Temperature Estimation and Control System, Method, and Apparatus for a Battery Pack Charger

Abstract

A battery pack charger includes a first circuit portion, a second circuit portion, an input voltage measurement circuit, a temperature measurement device, and a controller. The controller is configured to: measure an input voltage of the battery pack charger using the input voltage measurement circuit; measure a temperature of the second circuit portion using the temperature measurement device; and estimate a temperature of the first circuit portion based on the input voltage of the battery pack charger and the measured temperature of the second circuit portion. The controller is further configured to: perform control operations associated with the battery pack charger based on the estimated temperature of the first circuit portion.

Description

Technical Field

[0001] The present invention relates to a battery pack charger, a method of controlling the operation of a battery pack charger, and a charging circuit for a battery pack charger. Background Art

[0002] Electrical devices such as cordless power tools can be powered by rechargeable battery packs. The rechargeable battery packs can be charged in a compatible battery pack charger. Summary of the Invention

[0003] A battery pack charger for charging one or more battery packs includes: a first circuit portion for alternating current (“AC”) electrical or electronic components and a second circuit portion for direct current (“DC”) electrical or electronic components. The first circuit portion and the second circuit portion are separated or partitioned from each other within the housing of the battery pack charger. The first circuit portion includes a first heat sink or a first portion of a heat sink. The second circuit portion includes a second heat sink or a second portion of a heat sink. The first heat sink or the first portion of the heat sink is operable to dissipate heat from the AC electrical or electronic components in the first circuit portion. The second heat sink or the second portion of the heat sink is operable to dissipate heat from the DC electrical or electronic components in the second circuit portion.

[0004] The hottest part of the battery pack charger may be the first circuit portion, which includes AC electrical or electronic components. However, the temperature of the first circuit portion is not directly measured (e.g., using a thermistor). Instead, a temperature measuring device (e.g., a thermistor) is included in the second circuit portion, which includes DC electrical or electronic components. A controller within the battery pack charger measures the temperature of the second circuit portion using the temperature measuring device. The controller then estimates the temperature of the first circuit portion based on the measured temperature relative to the second circuit portion. However, the estimated temperature for the first circuit portion is affected by the input voltage of the first circuit portion (i.e., the AC input line voltage). Previously, the battery pack charger assumed an AC input line voltage of 120V AC, which would result in an incorrect temperature estimate if the value of the AC input line voltage was not 120V AC. To compensate for variations in the input voltage of the battery pack charger, the controller determines the estimated temperature of the first circuit portion based on the input voltage of the battery pack charger.

[0005] For example, the minimum input line voltage of the battery pack charger is about 85V AC. The expected input operating voltage of the battery pack charger is about 120V AC. The difference between the 120V AC input line voltage and the 85V AC input line voltage significantly affects the temperature of the first circuit portion of the battery pack charger. To account for or compensate for these variations in the input line voltage, the controller estimates the temperature of the first circuit portion based on both the measured temperature of the second circuit portion (e.g., using a thermistor) and the AC input line voltage.

[0006] The battery pack charger described herein includes a first circuit portion, a second circuit portion, an input voltage measurement circuit, a temperature measurement device, and a controller. The controller is configured to: measure the input voltage of the battery pack charger using the input voltage measurement circuit; measure the temperature of the second circuit portion using the temperature measurement device; and estimate the temperature of the first circuit portion based on the input voltage of the battery pack charger and the measured temperature of the second circuit portion. The controller is further configured to: select one of a plurality of relationships between the temperature of the second circuit portion and the temperature of the first circuit portion based on the input voltage of the battery pack charger to estimate the temperature of the first circuit portion. After estimating the temperature of the first circuit portion, one or more control operations associated with the charger may be performed (e.g., controlling a fan, turning off the charger, etc.).

[0007] In one aspect, there is provided a battery pack charger including a first circuit portion, a second circuit portion, an input voltage measurement circuit, a temperature measurement device, and a controller. The controller is configured to: measure the input voltage of the battery pack charger using the input voltage measurement circuit; measure the temperature of the second circuit portion using the temperature measurement device; estimate the temperature of the first circuit portion based on the input voltage of the battery pack charger and the measured temperature of the second circuit portion; and perform a control operation associated with the battery pack charger based on the estimated temperature of the first circuit portion.

