Temperature rise detection device of winding coil and electric power steering system

Abstract

The utility model relates to the technical field of automobile parts, and provides a temperature rise detection device of a winding coil and an electric power steering system. The winding coil is connected in series with a sampling resistor, and the temperature rise detection device comprises a potential difference detection circuit which is connected with the two ends of the winding coil and is used for detecting the potential difference between the two ends of the winding coil in a working state; the current detection circuit is connected with the two ends of the sampling resistor, and the current detection circuit is used for detecting current flowing through the sampling resistor in a working state; and the resistance value detection module is connected with the potential difference detection circuit and the current detection circuit, and the resistance value detection module is used for detecting the resistance value of the winding coil according to the potential difference detected by the potential difference detection circuit and the current detected by the current detection circuit. According to the utility model, the temperature rise condition of the winding coil is obtained by detecting the dynamic resistance value of the winding coil in the working state on line, so that the reliability and safety of the winding coil and the electrical equipment are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of automobile parts, and concretely relates to winding coil temperature rise detection device and electric power steering system. BACKGROUND

[0002] Winding coil is applied in electrical equipment such as motor, transformer. In the working process of electrical equipment, winding coil will have obvious temperature rise. Because winding coil is closed inside, at present, the temperature rise of winding coil is derived by detecting the temperature change of the part near winding coil, for example, sticking temperature sensor on the part near winding coil, by detecting the temperature change of the part.

[0003] At present, the temperature change of winding coil cannot be directly detected, and the detection result has big error, which is not conducive to the reliability control of electrical equipment.

[0004] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the utility model, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. UTILITY MODEL CONTENT

[0005] Therefore, the utility model provides a winding coil temperature rise detection device and electric power steering system, which obtains the temperature rise of winding coil by detecting the dynamic resistance value of winding coil in working state, so as to improve the reliability and safety of winding coil and electrical equipment.

[0006] One aspect of the utility model provides a winding coil temperature rise detection device, the winding coil is connected in series with a sampling resistor, and the winding coil temperature rise detection device comprises: a potential difference detection circuit, comprising a first operational amplifier, two input ends of the first operational amplifier are connected with two ends of the winding coil respectively, and the potential difference detection circuit is used for detecting the potential difference between two ends of the winding coil in working state; a current detection circuit, comprising a second operational amplifier, two input ends of the second operational amplifier are connected with two ends of the sampling resistor respectively, the second operational amplifier is used for collecting the potential difference between two ends of the sampling resistor in the working state, and the current detection circuit is used for detecting the current flowing through the winding coil in the working state; and a resistance value detection module, connected with the potential difference detection circuit and the current detection circuit, and the resistance value detection module is used for detecting the resistance value of the winding coil according to the potential difference detected by the potential difference detection circuit and the current detected by the current detection circuit.

[0007] The utility model discloses a sampling resistance, potential difference detection circuit, current detection circuit, resistance value detection module and other circuit modules are added in the working loop of winding coil. Under the working state of electrical equipment: potential difference detection circuit utilizes the differential amplification function of first operational amplifier, based on the virtual break and virtual short principle of operational amplifier, gathers the potential difference of winding coil both ends, current detection circuit utilizes the differential amplification function of second operational amplifier, based on the virtual break and virtual short principle of operational amplifier, gathers the potential difference of sampling resistance both ends, and further utilizes the characteristic of sampling resistance and winding coil series connection, obtains the current of winding coil, and resistance value detection module calculates the resistance value of winding coil accurately according to the potential difference and current of winding coil both ends gathered. According to the characteristic of winding coil, its resistance value will increase with the increase of temperature, thereby, based on the change condition of the resistance value of winding coil detected under the working state of electrical equipment, can accurately know the temperature rise of winding coil.

[0008] In some embodiments, the resistance value of the winding coil satisfies:

[0009]

[0010] Wherein, U O1 is the potential difference detected by the potential difference detection circuit, I S is the current detected by the current detection circuit, and t is the working time of the winding coil.

