Claims:
1. A system comprising a cooling fan, said system configured to obtain a first feedback from NTC sensor of an insulated gate bipolar transistor (IGBT), a second feedback from current sensing circuit of the cooling fan, and a third feedback from a thermal switch placed on a heatsink, wherein said system is configured to issue a trip signal to the cooling fan if any of the first feedback, the second feedback, or the third feedback are indicative of a trip condition.
2. The system of claim 1, wherein the first feedback, the second feedback, or the third feedback are indicative of the trip condition when their value is true.
3. The system of claim 1, wherein when the trip signal is issued, power supply is isolated and cut-off from the cooling fan.
4. The system of claim 1, wherein the system further comprises a DSP that receives and processes the first feedback, the second feedback, and the third feedback.
5. The system of claim 1, wherein the system further comprises a hardware IGBT gate driver that issues the trip signal.
6. The system of claim 1, wherein said system is configured in a low voltage (LV) drive.
7. The system of claim 6, wherein the drive receives a stop command when the trip signal is issued, and wherein said stop command is issued by inhibition of inverter pulses.
8. The system of claim 6, wherein the drive further comprises a gate driver module that is operatively coupled with a motor that in turn drives a pump.
9. A method of protecting a cooling fan, said method comprising the steps of:
Obtaining a first feedback from NTC sensor of an insulated gate bipolar transistor (IGBT);
Obtaining a second feedback from current sensing circuit of the cooling fan;
Obtaining a third feedback from a thermal switch placed on a heatsink;
Issuing a trip signal to the cooling fan if any of the first feedback, the second feedback, or the third feedback are indicative of a trip condition.
10. The method of claim 9, wherein when the trip signal is issued, power supply is isolated and cut-off from the cooling fan
, Description:
TECHNICAL FIELD
[0001] The present disclosure generally relates to the field of failure protection of electrical devices. In particular, the present disclosure pertains to failure protection systems for cooling fans.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Cooling fans are typically used for thermal management of heat trapped in electrical/electronic devices such as in Low Voltage (LV) drives. Various electrical and electronic devices employ a cooling fan to cool heat generated by the devices when they operate. Such devices typically consist of information processors such as a computer, office automation (OA) appliances, home electronic appliances, electric power equipment, and so on. Typically, the motor shaft rotation rate and the cooling fan airflow rate are determined in consideration of the expected temperature of the device.As cooling fansare among the most vulnerable and critical parts in such devices, and can affect power handling capacity of the devices, if the fan fails, it tries to draw more current or trips/fails the power supply of the device/system which blocks switching of the inverter powering the motor-load system.
[0004] There is therefore a need for a protection system that solves the above-mentioned problem by isolating fan in case of fan fault and intimates control system regarding the same.
[0005] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[0006] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[0007] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0008] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0009] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.

OBJECTS OF THE INVENTION
[0010] A general object of the present disclosure is to enable efficient fan isolation and fan fault detection.
[0011] Another object of the present disclosure is to use a combination of hardware and software for fan and drive protection.
[0012] Another object of the present disclosure is to incorporate fan current sensing input along with thermal feedback to give a full proof arrangement for fan protection and enable isolation of the entire power supply from powering fan.

SUMMARY
[0013] The present disclosure generally relates to the field of failure protection of electrical devices. In particular, the present disclosure pertains to failure protection systems for cooling fans.
[0014] In an aspect, the present disclosure relates to a system comprising a cooling fan, said system configured to obtain a first feedback from NTC sensor of an insulated gate bipolar transistor (IGBT), a second feedback from current sensing circuit of the cooling fan, and a third feedback from a thermal switch placed on a heatsink, wherein said system is configured to issue a trip signal to the cooling fan if any of the first feedback, the second feedback, or the third feedback are indicative of a trip condition.
[0015] In an aspect, the first feedback, the second feedback, or the third feedback are indicative of the trip condition when their value is true. In another aspect, when the trip signal is issued, power supply can be isolated and cut-off from the cooling fan or the entire drive system can be shut down.
[0016] In another aspect, the system can further include a DSP that receives and processes the first feedback, the second feedback, and the third feedback, and further include a hardware IGBT gate driver that issues the trip signal.
[0017] In an aspect, the proposed system can be configured in a low voltage (LV) drive that can receive a stop command when the trip signal is issued, wherein the stop command can be issued by inhibition of inverter pulses. In an aspect, the drive can further include a gate driver module that can be operatively coupled with a motor that in turn can drive a pump.
[0018] The present disclosure further relates to a method of protecting a cooling fan, said method comprising the steps of: obtaining a first feedback from NTC sensor of an insulated gate bipolar transistor (IGBT);obtaining a second feedback from current sensing circuit of the cooling fan; obtaining a third feedback from a thermal switch placed on a heat sink; and issuing a trip signal to the cooling fan if any of the first feedback, the second feedback, or the third feedback are indicative of a trip condition.
[0019] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0021] FIG.1 illustrates an exemplary Low Voltage (LV) drive comprising a power supply and protection module in which aspects of the present disclosure can be implemented.
[0022] FIG. 2 illustrates exemplary constructional details of the proposed power supply and protection module in which aspects of the present disclosure can be implemented.