[0008] Optionally, the battery pack charger further includes a fan.

[0009] Optionally, the control operation includes controlling the fan.

[0010] Optionally, the controller is further configured to: select one of a plurality of relationships between the temperature of the second circuit portion and the temperature of the first circuit portion based on the input voltage of the battery pack charger to estimate the temperature of the first circuit portion.

[0011] Optionally, the controller is further configured to: select the first of the plurality of relationships between the temperature of the second circuit portion and the temperature of the first circuit portion when the input voltage of the battery pack charger is less than a first voltage value.

[0012] Optionally, the first of the plurality of relationships is a scalar value proportional to the input voltage.

[0013] Optionally, the controller is further configured to: select the second of the plurality of relationships between the temperature of the second circuit portion and the temperature of the first circuit portion when the input voltage of the battery pack charger is greater than or equal to the first voltage value.

[0014] On the other hand, a method for controlling the operation of a battery pack charger is provided. The method includes: measuring the input voltage of the battery pack charger using an input voltage measurement circuit; measuring the temperature of a second circuit portion using a temperature measurement device; estimating the temperature of a first circuit portion based on the input voltage of the battery pack charger and the measured temperature of the second circuit portion; and performing a control operation associated with the battery pack charger based on the estimated temperature of the first circuit portion.

[0015] Optionally, controlling the operation of the battery pack charger includes controlling a fan.

[0016] Optionally, controlling the fan includes increasing the rotational speed of the fan or decreasing the rotational speed of the fan.

[0017] Optionally, the method further includes: selecting one of a plurality of relationships between the temperature of the second circuit portion and the temperature of the first circuit portion based on the input voltage of the battery pack charger to estimate the temperature of the first circuit portion.

[0018] Optionally, the method further includes: when the input voltage of the battery pack charger is less than a first voltage value, selecting a first one of the plurality of relationships between the temperature of the second circuit portion and the temperature of the first circuit portion.

[0019] Optionally, the first one of the plurality of relationships is a scalar value proportional to the input voltage.

[0020] Optionally, the method further includes: when the input voltage of the battery pack charger is greater than or equal to the first voltage value, selecting a second one of the plurality of relationships between the temperature of the second circuit portion and the temperature of the first circuit portion.

[0021] In yet another aspect, a charging circuit for a battery pack charger is provided, including a first circuit portion and a second circuit portion. The first circuit portion has an isolated power supply and a power input circuit. The power input circuit is configured to: receive a voltage from the isolated power supply and generate a DC voltage signal. The second circuit portion has a temperature measurement component and a control circuit. The temperature measurement component is configured to generate a signal related to the temperature of the second circuit portion. The control circuit is configured to: receive the DC voltage signal; receive the signal related to the temperature of the second circuit portion; estimate the temperature of the first circuit portion based on the DC voltage signal and the signal related to the temperature of the second circuit portion; and control an operation associated with the battery pack charger based on the estimated temperature of the first circuit portion.

[0022] Optionally, the first circuit portion further includes a diode bridge.

[0023] Optionally, the isolated power supply includes a primary winding and a secondary winding.

[0024] Optionally, the power input circuit includes: a diode connected to the secondary winding of the isolated power supply; a filter capacitor connected to the diode; and a voltage dividing circuit connected to the diode and the filter capacitor.

[0025] Optionally, the voltage divider circuit includes a first resistor and a second resistor.

[0026] Optionally, the DC voltage signal corresponds to the node between the first resistor and the second resistor.

[0027] Before explaining any embodiments in detail, it should be understood that the present invention and the application of the embodiments are not limited to the construction details and component arrangements set forth in the following description or shown in the drawings. The present invention and the embodiments can be practiced or implemented in various ways. Additionally, it should be understood that the terminology and terms used herein are for the purpose of description and should not be regarded as restrictive. The use of "comprising", "including" or "having" and their variations is intended to cover the items listed hereinafter and their equivalents as well as additional items. Unless otherwise stated or limited, the terms "mounted", "connected", "supported" and "coupled" and their variations are used in a broad sense and cover direct and indirect mounting, connection, support and coupling.

