CN110940905A - MOSFET internal resistance detection circuit and method for detecting temperature of MOSFET by using same - Google Patents
MOSFET internal resistance detection circuit and method for detecting temperature of MOSFET by using same Download PDFInfo
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- CN110940905A CN110940905A CN201911281413.0A CN201911281413A CN110940905A CN 110940905 A CN110940905 A CN 110940905A CN 201911281413 A CN201911281413 A CN 201911281413A CN 110940905 A CN110940905 A CN 110940905A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/26—Testing of individual semiconductor devices
- G01R31/2607—Circuits therefor
- G01R31/2621—Circuits therefor for testing field effect transistors, i.e. FET's
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/14—Measuring resistance by measuring current or voltage obtained from a reference source
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/26—Testing of individual semiconductor devices
- G01R31/2607—Circuits therefor
- G01R31/2621—Circuits therefor for testing field effect transistors, i.e. FET's
- G01R31/2628—Circuits therefor for testing field effect transistors, i.e. FET's for measuring thermal properties thereof
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- Measurement Of Current Or Voltage (AREA)
Abstract
The invention relates to the technical field of circuit detection, in particular to a MOSFET (metal-oxide-semiconductor field effect transistor) internal resistance detection circuit and a method for detecting the temperature of an MOSFET by using the MOSFET internal resistance change detection circuit. A MOSFET internal resistance detection circuit comprises a detection circuit and a bus sampling resistance voltage division sampling circuit, wherein the detection circuit is arranged in a motor controller, and is used for measuring bus sampling resistance voltage division; the MOSFET internal resistance voltage division sampling circuit is used for measuring the internal resistance voltage division of the MOSFET; and calculating the internal resistance of the MOSFET by using ohm's law according to the measured voltage division of the bus sampling resistor and the measured voltage division of the internal resistance of the MOSFET. The invention implants two algorithms in the software of the motor controller, an algorithm for reconstructing the phase current of the motor by utilizing the bus current and an algorithm for detecting the phase current of the motor by utilizing the partial pressure of the MOSFET, and the phase current value obtained from the internal resistance of the MOSFET is different from the phase current value obtained from the bus sampling resistor under different temperature conditions. The junction temperature of the current MOSFET can be obtained according to the proportional relation of the feedback voltages of the current MOSFET and the current MOSFET.
Description
Technical Field
The invention relates to the technical field of circuit detection, in particular to a MOSFET (metal-oxide-semiconductor field effect transistor) internal resistance detection circuit and a method for detecting the temperature of an MOSFET by using the MOSFET internal resistance change detection circuit.
Background
The internal resistance value of the MOSFET has the characteristic of changing along with the temperature, so that the phase current value obtained from the internal resistance of the MOSFET is different from the phase current value obtained from the bus sampling resistor under different temperature conditions.
In the prior art, a detection method for a MOSFET of a motor controller generally adopts a mode that a temperature sensor is placed near or inside the MOSFET, the temperature of the MOSFET is sensed through heat conduction, and the temperature sensor converts a temperature signal into an electric signal and transmits the electric signal to a user so as to measure the temperature of the position. However, the detection method of the motor controller MOSFET in the prior art has the following problems that the detection method is greatly influenced by the placement position of the sensor, and the temperature information of the whole MOSFET cannot be acquired.
Disclosure of Invention
The invention aims to provide a MOSFET internal resistance detection circuit built in a motor controller, which tests the temperature change of the MOSFET through the internal resistance change of the MOSFET. In order to realize the purpose, the invention provides the following technical scheme:
a MOSFET internal resistance detection circuit comprises a detection circuit arranged in a motor controller, wherein the detection circuit comprises a bus sampling resistance voltage division sampling circuit for measuring bus sampling resistance voltage division; the MOSFET internal resistance voltage division sampling circuit is used for measuring the internal resistance voltage division of the MOSFET; and the MOSFET internal resistance calculation circuit is used for calculating the MOSFET internal resistance.
Further, the bus sampling resistor voltage division sampling circuit comprises a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R3 and a resistor R4 which are connected in series, a resistor R5 and a resistor R6 which are connected in series, two groups of resistors which are connected in series are connected in parallel to the bus sampling resistor and then connected to the operational amplifier, wherein the resistor R4 is connected with a 3.3V or 5V low-voltage power supply, and the resistor R6 is connected to the output end of the operational amplifier.
Furthermore, the MOSFET internal resistance voltage division sampling circuit comprises a resistor R7 connected with the MOSEFT gate in series, a diode is connected with a resistor R10 in parallel, the input end of the R7 series diode is connected with a resistor R10, the resistors R8 and R9 are connected in series, the resistors R8 and R9 are connected with the output end of the diode and the resistor R10, the resistor R8 is connected with a 3.3V or 5V weak current power supply, the resistor R9 is connected with the negative pole, and the other end of the R10 is connected with an operational amplifier; the MOSEFT drain is connected with a resistor R11 in series, and a resistor R11 is connected with the operational amplifier and a resistor R12.
