Linear sampling system for IGBT modules

Abstract

The present invention belongs to the field of measurement technology, specifically relates to temperature measurement, and more particularly to a linear sampling system for an IGBT module, comprising: a control module, and a temperature sampling circuit and a voltage sampling circuit electrically connected to the control module; the temperature sampling circuit is electrically connected to the voltage sampling circuit, the voltage output by the temperature sampling circuit is input to the control module after passing through the voltage sampling circuit, and the control module is configured to obtain corresponding temperature data according to the voltage; and a switching module is provided in the temperature sampling circuit, and an NTC resistor in the temperature sampling circuit is isolated by the switching module. At this time, the control module is configured to judge whether other parts in the temperature sampling circuit are normal according to the voltage, thereby realizing the detection of other parts in the temperature sampling circuit, ensuring that other parts in the temperature sampling circuit are normal during the detection process, and ensuring that the temperature can be accurately detected.

Description

Technical Field

[0001] The invention belongs to the field of measurement technology, and specifically relates to temperature measurement, and in particular to a linear sampling system for an IGBT module. Background Art

[0002] In the new energy vehicle drive system, the IGBT module is connected to the NTC resistor. The NTC resistance value is different at different temperatures. Therefore, the temperature value in the IGBT module can be read by reading the resistance value of the NTC resistor. In addition to the NTC resistor, other resistors are also provided in the temperature sampling circuit. When other resistors have problems, the voltage output by the temperature sampling circuit will be abnormal. For example, because the on-off current and on-off voltage are large, it will affect components such as resistors. The IGBT module itself will not be affected, but the components in the temperature sampling circuit set around the IGBT module will be affected and abnormal or damaged, and it will not be able to accurately reflect the resistance value of the NTC resistor, resulting in the inability to accurately detect the temperature at this time; and in order to make the temperature of the NTC resistor closest to the temperature of the IGBT chip, the spacing between the NTC resistor and the IGBT chip of most manufacturers cannot meet the safety requirements. The relationship between the resistance value of the related NTC resistor and the temperature is an exponential change relationship. Direct voltage division to read the temperature value will have problems with poor linearity and low resolution.

[0003] Therefore, since the temperature sampling circuit constructed by the NTC resistor cannot be accurately and precisely detected when the other resistors are abnormal or damaged, it is necessary to design a linear sampling system for the IGBT module.

[0004] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the invention

[0005] The embodiments of the present disclosure at least provide a linear sampling system for an IGBT module.

[0006] In a first aspect, an embodiment of the present disclosure provides a linear sampling system for an IGBT module, comprising:

[0007] A control module, and a temperature sampling circuit and a voltage sampling circuit electrically connected to the control module;

[0008] The temperature sampling circuit is electrically connected to the voltage sampling circuit, the voltage output by the temperature sampling circuit is input to the control module after passing through the voltage sampling circuit, and the control module is configured to obtain corresponding temperature data according to the voltage; and

[0009] The temperature sampling circuit is provided with a switching module, and the NTC resistor in the temperature sampling circuit is isolated by the switching module. At this time, the control module is configured to determine whether other parts in the temperature sampling circuit are normal according to the voltage.

[0010] In an optional implementation, the temperature sampling circuit includes: a resistor R1, a resistor R2, a resistor R3 and an NTC resistor;

[0011] One end of the resistor R1 is connected to a constant current source, and the other end is connected to one end of the NTC resistor;

[0012] One end of the NTC resistor connected to the resistor R1 is connected to the voltage sampling circuit, and the other end of the NTC resistor is connected to one end of the resistor R3;

[0013] One end of the resistor R2 is connected to the other end of the resistor R3 , and one end of the resistor R2 is connected to one end of the NTC resistor.

[0014] In an optional implementation, a switching module is connected in parallel at both ends of the NTC resistor;

[0015] When the switching module is turned on, the NTC resistor is isolated.

[0016] In an optional embodiment, when the NTC resistor is isolated, the control module is configured to compare the acquired real-time voltage with the preset voltage. If the real-time voltage is the same as the preset voltage, the resistors R1, R2 and R3 are judged to be normal, otherwise they are judged to be abnormal.

[0017] In an optional embodiment, after determining that resistors R1, R2, and R3 are normal, the NTC resistor is reconnected to the temperature sampling circuit by disconnecting the switching module. At this time, the control module continues to obtain the current output by the constant current source. The control module is configured to determine whether the current fluctuation exceeds a preset fluctuation range based on the current output by the constant current source. If so, it is determined that the load of the constant current source exceeds its tolerance range.

