Electric tool

Abstract

The power tool includes a motor, a power source, and a printed circuit board ("PCB") electrically connected to the motor and the power source. The PCB is mounted to the motor. The PCB includes a plurality of wide bandgap semiconductor switches configured as inverters for controlling power supplied to the motor by the power source.

Description

[0001] Related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 288,264, filed December 10, 2021, and U.S. Provisional Patent Application No. 63 / 292,585, filed December 22, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The specific embodiments described in this application relate to inverters included in electrical equipment such as power tools. Utility Model Content

[0004] The power tool described in this application includes a motor, a power supply, and a printed circuit board (“PCB”) electrically connected to the motor and the power supply. The PCB is mounted to the motor. The PCB includes a plurality of wide-bandgap semiconductor switches configured as inverters for controlling the power supplied to the motor.

[0005] In some aspects, the motor includes a frame, and the PCB is mounted directly to the frame.

[0006] In some respects, the motor is configured to act as a heat sink for the inverter.

[0007] In some respects, power tools include a radiator, to which the PCB is mounted, and to which the radiator is mounted.

[0008] In some respects, the radiator is cooled by air.

[0009] In some respects, power tools include an input capacitor, and the input capacitor and inverter are mounted on the same side of the PCB.

[0010] In some respects, power tools include a heat sink connected to the motor.

[0011] In some cases, the heat sink is connected to the heat pipe, which in turn is connected to the radiator.

[0012] In some aspects, the motor, PCB, and heat sink are housed in a completely enclosed structure.

[0013] In some aspects, the PCB includes at least one ceramic chip capacitor.

[0014] In some respects, the motor is configured to rotate at 75,000 revolutions per minute or higher.

[0015] In some respects, the motor is configured to rotate at 100,000 revolutions per minute or higher.

[0016] The power tool described in this application includes a motor, a battery pack interface configured to receive a battery pack, and an inverter electrically connected to the motor and the battery pack interface. The inverter includes a plurality of wide bandgap semiconductor switches configured to control the power supplied by the battery pack to the motor, wherein the bandgap of the plurality of wide bandgap semiconductor switches is approximately 3 electron volts (“eV”) or higher.

[0017] In some respects, the motor is configured to act as a heat sink for the inverter.

[0018] In some respects, power tools include a radiator, and the inverter is mounted to the motor via the radiator.

[0019] In some respects, power tools include a heat sink connected to the motor.

[0020] The power tools described in this application include a motor configured to rotate at 75,000 revolutions per minute or higher; a power supply; and a printed circuit board (“PCB”) electrically connected to the motor and the power supply, the PCB including a plurality of wide-bandgap semiconductor switches configured as inverters for controlling the power supplied by the power supply to the motor.

[0021] In some respects, the motor includes a frame, and the PCB is directly mounted to the frame.

[0022] In some respects, power tools include a radiator, a PCB mounted to the radiator, and the radiator mounted to the motor.

[0023] In some aspects, power tools include a heat sink connected to a motor, and the heat sink is connected to a heat pipe, which is connected to a radiator.

[0024] In some aspects, the PCB includes at least one ceramic chip capacitor.

[0025] In some cases, the PCB is mounted onto the motor.

[0026] In some respects, the inverter is a five-level flying capacitor multilevel inverter.

[0027] Before explaining any specific implementation in detail, it should be understood that the specific implementation is not limited to the application of the configuration details and component arrangements shown in the following description or the accompanying drawings. Specific implementations can be carried out or realized in various ways. Furthermore, it should be understood that the wording and terminology used in this application are for illustrative purposes only and should not be considered limiting. The use of "comprising," "including," "having," and variations thereof means to cover both the items listed thereafter and their equivalents and additional items. Unless specifically specified or limited, the terms "installation," "connection," "support," "coupled," and variations thereof are used in a broad sense to cover both direct installation, connection, support, and coupling as well as indirect installation, connection, support, and coupling.

