A temperature acquisition and verification method for implementing functional safety

Abstract

The present invention discloses a temperature acquisition and verification method for implementing functional safety. This method utilizes a temperature acquisition and verification circuit, which includes a temperature sensor DC+, DC−, a first temperature identification circuit, a second temperature identification circuit, an MCU control module, and a safety module. The MCU control module includes a temperature calculation module, a data upload module, and a signal output module. The signal output module includes a temperature information module and a fault information module. The DC+ terminal collects temperature signals through multiplexed sampling, and then the calculated values obtained by using various algorithms are mutually verified, and the data is further mutually verified with the data obtained from the DC− terminal. The present invention enables a non-functional safety temperature sensor to achieve the functional safety target through the mutual verification of additional circuits and different temperature acquisition algorithms, can make ordinary temperature sensors meet the level of functional safety requirements, is applicable to charging devices, is inexpensive, safe and affordable, and meets the needs of manufacturers.

Description

Technical Field

[0001] The present invention belongs to the technical field of power supply sockets, and particularly relates to a temperature acquisition and verification method for realizing functional safety. Background Art

[0002] Both battery electric vehicles (BEVs) and hybrid electric vehicles can be powered by on-vehicle power supplies and drive wheels with motors. Since BEVs and hybrid electric vehicles use electric power to drive the vehicle, there is no exhaust emission during driving, and the environmental impact is relatively small compared with traditional fuel vehicles, so their application prospects are broad.

[0003] BEVs and hybrid electric vehicles are powered by batteries and need to supply power to the batteries. Especially for BEVs, it is necessary to insert a cable charging plug into the charging socket of the BEV at a charging station and use alternating current to charge the battery of the BEV. Since the charging plug and the charging socket adopt a plug-in structure, long-term repeated plugging and unplugging of the charging plug or improper plugging may cause an increase in the contact resistance between the charging plug and the charging socket, resulting in an excessive temperature rise at the contact position, melting of the plastic of the socket and the rubber of the plug, and there are potential safety hazards.

[0004] In the national standard GB / T18487.1-2015, it is described that for application occasions where the rated charging current is greater than 16A, temperature monitoring devices should be provided for both power supply sockets and vehicle sockets, and power supply equipment and BEVs should have temperature detection and over-temperature protection functions; it is relatively common in the market to achieve the temperature acquisition function, but currently most international vehicle manufacturers require that the temperature acquisition function reaches above functional safety level B, and a chip with functional safety is synthesized on the temperature sensor, that is, a temperature sensor containing a functional safety chip that meets the functional safety requirements is selected. However, this kind of temperature sensor is extremely expensive and the materials are in short supply. Summary of the Invention

[0005] In view of this, to solve the above-mentioned deficiencies of the prior art, the purpose of the present invention is to provide a temperature acquisition and verification method for realizing functional safety, which achieves the functional safety goal through the mutual verification of an additional circuit and different temperature acquisition algorithms, so that an ordinary temperature sensor reaches the level of functional safety requirements.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a temperature acquisition and verification method for implementing functional safety. This method utilizes a temperature acquisition and verification circuit, and the temperature acquisition and verification circuit includes a temperature sensor DC+, DC-, a first temperature identification circuit, a second temperature identification circuit, an MCU control module, and a safety module. The MCU control module includes a temperature calculation module, a data upload module, and a signal output module. The signal output module includes a temperature information module and a fault information module. The safety module includes a third temperature identification circuit, a fourth temperature identification circuit, a temperature verification module, and a fault determination module. The temperature calculation module includes a first DC+ temperature calculation module and a first DC- temperature calculation module. The temperature verification module includes a second DC+ temperature calculation module, a second DC- temperature calculation module, and a temperature verification module. The fault determination module includes a fault identification and a fault reporting module;

[0007] The method includes the following steps:

[0008] Step 1, the temperature sensor respectively transmits the DC+ and DC- terminal temperatures to the four-way temperature identification circuit;

[0009] Step 2, the temperature signals collected by the first temperature identification circuit and the second temperature identification circuit are sent to the MCU control module for processing;