[0028] Furthermore, it should be understood that the embodiments can include hardware, software, and electronic components or modules. For the purpose of discussion, these hardware, software, and electronic components or modules can be shown and described as if most components are implemented only in hardware. However, those of ordinary skill in the art will recognize, based on a reading of this detailed description, that in at least one embodiment, the electronic aspects can be implemented in software (e.g., stored on a non-transitory computer-readable medium) that can be executed by one or more processing units (e.g., a microprocessor and / or an application-specific integrated circuit ("ASIC")). Therefore, it should be noted that the embodiments can be implemented using multiple hardware- and software-based devices and multiple different structural components. For example, the "server" and "computing device" described in the specification can include one or more processing units, one or more computer-readable medium modules, one or more input / output interfaces, and different connections (e.g., a system bus) that connect multiple components.

[0029] Other aspects of the embodiments will become apparent by considering the detailed description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1A is a perspective view of a battery pack charger according to an embodiment described herein.

[0031] Figure 1B is a perspective view of a battery pack charger according to an embodiment described herein.

[0032] Figure 2is according to an embodiment described herein Figure 1A and Figure 1B electromechanical diagram of a battery pack charger.

[0033] Figure 3 is according to an embodiment described herein for Figure 1A and Figure 1B electromechanical diagram of a controller of a battery pack charger.

[0034] Figure 4 is according to an embodiment described herein for Figure 1A and Figure 1B electrical schematic diagram of a power input circuit of a battery pack charger.

[0035] Figure 5 is according to an embodiment described herein for Figure 1A and Figure 1B temperature estimation and control process of a battery pack charger. DETAILED DESCRIPTION

[0036] The embodiments described herein provide systems, methods, and devices for estimating the temperature within a battery pack charger and controlling the battery pack charger based on the estimated temperature. The battery pack charger includes a first or AC circuit portion and a second or DC circuit portion. The controller of the battery pack charger is configured to: measure the input voltage to the battery pack charger using a power input circuit, measure the temperature of the second circuit portion using a thermistor, and estimate the temperature of the first circuit portion based on the input voltage to the battery pack charger and the measured temperature of the second circuit portion. The controller estimates the temperature of the first circuit portion by selecting one of a plurality of relationships or correlations between the temperature of the second circuit portion and the temperature of the first circuit portion. The controller selects one of the plurality of relationships or correlations based on the measured input voltage to the battery pack charger. After the controller estimates the temperature of the first circuit portion, the controller is configured to perform one or more control operations associated with the battery pack charger, such as controlling a fan, shutting down the battery pack charger, etc. By performing one or more control operations, the controller can maintain the battery pack charger at an appropriate operating temperature (i.e., an operating temperature between a predefined low temperature threshold [e.g., 40°F] and a predefined high temperature threshold [e.g., 105°F]).

[0037] Figure 1A Illustrates a battery pack charger or charger 100. The battery pack charger 100 includes a housing portion 105 and an alternating current (AC) input power plug 110. The battery pack charger 100 can be configured to charge one or more battery packs having one or more nominal voltage values. For example, Figure 1AThe battery pack charger 100 shown is configured to charge a first type of battery pack using the first battery pack receiving portion or interface 115 and to charge a second type of battery pack using the second battery pack receiving portion or interface 120. For example, the first type of battery pack is a 12V battery pack having a pole that inserts into the first battery pack receiving portion 115. For example, the second type of battery pack is an 18V battery pack having a plurality of rails for slidably attaching the battery pack to the second battery pack receiving portion 120.

[0038] Figure 1B A battery pack charger or charger 100B is shown. The battery pack charger 100 includes a housing portion 105. The battery pack charger 100B can be configured to charge a battery pack having one or more nominal voltage values. For example, Figure 1B The battery pack charger 100B shown is configured to charge a battery pack using the battery pack receiving portion or interface 115B. For example, the battery pack is an 80V battery pack having a plurality of rails for slidably attaching the battery pack to the battery pack receiving portion 115B.