[0028] Furthermore, it should be understood that specific implementations may include hardware, software, and electronic components or modules, and for illustrative purposes, these hardware, software, and electronic components or modules may be shown and described as if most of the components were implemented solely in hardware. However, based on a reading of the specific implementations of this application, those skilled in the art will recognize that in at least one implementation, the electronic aspects may be implemented in software (e.g., stored on a non-transitory computer-readable medium), and the software may be executed by one or more processing units such as microprocessors and / or application-specific integrated circuits (“ASICs”). Therefore, it should be noted that a plurality of hardware and software-based devices and a plurality of different structural components may be used to implement specific implementations. For example, “server,” “computing device,” “controller,” and “processor” as described in this specification may include one or more processing units, one or more computer-readable medium modules, one or more input / output interfaces, and various connectors (e.g., system buses) connecting these components.

[0029] Relative terms such as “about,” “approximately,” “substantially,” etc., used in relation to quantity or condition will be understood by those skilled in the art to include the stated value, and the meaning of the term is determined by the context (e.g., the term includes at least the degree of error associated with measurement accuracy, the tolerance associated with a particular value [e.g., manufacturing, assembly, use, etc.]). Such terms should also be considered to disclose a range defined by the absolute values ​​of the two endpoints. For example, the statement “from about 2 to about 4” also discloses a range “from 2 to 4.” Relative terms can refer to positive or negative percentages of indicated values ​​(e.g., 1%, 5%, 10%, or more).

[0030] It should be understood that although some figures illustrate hardware and software located within a particular device, these depictions are for illustrative purposes only. Functions performed by a single component as described in this application may be performed by multiple components in a distributed manner. Similarly, functions performed by multiple components may be combined and performed by a single component. In some specific embodiments, the illustrated components may be combined or divided into separate software, firmware, and / or hardware. For example, logical operations and processing may be distributed among multiple electronic processors, rather than residing within and being performed by a single electronic processor. Regardless of their combination or division, hardware and software components may reside within the same computing device or may be distributed among different computing devices connected via one or more networks or other suitable communication links. Similarly, the component performing a specific function may also perform additional functions not described in this application. For example, a device or structure "configured" in a certain way is configured at least in this manner, but may also be configured in a manner not explicitly listed.

[0031] Other aspects of the specific implementation will become apparent from consideration of the detailed embodiments and accompanying drawings. Attached Figure Description

[0032] Figure 1 Power tools according to specific embodiments described in this application are shown.

[0033] Figure 2 This application illustrates a specific embodiment for use with Figure 1 Control system of power tools.

[0034] Figure 3A , 3B Both 3C and 3C have shown exemplary embodiments of wide bandgap (WBG) inverters according to the specific embodiments described in this application.

[0035] Figure 3D Various components of a PCB configured as a WBG inverter according to a specific embodiment described in this application are shown.

[0036] Figure 3E The tables shown include those according to specific embodiments described in this application, such as... Figure 3C The switching states of the five-level flying capacitor multilevel inverter are described.

[0037] Figure 4A , 4B 4C illustrates an exemplary layout of a PCB configured as a WBG inverter according to a specific embodiment described in this application.

[0038] Figure 5An exemplary embodiment of a motor according to the specific embodiments described in this application is shown, wherein the motor includes a WBG inverter directly coupled to the motor.

[0039] Figure 6 An exemplary embodiment of a WBG inverter according to the specific embodiments described in this application is shown, wherein the WBG inverter is coupled to the motor via a heat sink.

[0040] Figure 7A An exemplary embodiment of a WBG inverter according to the specific embodiments described in this application is shown, wherein the WBG inverter is coupled to a motor via a heat sink, and the heat sink is coupled to a thermal power device.