[0010] The first DC+ temperature calculation module and the first DC- temperature calculation module obtain the temperature values T +1 、T -1 and send them to the data upload module. The data upload module sends the temperature values T +1 and T -1 to the temperature verification module and synchronously packages and uploads them to the temperature information module;

[0011] Step 3, the temperature signals collected by the third temperature identification circuit and the fourth temperature identification circuit are sent to the safety module for processing;

[0012] The second DC+ temperature calculation module and the second DC- temperature calculation module obtain the temperature values T +2 and T -2 and send them to the temperature verification module;

[0013] Step 4, the temperature verification module verifies the temperature values T +1 、T -1 sent by the data upload module and the temperature values T +2 、T -2 sent by the safety module to obtain the temperature credibility status;

[0014] In step 5, after the fault identification module identifies the trusted state, it determines whether a functional safety-related fault has occurred. If a safety fault occurs, the fault information is sent through the fault reporting module and stored in the fault information module.

[0015] In step 6, the signal output module of the final MCU integrates and outputs the temperature information and the fault information.

[0016] Furthermore, in step 1, the temperature sensor DC+ transmits the temperature data of the DC+ terminal to the first temperature identification circuit and the third temperature identification circuit respectively.

[0017] Furthermore, in step 1, the temperature sensor DC- transmits the temperature data of the DC- terminal to the second temperature identification circuit and the fourth temperature identification circuit respectively.

[0018] Furthermore, in step 4, the temperature verification module conducts verification, including the following specific steps:

[0019] Step 4.1: Compare the temperature value T of the DC+ terminal +1 with T +2 . If the difference is greater than or equal to n%, upload the temperature calculation result of the DC+ terminal and report a fault; if the difference is less than n%, upload the temperature calculated value T of the DC+ terminal + ;

[0020] Step 4.2: Compare the temperature value T of the DC- terminal -1 with T -2 . If the difference is greater than or equal to n%, upload the temperature calculation result of the DC- terminal and report a fault; if the difference is less than n%, upload the temperature calculated value T of the DC- terminal - ;

[0021] Step 4.3: Compare the temperature values T + and T - uploaded in the above steps under the fault-free state of the DC+ terminal and the DC- terminal. If the difference between T + and T - is less than m%, it is determined that the functional safety level requirements are met, and the temperature data is directly uploaded; if the difference is greater than or equal to m%, it is determined that a fault has occurred in the link, and a fault is reported.

[0022] Among them, n% is the deviation obtained to meet the functional safety level requirements, and m% is the probability of meeting the functional safety requirements.

[0023] Furthermore, the temperature calculation result of the DC+ terminal in step 4.1 includes the difference between T +1 and T +2 , and the comparison result of the difference with n%.

[0024] Further, the DC-terminal temperature calculation result described in step 4.2 includes T -1 and T -2 The difference between them, and the comparison result of the difference with n%.

[0025] Further, the calculated value T of the DC+ terminal temperature described in step 4.1 + Satisfies the following conditions:

[0026]

[0027] Further, the calculated value T of the DC-terminal temperature described in step 4.2 - Satisfies the following conditions:

[0028]

[0029] Further, the temperature verification module and the fault determination are set in the MCU control module.

[0030] Further, in step 2, the first temperature calculation method uses the look-up table method, and in step 3, the second temperature calculation method uses the formula calculation method.

[0031] Further, in step 2, the first temperature calculation method uses the formula calculation method, and in step 3, the second temperature calculation method uses the look-up table method.