[0039] The battery packs can each include a plurality of lithium-based battery cells having a chemical composition such as lithium cobalt (“Li-Co”), lithium manganese (“Li-Mn”), or Li-Mn spinel. In some embodiments, the battery cells have other suitable lithium or lithium-based chemistries, such as lithium-based chemistries including manganese, etc. The battery cells within each battery pack are operable to provide electrical power (e.g., voltage and current) to one or more power tools.

[0040] Figure 2 is an electromechanical diagram of the battery pack charger 100 or 100B. For illustrative purposes, the electromechanical diagram will be described with respect to the battery pack charger 100. Figure 2Shown is an input power electronic device and a controller or control circuit 200 for controlling the operation of a battery pack charger 100. In addition to the controller 200, the battery pack charger 100 further includes a power control module 205, a fan control module 210, a power input or input voltage measurement circuit module 215, a first heat sink 220, and a second heat sink 225 (e.g., a heat sink for power semiconductors). In some embodiments, the first heat sink 220 and the second heat sink 225 are combined into a single heat sink that is partially used to dissipate heat generated by DC components and partially used to dissipate heat generated by AC components. Associated with or in thermal communication with the first heat sink 220 are a first electrical or electronic component 230, a second electrical or electronic component 235, and a third electrical or electronic component 240. For example, the first, second, and third components 230, 235, and 240 may be switches, diodes, resistors, or another component associated with the first heat sink 220 that generates heat to be dissipated by the first heat sink 220. In other embodiments, more or fewer electrical or electronic components may be associated with or in thermal communication with the first heat sink 220, and providing three such components is for illustrative purposes only.

[0041] The charger 100 further includes a fan 245, a thermistor 250, a diode bridge 255, and an isolated power supply or isolated transformer 260. The diode bridge 255 and the isolated power supply or isolated transformer 260 are combined with, for example, a capacitor C1 and the power input circuit module 215 to form a power converter 265. The power converter 265, the first component 230, the second component 235, the third component 240, and the first heat sink 220 may generally be referred to as the first or AC circuit section. The controller 200, the power control module 205, the fan control module 210, the second heat sink 225, the thermistor 250, and the fan 245 may generally be referred to as the second or DC circuit section. The power converter 265 obtains an AC input line voltage from an AC input power plug 110 and converts the AC input line voltage into one or more safe, isolated DC voltages that can be used to power components within the battery pack charger 100.

[0042] For example, an AC input line voltage (assumed to be approximately sinusoidal) enters the power converter 265 and is rectified by the diode bridge 255 and filtered by the capacitor C1 to produce a DC bus voltage. The value of the DC bus voltage is equal to the root mean square (“RMS”) line voltage multiplied by the square root of 2, as shown in Equation 1 below:

[0043]

[0044] DC voltage V DCThen it is used by the isolated power supply 260 to generate one or more safe, isolated DC voltages that can be used to power electronic components within the battery pack charger 100. The isolated power supply 260 includes a transformer having a primary winding and a secondary winding. The voltage on the secondary winding of the transformer represents the magnitude of the voltage on the primary winding of the transformer, but is scaled by the turns ratio of the transformer, as shown in Equation 2 below:

[0045]

[0046] where N S is the number of turns of the secondary winding of the transformer, N P is the number of turns of the primary winding of the transformer, V PRI is the voltage of the primary winding, and V SEC is the voltage of the secondary winding. The relationship of Equation 2 enables the controller 200 to perform isolated line voltage measurements on the user side of the charger electronics (i.e., the DC circuit section).

[0047] The output voltage of the isolated power supply 260 or the power converter 265 can be provided to the controller 200 and used to power components such as the power control module 205, the fan control module 210, and the fan 245. The power control module 205 is configured to control the charging power provided to the first battery pack receiving portion 115 and the second battery pack receiving portion 120 to charge one or more battery packs. The fan control module 210 is electrically connected to the fan 245 to provide operating power and control to the fan 245.

