A brushless axial flow fan controller
By using current mirrors and current sources for current sampling and comparison in brushless motor controllers, the high power and heat problems caused by resistance sampling are solved, and overcurrent detection of low power and low heat is achieved.
Patent Information
- Application Number
- CN202421369100.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-14
- Publication Date
- 2025-04-11
- Estimated Expiration
- 2034-06-14
AI Technical Summary
The current flow to the brushless motor controller through resistive sampling of the current flow to the brushless motor has problems such as large power consumption and generating more thermal energy.
The first current mirror and the second current mirror are used to collect the current magnitude of the output of the PWM drive unit and compare it with the inverter to realize overcurrent detection.
Compared with the use of sampling resistors for detection, the power consumption is small and the heat production is low, which achieves effective overcurrent protection.
Smart Images
Figure CN222750343U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of brushless motor controllers, in particular to a brushless axial flow fan controller. Background Art
[0002] Brushless motors are gradually being used in new energy vehicles and drones due to their advantages such as high efficiency, strong overload capacity, large speed range, small size, stable operation and high power density. At present, the operation and drive of brushless motors are all completed through brushless motor controllers, which control the current flow direction of the brushless motor coils. Specifically, the brushless motor controller includes a control unit and a drive unit, and the control unit controls the power flow direction of the brushless motor coils through the drive unit.
[0003] When in use, the brushless motor controller needs to detect the current flowing to the brushless motor. When the current flowing to the brushless motor is too large, the brushless motor will be stopped from being powered, thereby achieving overcurrent protection. At present, the brushless motor controller sets a sampling resistor and detects the voltage across the sampling resistor to obtain the voltage drop on the sampling resistor. The current flowing to the brushless motor can be obtained by dividing the voltage drop by the resistance value of the sampling resistor. However, in actual use, sampling through the sampling resistor consumes a lot of power and generates a lot of heat, which is not conducive to actual use. Utility Model Content
[0004] In view of the shortcomings of the background technology, the utility model provides a brushless axial flow fan controller. The technical problem to be solved is that the current fan controller samples the current flowing to the brushless motor through a resistor, which has the problems of high power consumption and high heat generation.
[0005] In order to solve the above technical problems, the utility model provides the following technical solutions: a brushless axial flow fan controller, comprising a control unit 1 and a PWM drive unit 2, wherein the control unit is electrically connected to the PWM drive unit to adjust the output voltage of the PWM drive unit;
[0006] It also includes a first current mirror, a second current mirror, a current source and an inverter; the main branch of the first current mirror is electrically connected to the voltage output end of the PWM drive unit, the slave branch of the first current mirror is electrically connected to the main branch of the second current mirror, the slave branch of the second current mirror is electrically connected to the output end of the current source, the output end of the current source is electrically connected to the input end of the inverter, and the output end of the inverter is electrically connected to the control unit.
[0007] In some implementation manner, the main branch of the first current mirror includes a MOS transistor P20, and the slave branch of the first current mirror includes a MOS transistor P21;
[0008] The source of the MOS transistor P20 is electrically connected to the source of the MOS transistor P21 and the voltage output end of the PWM driving unit respectively, the gate of the MOS transistor P20 is electrically connected to the drain of the MOS transistor P20 and the gate of the MOS transistor P21 respectively, and the drain of the MOS transistor P21 is electrically connected to the main branch of the second current mirror.
[0009] In a certain implementation manner, both the MOS transistor P20 and the MOS transistor P21 are PMOS transistors.
[0010] In a certain embodiment, the main branch of the second current mirror includes a MOS transistor N20, and the slave branch of the second current mirror includes a MOS transistor N21. The drain of the MOS transistor N20 is electrically connected to the gate of the MOS transistor N20, the gate of the MOS transistor N21, and the drain of the MOS transistor P21, respectively. The drain of the MOS transistor N21 is electrically connected to the output end of the current source, and the sources of the MOS transistor N20 and the MOS transistor N21 are both grounded.
[0011] In some implementations, both the MOS transistor N20 and the MOS transistor N21 are NMOS transistors.
[0012] In a certain implementation manner, the current source includes a comparator CMP, a MOS transistor N10, a resistor R1, a MOS transistor P10, and a MOS transistor P11;
[0013] The positive input terminal of the comparator CMP is used to input a reference voltage VIN, the negative input terminal of the comparator CMP is electrically connected to one end of the resistor R1 and the drain of the MOS tube N10 respectively, the other end of the resistor R1 is grounded, the output terminal of the comparator CMP is electrically connected to the gate of the MOS tube N10, the drain of the MOS tube N10 is electrically connected to the drain of the MOS tube P10, the gate of the MOS tube P10 and the gate of the MOS tube P11 respectively, the source of the MOS tube P10 is electrically connected to the source of the MOS tube P11, and is used to access the power supply VCC, and the drain of the MOS tube P11 is electrically connected to the slave branch of the second current mirror.
[0014] In some implementations, the MOS transistor N10 is an NMOS transistor.