[0011] Thus, the resistance value of the winding coil is accurately calculated by using the potential difference (U O1 ) of both ends of the winding coil, the current I S flowing through the winding coil and the working time t of the winding coil during the working process of the electrical equipment.

[0012] In some embodiments, the temperature rise detection device further comprises a temperature rise value detection module connected with the resistance value detection module, and the temperature rise value detection module is used for detecting the temperature rise value of the winding coil according to the resistance value of the winding coil.

[0013] The way that the temperature rise value detection module calculates the temperature rise value of the winding coil according to the resistance value of the winding coil can be configured according to the inherent characteristics of the winding coil or the previous test.

[0014] In some embodiments, the temperature rise value Δt of the winding coil satisfies:

[0015]

[0016] Wherein, R is the resistance value detected by the resistance value detection module, R0 is the resistance value of the winding coil at the beginning of the working state, k is the heat transfer coefficient of the winding coil, and t emp1is the ambient temperature at the beginning of the working state, t emp2 is the real-time ambient temperature.

[0017] In this way, the temperature rise value detection module can calculate the temperature rise value of the winding coil in real time and accurately according to the changing resistance value of the winding coil.

[0018] In some embodiments, the potential difference detection circuit further comprises: a first current-limiting resistor connected between the positive electrode of the winding coil and the inverting input terminal of the first operational amplifier; a first negative feedback resistor connected between the output terminal and the inverting input terminal of the first operational amplifier; a second current-limiting resistor connected between the negative electrode of the winding coil and the non-inverting input terminal of the first operational amplifier; and a first pull-down resistor connected to the non-inverting input terminal of the first operational amplifier and grounded.

[0019] The first operational amplifier and the first current-limiting resistor, the second current-limiting resistor, the first negative feedback resistor, and the first pull-down resistor form a differential circuit that can accurately collect the potential difference between the two ends of the winding coil in the working state of the electrical equipment. Specifically, based on the resistance values of the resistors, the collected potential difference, and the output voltage of the first operational amplifier, the potential difference between the two ends of the winding coil can be accurately calculated according to the virtual break and virtual short principles of the operational amplifier.

[0020] In some embodiments, the resistance values of the first current-limiting resistor, the first negative feedback resistor, the second current-limiting resistor, and the first pull-down resistor are equal.

[0021] In this way, the calculation of the potential difference between the two ends of the winding coil can be simplified.

[0022] In some embodiments, the current detection circuit further comprises: a third current-limiting resistor connected between the positive electrode of the sampling resistor and the inverting input terminal of the second operational amplifier; a second negative feedback resistor connected between the output terminal and the inverting input terminal of the second operational amplifier; a fourth current-limiting resistor connected between the negative electrode of the sampling resistor and the non-inverting input terminal of the second operational amplifier; and a second pull-down resistor connected to the non-inverting input terminal of the second operational amplifier and grounded.

[0023] The second operational amplifier and the third current-limiting resistor, the fourth current-limiting resistor, the second negative feedback resistor, and the second pull-down resistor form a differential circuit that can accurately collect the potential difference between the two ends of the sampling resistor. Specifically, based on the resistance values of the resistors, the collected potential difference, and the output voltage of the second operational amplifier, the potential difference between the two ends of the sampling resistor in the working state of the electrical equipment can be accurately calculated. Combined with the resistance value of the sampling resistor and the characteristic of the series connection of the sampling resistor and the winding coil, the current flowing through the winding coil in the working state of the electrical equipment can be conveniently calculated.

[0024] In some embodiments, the third current-limiting resistor, the second negative feedback resistor, the fourth current-limiting resistor and the second pull-down resistor have equal resistance values.

[0025] In this way, the calculation of the potential difference across the sampling resistor can be simplified.

[0026] In some embodiments, the first operational amplifier and the second operational amplifier are powered on when the winding coil is in the working state.