Further, the MOSFET settlement circuit schematic diagram comprises a power supply, a MOSFET and a bus sampling resistor R2 which are sequentially connected in series.
The invention also provides a method for detecting the temperature of the MOSFET by using the change of the internal resistance of the MOSFET, which comprises the following steps:
step S1, measuring the partial pressure of the bus sampling resistance;
step S2, measuring the partial pressure of the MOSFET internal resistance;
step S3, calculating the internal resistance of the MOSFET according to the partial voltage of the bus sampling resistor measured in step S1 and the partial voltage of the internal resistance of the MOSFET measured in step S2;
and step S4, acquiring the junction temperature of the current MOSFET according to the proportional relation between the phase current value acquired from the MOSFET internal resistance and the phase current value acquired from the bus sampling resistance.
Further, the bus sampling resistor voltage division sampling circuit comprises a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R3 and a resistor R4 which are connected in series, a resistor R5 and a resistor R6 which are connected in series, two groups of resistors which are connected in series are connected in parallel to the bus sampling resistor and then connected to an operational amplifier, wherein the resistor R4 is connected with a 3.3V or 5V low-voltage power supply, and the resistor R6 is connected to the output end of the operational amplifier.
Furthermore, the MOSFET internal resistance voltage division sampling circuit comprises a resistor R7 connected with the MOSEFT gate in series, a diode is connected with a resistor R10 in parallel, the input end of the R7 series diode is connected with a resistor R10, the resistors R8 and R9 are connected in series, the resistors R8 and R9 are connected with the output end of the diode and the resistor R10, the resistor R8 is connected with a 3.3V or 5V weak current power supply, the resistor R9 is connected with the negative pole, and the other end of the R10 is connected with an operational amplifier; the MOSEFT drain is connected with a resistor R11 in series, and a resistor R11 is connected with the operational amplifier and a resistor R12.
The invention implants two algorithms in the software of a motor controller, wherein one algorithm is an algorithm for reconstructing the phase current of a motor by utilizing the current of a bus, the other algorithm is an algorithm for detecting the phase current of the motor by utilizing the voltage division of an MOSFET, and the phase current value obtained from the internal resistance of the MOSFET is different from the phase current value obtained from the sampling resistance of the bus under different temperature conditions. The junction temperature of the current MOSFET can be obtained according to the proportional relation of the feedback voltages, and the temperature of the MOSFET of the motor controller in the working state can be obtained by using the method on occasions with low precision requirements and high cost pressure.
Drawings
FIG. 1 is a schematic diagram of MOSFET internal resistance calculation;
FIG. 2 is a sampling circuit for bus sampling resistor voltage division;
FIG. 3 is a sampling circuit for voltage division of the internal resistance of the MOSFET;
FIG. 4 is a graph of MOSFET internal resistance versus temperature;
in fig. 1, R1 represents the internal resistance of the MOSFET, R2 represents the sampling resistance of the bus current, and U1 and U2 represent different voltage drop values that occur when the current in the battery flows through the two resistors R1 and R2.
Detailed Description
The invention is further described below with reference to examples and figures.
Example 1
As shown in fig. 1-3, a MOSFET internal resistance detection circuit includes a detection circuit built in a motor controller, the detection circuit includes a bus sampling resistance voltage division sampling circuit for detecting bus sampling resistance voltage division; the MOSFET internal resistance voltage division sampling circuit is used for measuring the internal resistance voltage division of the MOSFET; and the MOSFET internal resistance detection circuit is used for detecting the internal resistance of the MOSFET.
Specifically, the bus sampling resistor voltage division sampling circuit comprises 4 resistors R3, R4, R5 and R6, wherein the resistors R3 and R4 are connected in series, the resistors R5 and R6 are connected in series, the two groups of resistors after being connected in series are connected in parallel to the bus sampling resistor and then connected to the input end of an operational amplifier, the resistor R4 is connected with a 3.3V or 5V low-voltage power supply, and the resistor R6 is connected to the output end of the operational amplifier. When the circuit is connected, the bus sampling resistor needs to be connected with the negative electrode of the power supply.