[0018] In an optional embodiment, after determining that resistors R1, R2, and R3 are normal, the NTC resistor is reconnected to the temperature sampling circuit by disconnecting the switching module. At this time, the control module continuously obtains the continuous voltage output by the voltage sampling circuit. The control module is configured to obtain a real-time relative linear curve of voltage and temperature values ​​based on the continuous voltage, and compare the relative linear curve of historical voltage and temperature values ​​in the stored historical data with the real-time relative linear curve of voltage and temperature values. If the two are the same, the NTC resistor is judged to be normal; if they are different, the NTC resistor is judged to be abnormal.

[0019] In an optional implementation, when the switching module is just turned on or off, the control module is configured to obtain the real-time voltage or the continuous voltage after a preset time interval.

[0020] The beneficial effect of the present invention is that the linear sampling system for an IGBT module comprises: a control module, and a temperature sampling circuit and a voltage sampling circuit electrically connected to the control module; the temperature sampling circuit is electrically connected to the voltage sampling circuit, the voltage output by the temperature sampling circuit is input to the control module after passing through the voltage sampling circuit, and the control module is configured to obtain corresponding temperature data according to the voltage; and a switching module is provided in the temperature sampling circuit, and the NTC resistor in the temperature sampling circuit is isolated by the switching module. At this time, the control module is configured to judge whether other parts in the temperature sampling circuit are normal according to the voltage, thereby realizing the detection of other parts in the temperature sampling circuit, ensuring that other parts in the temperature sampling circuit are normal during the detection process, and ensuring that the temperature can be accurately detected.

[0021] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0022] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, this article specifically cites preferred embodiments and provides detailed descriptions as follows in conjunction with the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A principle block diagram of a linear sampling system for an IGBT module provided in an embodiment of the present disclosure;

[0025] Figure 2 A schematic diagram of a voltage sampling circuit provided by an embodiment of the present disclosure;

[0026] Figure 3 A schematic diagram of a temperature sampling circuit without a switching module provided in an embodiment of the present disclosure;

[0027] Figure 4 A schematic diagram of a temperature sampling circuit provided with a triode as a switching module provided in an embodiment of the present disclosure;

[0028] Figure 5 A schematic diagram of a temperature sampling circuit provided with a relay as a switching module provided in an embodiment of the present disclosure;

[0029] Figure 6 A relatively linear schematic diagram of voltage value and temperature value provided for an embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Therefore, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, so that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like are used to "serve as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. On the contrary, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0032] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0033] like Figure 1 and Figure 2As shown, at least one disclosed embodiment provides a linear sampling system for an IGBT module, including: a control module, and a temperature sampling circuit and a voltage sampling circuit electrically connected to the control module; the temperature sampling circuit is electrically connected to the voltage sampling circuit, the voltage output by the temperature sampling circuit is input to the control module after passing through the voltage sampling circuit, and the control module is configured to obtain corresponding temperature data according to the voltage; and a switching module is provided in the temperature sampling circuit, and the NTC resistor in the temperature sampling circuit is isolated by the switching module. At this time, the control module is configured to determine whether other parts in the temperature sampling circuit are normal according to the voltage, thereby realizing the detection of other parts in the temperature sampling circuit, ensuring that other parts in the temperature sampling circuit are normal during the detection process, and ensuring that the temperature can be accurately detected.

[0034] The voltage sampling circuit is an existing voltage sampling circuit, wherein A2 is connected to a control module, specifically, resistors R4 and R5 are connected in series, one end of the resistors R4 and R5 is connected to one end of the resistors R1 and NTC resistor, the other end of the resistor R5 is connected to a power supply, the other end of the resistor R4 is grounded, one end of the capacitor C6 is connected to one end of the positive electrode of the diode U3, the other end of the capacitor C6 is grounded, the negative electrode of the diode U3 is connected to the power supply, one end of the capacitor C6 connected to the diode U3 is connected to the control module, and one end of the capacitor C6 connected to the diode U3 is connected to one end of the resistors R4 and R5; Figure 2 The A1 position in corresponds to each temperature sampling circuit, so that the voltage sampling circuit is connected to the corresponding temperature sampling circuit.

