Fan circuit for servers

Abstract

This utility model discloses a fan circuit for a server, comprising: an MCU module, a high-voltage hot-swappable soft-switching circuit, a π-type filter circuit, a three-phase inverter bridge circuit, and a motor and bus overcurrent protection circuit. The input terminal of the high-voltage hot-swappable soft-switching circuit is connected to an external power supply. The output terminal of the high-voltage hot-swappable soft-switching circuit is connected to the input terminal of the π-type filter circuit, and the output terminal of the π-type filter circuit is connected to the power input terminal of the three-phase inverter bridge circuit. The upper bridge arm of the three-phase inverter bridge circuit is connected to the bridge arm control terminal of the MCU module, and the lower bridge arm of the three-phase inverter bridge circuit is connected to the input terminal of the motor. The voltage sampling output terminal of the motor is connected to the voltage sampling input terminal of the MCU module. The input terminal of the bus overcurrent protection circuit is connected to the bus current output terminal of the three-phase inverter bridge circuit, and the output terminal of the bus overcurrent protection circuit is connected to the bus current detection terminal of the MCU module. This utility model's fan circuit achieves high efficiency, energy saving, noise reduction, environmental protection, and high stability.

Description

Technical Field

[0001] This utility model relates to the field of server technology, and in particular to a fan circuit used in servers. Background Technology

[0002] With the widespread adoption of servers, server heat dissipation has become a major concern. Currently, one of the primary heat dissipation methods for servers is through fans. However, with the increasing market demands for energy conservation and environmental protection, the high stability, high efficiency, and energy saving of DC cooling fans have become the main market requirements.

[0003] For example, Chinese utility model patent CN 221779705 U discloses a cooling fan control circuit that solves the problems of high failure rate and poor stability of existing servo cooling fans. This utility model patent uses PWM-controlled fan cooling in an integrated servo motor system, reducing the size and weight of the heat sink on the rear cover of the motor. Controlled by an MCU control unit, it adjusts the fan speed according to different temperature environments, improving the servo motor's heat dissipation performance while effectively enhancing the stability of the cooling fan operation.

[0004] However, the aforementioned patented solutions still fail to address issues such as stability problems, high noise levels, and high heat loss during the fan startup phase. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a fan circuit for servers that achieves high efficiency, energy saving, noise reduction, environmental protection, and high stability.

[0006] A fan circuit for a server includes: an MCU module, a high-voltage hot-swap soft-switching circuit, a π-type filter circuit, a three-phase inverter bridge circuit, and a motor and bus overcurrent protection circuit. The input of the high-voltage hot-swap soft-switching circuit is connected to an external power supply. The output of the high-voltage hot-swap soft-switching circuit is connected to the input of the π-type filter circuit, and the output of the π-type filter circuit is connected to the power input of the three-phase inverter bridge circuit. The upper bridge arm of the three-phase inverter bridge circuit is connected to the bridge arm control terminal of the MCU module, and the lower bridge arm of the three-phase inverter bridge circuit is connected to the input of the motor. The voltage sampling output of the motor is connected to the voltage sampling input of the MCU module. The input of the bus overcurrent protection circuit is connected to the bus current output of the three-phase inverter bridge circuit, and the output of the bus overcurrent protection circuit is connected to the bus current detection terminal of the MCU module.

[0007] The MCU module integrates an 8051 core and a motor control engine.

[0008] In one embodiment, the high-voltage hot-swap soft-switching circuit includes: a first capacitor C1, a first resistor R1, and a first switching unit Q1. One end of the first capacitor C1 is connected to the external power supply, and the other end of the first capacitor C1 is grounded. The first resistor R1 and the first capacitor C1 are connected in parallel to form a parallel circuit unit. The output terminal of the parallel circuit unit is connected to the input terminal of the π-type filter circuit.

[0009] In one embodiment, the π-type filter circuit includes: a second capacitor C2, a third capacitor C3, and a first inductor L1; one end of the second capacitor C2 serves as the input terminal of the π-type filter circuit and is connected to the output terminal of the high-voltage hot-swap soft-switching circuit, and the other end of the second capacitor C2 is grounded; one end of the second capacitor C2 is also connected in series with the first inductor L1 and then connected to one end of the third capacitor C3, one end of the third capacitor C3 is also connected to an external power supply, and the other end of the third capacitor C3 is grounded; the connection node between the first inductor L1 and the third capacitor C3 serves as the output terminal of the π-type filter circuit and is connected to the power input terminal of the three-phase inverter bridge circuit.