[0015] In some implementation manner, both the MOS transistor P11 and the MOS transistor P10 are PMOS transistors.
[0016] In some implementations, the control unit is a single chip microcomputer.
[0017] In a certain embodiment, the utility model further includes a digital-to-analog conversion unit, the control unit is electrically connected to the positive input terminal of the comparator through the digital-to-analog conversion unit, and the digital-to-analog conversion unit is controlled by the control unit to input a reference voltage VIN to the positive input terminal of the comparator CMP.
[0018] Compared with the prior art, the utility model has the following beneficial effects: the utility model collects the current output by the PWM drive unit through the first current mirror and the second current mirror, then compares the collected current with the current of the current source, and inverts the comparison result through the inverter, so that it can judge whether the collected current is greater than the current source current according to the output signal of the inverter, thereby realizing overcurrent detection, and compared with using a sampling resistor for detection, the utility model has low power consumption and low heat generation. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a schematic diagram of the structure of the utility model in the embodiment;
[0020] Figure 2 is a circuit diagram of a first current mirror and a second current mirror in an embodiment;
[0021] Figure 3 is a circuit diagram of a current source in an embodiment. DETAILED DESCRIPTION
[0022] Now the utility model is further described in detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the utility model in a schematic manner, and therefore only show the components related to the utility model.
[0023] like Figure 1 As shown, a brushless axial flow fan controller includes a control unit 1 and a PWM drive unit 2, wherein the control unit 1 is electrically connected to the PWM drive unit 2 to adjust the output voltage of the PWM drive unit 2;
[0024] It also includes a first current mirror 3, a second current mirror 4, a current source 5 and an inverter 6; the main branch of the first current mirror 3 is electrically connected to the voltage output end of the PWM drive unit 2, the slave branch of the first current mirror 3 is electrically connected to the main branch of the second current mirror 4, the slave branch of the second current mirror 4 is electrically connected to the output end of the current source 5, the output end of the current source 4 is electrically connected to the input end of the inverter 6, and the output end of the inverter 6 is electrically connected to the control unit 1.
[0025] In actual use, the utility model collects the current output by the PWM drive unit 2 through the first current mirror 3 and the second current mirror 4, and then compares the collected current with the current of the current source 5. The comparison result is inverted by the inverter 6, so that it can be judged whether the collected current is greater than the current source current based on the output signal of the inverter 6, thereby realizing overcurrent detection. Compared with the use of sampling resistors for detection, the utility model has low power consumption and low heat generation.
[0026] like Figure 2As shown, in this embodiment, the main branch of the first current mirror 3 includes a MOS transistor P20, and the slave branch of the first current mirror 3 includes a MOS transistor P21;
[0027] The source of the MOS transistor P20 is electrically connected to the source of the MOS transistor P21 and the voltage output end of the PWM driving unit 2 respectively, the gate of the MOS transistor P20 is electrically connected to the drain of the MOS transistor P20 and the gate of the MOS transistor P21 respectively, and the drain of the MOS transistor P21 is electrically connected to the main branch of the second current mirror 4.
[0028] In addition, both the MOS tube P20 and the MOS tube P21 are PMOS tubes.
[0029] like Figure 2 As shown, in this embodiment, the main branch of the second current mirror 4 includes a MOS transistor N20, and the slave branch of the second current mirror 4 includes a MOS transistor N21;
[0030] The drain of MOS transistor N20 is electrically connected to the gate of MOS transistor N20, the gate of MOS transistor N21 and the drain of MOS transistor P21 respectively. The drain of MOS transistor N21 is electrically connected to the output end of current source 5. The sources of MOS transistor N20 and MOS transistor N21 are both grounded.
[0031] In addition, in this embodiment, the MOS transistor N20 and the MOS transistor N21 are both NMOS transistors.
[0032] In this embodiment, the output current of the PWM driving unit 2 can be sampled by the first current mirror 3 and the second current mirror 4, and compared with the output current of the current source 5. In addition, the current sampling ratio can be adjusted by adjusting the ratio of the width-to-length ratio of the MOS transistor P20 to the MOS transistor P21 and adjusting the ratio of the width-to-length ratio of the MOS transistor N20 to the MOS transistor N21.
[0033] like Figure 3 As shown, in this embodiment, the current source 5 includes a comparator CMP, a MOS transistor N10, a resistor R1, a MOS transistor P10 and a MOS transistor P11;
[0034] The positive input terminal of the comparator CMP is used to input a reference voltage VIN, the negative input terminal of the comparator CMP is electrically connected to one end of the resistor R1 and the drain of the MOS transistor N10 respectively, the other end of the resistor R1 is grounded, the output terminal of the comparator CMP is electrically connected to the gate of the MOS transistor N10, the drain of the MOS transistor N10 is electrically connected to the drain of the MOS transistor P10, the gate of the MOS transistor P10 and the gate of the MOS transistor P11 respectively, the source of the MOS transistor P10 is electrically connected to the source of the MOS transistor P11, and is used to access the power supply VCC, and the drain of the MOS transistor P11 is electrically connected to the slave branch of the second current mirror 4.
