CN-122026573-A - Battery charger with hybrid flyback converter

Abstract

A battery charger has a housing including a battery interface for removably receiving a battery and a power input. The battery charger includes a hybrid flyback converter having a primary side including a DC-DC half-bridge and a secondary side including a synchronous rectifier. The hybrid flyback converter is electrically connected between the power supply input and the battery pack interface and is configured to provide charging power from the power supply input to the battery pack interface.

Inventors

• Nicholas S. Brooks
• Weiweike S. Nagar
• Paul C. Zhao

Assignees

• 米沃奇电动工具公司

Dates

Publication Date

20260512

Application Date

20251107

Priority Date

20241107

Claims (20)

1. 1. A battery charger comprising: A housing; A power supply input; a battery pack interface disposed on the housing and configured to removably receive a battery pack; A hybrid flyback converter having a primary side and a secondary side, the primary side including a DC-DC half-bridge, the secondary side including a synchronous rectifier electrically connected between the power input and the battery pack interface, the hybrid flyback converter configured to provide charging power from the power input to the battery pack interface, and A controller electrically connected to the hybrid flyback converter and configured to control an amount of power provided on the secondary side.
2. 2. The battery charger of claim 1, further comprising: an input rectifier electrically connected between the power supply input and the hybrid flyback converter, the input rectifier configured to convert AC power from the power supply input to DC power, wherein the DC power is provided to the hybrid flyback converter.
3. 3. The battery charger of claim 2, wherein the hybrid flyback converter comprises a plurality of switches, and wherein the controller is configured to control the plurality of switches to convert DC power between the power supply input and the battery interface.
4. 4. The battery charger of claim 3, further comprising a power factor correction boost converter electrically connected between the input rectifier and the DC-DC half-bridge of the hybrid flyback converter.
5. 5. The battery charger of claim 4, wherein the controller comprises a single controller for controlling the power factor correction boost converter and the hybrid flyback converter disposed on a single chip.
6. 6. The battery charger of claim 1, wherein the synchronous rectifier comprises at least one switch, wherein the at least one switch is a MOSFET.
7. 7. The battery charger of claim 1, further comprising a fan disposed within the housing and configured to cool electronics within the housing and/or within the battery.
8. 8. The battery charger of claim 7, further comprising: An AC current sensor disposed in a current path between the power input and the battery pack interface, and A fan control circuit electrically connected to the AC current sensor and configured to control the fan based on an AC current measured by the AC current sensor.
9. 9. The battery charger of claim 1, wherein the battery pack interface is a first type of battery pack interface configured to receive a first type of battery pack, further comprising a second type of battery pack interface disposed on the housing and configured to receive a second type of battery pack different from the first type of battery pack.
10. 10. The battery charger of claim 9, wherein the first type of battery has a nominal voltage of 18V and the second type of battery has a nominal voltage of 12V.
11. 11. The battery charger of claim 1, further comprising a plurality of battery interfaces on the housing, the plurality of battery interfaces being divided into groups, each group comprising at least two battery interfaces.
12. 12. The battery charger of claim 11, wherein the first group comprises a plurality of first type battery interfaces and the second group comprises a plurality of first type battery interfaces and a second type battery interface.
13. 13. The battery charger of claim 12, wherein only one battery pack at a time in each pack is charged.
14. 14. The battery charger of claim 1, wherein the total power output of the battery charger is 760 watts.
15. 15. A battery charger comprising: A housing including a battery pack interface configured to removably receive a battery pack; A power supply input; a power circuit electrically connected between the power input and the battery pack interface and configured to provide charging power from the power input to the battery pack interface; A fan disposed within the housing and proximate the battery pack interface; An AC current sensor electrically connected between the power supply input and an input of the power supply circuit, the AC current sensor configured to measure an AC current, and A fan control circuit electrically connected to the AC current sensor and the fan, the fan control circuit configured to control the fan based on the AC current.
16. 16. The battery charger of claim 15, wherein the fan control circuit is configured to activate the fan when the AC current exceeds a first threshold.
17. 17. The battery charger of claim 16, wherein the fan control circuit is configured to disable the fan when the AC current falls below a second threshold and the fan is enabled.
18. 18. The battery charger of claim 17, wherein the AC current is measured as a root mean square current, the first threshold is 2 amperes root mean square, and the second threshold is a hysteresis amount that is lower than the first threshold.
19. 19. A method of controlling a fan for a battery charger, the method comprising: Measuring a root mean square AC current with an AC current sensor electrically connected between a power input of the battery charger and a battery pack interface of the battery charger, the battery pack interface configured to removably receive a battery pack; Activating the fan when the root mean square AC current exceeds a first threshold value, and The fan is disabled when the root mean square AC current subsequently falls below a second threshold.
20. 20. The method of claim 19, wherein the second threshold is lower than the first threshold.