[0010] In one embodiment, the fan circuit applied to the server further includes a back EMF isolation absorption circuit;

[0011] The input terminal of the back EMF isolation and absorption circuit is connected to the output terminal of the π-type filter circuit, and the output terminal of the back EMF isolation and absorption circuit is connected to the power input terminal of the three-phase inverter bridge circuit.

[0012] In one embodiment, the back EMF isolation and absorption circuit includes: a first diode unit D1, a fourth capacitor C4, and a first Zener diode ZD1; the positive terminal of the first diode unit D1 is connected to the output terminal of the π-type filter circuit as the input terminal of the back EMF isolation and absorption circuit; one end of the fourth capacitor C4 is connected to the negative terminal of the first diode unit D1, and the other end of the fourth capacitor C4 is grounded; the first Zener diode ZD1 is connected in parallel with the fourth capacitor C4, and the positive terminal of the first Zener diode ZD1 is grounded; the first Zener diode ZD1 is connected to the power input terminal of the three-phase inverter bridge circuit as the output terminal of the back EMF isolation and absorption circuit.

[0013] In one embodiment, the MCU module is an FU68 series microcontroller.

[0014] In one embodiment, the fan circuit applied to the server further includes a DC-DC buck converter, the input of which is connected to the output of a π-type filter circuit, and the output of which is connected to the power input of the MCU module.

[0015] In one embodiment, the fan circuit applied to the server further includes an over / under voltage detection circuit, the input of which is connected to the output of a π-type filter circuit, and the output of which is connected to the over / under voltage detection terminal of the MCU module.

[0016] In one embodiment, the fan circuit applied to the server further includes a dual-isolation protection PWM signal input circuit, the input terminal of which is externally connected to a PWM signal, and the output terminal of which is connected to the PWM control terminal of the MCU module.

[0017] In one embodiment, the fan circuit applied to the server further includes an FG isolation output circuit, wherein an FG signal is input to the input terminal of the FG isolation output circuit, and the output terminal of the FG isolation output circuit is connected to the isolation detection terminal of the MCU module.

[0018] This utility model's MCU module integrates an 8051 core and a motor control engine, and adopts a high-voltage hot-swappable soft-switching circuit and a π-type filter circuit; it achieves high-voltage, low-current operation to reduce heat loss, improve power efficiency, and achieve high efficiency, energy saving, noise reduction, and environmental protection; it also realizes electronic switching to eliminate instantaneous sparking and surge phenomena when the fan starts, resulting in high stability. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic block diagram of a fan circuit according to an embodiment of this application;

[0021] Figure 2 This is a vector control schematic diagram of a fan circuit shown in one embodiment of this application;

[0022] Figure 3 This is an overall schematic diagram of a fan circuit shown in one embodiment of this application;

[0023] Figure 4 This is a schematic diagram of a hot-swap soft-switching circuit, a π-type filter circuit, and a back EMF isolation and absorption circuit, as shown in an embodiment of this application.

[0024] Figure 5This is a schematic diagram of a dual-isolation protection PWM signal input circuit according to an embodiment of this application;

[0025] Figure 6 This is a schematic diagram of a DC-DC step-down circuit according to an embodiment of this application;

[0026] Figure 7 This is a schematic diagram of an over / under voltage detection circuit according to an embodiment of this application. Detailed Implementation

[0027] To facilitate understanding of this utility model, a more comprehensive description of it is provided below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of this utility model. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this utility model.

[0028] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] Please see Figure 1This embodiment discloses a fan circuit for a server, including: an MCU module, a high-voltage hot-swappable soft-switching circuit, a π-type filter circuit, a three-phase inverter bridge circuit, and a motor and bus overcurrent protection circuit. The input of the high-voltage hot-swappable soft-switching circuit is externally powered. The output of the high-voltage hot-swappable soft-switching circuit is connected to the input of the π-type filter circuit, the output of the π-type filter circuit is connected to the power input of the three-phase inverter bridge circuit, the upper bridge arm of the three-phase inverter bridge circuit is connected to the bridge arm control terminal of the MCU module, and the lower bridge arm of the three-phase inverter bridge circuit is connected to the input of the motor. The voltage sampling output of the motor is connected to the voltage sampling input of the MCU module. The input of the bus overcurrent protection circuit is connected to the bus current output of the three-phase inverter bridge circuit, and the output of the bus overcurrent protection circuit is connected to the bus current detection terminal of the MCU module. The MCU module integrates an 8051 core and a motor control engine. Specifically, the MCU module is an FU68 series microcontroller.