[0035] like Figure 3As shown, in an optional embodiment, the temperature sampling circuit includes: a resistor R1, a resistor R2, a resistor R3 and an NTC resistor; the resistance of the resistor R1 is 1400Ω, the resistance of the resistor R2 is 5kΩ, and the resistance of the resistor R3 is 500Ω; one end of the resistor R1 is connected to a constant current source, and the other end is connected to one end of the NTC resistor; the end of the NTC resistor connected to the resistor R1 is connected to a voltage sampling circuit, and the other end of the NTC resistor is connected to one end of the resistor R3; one end of the resistor R2 is connected to the other end of the resistor R3, and one end of the resistor R2 is connected to one end of the NTC resistor; the ends of the resistor R2 and the resistor R3 are grounded at the same time; the constant current source is the output of the power module; the NTC resistor is a negative temperature coefficient temperature sensor built into the IGBT module, -4 The typical resistance value at 0℃ is 117791Ω, and the typical resistance value at 150℃ is 176Ω; the resistor R2, the resistor R3 and the NTC resistor are connected in series and then in parallel, so that the resistance value of this resistor combination is relatively linear in the range of -40℃-150℃. Based on the relatively linear resistor combination, after passing through the i_sense current, the i_sense current is the current output by the constant current source, and the voltage is also relatively linear to achieve relatively high-resolution temperature reading; the control module can obtain the resistance value of the NTC resistor according to the voltage output by the voltage sampling circuit, and then obtain the corresponding temperature according to the resistance value of the NTC resistor; the resistor R1 is added to be connected in parallel with the aforementioned resistor combination to achieve the overall voltage range biased to 1V - 4V range, which meets the voltage range corresponding to the analog input port of some chips; ordinary chip resistors (resistors R2 and R3) are used in combination to improve the sampling linearity of the IGBT temperature value, and ordinary chip resistors are low in price and extremely cost-effective; each resistor is connected in series and parallel to optimize the linearity of the high-voltage side NTC resistor sampling and improve the accuracy of IGBT temperature sampling. The common temperature range is -20℃ - 90℃ (software protection point). The voltage value and temperature value are relatively linear. Figure 6 shown.

[0036] See also Figure 3 , Figure 3 The A1 terminal of the temperature sampling circuit is connected to Figure 2 The A1 terminal of the medium voltage sampling circuit is connected to realize signal transmission. Figure 3 In the middle, I_SENSE is connected to a constant current source, and the current output by the constant current source is the i_sense current.

[0037] In an optional embodiment, a switching module is connected in parallel at both ends of the NTC resistor; when the switching module is turned on, the NTC resistor is isolated, so as to facilitate detection and judgment of the remaining resistors R1, R2 and R3. The resistance values ​​of the resistors R1, R2 and R3 are known and determined, and these resistance values ​​are pre-set in the control module. Then, when the NTC resistor is isolated, the voltages corresponding to the resistors R1, R2 and R3 are unique and stable, and the unique and stable voltage is stored in the control module as a preset voltage to facilitate subsequent judgment of the states of the resistors R1, R2 and R3.

[0038] like Figure 4 and Figure 5 As shown, specifically, the switching module may be a transistor Q1, which isolates the NTC resistor when it is turned on; the switching module may be a relay U4, which is usually not isolated, and isolates the NTC resistor when the relay U4 is switched.

[0039] See also Figure 4 , Figure 4 The A1 terminal of the temperature sampling circuit is connected to Figure 2 The A1 terminal of the medium voltage sampling circuit is connected to realize signal transmission. Figure 4 NET5 is connected to the control module, and the control module directly sends the control signal to the transistor Q1 through NET5.

[0040] See also Figure 5 , Figure 5 The A1 terminal of the temperature sampling circuit is connected to Figure 2 The A1 terminal of the medium voltage sampling circuit is connected to realize signal transmission. Figure 5 In the middle, I_SENSE is connected to a constant current source, and the current output by the constant current source is the i_sense current.

[0041] One end of the NTC resistor connected to the resistor R3 is connected to the emitter of the transistor Q1, the other end of the NTC resistor is connected to the collector of the transistor Q1, and the base of the transistor Q1 is connected to the control module, that is, Figure 4 NET5 connection control module.

