Cooling Fan Module

• US 20160208810A1
• Filed: 01/05/2016
• Published: 07/21/2016
• Est. Priority Date: 01/05/2015
• Status: Active Grant

• Current Assignee: Johnson Electric International AG (Johnson Electric Holdings Limited)
• Original Assignee: Johnson Electric SA 125 Rue de Progres La Chaux de Fonds Switzerland (Johnson Electric Holdings Limited)
• Inventors: YU, Long, ZHANG, Qiu Yang, TSE, Kwok Kuen, DONG, Jian, QIN, Rui Feng
• Granted Patent: US 10,753,365 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F04D 19/002 Axial flow fans
• CPC Class Codes: F04D 25/06 the pump being electrically driven F04D25/08 takes precedence
• CPC Class Codes: F04D 25/068 Mechanical details of the pump control unit pump control details F04D27/00
• CPC Class Codes: F04D 25/0693 Details or arrangements of the wiring
• CPC Class Codes: F04D 27/004 by varying driving speed
• CPC Class Codes: H02K 5/225 Terminal boxes or connection arrangements specially adapted for submersible motors H02K5/132
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A cooling fan module for a heat exchanger or the like, has a motor, a fan driven by the motor and a speed controller connected between the motor and a power supply. The speed controller is configured to operate the motor in a high speed mode and a low speed mode. The speed controller includes a high speed branch and a low speed branch connected in parallel. The low speed branch includes a pulse width modulation circuit configured to reduce an average voltage by a fixed duty ratio to achieve a low speed operation of the motor. By eliminating the conventional voltage dropping resistor, the speed controller reduces the power consumption, thus increasing the efficiency of the module, in the low speed mode of operation.

Claims

1. A cooling fan module comprising:

a motor, a fan driven by the motor and a speed controller connected in series between the motor and a power supply for the motor, wherein the speed controller comprises a high speed branch and a low speed branch which are connected in parallel, the low speed branch comprises a pulse width modulation circuit connected in series, and the pulse width modulation circuit is configured to reduce an average voltage by a fixed duty ratio to achieve a low speed operation of the motor.

2. The cooling fan module of claim 1, wherein the low speed branch further comprises a voltage modulation circuit connected in series, and the voltage modulation circuit is configured to disconnect the low speed branch via the pulse width modulation circuit where an input voltage is higher than a preset high voltage threshold or lower than a preset low voltage threshold.

3. The cooling fan module of claim 1, wherein the low speed branch further comprises a current protection circuit, the current protection circuit comprises a current measurement resistor and a switch circuit connected in series and the current protection circuit is configured to control the switch circuit to adjust the current to be within a preset current threshold via the pulse width modulation circuit, when a current flowing through the current measurement resistor is larger than the preset current threshold.

4. The cooling fan module of claim 3, wherein the switch circuit comprises a gate drive and a MOS transistor, an output signal of the pulse width modulation circuit is inputted to an input terminal of the gate drive and an output signal of the gate drive is inputted to the MOS transistor.

5. The cooling fan module of claim 1, wherein the low speed branch further comprises a temperature detection circuit configured to measure a temperature.

6. The cooling fan module of claim 1, wherein the speed controller comprises a printed circuit board supporting the pulse width modulation circuit.

7. The cooling fan module of claim 6, wherein the speed controller comprises a shell and a heat sink which are fitted together to form an outer shell of the speed controller, and the printed circuit board is installed inside the outer shell and heat is dissipated through the heat sink.

8. The cooling fan module of claim 7, wherein the heat sink comprises several fingers extending outwardly to increase heat dissipation.

9. The cooling fan module of claim 7, wherein inductors and capacitors are installed on the printed circuit board, the inductors and the capacitors protrude from the printed circuit board in a direction towards the heat sink, and the heat sink has a cavity to accommodate the inductors and the capacitors.

10. The cooling fan module of claim 9, wherein the heat sink comprises fingers extending outwardly from a back of the cavity to increase heat dissipation.

11. The cooling fan module of claim 7, wherein the low speed branch further comprises a voltage modulation circuit connected in series, and the voltage modulation circuit is configured to disconnect the low speed branch via the pulse width modulation circuit where an input voltage is higher than a preset high voltage threshold or lower than a preset low voltage threshold.

12. The cooling fan module of claim 11, wherein the low speed branch further comprises a current protection circuit, the current protection circuit comprises a current measurement resistor and a switch circuit connected in series and the current protection circuit is configured to control the switch circuit to adjust the current to be within a preset current threshold via the pulse width modulation circuit, when a current flowing through the current measurement resistor is larger than the preset current threshold.

13. The cooling fan module of claim 12, wherein the switch circuit comprises a gate drive and a MOS transistor, an output signal of the pulse width modulation circuit is inputted to an input terminal of the gate drive and an output signal of the gate drive is inputted to the MOS transistor.