[0031] The MCU module of the fan circuit in this embodiment uses a chip integrating an 8051 core and a motor control engine, which can be applied to high-speed, high-power DC fan products. It employs a sensorless FOC control algorithm, significantly reducing fan noise and vibration and achieving precise commutation. Simultaneously, through the cooperation of a high-voltage hot-swappable soft-switching circuit and a π-type filter circuit, surges are eliminated while electronically delaying the switch, ensuring stable fan startup and operation. Furthermore, in this embodiment, the high-voltage hot-swappable soft-switching circuit isolates the instantaneous sparking phenomenon during front-end voltage contact under energized operation, providing fan switch protection. This invention also uses a bus overcurrent protection circuit to monitor the motor's bus current in real time and feed it back to the MCU module. The MCU module then controls and adjusts the motor's operating current, thereby achieving current loop control to eliminate the problem of starting current overshoot.

[0032] The FU68 series microcontrollers integrate a high-speed arithmetic unit, comparator, pre-driver, high-speed ADC, high-speed multiplier / divider, CRC / SPI, I2C, UART, various timers, PWM, and high-voltage LDO. Please refer to [link / reference]. Figure 2 The system control process of this utility model applied to the fan circuit of a server is as follows:

[0033] (1) Measure the three-phase stator current of the motor to obtain Ia and Ib; convert the three-phase current to two-phase currents Iα and Iβ through Clark.

[0034] (2) Based on the motor angle calculated in the previous iteration of the control loop, the mutually orthogonal currents Id and Iq in the rotating coordinate system are obtained by Park transformation.

[0035] (3) Adjust the parameters of the PI controller to obtain Vd and Vq, which are the voltage vectors to be applied to the motor.

[0036] (4) Input Vα, Vβ, Iα and Iβ, and the rotor position estimation method estimates the new motor angle and speed.

[0037] (5) By using the new motor angle, Vd and Vq are transformed to the two-phase stationary coordinate system via Park inverse transformation. This calculation will generate the next quadrature voltage values ​​Vα and Vβ. Then, the SVPWM algorithm is used to determine which magnetic region the synthesized voltage vector is located in, and the conduction time of each bridge arm switch of the three phases is calculated. Finally, the three-phase voltage required by the motor is output through the three-phase inverter drive module.

[0038] Please see Figure 3 and Figure 4 In this embodiment, the high-voltage hot-swap soft-switching circuit includes: a first capacitor C1, a first resistor R1, and a first switching unit Q1. One end of the first capacitor C1 is connected to an external power supply, and the other end of the first capacitor C1 is grounded. The first resistor R1 and the first capacitor C1 are connected in parallel to form a parallel circuit unit. The output terminal of the parallel circuit unit is connected to the input terminal of the π-type filter circuit.

[0039] Please see Figure 3 and Figure 4 In this embodiment, the π-type filter circuit includes: a second capacitor C2, a third capacitor C3, and a first inductor L1; one end of the second capacitor C2 serves as the input terminal of the π-type filter circuit and is connected to the output terminal of the high-voltage hot-swap soft-switching circuit, while the other end of the second capacitor C2 is grounded; one end of the second capacitor C2 is also connected in series with the first inductor L1 and then connected to one end of the third capacitor C3, one end of the third capacitor C3 is also connected to an external power supply, and the other end of the third capacitor C3 is grounded; the connection node between the first inductor L1 and the third capacitor C3 serves as the output terminal of the π-type filter circuit and is connected to the power input terminal of the three-phase inverter bridge circuit.

[0040] Please see Figure 1 In this embodiment, the fan circuit applied to the server also includes a back EMF isolation and absorption circuit; the input terminal of the back EMF isolation and absorption circuit is connected to the output terminal of the π-type filter circuit, and the output terminal of the back EMF isolation and absorption circuit is connected to the power input terminal of the three-phase inverter bridge circuit. The fan circuit in this embodiment achieves dual surge protection through a high-voltage hot-swap soft-switching circuit, a π-type filter circuit, and a back EMF isolation and absorption circuit, and also features reverse voltage access protection, resulting in high stability.

[0041] Please see Figure 3 and Figure 4In this embodiment, the back EMF isolation absorption circuit includes: a first diode unit D1, a fourth capacitor C4, and a first Zener diode ZD1; the positive terminal of the first diode unit D1 serves as the input terminal of the back EMF isolation absorption circuit and is connected to the output terminal of the π-type filter circuit; one end of the fourth capacitor C4 is connected to the negative terminal of the first diode unit D1, and the other end of the fourth capacitor C4 is grounded; the first Zener diode ZD1 is connected in parallel with the fourth capacitor C4, and the positive terminal of the first Zener diode ZD1 is grounded; the first Zener diode ZD1 serves as the output terminal of the back EMF isolation absorption circuit and is connected to the power input terminal of the three-phase inverter bridge circuit.