[0048] Figure 3 The controller 200 is shown in more detail. The controller 200 is electrically connected and / or communicatively connected to various modules or components of the battery pack charger 100. For example, the illustrated controller 200 is connected to the first and second battery pack portions or interfaces 115, 120 through the power control module 205, the indicators 125, 130, the fan control module 210, the power input circuit 215, and the thermistor 250. The controller 200 includes a combination of hardware and software that is operable to control the operation of the battery pack charger 100, activate the indicators 125, 130 (e.g., one or more LEDs), estimate the temperature of the first heat sink 220, measure the temperature of the second heat sink 225, etc.

[0049] In some embodiments, controller 200 includes a plurality of electrical and electronic components that provide power, operation control, and protection to components and modules within controller 200 and / or battery pack charger 100. For example, controller 200 includes a processing unit 300 (e.g., an electronic processor, microprocessor, microcontroller, or other suitable programmable device), a memory 305, an input unit 310, an output unit 315, and the like. Processing unit 300 includes a control unit 320, an arithmetic logic unit (ALU) 325, and a plurality of registers 330 (shown as a set of registers in Figure 3 ), and is implemented using a known computer architecture (e.g., a modified Harvard architecture, von Neumann architecture, etc.). Processing unit 300, memory 305, input unit 310, output unit 315, and a plurality of modules connected to controller 200 are connected by one or more control and / or data buses (e.g., common bus 335). For illustrative purposes, the control and / or data bus is generally shown in Figure 3 . Referring to the invention described herein, those skilled in the art will know how to use one or more control and / or data buses for the interconnection and communication between various modules and components.

[0050] Memory 305 is a non-transitory computer-readable medium and includes, for example, a program storage area and a data storage area. The program storage area and the data storage area may include a combination of different types of memories, such as ROM, RAM (e.g., DRAM, SDRAM, etc.), EEPROM, flash memory, hard disk, SD card, or other suitable magnetic, optical, physical, or electronic storage devices. Processing unit 300 is connected to memory 305 and executes software instructions that can be stored in the RAM of memory 305 (e.g., during execution), in the ROM of memory 305 (e.g., on a substantially permanent basis), or in another non-transitory computer-readable medium (e.g., another memory or optical disc). The software included in the implementation of battery pack charger 100 may be stored in the memory 305 of controller 200. The software includes, for example, firmware, one or more application programs, program data, filters, rules, one or more program modules, and other executable instructions. Controller 200 is configured to retrieve and execute instructions related to the control processes and methods described herein from memory 305. In other configurations, controller 200 includes more, fewer, or different components.

[0051] The battery pack interfaces 115, 120 include a combination of mechanical and electrical components that are configured and operable to facilitate docking (e.g., mechanically, electrically, and communicatively connecting) of the battery pack charger 100 with the battery pack. For example, the battery pack interfaces 115, 120 are configured to receive power from the power control module 205 via the power line 340 between the power control module 205 and the battery pack interfaces 115, 120. The battery pack interfaces 115, 120 are also configured to communicatively connect to the power control module 205 via the communication line 345.

[0052] The controller 200 uses the thermistor 250 to measure the temperature associated with the DC circuit portion and the second heat sink 225, which is proportional to the output of the power converter 265. Based on the measured temperature of the DC circuit portion, the controller 200 estimates the temperature of the AC circuit portion and the first heat sink 220. The thermal relationship or gradient between the temperature measured by the thermistor 250 and other components of the battery pack charger 100 can be stored in the memory 305 of the controller 200. Thus, the temperature measured by the thermistor 250 can be used as an observation to estimate the temperature of other components of the battery pack charger 100. For example, the losses in the input portion of the power converter 265 are typically inversely proportional to the input voltage of the power converter 265. Without knowing the actual input voltage of the power converter 265, the thermal relationship between the temperature measured by the thermistor 250 and the power converter 265 (i.e., the AC circuit portion) may be invalid. By determining the input voltage of the power converter 265 (i.e., the AC input line voltage of the battery pack charger 100), the controller 200 can select the appropriate thermal relationship between the temperature measured by the thermistor 250 and the power converter 265 to determine the temperature of the AC circuit portion and the first heat sink 220.