Description

Battery charger with hybrid flyback converter RELATED APPLICATIONS The present application claims priority from U.S. provisional patent application No. 63/717,541 filed on 7, 11, 2024, which is incorporated herein by reference in its entirety. Technical Field The present invention relates to a converter assembly, and more particularly to a hybrid flyback converter for a battery charger. Disclosure of Invention Some power tools operate using a battery pack as their primary power source. The type of battery pack used varies depending on the power requirements of the particular power tool. The use of a single charger capable of accommodating multiple battery types has advantages in terms of space efficiency, cost savings, and convenience. To support faster charging across various battery types, the system may need to increase the total current delivered. However, higher charging currents may lead to increased temperatures. The fan may be used to regulate the temperature of the charger and the electronics of the battery pack. In some aspects, the techniques described herein relate to a battery charger including a housing, a power input, a battery interface disposed on the housing and configured to removably receive a battery, a hybrid flyback converter (hybrid flyback converter, HFC) having a primary side including a DC-DC half-bridge and a secondary side including a synchronous rectifier electrically connected between the power input and the battery interface, the HFC configured to provide charging power from the power input to the battery interface, and a controller electrically connected to the HFC and configured to control the amount of power provided on the secondary side. In some aspects, the technology described herein relates to a battery charger comprising a housing including a battery pack interface configured to removably receive a battery pack, a power supply input, a power supply circuit electrically connected between the power supply input and the battery pack interface and configured to provide charging power from the power supply input to the battery pack interface, a fan disposed within the housing and proximate to the battery pack interface, an AC current sensor electrically connected between the power supply input and an input of the power supply circuit, the AC current sensor configured to measure AC current, and a fan control circuit electrically connected to the AC current sensor and the fan, the fan control circuit configured to control the fan based on the AC current. In some aspects, the described technology relates to a method of controlling a fan for a battery charger, the method comprising measuring a Root Mean Square (RMS) AC current with an AC current sensor electrically connected between a power input of the battery charger and a battery interface of the battery charger, the battery interface being configured to removably receive the battery, enabling the fan when the RMS AC current exceeds a first threshold, and disabling the fan when the RMS AC current subsequently falls below a second threshold. Drawings Fig. 1 illustrates an example battery charger according to some aspects of the present disclosure. Fig. 2 illustrates an example of a first type of battery pack that may be housed in the example battery charger of fig. 1, in accordance with some aspects of the present disclosure. Fig. 3 illustrates an example of a second type of battery pack that may be housed in the example battery pack charger of fig. 1, in accordance with some aspects of the present disclosure. Fig. 4 illustrates a block diagram of an example configuration of a battery charger, in accordance with some aspects of the present disclosure. Fig. 5 illustrates a main power circuit board assembly with a converter assembly in accordance with some aspects of the present disclosure. Fig. 6 illustrates a block diagram of the converter assembly from fig. 5, in accordance with some aspects of the present disclosure. Fig. 7 illustrates a schematic diagram of an exemplary DC-DC half-bridge for use in the converter assembly of fig. 6, in accordance with some aspects of the present disclosure. Fig. 8 illustrates a block diagram of a low power auxiliary rail (low power auxiliary rail) from the converter assembly of fig. 6, in accordance with some aspects of the present disclosure. Fig. 9 illustrates a block diagram of an example configuration of a battery charger with a fan in accordance with some aspects of the present disclosure. FIG. 10 illustrates a flow chart of a method for controlling the fan of FIG. 5 in accordance with aspects of the present disclosure. Fig. 11 illustrates a first set of configurations of the battery charger of fig. 1, in accordance with some aspects of the present disclosure. Fig. 12 illustrates a second set of configurations of the battery charger of fig. 1, in accordance with some aspects of the present disclosure. Fig. 13 illustrates a flow chart of a method of controlling a fan for the battery c