[0042] Please see Figure 3 and Figure 6 In this embodiment, the fan circuit applied to the server also includes a DC-DC step-down circuit. The input terminal of the DC-DC step-down circuit is connected to the output terminal of the π-type filter circuit, and the output terminal of the DC-DC step-down circuit is connected to the power input terminal of the MCU module.

[0043] Please see Figure 3 and Figure 7 In this embodiment, the fan circuit applied to the server also includes an over / under voltage detection circuit. The input terminal of the over / under voltage detection circuit is connected to the output terminal of the π-type filter circuit, and the output terminal of the over / under voltage detection circuit is connected to the over / under voltage detection terminal of the MCU module. By monitoring the input voltage, accurate over / under voltage protection of the output voltage is achieved. Specifically, the over / under voltage detection circuit includes: a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and a ninth capacitor C9; one end of the fourth resistor R4 serves as the input terminal of the over / under voltage detection circuit and is connected to the output terminal of the π-type filter circuit, and the other end of the fourth resistor R4 is connected to ground in series with the fifth resistor R5; one end of the sixth resistor R6 is connected to the node of the fourth resistor R4 and the fifth resistor R5, and the other end is connected to one end of the ninth capacitor C9, and the other end of the ninth capacitor C9 is grounded; one end of the ninth capacitor C9 serves as the output terminal of the over / under voltage detection circuit and is connected to the over / under voltage detection terminal of the MCU module.

[0044] Please see Figure 3 and Figure 5In this embodiment, the fan circuit applied to the server also includes a dual-isolation protection PWM signal input circuit. The input terminal of the dual-isolation protection PWM signal input circuit is connected to an external PWM signal, and the output terminal of the dual-isolation protection PWM signal input circuit is connected to the PWM control terminal of the MCU module. The PWM signal is isolated and protected through the dual-isolation protection PWM signal input circuit. The dual-isolation protection PWM signal input circuit includes: a second diode D2, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twenty-first resistor R21, a twenty-fifth resistor R25, and a second NMOS transistor Q2. The negative terminal of the second diode D2 is connected to the PWM signal, and the positive terminal is connected to one end of the ninth resistor R9. The other end of the ninth resistor R9 is connected to a 5V voltage. The positive terminal of the second diode D2 is also connected to one end of the tenth resistor R10. The other end of the tenth resistor R10 is grounded. The positive terminal of the second diode D2 is also connected to one end of the eleventh resistor R11. The other end of the eleventh resistor R11 is connected to the gate (G) of the second NMOS transistor Q2. The drain (D) of the second NMOS transistor Q2 is connected to a 5V voltage after being connected in series with the twenty-fifth resistor R25. The drain of the second NMOS transistor Q2 is connected in series with the twenty-first resistor R21 as the output terminal of the dual-isolation protection PWM signal input circuit and connected to the PWM control terminal of the MCU module. The source (S) terminal of the second NMOS transistor Q2 is grounded.

[0045] Please see Figure 3 In this embodiment, the fan circuit applied to the server also includes an FG isolation output circuit. The input terminal of the FG isolation output circuit receives an FG signal, and the output terminal of the FG isolation output circuit is connected to the isolation detection terminal of the MCU module.

[0046] This invention relates to a fan circuit design for servers that features high voltage and low current, compared to low voltage and high current. This design reduces heat loss and increases conversion efficiency on the same circuit for the same power. Furthermore, it reduces design costs for external use and reduces the amount of wires required for the same power, thus saving costs.

[0047] This utility model's fan circuit for servos provides bus overcurrent protection for the input current, as well as corresponding phase current overcurrent protection during motor operation and stall, achieving dual protection for both bus and phase current. For stall protection, the duty level, start-up, and waiting times can be set, enabling self-protection. During stall, a low duty level allows for small-current attempts and multiple starts.

[0048] The working principle of this utility model:

[0049] The input terminal of the high-voltage hot-swap soft-switching circuit is connected to the external power supply VCC. When the DC fan is turned on, the high-voltage hot-swap soft-switching circuit forms an electronic soft-open switch. The power supply VCC is then fed into the back EMF isolation absorption circuit after surge filtering by the π-type filter circuit. The back EMF isolation absorption circuit absorbs the back EMF of the power supply VCC and then inputs a stable supply voltage VIN to the three-phase inverter bridge circuit to start the motor. At the same time, the bus overcurrent protection circuit detects the bus current and feeds back the overcurrent signal to the MCU module for overcurrent processing. The over / undervoltage detection circuit detects the output voltage of the π-type filter circuit and feeds back the voltage signal to the MCU module for over / undervoltage processing. The dual-isolation protection PWM signal input circuit isolates and protects the input PWM signal before inputting it to the MCU module.