[0041] Figure 7B An exemplary embodiment of a radiator coupled to a thermal power device is shown. Detailed Implementation

[0042] The specific embodiments described in this application relate to electrical devices such as power tools, which include a motor, a power supply, and a printed circuit board (“PCB”) electrically connected to the motor and the power supply. The PCB is configured as an inverter to control the voltage and frequency of the power supplied to the motor. The PCB is mounted to the motor. In some embodiments, the motor includes a frame, and the PCB is directly mounted to the frame. In some embodiments, the motor is configured to act as a heat sink. In some embodiments, the electrical device further includes a heat sink. In some embodiments, the PCB is mounted to the motor via a heat sink. In some embodiments, the heat sink is used for heat dissipation of the PCB. In some embodiments, the heat sink is cooled by air and provides additional cooling between the PCB and the motor. In some embodiments, the electrical device further includes a thermodynamic device. In some embodiments, the heat sink is coupled to the thermodynamic device. In some embodiments, the thermodynamic device is a heat sink connected to a heat pipe. In some embodiments, the motor, PCB, heat sink, and thermodynamic device are housed in a hermetically sealed configuration. In some embodiments, the PCB includes at least one ceramic chip capacitor. In some embodiments, the motor is an alternating current (AC) motor. In some specific implementations, the power source generates direct current (DC).

[0043] Figure 1 Power tool 100 is shown. Power tool 100 can be, for example, an impact wrench, drill, ratchet, saw, hammer drill, impact drill, rotary hammer, grinder, blower, trimmer, etc. Power tool 100 includes a motor (see...) Figure 2The power tool 100 is housed within a housing or motor housing 105. The power tool is configured to receive a power source 110, which provides direct current (DC) power to various components of the power tool 100, including the motor. The power source 110 may be a rechargeable power tool battery pack that uses, for example, a lithium-ion battery cell.

[0044] Figure 2 A control system 200 for a power tool 100 is shown. The control system 200 includes a controller 205. The controller 205 is electrically and / or communicatively connected to various modules or components of the power tool 100. For example, the controller 205 shown is electrically connected to a motor 202, a battery interface 210, a trigger switch 215 (connected to a trigger 220), one or more sensors or sensing circuits 225, one or more indicators 230, a user input module 235, a power input module 240, and an inverter or FET switch module 245. The controller 205 includes a combination of hardware and software, which, among other things, are operable to control the operation of the power tool 100, monitor the operation of the power tool 100, activate one or more indicators 230 (e.g., LEDs), etc.

[0045] Controller 205 includes a plurality of electrical and electronic components that provide power, operational control, and protection to components and modules within controller 205 and / or power tool 100. For example, among others, controller 205 includes a processing unit 250 (e.g., a microprocessor, microcontroller, electronic processor, electronic controller, or other suitable programmable device), memory 260, input unit 265, and output unit 270. Among others, processing unit 250 includes a control unit 275, an ALU 280, and a plurality of registers 285, and is implemented using known computer architectures (e.g., modified Harvard architecture and von Neumann architecture). Processing unit 250, memory 260, input unit 265, output unit 270, and various modules or circuits connected to controller 205 are connected via one or more control buses and / or data buses (e.g., common bus 290). Figure 2 The control bus and / or data bus are shown in general terms for illustrative purposes.

[0046] In some embodiments, memory 260 is a non-transitory computer-readable medium and includes program storage areas and data storage areas, etc. In some embodiments, the program storage areas and data storage areas include combinations of different types of memory, such as read-only memory (ROM), random access memory (RAM) (e.g., dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), etc.), electrically erasable programmable read-only memory (EEPROM), flash memory, hard disk, secure digital card (SD) card, or other suitable magnetic storage devices, optical storage devices, physical storage devices, or electronic storage devices. Processing unit 250 is connected to memory 260 and executes software instructions, which may be stored in the RAM of memory 260 (e.g., during execution), in the ROM of memory 260 (e.g., typically permanent storage), or in another non-transitory computer-readable medium (e.g., another type of memory or optical disc). In some embodiments, the software included in the power tool 100 embodiment is stored in the memory 260 of controller 205. For example, the software includes firmware, one or more applications, program data, filters, rules, one or more program modules, and other executable instructions. In some embodiments, the controller 205 is configured to retrieve and execute (among others) instructions related to the control processes and methods described herein from the memory 260. In other configurations, the controller 205 includes additional, fewer, or different components.