[0027] The first operational amplifier and the second operational amplifier are powered on when the winding coil is in the working state to collect the potential difference across the winding coil and the current flowing through the winding coil, detect the resistance value of the winding coil, and further detect the temperature rise value of the winding coil.

[0028] In another aspect, the utility model provides a kind of electric power assisted steering system, and the motor drive circuit of the electric power assisted steering system is equipped with the temperature rise detection device as described in any of the above embodiments.

[0029] The temperature rise detection device is used to monitor the temperature rise of motor winding of electric power assisted steering system, and timely early warning is carried out when the temperature rise of winding coil is detected to be abnormal, so as to ensure the stable and reliable operation of electric power assisted steering system.

[0030] Compared with the prior art, the utility model has at least the following beneficial effects:

[0031] The temperature rise detection device of the utility model detects the potential difference and current flowing through winding coil under the working state of electrical equipment by potential difference detection circuit and current detection circuit respectively, accurately calculates the dynamic resistance value of winding coil under the working state of electrical equipment by resistance value detection module, and accurately obtains the temperature rise of winding coil by combining the characteristics that the resistance value of winding coil under the working state of electrical equipment increases with temperature rise. The temperature rise detection device of the utility model can monitor the temperature rise of winding coil in real time and accurately during the working process of electrical equipment, and improve the reliability and safety of winding coil and electrical equipment.

[0032] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and cannot limit the utility model. BRIEF DESCRIPTION OF DRAWINGS

[0033] The drawings incorporated into the specification and forming a part thereof show, by way of illustration, embodiments in which the principles of the utility model are applied, and together with the general description given above and the detailed description given below, serve to explain the principles of the utility model. Obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0034] Figure 1 A structure schematic diagram of the temperature rise detection device of the winding coil in the embodiment of the present application is shown;

[0035] Figure 2 A structure schematic diagram of the potential difference detection circuit in the embodiment of the present application is shown;

[0036] Figure 3 A structure schematic diagram of the current detection circuit in the embodiment of the present application is shown;

[0037] Figure 4 A structure schematic diagram of the motor driving circuit of the electric power steering system is shown;

[0038] Figure 5 A voltage pulse signal loaded to the control end of the transistor in the working state is shown;

[0039] Figure 6 A change curve of the potential difference between the winding coil in the working state is shown;

[0040] Figure 7 A change curve of the potential difference between the sampling resistor in the working state is shown. DETAILED DESCRIPTION

[0041] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations may, however, be implemented in many different forms and should not be construed as limited to the implementations set forth herein. Rather, these implementations are provided as non-limiting examples, so that this disclosure will fully convey the scope of the example implementations to those skilled in the art.

[0042] The accompanying drawings are included to provide a further understanding of the present application and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application.

[0043] The terms "first", "second", and similar terms do not imply any order, quantity, or importance, but are used to distinguish one element from another, and the terms "include" and "have" are used to indicate that there are constituent elements, and do not exclude the possibility that other elements are present or additional elements are added.

[0044] It should be noted that the embodiments of the present application and the features in different embodiments can be combined with each other without conflict.

[0045] Figure 1 The structure of the temperature rise detection device of the winding coil is shown, and with reference to Figure 1 The temperature rise detection device of the winding coil provided by the embodiment of the present application comprises:

[0046] The potential difference detection circuit 100 comprises a first operational amplifier U1, two input ends of the first operational amplifier U1 are connected to two ends of the winding coil L, and the potential difference detection circuit 100 is used for detecting the potential difference between two ends of the winding coil L in a working state.

[0047] The current detection circuit 200 comprises a second operational amplifier U2, two input ends of the second operational amplifier U2 are connected to two ends of a sampling resistor R F connected in series with the winding coil L, and the second operational amplifier U2 is used for collecting the potential difference between two ends of the sampling resistor R F in the working state, and the current detection circuit 200 is used for detecting the current flowing through the winding coil L in the working state.