[0035] In addition, in this embodiment, the MOS transistor N10 is an NMOS transistor.
[0036] In addition, in this embodiment, both the MOS transistor P11 and the MOS transistor P10 are PMOS transistors.
[0037] In this embodiment, the current output by the current source 5 is VIN*K / R1, where K is the current replication proportional coefficient of the third current mirror formed by the PMOS tube P11 and the PMOS tube P10, wherein the size of K can be adjusted by adjusting the ratio of the width-to-length ratio of the PMOS tube P11 and the PMOS tube P10.
[0038] In addition, in this embodiment, the control unit is a single chip microcomputer.
[0039] In addition, in this embodiment, the utility model further includes a digital-to-analog conversion unit, and the control unit 1 is electrically connected to the positive input terminal of the comparator through the digital-to-analog conversion unit. The digital-to-analog conversion unit is controlled by the control unit 1 to input a reference voltage VIN to the positive input terminal of the comparator CMP.
[0040] In actual use, the control unit 1 can adjust the magnitude of the reference voltage VIN through the digital-to-analog conversion unit, thereby adjusting the magnitude of the current output by the current source 5, so as to set different overcurrent comparison points.
[0041] The above is based on the enlightenment of this utility model. Through the above description, relevant staff can make various changes and modifications without deviating from the technical idea of this utility model. The technical scope of this utility model is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.
Claims
1. A brushless axial flow fan controller, comprising a control unit and a PWM drive unit, wherein the control unit is electrically connected to the PWM drive unit to adjust the output voltage of the PWM drive unit, characterized in that: It also includes a first current mirror, a second current mirror, a current source and an inverter; the main branch of the first current mirror is electrically connected to the voltage output end of the PWM drive unit, the slave branch of the first current mirror is electrically connected to the main branch of the second current mirror, the slave branch of the second current mirror is electrically connected to the output end of the current source, the output end of the current source is electrically connected to the input end of the inverter, and the output end of the inverter is electrically connected to the control unit.
2. A brushless axial flow fan controller according to claim 1, characterized in that: The main branch of the first current mirror includes a MOS transistor P20, and the slave branch of the first current mirror includes a MOS transistor P21; The source of the MOS transistor P20 is electrically connected to the source of the MOS transistor P21 and the voltage output end of the PWM driving unit respectively, the gate of the MOS transistor P20 is electrically connected to the drain of the MOS transistor P20 and the gate of the MOS transistor P21 respectively, and the drain of the MOS transistor P21 is electrically connected to the main branch of the second current mirror.
3. A brushless axial flow fan controller according to claim 2, characterized in that: Both the MOS tube P20 and the MOS tube P21 are PMOS tubes.
4. A brushless axial flow fan controller according to claim 2, characterized in that: The main branch of the second current mirror includes a MOS transistor N20, and the slave branch of the second current mirror includes a MOS transistor N21. The drain of the MOS transistor N20 is electrically connected to the gate of the MOS transistor N20, the gate of the MOS transistor N21, and the drain of the MOS transistor P21 respectively. The drain of the MOS transistor N21 is electrically connected to the output end of the current source, and the sources of the MOS transistor N20 and the MOS transistor N21 are both grounded.
5. A brushless axial flow fan controller according to claim 4, characterized in that: Both the MOS tube N20 and the MOS tube N21 are NMOS tubes.
6. A brushless axial flow fan controller according to claim 1, characterized in that: The current source includes a comparator CMP, a MOS tube N10, a resistor R1, a MOS tube P10 and a MOS tube P11; The positive input terminal of the comparator CMP is used to input a reference voltage VIN, the negative input terminal of the comparator CMP is electrically connected to one end of the resistor R1 and the drain of the MOS tube N10 respectively, the other end of the resistor R1 is grounded, the output terminal of the comparator CMP is electrically connected to the gate of the MOS tube N10, the drain of the MOS tube N10 is electrically connected to the drain of the MOS tube P10, the gate of the MOS tube P10 and the gate of the MOS tube P11 respectively, the source of the MOS tube P10 is electrically connected to the source of the MOS tube P11, and is used to access the power supply VCC, and the drain of the MOS tube P11 is electrically connected to the slave branch of the second current mirror.
7. A brushless axial flow fan controller according to claim 6, characterized in that: The MOS tube N10 is an NMOS tube.
8. A brushless axial flow fan controller according to claim 6, characterized in that: The MOS transistor P11 and the MOS transistor P10 are both PMOS transistors.
9. A brushless axial flow fan controller according to claim 6, characterized in that: The control unit is a single chip microcomputer.
10. A brushless axial flow fan controller according to claim 9, characterized in that: It also includes a digital-to-analog conversion unit, through which the control unit is electrically connected to the positive input terminal of the comparator, and the digital-to-analog conversion unit is controlled by the control unit to input a reference voltage VIN to the positive input terminal of the comparator CMP.