the voltage divider circuit 702 is shown to have two resistors and the transfer function H is expressed as a function of the two resistors, it should be understood that the voltage divider circuit 702 may contain any number of resistors and the transfer function H may be any appropriate value.

[0067] Figures 9A and 9B are flowcharts of a process 900 for controlling the operating sequence of device 300 according to several embodiments, and in particular represent a process for determining the characteristics (e.g., capacity, impedance, etc.) of a battery pack electrically connected to device 300 based on a measured voltage, and for generating one or more control signals for controlling motor 405 using the determined characteristics. The operation of process 900 is illustrated with reference to specific examples described herein, but process 900 may be implemented in any suitable setting. The operations are shown once and in a specific order in Figures 9A and 9B, but the operations may be reordered and / or repeated as desired and appropriate. For example, different operations may be performed in parallel as appropriate. In various implementations, a battery pack with a higher capacity may exhibit a lower (smaller) voltage drop in response to a given current draw than a battery pack with a lower capacity. Accordingly, the voltage drop across the battery pack in response to a given current draw may be used to determine the capacity of the battery pack connected to device 300, and the controller 400 may operate device 300 according to a control mode optimized for the capacity of the battery pack. For example, in response to determining that the battery pack is a larger capacity battery pack, the controller 400 may control the motor 405 to operate at a higher operating parameter. Conversely, in response to determining that the battery pack is a smaller capacity battery pack, the controller 400 may control the motor 405 to operate at a lower operating parameter. In various embodiments, the operating parameter may be the speed of the motor 405. In some embodiments, the operating parameter may be the power output of the motor 405 (e.g., torque output τ × angular velocity ω). In some examples, the operating parameter may be the torque output of the motor 405. In various implementations, the operating parameter may be the motor's runtime (duration of operation).

[0068] In block 902, the controller 400 measures the no-load voltage signal of the battery pack connected to device 300 (such as battery pack 100 or 200 connected to interface section 310). For example, the voltage divider circuit 702 may step down the no-load voltage of the battery pack taken across the positive and negative terminals of the battery pack at the battery pack interface 410 when there is no current load on the battery pack (or there is a minimum current load). The analog-to-digital converter 704 may convert the analog no-load voltage of the battery pack into a digital no-load voltage signal and output the digital no-load voltage signal to the controller 400. In block 904, the controller 400 determines the no-load voltage of the battery pack based on the digital no-load voltage signal. In various implementations, the no-load voltage signal represents the stepped-down no-load voltage output from the voltage divider circuit 702, and the controller 400 converts the stepped-down no-load voltage into the no-load voltage of the battery pack according to the transfer function of the voltage divider circuit 702 (as described above with reference to, for example, Figures 7 and 8).

[0069] In block 906, the controller 400 determines a threshold based on the no-load voltage of the battery pack. In various implementations, the threshold may be set as a percentage of the no-load voltage. For example, the threshold may be set as a percentage of the no-load voltage, and a target voltage may be defined, where a measured voltage drop above the target voltage indicates a high-capacity battery pack, and a measured voltage drop below the target voltage indicates a low-capacity battery pack. In various implementations, the threshold may be set to a value of approximately 15%, 20%, 25%, 30%, 35%, or 40% (or other values ​​in the range of approximately 15% to approximately 40%). However, in some implementations, the threshold is set to other values, or various values ​​in between, such as approximately 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of the no-load voltage. In some embodiments, rather than calculating the threshold from a measurement, the controller 400 may have a pre-programmed threshold, which may be stored and associated with the threshold (e.g., through a lookup table or other data structure or data mapping mechanism). Thus, the controller 400 may determine the threshold by retrieving an appropriate threshold from memory after determining the no-load voltage. Also in some embodiments, the controller 400 may determine the no-load voltage of the battery pack based on other values, such as data communicated between the device 300 and the connected battery pack, stored voltage settings for the device 300, or a combination thereof. For example, the threshold may be set as a percentage of the nominal voltage of the battery pack and / or the nominal voltage of device 300. The nominal voltage may be the voltage that the battery pack is designed to output in normal operation and / or the voltage that device 300 is designed to receive from the battery pack in normal operation. For example, if the nominal voltage of the battery pack and / or device 300 is approximately 18 volts, the threshold may be set according to Table 1 below. [Table 1]

[0070] The controller 400 may be configured to determine a threshold without measuring the no-load voltage of the battery pack; however, measuring this voltage may allow the controller 400 to set an appropriate threshold based on the current state of the battery pack.