[0050] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A fan circuit for use in a server, characterized in that, include: The system includes an MCU module, a high-voltage hot-swap soft-switching circuit, a π-type filter circuit, a three-phase inverter bridge circuit, and a motor and bus overcurrent protection circuit. The input of the high-voltage hot-swap soft-switching circuit is connected to an external power supply. The output of the high-voltage hot-swap soft-switching circuit is connected to the input of the π-type filter circuit, and the output of the π-type filter circuit is connected to the power input of the three-phase inverter bridge circuit. The upper bridge arm of the three-phase inverter bridge circuit is connected to the bridge arm control terminal of the MCU module, and the lower bridge arm of the three-phase inverter bridge circuit is connected to the input of the motor. The voltage sampling output of the motor is connected to the voltage sampling input of the MCU module. The input of the bus overcurrent protection circuit is connected to the bus current output of the three-phase inverter bridge circuit, and the output of the bus overcurrent protection circuit is connected to the bus current detection terminal of the MCU module. The MCU module integrates an 8051 core and a motor control engine.

2. The fan circuit for a server according to claim 1, characterized in that, The high-voltage hot-swap soft-switching circuit includes: a first capacitor C1, a first resistor R1, and a first switching unit Q1. One end of the first capacitor C1 is connected to the external power supply, and the other end of the first capacitor C1 is grounded. The first resistor R1 and the first capacitor C1 are connected in parallel to form a parallel circuit unit. The output terminal of the parallel circuit unit is connected to the input terminal of the π-type filter circuit.

3. The fan circuit for a server according to claim 1, characterized in that, The π-type filter circuit includes: a second capacitor C2, a third capacitor C3, and a first inductor L1; one end of the second capacitor C2 serves as the input terminal of the π-type filter circuit and is connected to the output terminal of the high-voltage hot-swap soft-switching circuit, while the other end of the second capacitor C2 is grounded; one end of the second capacitor C2 is also connected in series with the first inductor L1 and then connected to one end of the third capacitor C3, one end of the third capacitor C3 is also connected to an external power supply, and the other end of the third capacitor C3 is grounded; the connection node between the first inductor L1 and the third capacitor C3 serves as the output terminal of the π-type filter circuit and is connected to the power input terminal of the three-phase inverter bridge circuit.

4. The fan circuit for a server according to claim 1, characterized in that, It also includes a back EMF isolation and absorption circuit; The input terminal of the back EMF isolation and absorption circuit is connected to the output terminal of the π-type filter circuit, and the output terminal of the back EMF isolation and absorption circuit is connected to the power input terminal of the three-phase inverter bridge circuit.

5. The fan circuit for a server according to claim 4, characterized in that, The back EMF isolation and absorption circuit includes: a first diode unit D1, a fourth capacitor C4, and a first Zener diode ZD1; the anode of the first diode unit D1 serves as the input terminal of the back EMF isolation and absorption circuit and is connected to the output terminal of the π-type filter circuit; one end of the fourth capacitor C4 is connected to the cathode of the first diode unit D1, and the other end of the fourth capacitor C4 is grounded; the first Zener diode ZD1 is connected in parallel with the fourth capacitor C4, and the anode of the first Zener diode ZD1 is grounded; the first Zener diode ZD1 serves as the output terminal of the back EMF isolation and absorption circuit and is connected to the power input terminal of the three-phase inverter bridge circuit.

6. The fan circuit for a server according to claim 1, characterized in that, The MCU module is a FU68 series microcontroller.

7. The fan circuit for a server according to claim 1, characterized in that, It also includes a DC-DC step-down circuit, the input of which is connected to the output of the π-type filter circuit, and the output of which is connected to the power input of the MCU module.

8. The fan circuit for a server according to claim 7, characterized in that, It also includes an over / under voltage detection circuit, the input of which is connected to the output of a π-type filter circuit, and the output of which is connected to the over / under voltage detection terminal of the MCU module.

9. The fan circuit for a server according to claim 1, characterized in that, It also includes a dual-isolation protection PWM signal input circuit, the input terminal of which is connected to an external PWM signal, and the output terminal of which is connected to the PWM control terminal of the MCU module.

10. The fan circuit for a server according to claim 1, characterized in that, It also includes an FG isolation output circuit, the input terminal of which receives an FG signal, and the output terminal of which is connected to the isolation detection terminal of the MCU module.

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