[0032] The beneficial effects of the present invention are:

[0033] The present invention enables a non-functional safety temperature sensor to achieve the functional safety goal through the mutual calibration of an additional circuit and different temperature acquisition algorithms, so that an ordinary temperature sensor can reach the level of functional safety requirements, and there is no need to select a temperature sensor containing a functional safety chip to meet the functional safety requirements, which is more practical;

[0034] The DC+ terminal collects temperature signals through multiple sampling, and then the calculated values obtained by using multiple algorithms are mutually verified, and the data is further mutually verified with the data obtained by the DC-terminal, so as to meet the functional safety solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0036] Figure 1 It is the structural logic diagram of the temperature acquisition and verification circuit of the present invention;

[0037] Figure 2 This is the flowchart of the temperature acquisition and verification method of the present invention. Specific implementation mode

[0038] The following specific embodiments are given to further clearly, completely and detailedly illustrate the technical solution of the present invention. This embodiment is the best embodiment based on the technical solution of the present invention, but the protection scope of the present invention is not limited to the following embodiments. Specific implementation mode:

[0040] A temperature acquisition and verification method for implementing functional safety, which uses a temperature acquisition and verification circuit. The temperature acquisition and verification circuit includes temperature sensors DC +, DC -, a first temperature identification circuit, a second temperature identification circuit, an MCU control module and a safety module. The MCU control module includes a temperature calculation module, a data upload module and a signal output module. The signal output module includes a temperature information module and a fault information module. The safety module includes a third temperature identification circuit, a fourth temperature identification circuit, a temperature verification module and a fault determination module. The temperature calculation module includes a first DC + temperature calculation module and a first DC - temperature calculation module. The temperature verification module includes a second DC + temperature calculation module, a second DC - temperature calculation module and a temperature verification module. The fault determination module includes a fault identification and a fault reporting module;

[0041] The method includes the following steps:

[0042] Step 1, the temperature sensors respectively transmit the temperatures of the DC + and DC - terminals to the four-way temperature identification circuit;

[0043] Step 2, the temperature signals collected by the first temperature identification circuit and the second temperature identification circuit are sent to the MCU control module for processing;

[0044] The first DC + temperature calculation module and the first DC - temperature calculation module obtain the temperature values T +1 , T -1 and send them to the data upload module. The data upload module sends the temperature values T +1 and T -1 to the temperature verification module and synchronously packs and uploads them to the temperature information module;

[0045] Step 3, the temperature signals collected by the third temperature identification circuit and the fourth temperature identification circuit are sent to the safety module for processing;

[0046] The second DC + temperature calculation module and the second DC - temperature calculation module obtain the temperature values T +2 and T -2 and send them to the temperature verification module;

[0047] Step 4, the temperature calibration module calibrates the temperature values T +1 and T -1 sent by the data upload module and the temperature values T +2 and T -2 sent by the safety module to obtain the temperature trust status; the specific steps are as follows:

[0048] Step 4.1, compare the temperature value T +1 of the DC+ terminal with T +2 . If the difference is greater than or equal to n%, upload the temperature calculation result of the DC+ terminal and report a fault; if the difference is less than n%, upload the temperature calculation value T + of the DC+ terminal;

[0049] Step 4.2, compare the temperature value T -1 of the DC- terminal with T -2 . If the difference is greater than or equal to n%, upload the temperature calculation result of the DC- terminal and report a fault; if the difference is less than n%, upload the temperature calculation value T - of the DC- terminal;

[0050] Step 4.3, compare the temperature values T + and T - uploaded in the above steps when the DC+ terminal and the DC- terminal are in a fault-free state. If the difference between T + and T - is less than m%, it is determined that the functional safety level requirements are met, and the temperature data is directly uploaded; if the difference is greater than or equal to m%, it is determined that a fault has occurred in the link, and a fault is reported;

[0051] Among them, n% is the deviation obtained to meet the functional safety level requirements, and m% is the probability of meeting the functional safety requirements;

[0052] Step 5, after the fault identification module identifies the trust status, it determines whether a functional safety-related fault has occurred. If a safety fault occurs, the fault information is sent through the fault reporting module and stored in the fault information module;

[0053] Step 6, finally, the signal output module of the MCU integrates and outputs the temperature information and the fault information.

[0054] Among them, the safety module is an additional circuit design that meets functional safety. Through the combined action of the additional circuit and the basic function module, different temperature acquisition algorithms are used for mutual verification, so as to achieve the effect of the functional safety goal and make the ordinary temperature sensor reach the level of functional safety requirements.