[0071] In various implementations, the threshold, the percentage decrease from the nominal voltage, and / or the percentage decrease from the no-load voltage can be set based on empirical data for a particular type of device and one or more loads (or ranges of loads). In some embodiments, the empirical data may include different operating applications or environments of the device 300, which may be used to establish the adjusted threshold. The controller 400 may be configured to adjust (e.g., increase or decrease) the threshold based on the current operating application or environment of the device 300 (e.g., based on the measured temperature, the operating mode of the device 300, accessories installed on the device 300, etc.).

[0072] In block 908, the controller 400 monitors the trigger switch 415 for activation (startup). Process 900 indicates a threshold set before the activation of the trigger switch 415 (for example, as part of the initialization or configuration process of device 300), but it should be understood that in some embodiments (see, for example, Figure 12 and related descriptions), the threshold determination described with respect to blocks 902-906 may occur after the activation of the trigger switch 415, but before the load is applied to the battery pack associated with the trigger activation. Measuring the no-load voltage in time for the application of the load may result in increased battery pack optimization, because a more accurate threshold may be set based on the current state of the battery pack.

[0073] As described above, the trigger switch 415 may be connected to a trigger 420, and the trigger 420 may actuate the trigger switch 415. In various implementations, the trigger switch 415 may include an on / off switch, and the actuation of the trigger 420 closes the on / off switch. In some embodiments, the trigger switch 415 may include a variable resistor, such as a potentiometer. The variable resistor may change the resistance of the trigger switch 415 based on the position of the trigger 420, which in turn changes the voltage and / or current of the signal output from the trigger switch 415 based on the position of the trigger 420. In some examples, the trigger switch 415 may include a Hall effect sensor. The Hall effect sensor may be used to detect the position of the trigger 420, and the voltage and / or current of the signal output from the trigger switch 415 may be adjusted based on the position of the trigger 420.

[0074] In the determination block 910, the controller 400 determines whether the trigger switch 415 has been activated. In response to the determination that the trigger switch 415 has not been activated ("no" in the determination block 910), the controller 400 continues to monitor the trigger switch for activation in block 912, and the process 900 returns to the determination block 910. In response to the controller 400's determination that the trigger switch 415 has been activated ("yes" in the determination block 910), the controller 400 generates one or more control signals for the motor 405 of device 300 in block 914. In various implementations, the control signals may be analog signals, such as voltage signals (e.g., continuous signals that may control the parameters of the motor 405 using changes in voltage) or current signals (e.g., continuous signals that may control the parameters of the motor 405 using changes in current). In some examples, the control signals may be digital signals, such as pulse-width modulation (PWM) signals. In an example where the control signal is a PWM signal, the duty cycle (e.g., the ratio of the on-time to the total duration of the signal) may be modulated to control the operating parameters of the motor 405. In various embodiments, the operating parameters of the motor 405 may include the speed, power, torque, and / or runtime of the motor 405.

[0075] In block 916, the controller 400 controls the motor 405 using the generated control signal. For example, in an implementation where the control signal is a PWM signal, the controller 400 may provide the control signal to the FET switching module 450, which may drive the motor 405 based on the control signal that loads the battery pack electrically connected to the device 300. In block 918, the controller 400 monitors the output voltage of the battery pack connected to the battery pack interface 410 (such as battery pack 100 or 200) upon application of the load. For example, the controller 400 monitors the digital signal output from the analog-to-digital converter 704. In block 918, the controller 400 determines the output voltage of the battery pack connected to the battery pack interface 410. For example, the controller 400 calculates the output voltage of the battery pack based on the digital signal output from the analog-to-digital converter 704, according to the techniques described above with reference to Figures 7 and 8.