DETAILED DESCRIPTION
[0023] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0024] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0025] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0026] The present disclosure generally relates to the field of failure protection of electrical devices. In particular, the present disclosure pertains to failure protection systems for cooling fans.
[0027] In an aspect, the present disclosure relates to a system comprising a cooling fan, said system configured to obtain a first feedback from NTC sensor of an insulated gate bipolar transistor (IGBT), a second feedback from current sensing circuit of the cooling fan, and a third feedback from a thermal switch placed on a heatsink, wherein said system is configured to issue a trip signal to the cooling fan if any of the first feedback, the second feedback, or the third feedback are indicative of a trip condition.
[0028] In an aspect, the first feedback, the second feedback, or the third feedback are indicative of the trip condition when their value is true. In another aspect, when the trip signal is issued, power supply can be isolated and cut-off from the cooling fan.
[0029] In another aspect, the system can further include a DSP that receives and processes the first feedback, the second feedback, and the third feedback, and further include a hardware IGBT gate driver that issues the trip signal.
[0030] In an aspect, the proposed system can be configured in a low voltage (LV) drive that can receive a stop command when the trip signal is issued, wherein the stop command can be issued by inhibition of inverter pulses. In an aspect, the drive can further include a gate driver module that can be operatively coupled with a motor that in turn can drive a pump.
[0031] The present disclosure further relates to a method of protecting a cooling fan, said method comprising the steps of: obtaining a first feedback from NTC sensor of an insulated gate bipolar transistor (IGBT);obtaining a second feedback from current sensing circuit of the cooling fan; obtaining a third feedback from a thermal switch placed on a heat sink; and issuing a trip signal to the cooling fan if any of the first feedback, the second feedback, or the third feedback are indicative of a trip condition.
[0032] FIG. 1 illustrates an exemplary Low Voltage (LV) drive 100 comprising a power supply and protection module 110 in which aspects of the present disclosure can be implemented. As can be seen, drive 100 can include, in a non-limiting manner, a three phase inverter 102, a three phase rectifier 104, a control mechanism for motor control 106, a motor 114, an input grid 120, an induction motor load 116a and 116b, a solar panel 122, power supply and protection module 110, a pump 118 run by the motor 114,, and a gate driver module 108. As would be appreciated, although aspects of the present disclosure have been explained with respect to an LV drive coupled with a motor that is configured to drive a pump, such an architecture is completely exemplary in nature and any other application of the proposed power supply and protection module 110 can be implemented, all of which potential applications, configurations, and constructions are completely within the scope of the present disclosure. Any other application of the proposed LV drive that incorporates the , power supply and protection module 110 is therefore well within the scope of the present disclosure.
[0033] In an aspect, as can be seen drive 100 can incorporate or be operatively coupled with a cooling fan that can be used for thermal management of the heat trapped in the drive. In an aspect, speed of the cooling fan can be controlled as per the temperature of the heat sink. As cooling fan can be among the most vulnerable and critical parts in the drive layout, and can affect power handling capacity of the drive, if the fan fails, it tries to draw more current or trips/fails the power supply of the drive system which blocks switching of the inverter powering the motor-load system. The proposed power supply and protection module 110 is configured to solve the mentioned problem by isolating the fan in case of fan fault and intimate the control system regarding the same.
[0034] With reference to FIG. 2 that illustrates exemplary constructional details of the proposed power supply and protection module 110 in which aspects of the present disclosure can be implemented, it can be seen that the module 110, in an exemplary embodiment/construction, can include means (such as specific circuits) to take three feedbacks, a first feedback 202 from NTC sensor of an insulated gate bipolar transistor (IGBT), a second feedback 204 from current sensing circuit of the cooling fan, and a third feedback 206 from a thermal switch placed on a heat sink. Module 110 can further include an error handling circuit 208 which triggers a trip signal to the cooling fan 214 when any of the feedback units 202, 204, 206 give a positive/true signal, based on which power supply is isolated and cut-off from the cooling fan 214. In an embodiment, module 110 can further include a control mechanism (implemented for instance as a DSP)210 that receives and processes the first feedback, the second feedback, and the third feedback, and a hardware IGBT gate driver 212 (also referred to as fan driver 212) that issues the trip signal.
[0035] In an aspect, module 110 can either be configured in a low voltage (LV) drive or be operatively coupled thereto. Any other change in construction of the proposed module 110 and/or the drive 100 is completely within the scope of the present disclosure. In an aspect, the drive can be configured to receive a stop command when the trip signal is issued, wherein the stop command can be issued by inhibition of inverter pulses.
[0036] In an aspect, as mentioned above, circuit of the proposed module 110 can be configured to receive three types of feedbacks, namely IGBT internal NTC feedback, feedback from thermal switch placed on heatsink, and feedback from current sensing circuit of cooling fan, wherein the fan can be given a trip signal based on identifying the trip condition if any of the above mentioned three signals is true, based on which secondary of the power supply can be isolated and hence cut off from the cooling fan, which prevents any damage to the power supply and in turn protect the entire system.
[0037] In an aspect, trip signal is issued considering all the three conditions, which signal then goes to the DSP 210 as well as hardware IGBT gate driver 212, making the fan isolated along with issuing a stop command to the drive through inhibition of the inverter pulses and therefore the load will not be powered until the fan is serviced again with healthy condition or until the user disables fan fault protection failure from user interface. Thus, both hardware and software protection are provided in case of fault fan condition.
[0038] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[0039] The present disclosure enables efficient fan isolation and fan fault detection.
[0040] The present disclosure enables use of a combination of hardware and software for fan and drive protection.
[0041] The present disclosure enables incorporation of fan current sensing input along with thermal feedback to give a full proof arrangement for fan protection and enable isolation of the entire power supply from powering fan.