[0053] After determining the temperature of the AC circuit portion and the first heat sink 220, the controller 200 provides information and / or control signals to the fan control module 210 to drive the fan 245. Driving the fan 245 includes starting the fan 245, stopping the fan 245, increasing the speed of the fan 245, decreasing the speed of the fan, etc. The fan 245 is driven to maintain the desired operating conditions of the battery pack charger 100. In some embodiments, the fan 245 is operated to maintain the temperature (e.g., the internal ambient temperature) of the battery pack charger 100 within a desired temperature range (e.g., between 40°F and 105°F). In other embodiments, the fan 245 is operated to maintain the temperature (e.g., the internal ambient temperature) of the battery pack charger 100 at a specific temperature (e.g., 85°F).

[0054] Figure 4Shown is a power input circuit 215 for converting the voltage from the secondary winding of an isolated power supply 260 into a DC voltage signal that can be used by a controller 200 to estimate the temperature of the AC circuit portion and a first heat sink 220. In some embodiments, the power input circuit 215 is connected in parallel with and taps from the output of the secondary winding of the isolated power supply 260. Thus, the power input circuit 215 can be used to determine the AC input line voltage, while the main output from the isolated power supply 260 can be used to provide a higher voltage (e.g., 15 VDC) for powering other components of the battery pack charger 100. The power input circuit 215 includes a diode D1 that is used to rectify the AC voltage from the secondary winding of the isolated power supply 260 into a DC voltage. The power input circuit 215 also includes a filter capacitor C2, an input resistor R1, a lower resistor R2, a bias resistor R3, and a DC reference voltage V DC .

[0055] The diode D1 is connected to the secondary winding of the isolated power supply 260. In some embodiments, the anode of the diode D1 is connected to the secondary winding of the isolated power supply 260. In other embodiments, the cathode of the diode D1 is connected to the secondary winding of the isolated power supply 260. Depending on the configuration of the diode D1, the positive or negative peak of the voltage of the secondary winding can be captured. The output of the diode D1 is applied across the filter capacitor C2. The filter capacitor C2 holds the peak voltage of the secondary winding by filtering and smoothing the output of the diode D1. The filtered voltage is then scaled down by a voltage divider circuit formed by the input resistor R1 and the lower resistor R2. The bias resistor R3 is used to provide a DC bias voltage V DC , the DC bias voltage V DC is added to or subtracted from a node 400 formed at the intersection of the input resistor R1, the lower resistor R2, and the bias resistor R3. The net voltage at the node 400 formed at the intersection of the input resistor R1, the lower resistor R2, and the bias resistor R3 is then represented as a DC voltage value between 0 VDC and 3 VDC. The voltage at the node 400 is provided to the controller 200 as a representation of the magnitude of the AC input line voltage to the battery pack charger 100. The controller 200 is configured to convert the voltage received from the node 400 into a value for the AC input line voltage. For example, in some embodiments, the controller can use a look-up table stored in a memory 305 that correlates the voltage of the node 400 with the AC input line voltage. In other embodiments, the controller 200 uses the values of the resistors R1, R2, and R3, the value of the reference voltage V DC , the VDC, and equations 1 and 2 to calculate a value for the AC input line voltage. In some embodiments, the controller 200 does not determine the actual value for the AC input line voltage. Instead, the controller 200 uses the voltage value measured at the node 400 to select an appropriate thermal relationship or correlation.

[0056] Figure 5 It is related to a process 500 of estimating the temperature of the AC circuit part and the first radiator 220 based on the measured temperature associated with the DC circuit part and the second radiator 225 and the AC input line voltage to the battery pack charger 100. At step 505, the controller 200 determines the temperature of the first circuit part (e.g., the DC circuit part and the second radiator 225) based on the output signal from a temperature sensor (such as the thermistor 250). After the controller 200 determines the temperature of the first circuit part, the controller 200 determines the AC input line voltage to the battery pack charger 100 (step 510). As described above regarding Figure 4 As described, the controller 200 can determine the AC input line voltage based on the value of the voltage measured at the node 400 of the power input circuit 215. For example, the voltage at the node 400 has a value between 0 VDC and 3 VDC. Based on the voltage value measured at the node 400, the controller 200 calculates or looks up (e.g., using a look-up table stored in the memory 305) the corresponding value of the AC input line voltage. In some embodiments, the controller 200 does not determine the actual value of the AC input line voltage. Instead, the controller uses the voltage value measured at the node 400 to select an appropriate thermal relationship or correlation. Whether the controller 200 determines the actual value of the AC input line voltage or uses the voltage value measured at the node 400, the voltage value used by the controller 200 to select the thermal relationship or correlation between the first circuit part and the second circuit part can be referred to as the input voltage value V IN .