[0076] In determination block 922, the controller 400 determines whether the battery pack output voltage is below a threshold. In various embodiments as described herein, the threshold may be determined dynamically by the controller 400 (for example, according to the process described above with reference to blocks 902-906). In other embodiments, the controller 400 may be pre-programmed with a threshold (for example, as described above with reference to process 900 and / or Table 1). In response to the determination that the battery pack output voltage is not below the threshold ("no" in determination block 922), the controller 400 continues to monitor the battery pack output voltage (for example, by monitoring the digital signal output from the analog-to-digital converter 704) in block 924, and process 900 returns to block 920. In response to the determination that the battery pack output voltage is below the threshold ("yes" in determination block 922), the controller 400 generates an updated control signal in block 926. For example, the updated control signal may reduce the operating parameters of the motor 405 (e.g., speed, power, torque, and / or runtime) compared to the control signal generated in block 914. In various implementations, the control signal may be an analog control signal used to drive the motor 405, and the updated control signal generated in block 926 may have reduced voltage, current, and / or duration compared to the control signal generated in block 914. In some examples, the control signal may be a PWM control signal provided to the FET switching module 450, and the updated control signal generated in block 926 may have a reincarnated duty cycle compared to the control signal generated in block 914. In some examples, the controller 400 may reduce the duration for which the control signal is provided to the motor 405. In block 928, the controller 400 provides the updated control signal to the motor 405 (e.g., via the FET switching module 450). From block 928, process 900 proceeds to block 924.

[0077] It should be understood that the threshold determination portion of process 900 may be performed as part of an initialization process, for example, when device 300 is powered on or reset. Thus, the determined threshold may be used in response to one or more trigger activations as shown in process 900 while device 300 is operating (for example, until device 300 is powered off or shut down). However, in other embodiments, the threshold determination portion of process 900 may be repeated in response to a requesting user, a specific input of device 300 at a given frequency, an operation or state, or a combination thereof.

[0078] Furthermore, it should be understood that measuring and monitoring the voltage of the battery pack while a load is applied may be performed while the trigger is activated, for a predetermined amount of time after initial activation, or until a predetermined condition or event occurs, or a combination thereof. For example, in some embodiments, a voltage sag may occur within the initial time after the trigger is activated, and therefore, voltage measurements may be performed during a limited time after trigger activation.

[0079] The control scheme implemented according to process 900 and Figures 9A-9B brings various technical advantages to the battery pack power supply device. For example, the controller 400 may dynamically determine the characteristics (such as capacity, impedance, etc.) of the battery pack connected to the device 300, and may dynamically adjust the control signals used to control the motor 405 so that the operating parameters (such as speed, power, torque, and / or runtime) of the motor 405 are optimized based on the characteristics of the battery pack, which may improve the performance of the battery pack and / or device 300. For example, the controller 400 may detect when one or more operating parameters of the motor 405 exceed the optimal performance envelope of the battery pack (e.g., by causing an excessive voltage drop in the battery pack), and may generate updated operating parameters to guide the operation of the motor 405 within the optimal performance envelope of the battery pack.

[0080] Figures 10A and 10B are flowcharts of a process 1000 for controlling the operation sequence of device 300 according to several embodiments, and in particular represent determining the characteristics (e.g., capacity, impedance, etc.) of a battery pack connected to device 300 via a measured voltage (e.g., voltage drop), and generating one or more control signals for controlling motor 405 using the determined characteristics. The operation of process 1000 is shown with reference to specific examples described herein, but process 1000 may be implemented in any suitable setting. The operations are shown once and in a specific order in Figures 10A and 10B, but the operations may be rearranged and / or repeated as desired and appropriate. For example, different operations may be performed in parallel as appropriate. In various implementations, process 900 monitors the battery pack when it drives the motor 405 and dynamically adjusts the operating parameters of the motor 405 during operation, but process 1000 may test the battery pack before operation and pre-select an optimized operating mode for the battery pack (for example, based on the determined characteristics of the battery pack). The selected operating mode may then be applied (for example, when the trigger is activated) without measuring and monitoring the voltage drop that occurs after the trigger is activated.

[0081] As shown in Figure 10A, in block 1002, the controller 400 measures the no-load voltage signal of the battery pack connected to device 300 (such as battery pack 100 or 200 connected to interface portion 310). In various embodiments, the controller 400 measures the no-load voltage signal as previously described with reference to block 902. In block 1004, the controller 400 determines the no-load voltage of the battery pack based on the no-load voltage signal (for example, as previously described with reference to block 904). In block 1006, the controller 400 determines a threshold based on the no-load voltage of the battery pack (for example, as previously described with reference to block 906). In various implementations, the controller 400 may be pre-programmed with a threshold (for example, as previously described with reference to process 900 and Figures 9A-9B).