[0048] The resistance value detection module 300 is connected with the potential difference detection circuit 100 and the current detection circuit 200, and the resistance value detection module 300 is used for detecting the resistance value of the winding coil L according to the potential difference detected by the potential difference detection circuit 100 and the current detected by the current detection circuit 200.

[0049] The utility model adds the sampling resistor R F , the potential difference detection circuit 100, the current detection circuit 200, the resistance value detection module 300 and other circuit modules in the working circuit of the winding coil L. In the working state of the electrical equipment: the potential difference detection circuit 100 utilizes the differential amplification function of the first operational amplifier U1, collects the potential difference between two ends of the winding coil L based on the virtual break and virtual short principle of the operational amplifier, the current detection circuit 200 utilizes the differential amplification function of the second operational amplifier U2, collects the potential difference between two ends of the sampling resistor RF based on the virtual break and virtual short principle of the operational amplifier, and further utilizes the characteristics that the sampling resistor R F is connected in series with the winding coil L to obtain the current flowing through the winding coil L, and the resistance value detection module 300 accurately calculates the resistance value of the winding coil L according to the collected potential difference between two ends of the winding coil L and the current flowing through.

[0050] Thus, the temperature rise detection device of this invention utilizes the potential difference detection circuit 100 and the current detection circuit 200 to detect the potential difference across the winding coil L and the current flowing through it during the operation of the electrical equipment, respectively. The resistance value detection module 300 accurately calculates the dynamic resistance value of the winding coil L during the operation of the electrical equipment. Combined with the characteristic that the resistance value of the winding coil L increases with temperature during the operation of the electrical equipment, the temperature rise of the winding coil L can be accurately determined. This temperature rise detection device of this invention can monitor the temperature rise of the winding coil L in real time and accurately during the operation of electrical equipment, improving the reliability and safety of the winding coil L and the electrical equipment.

[0051] In some embodiments, the resistance value of the winding coil L satisfies:

[0052]

[0053] Among them, U O1 I is the potential difference detected by the potential difference detection circuit 100. S t represents the current detected by the current detection circuit 200, and t represents the working time of the winding coil L.

[0054] Thus, the potential difference (U) across the winding coil L during the operation of the electrical equipment is utilized. O1 The current I flowing through the winding coil L S Given the working time t of the winding coil L, the resistance value of the winding coil L can be accurately calculated.

[0055] Specifically, the current I flowing through the winding coil L during the working time t. S The total work done is:

[0056]

[0057] Equation (1) can be obtained by solving R according to equation (2).

[0058] Furthermore, referring to Figure 1 As shown, in some embodiments, the temperature rise detection device further includes a temperature rise detection module 400, which is connected to the resistance detection module 300. The temperature rise detection module 400 is used to detect the temperature rise of the winding coil L based on the resistance value of the winding coil L.

[0059] The temperature rise detection module 400 calculates the temperature rise of the winding coil L based on the resistance value of the winding coil L, which can be based on the inherent characteristics of the winding coil L or the configuration of previous tests.

[0060] In some embodiments, the temperature rise Δt of the winding coil L satisfies:

[0061]

[0062] wherein, R is the resistance value detected by the resistance value detection module 300, R0 is the resistance value of the winding coil L at the beginning of the working state, which can be detected by the potential difference detection circuit 100, the current detection circuit 200 and the resistance value detection module 300 at the initial stage of the operation of the electrical equipment. K is the heat transfer coefficient of the winding coil L, for example, for the winding coil of copper wire material, K takes the value of 234.5, and for the winding coil of aluminum wire material, K takes the value of 225. t emp1 is the ambient temperature at the beginning of the working state, t emp2 is the real-time ambient temperature, t emp1 and t emp2 can be detected by the temperature sensor arranged in the environment where the electrical equipment is located.

[0063] In this way, the temperature rise value detection module calculates the temperature rise value of the winding coil L in real time and accurately according to the changing resistance value of the winding coil L.