[0042] In an optional embodiment, when the NTC resistor is isolated, the control module is configured to compare the acquired real-time voltage with the preset voltage. If the real-time voltage is the same as the preset voltage, the resistors R1, R2 and R3 are judged to be normal, otherwise they are judged to be abnormal. As the temperature sampling circuit is used for a longer time and more times, the resistors R1, R2 and R3 set therein will be damaged. If these resistors are not detected before temperature detection, the temperature finally obtained is inaccurate. Therefore, before the temperature detection starts, the NTC resistor is isolated to detect the resistors R1, R2 and R3, and the real-time voltage obtained at this time is compared with the preset voltage. If they are the same, it means that the resistors R1, R2 and R3 are normal at this time, and the subsequent temperature detection can be started.

[0043] In an optional embodiment, after determining that the resistors R1, R2, and R3 are normal, the NTC resistor is reconnected to the temperature sampling circuit by disconnecting the switching module. At this time, the control module continues to obtain the current output by the constant current source, and the control module is configured to determine whether the current fluctuation exceeds the preset fluctuation range based on the current output by the constant current source. If it exceeds, it is determined that the load of the constant current source exceeds its tolerance range; since the resistance value of the NTC resistor will change with the change of temperature, when the resistance value increases, it will cause the load of the constant current source, that is, the power module, to increase. At this time, the current output by the constant current source is obtained through the control module (a current sampling circuit can be connected between the constant current source and the control module, so that the control module can accurately obtain the current). If the current fluctuates at this time and the degree of fluctuation exceeds the preset fluctuation range, it is determined that the power module is abnormal at this time or the power module cannot meet the responsible requirements at this time, and the power module needs to be maintained or replaced.

[0044] In an optional embodiment, after judging that the resistors R1, R2 and R3 are normal, the NTC resistor is reconnected to the temperature sampling circuit by disconnecting the switching module. At this time, the control module continuously obtains the continuous voltage output by the voltage sampling circuit. The control module is configured to obtain a real-time voltage value and a relative linear curve of the temperature value according to the continuous voltage, and compare the historical voltage value and the relative linear curve of the temperature value in the stored historical data with the real-time voltage value and the relative linear curve of the temperature value. If the two are the same, the NTC resistor is judged to be normal, and if they are different, the NTC resistor is judged to be abnormal; each time the temperature is detected, a voltage value and a relative linear curve of the temperature value is generated, and each generated voltage value and the relative linear curve of the temperature value is stored as historical data to form a historical database constructed by the historical voltage value and the temperature value relative linear curve. The control module compares the real-time voltage value and the temperature value relative linear curve obtained according to the continuous voltage with the historical voltage value and the temperature value relative linear curve. If the two linear curves are the same or similar within the same temperature change range, the NTC resistor is judged to be normal. The method for judging that the two linear curves are similar can be that within the same temperature change range, the difference between the voltage values ​​corresponding to the two linear curves at each temperature is within an allowable range.

[0045] In an optional embodiment, when the switching module is just turned on or off, the control module is configured to obtain real-time voltage or continuous voltage after a preset time interval, the real-time voltage is the real-time voltage output by the voltage sampling circuit when the switching module just isolates the NTC resistor, and the continuous voltage is the continuous voltage output by the voltage sampling circuit that the control module continuously obtains when the NTC resistor is reconnected to the temperature sampling circuit; when the switching module just isolates the NTC resistor, the control module obtains the real-time voltage output by the voltage sampling circuit after a first preset time interval to avoid inaccurate real-time voltage output by the voltage sampling circuit due to mechanical delay or incomplete switching when the switching module is just switched. At this time, the real-time voltage data at this time will cause inaccurate judgment of the control module. Therefore, the control module delays the acquisition of data to reduce inaccurate judgment caused by inaccurate real-time voltage; similarly, when the switching module just reconnects the NTC resistor to the temperature sampling circuit, the control module also delays the acquisition of data to facilitate accurate judgment.

[0046] At least one other disclosed embodiment also provides a temperature sampling circuit used in the above-mentioned linear sampling system for IGBT modules, including: resistor R1, resistor R2, resistor R3 and NTC resistor; one end of the resistor R1 is connected to a constant current source, and the other end is connected to one end of the NTC resistor, and is also connected to a voltage sampling circuit; the other end of the NTC resistor is connected to one end of the resistor R3; one end of the resistor R2 is connected to the other end of the resistor R3, and one end of the resistor R2 is connected to one end of the NTC resistor.

[0047] In an optional implementation, a switching module is connected in parallel to both ends of the NTC resistor; when the switching module is turned on, the NTC resistor is isolated.