[0047] In some embodiments, the battery pack interface 210 includes a combination of mechanical components (e.g., rails, slots, latches, etc.) and electrical components (e.g., one or more terminals), configured and operable to connect the power tool 100 to the battery pack (e.g., mechanical, electrical, and communication connections). For example, power supplied to the power tool 100 by the battery pack 110 is supplied to the power input module 240 via the battery pack interface 210. In some embodiments, the power input module 240 includes a combination of active and passive components to regulate or control the power received from the battery pack 110 before supplying power to the controller 205. In some embodiments, the battery pack interface 210 also supplies power to an inverter 245 so that the inverter can selectively supply power to the motor 202 by switching. The battery pack interface 210 also includes, for example, a communication line 295 for establishing a communication line or link between the controller 205 and the battery pack 110.

[0048] In some embodiments, inverter 245 is configured on a printed circuit board (“PCB”) electrically connected to motor 202 and battery pack 110. In some embodiments, motor 202 is an alternating current (“AC”) motor. In some embodiments, inverter 245 is configured to control the voltage and frequency of the power supplied by battery pack 110 to motor 202. In some embodiments, the PCB includes logic decision devices or gate drivers, such as microcontrollers (MCUs), central processing units (CPUs), field-programmable gate arrays (FPGAs), etc., coupled to power electronic devices such as transistors. In some embodiments, the PCB includes WBG semiconductors to form a WBG inverter. In this application, “WBG semiconductor” refers to a semiconductor with a band gap wider than silicon. Typically, the band gap of silicon is about 1.1 electron volts (eV). WBG semiconductors can have a band gap of about 3 eV or greater. However, in some embodiments, the band gap of the WBG semiconductor used is less than 3 eV. Generally, the wider the band gap, the higher the critical electric field, which means that, relative to silicon, devices formed by wide band gap semiconductors of the same size may have a higher breakdown voltage.

[0049] By using WBG semiconductors, the WBG inverter 245 can be installed in smaller machines because the semiconductors are smaller, and WBG semiconductors enable higher operating frequencies and allow for higher operating temperatures. In some specific embodiments, using the WBG inverter 245 enables higher motor operating speeds (e.g., 75,000 to 100,000 rpm or higher, rather than, for example, 30,000 rpm). Furthermore, compared to inverters formed using silicon-based semiconductors, the WBG inverter 245 is smaller, has lower losses, better thermal conductivity, and allows for higher operating temperatures. Therefore, the WBG inverter 245 can be directly installed onto the motor 202 without much (if any) adverse effect (see...). Figure 5-7B In some implementations, the PCB includes ceramic chip capacitors, which are smaller, can operate at higher temperatures, and are more reliable than aluminum electrolytic capacitors. The WBG inverter 245 can increase the power of a given motor package, or achieve the same power in a smaller motor package.

[0050] Indicator 230 includes one or more light-emitting diodes (“LEDs”), etc. In some embodiments, indicator 230 is configured to display the status of power tool 100 or information associated with power tool 100. For example, indicator 230 may be configured to indicate measured electrical characteristics of power tool 100, equipment status, etc. User input module 235 is operatively coupled to controller 205, for example, to select a forward or reverse operating mode, torque and / or speed settings for power tool 100 (e.g., using a torque and / or speed switch), etc. In some embodiments, user input module 235 includes a combination of digital input or output devices and analog input or output devices required to achieve a desired level of control over power tool 100, such as one or more knobs, one or more dials, one or more switches, one or more buttons, etc.

[0051] Sensor 225 includes one or more current sensors, one or more speed sensors, one or more Hall effect sensors, one or more temperature sensors, etc. Within memory 260, controller 205 calculates or includes predetermined operating thresholds and limits for the operation of power tool 100. For example, when controller 205 detects or predicts a potential thermal failure (such as a FET, motor 202, etc.), it can limit or interrupt power to motor 202 until the probability of thermal failure decreases.