Specifically, the MOSFET internal resistance voltage division sampling circuit comprises a resistor R7 connected with a MOSEFT gate in series, a diode connected with a resistor R10 in parallel, a diode connected with a resistor R10 after R7 is connected with the diode in series and in parallel, the resistor R7 is connected with the input end of the diode and a resistor R10, resistors R8 and R9 are connected with each other in series, the resistors R8 and R9 are connected with the output end of the diode and the resistor R10, the resistor R8 is connected with a 3.3V or 5V weak current power supply, the resistor R9 is connected with the negative electrode, and the other end of the R10 is connected with an operational amplifier; the MOSEFT drain is connected with a resistor R11 in series, and a resistor R11 is connected with the operational amplifier and a resistor R12.
Specifically, the MOSFET internal resistance detection circuit comprises a power supply, a MOSFET and a bus sampling resistor R2 which are sequentially connected in series. When the current in the battery flows through the two resistors R1 and R2, different voltage drops U1 and U2 are generated, and according to ohm's law I = U/R, when R2, U2 and U1 know, the resistance value of R1 is calculated by the three quantities.
The working principle of the invention is that firstly, the voltage U2 of the bus sampling resistor is measured according to the graph of figure 2, then the voltage U1 at two ends of the MOSFET (at the lower bridge arm) can be measured when the MOSFET is opened according to the graph of figure 3, and then the internal resistance R1 of the MOSFET is calculated according to the graph of figure 1 and ohm's law.
Example 2
The embodiment provides a method for detecting the temperature of a MOSFET (metal oxide semiconductor field effect transistor) by using the internal resistance change of the MOSFET, which specifically comprises the following steps:
step S1, measuring the partial pressure of the bus sampling resistance;
step S2, measuring the partial pressure of the MOSFET internal resistance;
step S3, calculating the internal resistance of the MOSFET according to the partial voltage of the bus sampling resistor measured in step S1 and the partial voltage of the internal resistance of the MOSFET measured in step S2;
and step S4, acquiring the junction temperature of the current MOSFET according to the proportional relation between the phase current value acquired from the MOSFET internal resistance and the phase current value acquired from the bus sampling resistance.
In step S1, according to fig. 1, the bus sampling resistor voltage division sampling circuit includes 4 resistors R3, R4, R5, R6, R3 and R4 connected in series, R5 and R6 connected in series, and the two series resistors are connected in parallel to the bus sampling resistor and then connected to the operational amplifier, where the resistor R4 is connected to a low voltage power supply of 3.3V or 5V, and the resistor R6 is connected to the output terminal of the operational amplifier.
In step S2, according to fig. 2, the MOSFET internal resistance voltage division sampling circuit includes a resistor R7 connected in series with the MOSFET gate, the diode is connected in parallel with a resistor R10, the input end of the diode connected in series with R7 is connected in series with a resistor R10, resistors R8 and R9 are connected in series, resistors R8 and R9 are both connected to the output end of the diode and a resistor R10, the resistor R8 is connected to a 3.3V or 5V weak current power supply, the resistor R9 is connected to the negative pole, and the other end of R10 is connected to the operational amplifier; the MOSEFT drain is connected with a resistor R11 in series, and a resistor R11 is connected with the operational amplifier and a resistor R12.
Then, the internal resistance of the MOSFET is calculated.
In a motor controller for detecting motor phase current by using MOSFET internal resistance, the current motor phase current can be obtained by the voltage division generated when the motor phase current flows through the MOSFET internal resistance. And an algorithm for reconstructing the motor phase current by using the bus current is implanted into the software of the controller. Generally, the temperature drift of the sampled resistor of the bus is small, and the internal resistance of the MOSFET has a characteristic of changing with temperature as shown in fig. 4. The phase current value obtained from the internal resistance of the MOSFET is different from the phase current value obtained from the bus sampling resistance under different temperature conditions. According to the proportional relation of the feedback currents, the junction temperature of the current MOSFET can be obtained, and according to experiments, the precision of the current MOSFET can reach +/-5 ℃, so that the temperature of the MOSFET of the motor controller in a working state can be obtained by using the method on occasions with low precision requirements and high cost pressure.
In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships conventionally put in use of products of the present invention, and are only for convenience of description and simplification of description, but do not indicate or imply that the devices or elements referred to must have specific orientations, be constructed in specific orientations, and be operated, and thus, should not be construed as limiting the present invention.
In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," and "connected" are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Finally, it should be noted that: the above embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention; thus, while the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted; all such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and protected by the following claims.
Claims (7)
1. A MOSFET internal resistance detection circuit is characterized in that: the detection circuit is arranged in a motor controller and comprises a bus sampling resistance voltage division sampling circuit for measuring bus sampling resistance voltage division; the MOSFET internal resistance voltage division sampling circuit is used for measuring the internal resistance voltage division of the MOSFET; and calculating the internal resistance of the MOSFET by using ohm's law according to the measured voltage division of the bus sampling resistor and the voltage division of the internal resistance of the MOSFET.