[0082] In block 1008, the controller 400 initiates a test current draw from the battery pack connected to the battery pack interface 410 (such as battery pack 100 or 200). In block 1010, the controller 400 monitors the output voltage of the battery pack during the test current draw. For example, the controller 400 monitors the digital signal output from the analog-to-digital converter 704. In block 1012, the controller 400 determines the output voltage of the battery pack during the test current draw. For example, the controller 400 calculates the output voltage of the battery pack based on the digital signal output from the analog-to-digital converter 704, according to the techniques described above with reference to Figures 7 and 8. In determination block 1014, the controller 400 determines whether the output voltage of the connected battery pack is below a threshold. In various implementations, the threshold may be any of the thresholds described above with reference to determination block 922 of process 900. In response to a determination that the output voltage of the battery pack is not below a threshold ("No" in determination block 1014), the controller 400 selects a first operating mode in block 1016, and process 1000 proceeds to block 1018. In response to a determination that the output voltage of the battery pack is below a threshold ("Yes" in determination block 1014), the controller 400 selects a second operating mode in block 1020, and process 1000 proceeds to block 1018. The first operating mode may be associated with a first battery pack capacity (or capacity range), and the second operating mode may be associated with a second lower battery pack capacity (or capacity range).

[0083] In block 1018, after selecting the operating mode, the controller 400 monitors the trigger switch 415 for activation. In decision block 1022, the controller 400 determines whether the trigger switch 415 has been activated. In response to a determination that the trigger switch is not activated ("no" in decision block 1022), the controller 400 continues monitoring the trigger switch 415 in block 1024, and process 1000 returns to decision block 1022. In response to a determination that the trigger switch has been activated ("yes" in decision block 1022), the controller 400 generates a control signal for the motor according to the selected control mode (in block 1026). In response to the selection of a first control mode, the controller 400 generates a control signal to control the motor 405 with baseline operating parameters (such as baseline speed, power, torque, and / or runtime). In response to the selection of the second mode, the controller 400 generates an updated or modified control signal that controls the motor 405 with reduced operating parameters relative to the baseline operating parameters.

[0084] In various implementations, the baseline operating parameter may include a first speed, and the reduced operating parameter may include a second speed less than the first speed. In some examples, the baseline operating parameter may include a first power, and the reduced operating parameter may include a second power less than the first power. In some embodiments, the baseline operating parameter may include a first torque, and the reduced operating parameter may include a second torque less than the first torque. In various implementations, the baseline operating parameter may include a first runtime, and the reduced operating parameter may include a second runtime having a shorter duration than the first runtime. In block 1028, the controller 400 provides control signals to the motor 405 (e.g., via the FET switching module 450).

[0085] It should be understood that in some embodiments, more than two control modes may be used, and each control mode may be associated with a different control signal for the motor 405. When more than two control modes are used, more than two thresholds (e.g., different thresholds to identify different voltage drops) may be used to determine the appropriate control mode given the capacity of the connected battery pack.

[0086] The controller 400 may repeat the control mode selection portion of process 1000 in response to specific conditions or inputs according to a predetermined frequency, or a combination thereof. For example, the controller 400 may be configured to repeat the control mode selection portion of process 1000 after a predetermined time period, or a combination thereof, each time the device 300 is powered on or reset.

[0087] Therefore, similar to process 900, the control scheme implemented according to process 1000 offers various technical advantages to the battery pack power supply device. Furthermore, the use of test current draw allows the control mode to be initially set for device 300, which can simplify motor control after trigger activation (by reducing the need for voltage measurement and monitoring compared to process 900, for example).

[0088] Furthermore, in some examples, the controller 400 may be programmed to implement process 900, process 1000, or both processes 900 and 1000. Also, in some implementations, the controller 400 may be programmed to combine aspects of processes 900 and 1000 in various ways. For example, in some implementations of process 1000, the controller 400 may be configured to omit block 1008 (test current draw) and execute blocks 1012-1020 after the initial activation of the trigger switch 415 (for example, after the first time point, after the controller 400 detects that the trigger switch 415 was in the determination block 1022). In such an example, the controller 400 monitors the voltage signal output from the analog-to-digital converter 704 when the battery pack drives the motor 405 (instead of monitoring the voltage signal during test current draw) in block 1010 and selects an appropriate control mode for the subsequent operation of device 300. Therefore, in this implementation, the control mode can be selected during one of the trigger activations (e.g., the first activation after device 300 is turned on), which may reduce or eliminate the need to implement test current draw and may reduce or eliminate the need to measure and monitor the battery pack voltage during subsequent trigger activations.