[0052] Figure 3A , 3B Exemplary embodiments 300, 310, and 320 of a WBG inverter 245 for a power tool 100 are shown in [reference 1] and [reference 2], respectively. Exemplary embodiment 310 is implemented using components such as bipolar junction transistors (BJTs), metal-oxide-semiconductor field-effect transistors (MOSFETs), and insulated-gate bipolar transistors (IGBTs), etc. Figure 3D As shown. Exemplary implementation 320 is a five-level flying capacitor multilevel inverter, but the power tool 100 may also use other types of multilevel inverters. Figure 3E A table showing the switching states of the five-level flying capacitor multilevel inverter 320 is provided.

[0053] Figure 4A , 4BExamples 400, 410, and 420 of a PCB configured as a WBG inverter 245 are shown in Figures 4C and 4C, respectively. Exemplary layouts 400, 410, and 420 describe power flow to manage the paths of current flow and return. Exemplary layout 400 is a lateral power loop 405 for a WBG half-bridge configuration (i.e., the input capacitor and power input are located on the same side of the PCB). Power loop 405 generates a magnetic field that induces a current in the shielding layer of the PCB, and this current flows in the opposite direction to that of power loop 405. The current in the shielding layer generates a magnetic field that counteracts the magnetic field of the original power loop, resulting in magnetic field cancellation. The shielding layer is positioned immediately adjacent to power loop 405 (e.g., as a second layer of the PCB) to minimize power loop inductance in the lateral power loop configuration.

[0054] The exemplary layout 410 is a vertical power loop 415 for a WBG half-bridge configuration (i.e., the input capacitor and power input are located on opposite sides of the PCB). As the thickness of the PCB decreases, the area of ​​the power loop 415 also decreases. The current flowing in opposite directions on the top and bottom layers of the PCB achieves magnetic self-cancellation.

[0055] Exemplary layout 420 is an optimized power loop 425 for a WBG half-bridge configuration (i.e., the input capacitor and power input are located on the same side of the PCB). The optimized power loop 425 uses a first inner layer ( Figure 4C (Right side) serves as the return path for the power circuit. The return path is located in power circuit 425 on the PCB. Figure 4C (Left side) Directly below the top layer. This positioning achieves a minimum physical loop area while also benefiting from magnetic self-cancellation.

[0056] Figure 5 An exemplary embodiment 500 is shown, comprising a WBG inverter 245 directly coupled to a motor 202 (e.g., the frame of the motor 202). In the depicted embodiment, the thermal properties of the motor 202 act as a heat sink for the WBG inverter 245. Any of layouts 400, 410, and 420 can be used when implementing the WBG inverter 245.

[0057] Figure 6An exemplary embodiment 600 is shown, comprising a WBG inverter 245 coupled to a motor 202 via a heatsink 602. The inverter 245 is mounted to the heatsink 602, and a heatsink 603 is mounted to the motor 202. In this embodiment, the heatsink 602 is used for cooling the WBG inverter 245. In some embodiments, the heatsink 602 is cooled by air (e.g., by a fan) and provides additional cooling between the WBG inverter 245 and the motor 202. Any of layouts 400, 410, and 420 can be used when implementing the WBG inverter 245.

[0058] Figure 7A An exemplary embodiment 700 of a WBG inverter 245 is shown, comprising a heat sink 702 coupled to a motor 202, which is coupled to a heat pipe or thermal power device 704. Exemplary embodiment 700 can be used in demanding applications where forced air cooling is not feasible, such as in fully enclosed structures (e.g., without openings to enhance entry protection) or in diving applications. Any of layouts 400, 410, and 420 can be used when implementing the WBG inverter 245.

[0059] Figure 7B An exemplary embodiment 710 is shown, in which a heat sink 702 coupled to a thermally powered device 704 is depicted. In the depicted embodiment, the heat sink 702 is thermally connected to a radiator 706 via a heat pipe 704.