[0048] At least one other disclosed embodiment also provides a working method adopted by the above-mentioned linear sampling system for IGBT modules, including: the voltage output by the temperature sampling circuit is input into the control module after passing through the voltage sampling circuit, and the control module obtains the corresponding temperature data according to the voltage; and a switching module is provided in the temperature sampling circuit, and the NTC resistor in the temperature sampling circuit is isolated by the switching module. At this time, the control module determines whether other parts of the temperature sampling circuit are normal according to the voltage.

[0049] In summary, the linear sampling system for the IGBT module includes: a control module, and a temperature sampling circuit and a voltage sampling circuit electrically connected to the control module; the temperature sampling circuit is electrically connected to the voltage sampling circuit, the voltage output by the temperature sampling circuit is input to the control module after passing through the voltage sampling circuit, and the control module is configured to obtain corresponding temperature data according to the voltage; and a switching module is provided in the temperature sampling circuit, and the NTC resistor in the temperature sampling circuit is isolated by the switching module. At this time, the control module is configured to judge whether other parts in the temperature sampling circuit are normal according to the voltage, thereby realizing the detection of other parts in the temperature sampling circuit, ensuring that other parts in the temperature sampling circuit are normal during the detection process, and ensuring that the temperature can be accurately detected.

[0050] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A linear sampling system for an IGBT module, characterized in that: include: A control module, and a temperature sampling circuit and a voltage sampling circuit electrically connected to the control module; The temperature sampling circuit is electrically connected to the voltage sampling circuit, the voltage output by the temperature sampling circuit is input to the control module after passing through the voltage sampling circuit, and the control module is configured to obtain corresponding temperature data according to the voltage; and The temperature sampling circuit is provided with a switching module, through which the NTC resistor in the temperature sampling circuit is isolated. At this time, the control module is configured to determine whether other parts in the temperature sampling circuit are normal according to the voltage; The temperature sampling circuit comprises: a resistor R1, a resistor R2, a resistor R3 and an NTC resistor; One end of the resistor R1 is connected to a constant current source, and the other end is connected to one end of the NTC resistor; One end of the NTC resistor connected to the resistor R1 is connected to the voltage sampling circuit, and the other end of the NTC resistor is connected to one end of the resistor R3; One end of the resistor R2 is connected to the other end of the resistor R3, and one end of the resistor R2 is connected to one end of the NTC resistor; A switching module is connected in parallel at both ends of the NTC resistor; When the switching module is turned on, the NTC resistor is isolated.

2. The linear sampling system for an IGBT module according to claim 1, characterized in that: When the NTC resistor is isolated, the control module is configured to compare the acquired real-time voltage with the preset voltage. If the real-time voltage is the same as the preset voltage, the resistors R1, R2 and R3 are judged to be normal, otherwise they are judged to be abnormal.

3. The linear sampling system for an IGBT module according to claim 2, characterized in that: After determining that the resistors R1, R2 and R3 are normal, the NTC resistor is reconnected to the temperature sampling circuit by disconnecting the switching module. At this time, the control module continues to obtain the current output by the constant current source. The control module is configured to determine whether the current fluctuation exceeds a preset fluctuation range based on the current output by the constant current source. If exceeded, it is determined that the load of the constant current source exceeds its tolerance range.

4. The linear sampling system for an IGBT module according to claim 2, characterized in that: After determining that the resistors R1, R2, and R3 are normal, the NTC resistor is reconnected to the temperature sampling circuit by disconnecting the switching module. At this time, the control module continuously obtains the continuous voltage output by the voltage sampling circuit. The control module is configured to obtain a real-time relative linear curve of voltage and temperature values ​​based on the continuous voltage, and compare the relative linear curve of historical voltage and temperature values ​​in the stored historical data with the real-time relative linear curve of voltage and temperature values. If the two are the same, the NTC resistor is judged to be normal; if they are different, the NTC resistor is judged to be abnormal.

5. The linear sampling system for an IGBT module according to any one of claims 2 to 4, characterized in that: When the switching module is just turned on or off, the control module is configured to obtain the real-time voltage or the continuous voltage after a preset time interval; The real-time voltage is the real-time voltage output by the voltage sampling circuit when the switching module just isolates the NTC resistor; The continuous voltage is the continuous voltage output by the voltage sampling circuit that the control module continuously obtains when the NTC resistor is reconnected to the temperature sampling circuit.

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