[0089] Furthermore, as described with respect to Figures 9A and 9B, in some examples, the threshold is determined in response to the activation of a device trigger, rather than as part of the initialization or configuration process of device 300. For example, Figure 11 is a block diagram showing process 1100 for implementing the control scheme by process 900 in Figures 9A-9B and / or process 1000 in Figures 10A-10B, and graph 1105 showing the measured voltage of the battery pack as a function of time. As shown in Figure 11, hardware (e.g., controller 400) may measure the voltage of the battery pack in a charged state ("SoC voltage") in response to the detection of activation of trigger 420 (e.g., pulling), but before the application of a load associated with the trigger activation. For example, the SoC voltage may be the no-load voltage determined as described above with respect to process 900 and Figures 9A-9B and / or process 1000 and Figures 10A-10B. The hardware may calculate a target voltage according to the SoC voltage. For example, as mentioned above, the target voltage may be a threshold and may be calculated as described above with reference to process 900 and / or Figures 9A-9B and / or process 1000 and / or Figures 10A-10B. After the target voltage is calculated, the hardware adjusts the operation of the device (e.g., tool) (such as the operating parameters of motor 405 as described for processes 900 and 1000) using the target voltage. As shown in Graph 1105, the hardware may control motor 405 to operate with a first operating parameter when the measured voltage of the battery pack is above the target voltage and a second operating parameter which is less than the first operating parameter when the measured voltage of the battery pack is below the target voltage. For example, in some implementations, when the no-load voltage of the battery pack is about 18 volts, the target voltage may be set to about 13.5 volts.

[0090] Figure 12 is a block diagram showing a feedback loop that may be used to implement the control scheme by process 900 in Figures 9A-9B, process 1000 in Figures 10A-10B, and / or process 1100 shown in Figure 11. As shown in Figure 12, the controller 400 may be configured to calculate a target voltage (such as the thresholds mentioned above with reference to processes 900 and / or 1000). The target voltage is provided to a proportional integral control loop (which may be implemented by the controller 400). Hardware (such as the controller 400) generates a control signal (such as a PWM signal) and provides it to the motor 405. The hardware measures the voltage of the battery pack when the battery pack is driving the motor 405 in response to the control signal and provides the measured voltage as feedback to the PI control loop. In response to the voltage feedback being above the target voltage, the hardware does not adjust the control signal. However, in response to the voltage feedback being below the target voltage, the hardware updates the control signal (for example, by reducing the duty cycle of the PWM signal).

[0091] Accordingly, the methods and systems described herein use the voltage drop of a battery pack to determine the characteristics of the battery pack and use those characteristics to optimize the operation of the motor of a battery-powered device (e.g., a power tool) based on the characteristics determined. For example, as mentioned above, the capacity of a battery pack can be based on various factors, and therefore different battery packs may exhibit different responses to the same applied load. For example, Figure 13 is a graph showing the voltage drop of a first battery pack in response to a load as a function of time, and Figure 14 is a graph showing the voltage drop of a second battery pack (having a lower capacity than the first battery pack) in response to the same load as a function of time. As shown in Figures 13 and 14, a battery pack with a higher capacity (like the first battery pack) may exhibit a lower voltage drop in response to a current load than a battery pack with a lower capacity (like the second battery pack).

[0092] Therefore, in some implementations, for example, during longer operating cycles, the output voltage of the battery pack may begin to decrease. In some scenarios, the output voltage of the battery pack may drop below a threshold voltage, and processes 900 and / or 1000 may respond by reducing the operating parameters of the motor 405. However, such a gradual decrease in the output voltage of the battery pack over longer operating cycles may not indicate the capacity of the battery pack. Therefore, it may be undesirable to unnecessarily restrict the operating parameters of the motor 405 in response to this gradual decrease in the output voltage of the battery pack. Accordingly, in some implementations, the thresholds at which the controller 400 reduces the operating parameters of the motor 405 (e.g., the threshold used in the decision block 922 of process 900 and / or the threshold used in the decision block 1014 of process 1000) are dynamically updated. By dynamically updating the thresholds, the operating parameters of the motor 405 are not unnecessarily restricted.

[0093] For example, Figure 16 shows graph 1602 illustrating the power output over time of motor 405 controlled according to a technique implemented without dynamic threshold updates, and graph 1604 illustrating the power output over time of motor 405 controlled according to a technique implemented with a dynamic threshold update process. As illustrated by graph 1602, the control scheme implemented without a dynamic threshold update process may reduce the operating parameters (such as output power) of motor 405 over longer operating cycles. In contrast, as illustrated by graph 1604, the control scheme implemented with a dynamic threshold update process may maintain consistent operating parameters (such as output power) of motor 405 over longer operating cycles.