2. The MOSFET internal resistance detection circuit according to claim 1, characterized in that: the bus sampling resistor voltage division sampling circuit comprises a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R3 and a resistor R4 which are connected in series, a resistor R5 and a resistor R6 which are connected in series, two groups of resistors connected in series are connected in parallel to the bus sampling resistor and then connected to an operational amplifier, wherein the resistor R4 is connected with a 3.3V or 5V low-voltage power supply, and the resistor R6 is connected to the output end of the operational amplifier.
3. The MOSFET internal resistance detection circuit according to claim 1, characterized in that: the MOSFET internal resistance voltage division sampling circuit comprises a resistor R7 connected with the MOSEFT gate in series, a diode is connected with a resistor R10 in parallel, the input end of a R7 series diode is connected with a resistor R10 in series, the resistors R8 and R9 are connected in series, the resistors R8 and R9 are both connected with the output end of the diode and the resistor R10, the resistor R8 is connected with a 3.3V or 5V weak current power supply, the resistor R9 is connected with the negative electrode, and the other end of the R10 is connected with an operational amplifier; the MOSEFT drain is connected with a resistor R11 in series, and a resistor R11 is connected with the operational amplifier and a resistor R12.
4. The MOSFET internal resistance detection circuit according to claim 1, characterized in that: the MOSFET internal resistance calculation circuit schematic diagram comprises a power supply, a MOSFET and a bus sampling resistor R2 which are sequentially connected in series.
5. A method for detecting the temperature of a MOSFET by using the internal resistance change of the MOSFET is characterized in that: the method comprises the following steps:
step S1, measuring the partial pressure of the bus sampling resistance;
step S2, measuring the partial pressure of the MOSFET internal resistance;
step S3, calculating the internal resistance of the MOSFET according to the partial voltage of the bus sampling resistor measured in step S1 and the partial voltage of the internal resistance of the MOSFET measured in step S2;
and step S4, acquiring the junction temperature of the current MOSFET according to the proportional relation between the phase current value acquired from the MOSFET internal resistance and the phase current value acquired from the bus sampling resistance.
6. The method of claim 5 for detecting the temperature of the MOSFET using the variation of the internal resistance of the MOSFET, wherein: the bus sampling resistor voltage division sampling circuit comprises a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R3 and a resistor R4 which are connected in series, a resistor R5 and a resistor R6 which are connected in series, two groups of resistors connected in series are connected in parallel to the bus sampling resistor and then connected to an operational amplifier, wherein the resistor R4 is connected with a 3.3V or 5V weak current power supply, and the resistor R6 is connected to the output end of an operational amplifier.
7. The method of claim 5 for detecting the temperature of the MOSFET using the variation of the internal resistance of the MOSFET, wherein: the MOSFET internal resistance voltage division sampling circuit comprises a resistor R7 connected with the MOSEFT gate in series, a diode is connected with a resistor R10 in parallel, the input end of a R7 series diode is connected with a resistor R10 in series, the resistors R8 and R9 are connected in series, the resistors R8 and R9 are both connected with the output end of the diode and the resistor R10, the resistor R8 is connected with a 3.3V or 5V weak current power supply, the resistor R9 is connected with the negative electrode, and the other end of the R10 is connected with an operational amplifier; the MOSEFT drain is connected with a resistor R11 in series, and a resistor R11 is connected with the operational amplifier and a resistor R12.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911281413.0A CN110940905A (en) | 2019-12-13 | 2019-12-13 | MOSFET internal resistance detection circuit and method for detecting temperature of MOSFET by using same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911281413.0A CN110940905A (en) | 2019-12-13 | 2019-12-13 | MOSFET internal resistance detection circuit and method for detecting temperature of MOSFET by using same |
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| CN110940905A true CN110940905A (en) | 2020-03-31 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201911281413.0A Withdrawn CN110940905A (en) | 2019-12-13 | 2019-12-13 | MOSFET internal resistance detection circuit and method for detecting temperature of MOSFET by using same |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113030683A (en) * | 2021-03-15 | 2021-06-25 | 五羊—本田摩托（广州）有限公司 | Method, medium and computer equipment for measuring temperature of power switch device |
| CN114236213A (en) * | 2021-11-16 | 2022-03-25 | 杭州阔博科技有限公司 | Low-cost current sampling circuit and method |
-
2019
- 2019-12-13 CN CN201911281413.0A patent/CN110940905A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113030683A (en) * | 2021-03-15 | 2021-06-25 | 五羊—本田摩托（广州）有限公司 | Method, medium and computer equipment for measuring temperature of power switch device |
| CN114236213A (en) * | 2021-11-16 | 2022-03-25 | 杭州阔博科技有限公司 | Low-cost current sampling circuit and method |
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