[0064] Figure 2 The structure of the potential difference detection circuit 100 is shown, which is combined with Figure 1 and Figure 2 In some embodiments, the potential difference detection circuit 100 further comprises: a first current-limiting resistor R1 connected between the positive electrode of the winding coil L and the inverting input terminal of the first operational amplifier U1; a first negative feedback resistor R2 connected between the output terminal and the inverting input terminal of the first operational amplifier U1; a second current-limiting resistor R3 connected between the negative electrode of the winding coil L and the non-inverting input terminal of the first operational amplifier U1; and a first pull-down resistor R4 connected to the non-inverting input terminal of the first operational amplifier U1 and grounded.

[0065] The first operational amplifier U1 and the first current-limiting resistor R1, the second current-limiting resistor R3, the first negative feedback resistor R2 and the first pull-down resistor R4 form a differential circuit capable of accurately collecting the potential difference between the two ends of the winding coil L under the working state of the electrical equipment. Specifically, based on the resistance values of the resistors and the potential difference collected by the first operational amplifier U1 and the voltage U O1 According to the virtual open and short principles of the operational amplifier, the potential difference between the two ends of the winding coil L can be accurately calculated.

[0066] In some embodiments, the resistance values of the first current-limiting resistor R1, the first negative feedback resistor R2, the second current-limiting resistor R3 and the first pull-down resistor R4 are equal. In this way, the calculation of the potential difference between the two ends of the winding coil L can be simplified.

[0067] Let the voltage at the inverting input terminal of the first operational amplifier U1 be U FL1 , and the voltage at the non-inverting input terminal be U FL2 , then the potential difference U FL between the two ends of the winding coil L isFL1 - U FL2 The output end of the first operational amplifier U1 is connected with the controller to detect the voltage U O1 According to the virtual open and virtual short principles of the operational amplifier, the following equation (3) is obtained:

[0068]

[0069] Wherein the resistance values of the first current-limiting resistor R1, the first negative feedback resistor R2, the second current-limiting resistor R3 and the first pull-down resistor R4 are equal, i.e. R1=R2=R3=R4, then the equation (3) is solved to obtain: U FL =U FL1 - U FL2 =U O1 That is, the voltage U O1 output by the first operational amplifier U1 under the working state of the electrical equipment is the potential difference between the two ends of the winding coil L.

[0070] Figure 3 The structure of the current detection circuit 200 is shown, which, in combination with Figure 1 and Figure 3 , in some embodiments, the current detection circuit 200 further comprises: a third current-limiting resistor R5 connected between the positive pole of the sampling resistor R F and the inverting input end of the second operational amplifier U2; a second negative feedback resistor R6 connected between the output end and the inverting input end of the second operational amplifier U2; a fourth current-limiting resistor R7 connected between the negative pole of the sampling resistor R F and the non-inverting input end of the second operational amplifier U2; and a second pull-down resistor R8 connected with the non-inverting input end of the second operational amplifier U2 and grounded.

[0071] The second operational amplifier U2 and the third current-limiting resistor R5, the fourth current-limiting resistor R7, the second negative feedback resistor R6 and the second pull-down resistor R8 form a differential circuit capable of accurately collecting the potential difference between the two ends of the sampling resistor RF. Specifically, based on the resistance values, the potential difference collected by the second operational amplifier U2 and the voltage U O2 output by the second operational amplifier U2, the potential difference between the two ends of the sampling resistor R F under the working state of the electrical equipment can be accurately calculated. In combination with the resistance value of the sampling resistor R F and the characteristics of the sampling resistor R F in series with the winding coil L, the current flowing through the winding coil L under the working state of the electrical equipment can be conveniently calculated.

[0072] In some embodiments, the resistance values of the third current-limiting resistor R5, the second negative feedback resistor R6, the fourth current-limiting resistor R7 and the second pull-down resistor R8 are equal. In this way, the sampling resistor RF The calculation of the potential difference across the two ends.