[0094] In some embodiments, the dynamic threshold update process uses a charge state (SoC) estimator algorithm that takes into account the pack voltage which progressively decreases as the tool is being used. As described above, this dynamic threshold update may be used for longer applications, such as when the user triggers the tool once and then uses it for several minutes. When the motor is operating, it is difficult to directly measure the pack voltage. Therefore, the SoC estimator estimates the pack's DCIR and pack voltage and uses this information to adjust the tool optimization processes 900 and 1000 described above, in particular, to avoid unnecessary power limitations during long applications (using device 300).

[0095] The SoC estimator uses the current difference (e.g., of inverter 451 which may be used to calculate the current difference of DC bus 452) and the voltage difference (e.g., of DC bus 452 output to inverter 451) during the operation cycle of device 300. This information is used to derive the DCIR (direct current internal resistance) for the battery pack, which can be added to the voltage to estimate where the resting voltage is when the tool stops drawing power. In other words, the SoC estimator adjusts the target voltage / threshold in processes 900 and 100 above to account for battery depletion over time. In some embodiments, the DCIR may be calculated according to the following equation (5).

Number

[0096] The resting voltage V of the battery pack rest can be calculated as a function of the calculated DCIR, where the calculated resting voltage V rest may represent an estimated value of the resting voltage of the battery pack after the motor 405 stops drawing load.

[0097] The controller 400 can use the calculated resting voltage V rest to update the threshold (e.g., the threshold used in decision block 922 and / or decision block 1014). In various implementations, the controller 400 calculates the updated threshold using the techniques described above with reference to block 906 and / or 1006, and uses the calculated resting voltage V rest of the battery pack instead of the no-load voltage of the battery pack.

[0098] Figure 17 is a block diagram 1700 illustrating measurements and calculations that may be used to implement the control scheme according to the dynamic updating threshold process described above. For example, the measured inverter load cycle and measured inverter current of inverter 451 may be used to estimate the current value on DC bus 452. The DC bus voltage and estimated current value of DCIR bus 452 may be used to estimate DCIR. The estimated current value on DC bus 452, estimated DCIR, and DC bus voltage may be used to estimate the quiescent voltage of the battery pack. The estimated quiescent voltage may be used by a voltage sag controller, which may be implemented by controller 400, to update the threshold voltage. Controller 400 may then control motor 405 using the updated threshold voltage. In some implementations, the estimated quiescent voltage of the battery pack may be used alternatively (either by itself or in conjunction with other data) as a voltage compared to a previously calculated threshold, which also avoids unnecessary power reductions during long applications.

[0099] Accordingly, the embodiments described herein use a threshold (e.g., target voltage) that represents a voltage drop or sag to distinguish a battery pack having one capacity (or other characteristic) from a battery pack having a different capacity (or other characteristic). As described above, the threshold may be set based on empirical data collected for devices and various battery packs in various operating applications and / or environments. For example, Figure 15 is a graph illustrating the battery pack voltage as a function of load, showing regions (e.g., specific load and pack voltage combinations) where the controller (hardware) generates updated control signals (e.g., a reduced PWM signal to reduce the operating parameters of motor 405) according to some embodiments described herein, and regions where the controller (hardware) does not generate updated control signals. As previously mentioned, some implementations may use multiple thresholds to establish more than two different categories of battery packs. Each category may be associated with a different control signal for motor 405 to optimize motor operation for the category of battery packs connected. Similarly, as previously stated, in some embodiments, the thresholds used by the systems and methods described herein may be further adjusted to take into account the operating applications and / or environments of the battery-powered devices and / or battery packs.

[0100] Therefore, the embodiments described herein provide, in particular, a system and method for controlling the operating sequence of a battery pack power supply device. Various configurations and advantages are described in the following claims.