[0057] At step 515, the input voltage V of the battery pack charger 100 IN is compared with a first voltage value V1 and a second voltage value V2. If the input voltage V of the battery pack charger 100 IN is greater than or equal to the first voltage value V1 and less than the second voltage value V2, then the controller 200 selects a first thermal relationship or correlation between the first circuit part and the second circuit part (step 520). The first thermal relationship or correlation corresponds to a first set of thermal data that can be stored in the memory 305 of the controller 200. For example, the thermal relationship or correlation between the first circuit part and the second circuit part is a scalar value that is proportional to the input voltage V IN . The determined temperature of the first circuit part can be multiplied by this scalar value to estimate the temperature of the second circuit part. When the input voltage V IN has a lower value, the estimated temperature of the second circuit part can have a proportionally lower value. As the input voltage V IN increases, the estimated temperature of the second circuit part also increases.

[0058] Refer again to Figure 5 and step 515. If the input voltage V IN is greater than or equal to the second voltage value V2, the controller 200 compares the input voltage V IN with the second voltage value V2 and the third voltage value V3 (step 525). If the input voltage V of the battery pack charger 100 IN is greater than or equal to the second voltage value V2 and less than the third voltage value V3, the controller 200 selects a second thermal relationship or correlation between the first circuit portion and the second circuit portion (step 530). The second thermal relationship or correlation corresponds to a second set of thermal data that can be stored in the memory 305 of the controller 200.

[0059] If in step 525 the input voltage V IN is greater than or equal to the third voltage value V3, the controller 200 compares the input voltage V IN with the third voltage value V3 and the fourth voltage value V4 (step 535). If the input voltage V of the battery pack charger 100 IN is greater than or equal to the third voltage value V3 and less than the fourth voltage value V4, the controller 200 selects a third thermal relationship or correlation between the first circuit portion and the second circuit portion (step 540). The third thermal relationship or correlation corresponds to a third set of thermal data that can be stored in the memory 305 of the controller 200. If in step 535, the input voltage V IN is greater than or equal to the fourth voltage value V4, the controller 200 selects a fourth thermal relationship or correlation between the first circuit portion and the second circuit portion (step 545). The fourth thermal relationship or correlation corresponds to a fourth set of thermal data that can be stored in the memory 305 of the controller 200.

[0060] After the controller 200 has selected a set of hot data in one of steps 520, 530, 540, or 545, the controller 200 uses the selected set of hot data to estimate the temperature of the second circuit portion (e.g., the AC circuit portion) (step 550). After the controller 200 has estimated the temperature of the second circuit portion, the controller 200 operates the battery pack charger 100 based on the estimated temperature of the second circuit portion (step 555). For example, the controller 200 may perform one or more control operations on the battery pack charger 100, including turning off the battery pack charger 100, starting the fan 245, turning off the fan 245, increasing the rotational speed of the fan 245, decreasing the rotational speed of the fan, etc. By performing one or more control operations, the controller 200 is able to maintain an appropriate operating temperature for the battery pack charger 100 (i.e., an operating temperature between a given low temperature threshold [e.g., 40°F] and a given high temperature threshold [e.g., 105°F]). In some embodiments, operating the battery pack charger 100 includes activating the indicators 125, 130 to indicate a temperature fault condition of the battery pack charger 100 (e.g., causing the indicators 125, 130 to blink).

[0061] Accordingly, the embodiments described herein provide a battery charger that includes a controller for estimating the temperature of an AC circuit portion based on a measured AC input line voltage and a measured temperature of a DC circuit portion. Various features and advantages are set forth in the claims.