[0055] The DC+ terminal can collect temperature signals through multiplexed sampling, and then use the calculated values obtained by multiple algorithms to cross-check each other. The data after cross-checking is then cross-checked with the data obtained in the same way at the DC- terminal. After the fault identification module identifies the trustworthy state, it determines whether a functional safety-related fault has occurred. If a safety fault occurs, it is stored in the fault information through the fault reporting module. Finally, the MCU integrates and outputs the temperature information and fault information.

[0056] Through the double cross-check of n% and m%, the safety level of temperature acquisition can be improved to meet the requirements of functional safety.

[0057] Further, in step 1, the temperature sensor DC+ transmits the temperature data of the DC+ terminal to the first temperature identification circuit and the third temperature identification circuit respectively.

[0058] Further, in step 1, the temperature sensor DC- transmits the temperature data of the DC- terminal to the second temperature identification circuit and the fourth temperature identification circuit respectively.

[0059] Further, in step 4, the temperature verification module performs verification.

[0060] Further, the temperature calculation result of the DC+ terminal in step 4.1 includes T +1 and T +2 The difference between them, and the comparison result of the difference with n%.

[0061] Further, the temperature calculation result of the DC- terminal in step 4.2 includes T -1 and T -2 The difference between them, and the comparison result of the difference with n%.

[0062] Further, the calculated temperature value T of the DC+ terminal in step 4.1 + Satisfies the following conditions:

[0063]

[0064] T + is a certain value between T +1 and T +2 , and can also be equal to T +1 or T +2 .

[0065] Further, the calculated temperature value T of the DC- terminal in step 4.2 - Satisfies the following conditions:

[0066]

[0067] T - is a certain value between T -1 and T -2a value between them, or can also be equal to T +1 or T +2 .

[0068] Furthermore, the temperature verification module and the fault determination are set within the MCU control module.

[0069] Furthermore, in step 2, the first temperature calculation method uses the look-up table method, and in step 3, the second temperature calculation method uses the formula calculation method.

[0070] Furthermore, in step 2, the first temperature calculation method uses the formula calculation method, and in step 3, the second temperature calculation method uses the look-up table method.

[0071] By using different temperature acquisition algorithms to mutually verify the acquired temperature, the deviation obtained to meet the requirements of the functional safety level, and the probability of meeting the functional safety requirements, the calculation accuracy is higher, the verification effect is better, and the non-functional safety temperature sensors in the temperature detection scheme reach the functional safety level A / functional safety level B / functional safety level C / functional safety level D.

[0072] In summary, the present invention collects temperature signals through multi-channel sampling, then mutually verifies the calculated values obtained by using multiple algorithms, and the data is also mutually verified with the data obtained from the DC-terminal. The calculation accuracy is higher, the verification effect is better, enabling the non-functional safety temperature sensors in the temperature detection scheme to reach the functional safety level, without the need for temperature sensors containing functional safety chips to meet the functional safety requirements. It is applicable to charging devices, is inexpensive, safe and cost-effective, and meets the requirements of manufacturers.

[0073] The above has shown and described the main features, basic principles and advantages of the present invention. Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have various changes and improvements according to the actual situation, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for temperature acquisition and verification to achieve functional safety, characterized in that : This method utilizes a temperature acquisition and verification circuit, which includes temperature sensors DC+ and DC-, a first temperature identification circuit, a second temperature identification circuit, an MCU control module, and a safety module. The MCU control module includes a temperature calculation module, a data upload module, and a signal output module. The signal output module includes a temperature information module and a fault information module. The safety module includes a third temperature identification circuit, a fourth temperature identification circuit, a temperature verification module, and a fault determination module. The temperature calculation module includes a first DC+ temperature calculation module and a first DC- temperature calculation module. The temperature verification module includes a second DC+ temperature calculation module, a second DC- temperature calculation module, and a temperature verification module. The fault determination module includes a fault identification and a fault reporting module; The method includes the following steps: Step 1, the temperature sensors respectively transmit the temperatures of the DC+ and DC- terminals to the four-way temperature identification circuit; Step 2, the temperature signals collected by the first temperature identification circuit and the second temperature identification circuit are sent to the MCU control module for processing; The first DC+ temperature calculation module and the first DC- temperature calculation module obtain the temperature values T +1 , T -1 and send them to the data upload module, which sends the temperature values T +1 and T -1 to the temperature verification module and synchronously packages and uploads them to the temperature information module; Step 3, the temperature signals collected by the third temperature identification circuit and the fourth temperature identification circuit are sent to the safety module for processing; The second DC+ temperature calculation module and the second DC- temperature calculation module obtain the temperature values T +2 and T -2 and send them to the temperature verification module; Step 4, the temperature verification module verifies the temperature values T +1 , T -1 sent by the data upload module and the temperature values T +2 , T -2 sent by the security module, and obtains the temperature trust status; Step 5, after the fault identification module identifies the trusted state, it determines whether there are function safety-related faults. If a safety fault occurs, the fault information is sent and stored in the fault information module through the fault reporting module; Step 6, finally, the signal output module of the MCU integrates and outputs the temperature information and the fault information.