[0073] Let the voltage of the inverting input end of the second operational amplifier U2 be U RF1 , and the voltage of the non-inverting input end be U RF2 , then the potential difference across the sampling resistor RFR F is U RF = U RF1 -U RF2 . The output end of the second operational amplifier U2 is connected with the controller to detect the voltage U O2 output by the second operational amplifier U2. According to the virtual break and virtual short principle of the operational amplifier, the following equation (4) is obtained:

[0074]

[0075] Wherein the third current-limiting resistor R5, the second negative feedback resistor R6, the fourth current-limiting resistor R7 and the second pull-down resistor R8 have equal resistance values, i.e. R5=R6=R7=R8, then solving equation (4) can obtain: U RF = U RF1 -U RF2 = U O2 . That is, the voltage U O2 output by the second operational amplifier U2 under the working state of the electrical equipment is the potential difference across the sampling resistor R F .

[0076] Further, the current I S flowing across the sampling resistor R F is I S = U O2 ÷R F , wherein R F is a known resistance value.

[0077] In some embodiments, the first operational amplifier U1 and the second operational amplifier U2 are powered on to run when the winding coil L is in the working state.

[0078] The first operational amplifier U1 and the second operational amplifier U2 are powered on to run when the winding coil L is in the working state, to collect the potential difference across the winding coil L and the current flowing through the winding coil L, detect the resistance value of the winding coil L, and further detect the temperature rise value of the winding coil L.

[0079] The utility model embodiment further provides an electric power assisted steering system, and a motor drive circuit of the electric power assisted steering system is configured with the temperature rise detection device of any of the above embodiments. The temperature rise detection device is used to accurately and timely detect and monitor the temperature rise of the motor winding of the electric power assisted steering system, and timely warning is given when the temperature rise of the winding coil is detected to be abnormal, so that stable and reliable operation of the electric power assisted steering system is ensured.

[0080] In one specific example, an electric power steering system employs a three-phase DC brushless motor to provide assistance, with reference to Figure 4 The motor drive circuit is shown, including six transistors (Q1, Q2, Q3, Q4, Q5, Q6) and three-phase winding coils (L1, L2, L3). In the working state, the six transistors are opened in a certain order to drive the corresponding winding coils to work.

[0081] In combination with Figures 1 to 7 When transistors Q1 and Q5 are opened simultaneously under the action of voltage pulse signal 500, winding coils (L1 and L3) are loaded with high level from power supply end V_PHASE, potential difference detection circuit 100 connected across winding coils (L1 and L3) detects potential difference signal 600 across winding coils (L1 and L3), current detection circuit 200 connected across sampling resistor R F detects current signal 700 flowing through winding coils (L1 and L3), and then resistance value detection module 300 and temperature rise value detection module detect the resistance value change and temperature rise value change of winding coils (L1 and L3) within a certain working time, respectively. Similarly, when the G2 end of transistor Q2 and the G4 end of transistor Q4 receive a voltage pulse signal, winding coils (L1 and L2) are loaded with high level from power supply end V_PHASE, potential difference detection circuit 100 connected across winding coils (L1 and L2) detects potential difference signal across winding coils (L1 and L2), and current detection circuit 200 connected across sampling resistor R F detects current signal flowing through winding coils (L1 and L2), and then resistance value detection module 300 and temperature rise value detection module detect the resistance value change and temperature rise value change of winding coils (L1 and L2) within a certain working time, respectively. When the G3 end of transistor Q3 and the G6 end of transistor Q6 receive a voltage pulse signal, winding coils (L2 and L3) are loaded with high level from power supply end V_PHASE, potential difference detection circuit 100 connected across winding coils (L2 and L3) detects potential difference signal across winding coils (L2 and L3), and current detection circuit 200 connected across sampling resistor R F detects current signal flowing through winding coils (L2 and L3), and then resistance value detection module 300 and temperature rise value detection module detect the resistance value change and temperature rise value change of winding coils (L2 and L3) within a certain working time, respectively.