Claims

1. An interface configured to receive a battery pack, A sensing circuit configured to detect the voltage of the battery pack, Includes an electronic controller, A battery pack power supply device, The aforementioned electronic controller is A first signal indicating the no-load voltage of the battery pack is received from the sensing circuit. The threshold voltage is calculated as the rate of decrease of the no-load voltage. A control signal for driving the electric motor of the battery pack power supply device in response to the activation of a trigger switch, which generates a control signal to drive the electric motor to operate with a first operating parameter, A second signal indicating the output voltage of the battery pack while the electric motor is operating is received from the sensing circuit. The control signal is updated in response to the second signal indicating that the output voltage is below the threshold voltage. It is configured in such a way, The first operating parameter includes at least one of power output, torque output, and operating duration. The updated control signal drives the electric motor to operate with a second operating parameter, the second operating parameter being of the same type as the first operating parameter and reduced relative to the first operating parameter. Battery pack power supply device.

2. The battery pack power supply device according to claim 1, wherein the reduction rate is a 25% reduction.

3. The battery pack power supply device according to claim 1, wherein the nominal input voltage of the battery pack power supply device is 18 volts and the threshold voltage is 13.5 volts.

4. The control signal includes a first pulse-width modulated signal, The updated control signal includes a second pulse-width modulated signal, The duty cycle of the first pulse width modulated signal is greater than the duty cycle of the second pulse width modulated signal. The battery pack power supply device according to claim 1.

5. The first operating parameter is the first power output, The second operating parameter is the second power output, The first power output is greater than the second power output. The battery pack power supply device according to claim 1.

6. The first operating parameter is the first torque output, The second operating parameter is the second torque output, The first torque output is greater than the second torque output. The battery pack power supply device according to claim 1.

7. The first operating parameter is the first operating duration, The second operating parameter is the second operating duration, The first operating duration is greater than the second operating duration. The battery pack power supply device according to claim 1.

8. Electric motor and, An interface configured to receive a battery pack that supplies power to the electric motor, A sensing circuit configured to detect the voltage of the battery pack, Includes an electronic controller, A battery pack power supply device, The aforementioned electronic controller is Start drawing test current from the aforementioned battery pack. A first signal indicating the output voltage of the battery pack during the test current draw is received from the sensing circuit. The threshold voltage is calculated as the rate of decrease of the output voltage. In response to the first signal indicating that the output voltage is not below a threshold voltage, a first control mode for controlling the electric motor is selected. In response to the first signal indicating that the output voltage is below the threshold voltage, a second control mode for controlling the electric motor is selected. It is configured in such a way, The electronic controller is configured to generate a first control signal for controlling the electric motor in the first control mode, the first control signal drives the electric motor and operates it with first operating parameters, the first operating parameters include at least one of power output, torque output, and operating duration. The electronic controller is configured to generate a second control signal for controlling the electric motor in the second control mode, the second control signal drives the electric motor and operates it with a second operating parameter, the second operating parameter being of the same type as the first operating parameter and reduced relative to the first operating parameter. Battery pack power supply device.

9. The battery pack power supply device according to claim 8, wherein the reduction rate is a 25% reduction.

10. The battery pack power supply device according to claim 8, wherein the designed output voltage of the battery pack is 18 volts and the threshold voltage is 13.5 volts.

11. The first control signal is a pulse-width modulated signal having a first duty cycle, The second control signal is a pulse-width modulated signal having a second duty cycle, The first duty cycle is greater than the second duty cycle. The battery pack power supply device according to claim 8.

12. The first control signal controls the electric motor to operate at a first power output. The second control signal controls the electric motor to operate with a second power output. The first power output is greater than the second power output. The battery pack power supply device according to claim 8.

13. The first control signal controls the electric motor to operate with a first torque output. The second control signal controls the electric motor to operate with a second torque output. The first torque output is greater than the second torque output. The battery pack power supply device according to claim 8.

14. The first control signal controls the electric motor to operate over a first duration. The second control signal controls the electric motor to operate over a second duration. The first duration is longer than the second duration. The battery pack power supply device according to claim 8.

15. A method for operating a battery pack power supply device, In response to the activation of the trigger switch, The controller measures a first voltage of the battery pack electrically connected to the battery pack power supply device before the activation of the trigger switch and the application of the associated load, The controller calculates the target voltage as the rate of decrease of the first voltage, During the application of the load associated with the activation of the trigger switch, To measure the second voltage of the aforementioned battery pack, Comparing the second voltage with the target voltage, This includes modifying the operation of the battery pack power supply device by reducing the duty cycle of the pulse width modulation control signal for the electric motor of the battery pack power supply device in response to the second voltage being less than the target voltage, method.

16. The method according to claim 15, wherein reducing the duty cycle includes reducing the duty cycle using a proportional-integral control loop.

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