2. The method for temperature acquisition and verification to achieve functional safety according to claim 1, characterized in that : In Step 1, the temperature sensor DC+ transmits the temperature data of the DC+ terminal to the first temperature identification circuit and the third temperature identification circuit respectively, and the temperature sensor DC- transmits the temperature data of the DC- terminal to the second temperature identification circuit and the fourth temperature identification circuit respectively.

3. The method for temperature acquisition and verification to achieve functional safety according to claim 1, characterized in that : In Step 4, the temperature verification module conducts verification, including the following specific steps: Step 4.1: Compare the temperature value T of the DC+ terminal +1 with T +2 . If the difference is greater than or equal to n%, upload the calculation result of the DC+ terminal temperature and report a fault; if the difference is less than n%, upload the calculated value T + of the DC+ terminal temperature; Step 4.2, compare the temperature value T of the DC-terminal -1 with T -2 , if the difference is greater than or equal to n%, upload the DC-terminal temperature calculation result and report a fault; if the difference is less than n%, upload the DC-terminal temperature calculated value T - ; Step 4.3: The temperature values T + and T - uploaded in the above steps when the DC+ terminal and the DC- terminal are in a fault-free state are compared. If the difference between T + and T - is less than m%, it is determined that the functional safety level requirements are met, and the temperature data is directly uploaded; if the difference is greater than or equal to m%, it is determined that a link failure has occurred and a fault is reported. Where n% is the deviation obtained to meet the requirements of the functional safety level, and m% is the probability of meeting the functional safety requirements.

4. The method for temperature acquisition and verification to achieve functional safety according to claim 3, characterized in that : The DC+ terminal temperature calculation result described in Step 4.1 includes T +1 and T +2 the difference between them, and the comparison result of the difference with n%.

5. The method for temperature acquisition and verification to achieve functional safety according to claim 3, characterized in that : The DC-terminal temperature calculation result described in Step 4.2 includes T -1 and T -2 's difference value and the comparison result between the difference value and n%.

6. The method for temperature acquisition and verification to achieve functional safety according to claim 4, characterized in that : The calculated value T of the temperature of the DC+ terminal described in Step 4.1 + satisfies the following conditions: T + ∈ [T +1 , T +2 .

7. The method for temperature acquisition and verification to achieve functional safety according to claim 5, characterized in that : The calculated value T of the DC-terminal temperature described in Step 4.2 - satisfies the following conditions: T - ∈ [T -1 , T -2 .

8. The method for temperature acquisition and verification to achieve functional safety according to claim 1, characterized in that : The temperature verification module and the fault determination are set within the MCU control module.

9. The method for temperature acquisition and verification to achieve functional safety according to claim 1, characterized in that : In Step 2, the first temperature calculation method uses the look-up table method, and in Step 3, the second temperature calculation method uses the formula calculation method.

10. The method for temperature acquisition and verification to achieve functional safety according to claim 1, characterized in that : In Step 2, the first temperature calculation method uses the formula calculation method, and in Step 3, the second temperature calculation method uses the look-up table method.

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