Claims

1. A battery pack charger, comprising: A first circuit portion; A second circuit portion; An input voltage measurement circuit; A temperature measurement device; And A controller configured to: Measure the input voltage of the battery pack charger using the input voltage measurement circuit; Measure the temperature of the second circuit portion using the temperature measurement device; Estimate the temperature of the first circuit portion based on the input voltage of the battery pack charger and the measured temperature of the second circuit portion; And Perform control operations associated with the battery pack charger based on the estimated temperature of the first circuit portion.

2. The battery pack charger according to claim 1, further comprising a fan.

3. The battery pack charger according to claim 2, wherein, The control operation includes controlling the fan.

4. The battery pack charger according to claim 1, wherein, The controller is further configured to: Select one of a plurality of relationships between the temperature of the second circuit portion and the temperature of the first circuit portion based on the input voltage of the battery pack charger to estimate the temperature of the first circuit portion.

5. The battery pack charger according to claim 4, wherein, The controller is further configured to: When the input voltage of the battery pack charger is less than a first voltage value, select a first one of the plurality of relationships between the temperature of the second circuit portion and the temperature of the first circuit portion.

6. The battery pack charger according to claim 5, wherein, The first one of the plurality of relationships is a scalar value proportional to the input voltage.

7. The battery pack charger according to claim 6, wherein, The controller is further configured to: When the input voltage of the battery pack charger is greater than or equal to the first voltage value, select a second one of the plurality of relationships between the temperature of the second circuit portion and the temperature of the first circuit portion.

8. A method for controlling the operation of a battery pack charger, the method comprising: Measuring the input voltage of the battery pack charger using an input voltage measurement circuit; Measuring the temperature of a second circuit portion using a temperature measurement device; Estimating the temperature of a first circuit portion based on the input voltage of the battery pack charger and the measured temperature of the second circuit portion; And Controlling the operation of the battery pack charger based on the estimated temperature of the first circuit portion.

9. The method according to claim 8, wherein, Controlling the operation of the battery pack charger includes controlling a fan.

10. The method according to claim 9, wherein, Controlling the fan includes increasing the rotational speed of the fan or decreasing the rotational speed of the fan.

11. The method according to claim 8, further comprising: Selecting one of a plurality of relationships between the temperature of the second circuit portion and the temperature of the first circuit portion based on the input voltage of the battery pack charger to estimate the temperature of the first circuit portion.

12. The method according to claim 11, further comprising: When the input voltage of the battery pack charger is less than a first voltage value, selecting a first one of the plurality of relationships between the temperature of the second circuit portion and the temperature of the first circuit portion.

13. The method according to claim 12, wherein, The first one of the plurality of relationships is a scalar value proportional to the input voltage.

14. The method according to claim 13, further comprising: When the input voltage of the battery pack charger is greater than or equal to the first voltage value, selecting a second one of the plurality of relationships between the temperature of the second circuit portion and the temperature of the first circuit portion.

15. A charging circuit for a battery pack charger, comprising: A first circuit portion having: An isolated power supply, and A power input circuit configured to: Receive a voltage from the isolated power supply, and Generate a DC voltage signal; And A second circuit portion having: A temperature measurement component configured to generate a signal related to the temperature of the second circuit portion, and a control circuit configured to: Receive the DC voltage signal; Receive the signal related to the temperature of the second circuit portion; Estimate the temperature of the first circuit portion based on the DC voltage signal and the signal related to the temperature of the second circuit portion; And Control operations associated with the battery pack charger based on the estimated temperature of the first circuit portion.

16. The charging circuit according to claim 15, wherein, The first circuit portion further includes a diode bridge.

17. The charging circuit according to claim 15, wherein, The isolated power supply includes a primary winding and a secondary winding.

18. The charging circuit according to claim 17, wherein, The power input circuit includes: A diode connected to the secondary winding of the isolated power supply; A filter capacitor connected to the diode; and A voltage dividing circuit connected to the diode and the filter capacitor.

19. The charging circuit according to claim 18, wherein, The voltage dividing circuit includes a first resistor and a second resistor.

20. The charging circuit according to claim 19, wherein The DC voltage signal corresponds to a node between the first resistor and the second resistor.

Images