[0060] In each of the exemplary embodiments 500, 600, and 700, the WBG inverter 245 is coupled to the battery pack 110, such as Figure 2 As shown. In some embodiments, the depicted WBG inverter 245 (PCB) is fastened to motor 202, heat sink 602, or heat plate 702.

[0061] Therefore, among other things, the specific embodiments described in this application provide a power tool including a printed circuit board, wherein the printed circuit board has an embedded busbar. The following claims claim various features and advantages.

Claims

1. A power tool, characterized in that, include: Electric motor; power supply; as well as A printed circuit board electrically connected to the motor and the power supply, the printed circuit board being mounted to the motor, the printed circuit board including a plurality of wide-bandgap semiconductor switches configured as an inverter for controlling the power supplied by the power supply to the motor.

2. The power tool according to claim 1, characterized in that, The motor includes a frame, wherein the printed circuit board is directly mounted to the frame.

3. The power tool according to claim 2, characterized in that, The motor is configured to act as a heat sink for the inverter.

4. The power tool according to claim 1, characterized in that, The device further includes a heat sink, wherein the printed circuit board is mounted to the heat sink, and the heat sink is mounted to the motor.

5. The power tool according to claim 4, characterized in that, The radiator is cooled by air.

6. The power tool according to claim 4, characterized in that, It further includes an input capacitor, wherein the input capacitor and the inverter are mounted on the same side of the printed circuit board.

7. The power tool according to claim 1, characterized in that, It further includes a heat sink connected to the motor.

8. The power tool according to claim 7, characterized in that, The heat sink is connected to a heat pipe, which in turn is connected to a radiator.

9. The power tool according to claim 8, characterized in that, The motor, the printed circuit board, and the heat sink are housed in a completely sealed structure.

10. The power tool according to claim 1, characterized in that, The printed circuit board includes at least one ceramic chip capacitor.

11. The power tool according to claim 1, characterized in that, The motor is configured to rotate at 75,000 revolutions per minute or higher.

12. The power tool according to claim 11, characterized in that, The motor is configured to rotate at 100,000 revolutions per minute or higher.

13. A power tool, characterized in that, include: Electric motor; Battery pack interface, configured to receive a battery pack; An inverter, electrically connected to the interface between the motor and the battery pack, includes a plurality of wide-bandgap semiconductor switches and is configured to control the power supplied by the battery pack to the motor. The band gap of the plurality of wide bandgap semiconductor switches is approximately 3 electron volts or more.

14. The power tool according to claim 13, characterized in that, The motor is configured to act as a heat sink for the inverter.

15. The power tool according to claim 13, characterized in that, Further includes: heat sink, The inverter is mounted to the motor via the heat sink.

16. The power tool according to claim 13, characterized in that, It further includes a heat sink connected to the motor.

17. A power tool, characterized in that, include: An electric motor configured to rotate at 75,000 revolutions per minute or higher; power supply; A printed circuit board, electrically connected to the motor and the power supply, the printed circuit board comprising: A plurality of wide-bandgap semiconductor switches are configured as inverters to control the power supplied by the power source to the motor.

18. The power tool according to claim 17, characterized in that, The motor includes a frame, wherein the printed circuit board is directly mounted to the frame.

19. The power tool according to claim 17, characterized in that, The device further includes a heat sink, wherein the printed circuit board is mounted to the heat sink, and the heat sink is mounted to the motor.

20. The power tool according to claim 17, characterized in that, It further includes a heat sink connected to the motor, wherein the heat sink is connected to a heat pipe, and the heat pipe is connected to a radiator.

21. The power tool according to claim 17, characterized in that, The printed circuit board includes at least one ceramic chip capacitor.

22. The power tool according to claim 17, characterized in that, The printed circuit board is mounted to the motor.

23. The power tool according to claim 17, characterized in that, The inverter is a five-level flying capacitor multilevel inverter.

Images