[0082] The above is further detailed description of the utility model in combination with specific preferred embodiments, and cannot be deemed as limitation of the specific implementation of the utility model to these descriptions. For ordinary skilled persons in the technical field to which the utility model belongs, without departing from the concept of the utility model, a number of simple deductions or substitutions can be made, and all of them shall be deemed as belonging to the protection scope of the utility model.

Claims

1. A temperature rise detection device for a winding coil, characterized in that, The winding coil is connected with a sampling resistor in series, and the temperature rise detection device comprises: a potential difference detection circuit comprising a first operational amplifier, two input ends of the first operational amplifier being connected with two ends of the winding coil respectively, the potential difference detection circuit being used for detecting a potential difference between the two ends of the winding coil in a working state; a current detection circuit comprising a second operational amplifier, two input ends of the second operational amplifier being connected with two ends of the sampling resistor respectively, the second operational amplifier being used for collecting a potential difference between the two ends of the sampling resistor in the working state, the current detection circuit being used for detecting a current flowing through the winding coil in the working state; a resistance value detection module connected with the potential difference detection circuit and the current detection circuit, the resistance value detection module being used for detecting a resistance value of the winding coil according to the potential difference detected by the potential difference detection circuit and the current detected by the current detection circuit.

2. The temperature rise detection device of claim 1, wherein The resistance value of the winding coil satisfies: wherein U O1 is the potential difference detected by the potential difference detection circuit, I S is the current detected by the current detection circuit, and t is the operating time of the winding coil.

3. The temperature rise detection device of claim 1, wherein further comprising: a temperature rise value detection module connected with the resistance value detection module, the temperature rise value detection module being used for detecting a temperature rise value of the winding coil according to the resistance value of the winding coil.

4. The temperature rise detection device of claim 3, wherein The temperature rise value Δt of the winding coil satisfies: wherein R is the resistance value detected by the resistance value detection module, R0 is the resistance value of the winding coil at the beginning of the working state, k is the heat transfer coefficient of the winding coil, t emp1 is the environmental temperature at the beginning of the working state, t emp2 is the real-time environmental temperature.

5. The temperature rise detection device of claim 1, wherein The potential difference detection circuit further comprises: a first current-limiting resistor connected between a positive electrode of the winding coil and an inverting input end of the first operational amplifier; a first negative feedback resistor connected between an output end and the inverting input end of the first operational amplifier; a second current-limiting resistor connected between a negative electrode of the winding coil and a non-inverting input end of the first operational amplifier; a first pull-down resistor connected with the non-inverting input end of the first operational amplifier and grounded.

6. The temperature rise detection device of claim 5, wherein The resistance values of the first current-limiting resistor, the first negative feedback resistor, the second current-limiting resistor and the first pull-down resistor are equal.

7. The temperature rise detection device of claim 1, wherein The current detection circuit further comprises: a third current-limiting resistor connected between a positive electrode of the sampling resistor and an inverting input end of the second operational amplifier; a second negative feedback resistor connected between an output end and the inverting input end of the second operational amplifier; a fourth current-limiting resistor connected between a negative electrode of the sampling resistor and a non-inverting input end of the second operational amplifier; a second pull-down resistor connected with the non-inverting input end of the second operational amplifier and grounded.

8. The temperature rise detection device of claim 7, wherein The resistance values of the third current-limiting resistor, the second negative feedback resistor, the fourth current-limiting resistor and the second pull-down resistor are equal.

9. The temperature rise detection device of any one of claims 1-8, wherein, The first operational amplifier and the second operational amplifier are powered on when the winding coil is in the working state.

10. An electric power assisted steering system characterised in that, The motor drive circuit of the electric power steering system is configured with the temperature rise detection device according to any one of claims 1-9.

Images