Acquisition voltage compensation circuit of vehicle thermal management controller and vehicle

Abstract

The invention relates to an acquisition voltage compensation circuit of a whole vehicle thermal management controller and a vehicle, which are used for solving the problem that the output voltage sampling precision of the thermal management controller on a sensor is poor due to inconsistent power supply of the sensor and power supply of an ADC (Analog to Digital Converter) module. The circuit comprises a controller, a first voltage reduction module, a second voltage reduction module, a voltage difference processing module and a sensor, wherein the controller comprises an ADC module and a main control chip; the first step-down module supplies power to the master control chip after reducing the voltage of the whole vehicle low-voltage power supply, the second step-down circuit supplies power to the sensor after reducing the voltage of the whole vehicle low-voltage power supply, and the voltage difference processing module performs voltage difference amplification on the power supply voltage of the controller and the sensor; the main control chip compensates the output voltage of the sensor according to the voltage difference amplification value and the power supply voltage of the controller to obtain compensation voltage; the ADC module obtains a sampling binary number through conversion according to the compensation voltage and the power supply voltage of the controller; and the ADC module determines a sampling voltage for software processing of the main control chip according to the sampling binary number and the power supply voltage of the controller.

Description

Technical Field

[0001] The present application relates to a vehicle thermal management system, specifically a collection voltage compensation circuit of a vehicle thermal management controller and a vehicle. Background Art

[0002] The purpose of the technical iteration of the thermal management system of new energy vehicles is to achieve internal matching of the heat and cooling requirements of each circuit, thereby reducing battery energy consumption while meeting cooling and heating needs; the thermal management circuits of pure electric vehicles mainly include automotive air-conditioning circuits (passenger compartment thermal management circuits), battery thermal management circuits, and motor thermal management circuits.

[0003] For the current thermal management control integrated modules, most of them will integrate a series of motor control modules such as water pumps, water valves, electronic expansion valves, etc. into the controller. The controller collects external temperature, humidity, pressure, sunlight and other sensor signals, and uses software algorithms to determine the current system heating or cooling needs and drive the corresponding load to work.

[0004] The entire working logic of the thermal management controller is derived from the sampling of sensor signals, so the sampling accuracy of the sensor is required to be high. The sampling accuracy of the sensor signal is not only related to the resolution of the ADC module of the main control chip, software linear fitting, etc., but also to the power supply.

[0005] Take pressure sensor as an example:

[0006] The sensor output voltage V is: VI = K*V sensor

[0007] The binary number ΔADC collected by the ADC module is:

[0008] ΔADC=(2 n -1)*VI / V ADC =(2 n -1)*K*V sensor / V ADC

[0009] In the above formula, K is a coefficient that changes with pressure, V sensor is the power supply voltage of the sensor, VADC is the power supply voltage of the ADC module, n is the resolution of the ADC module (commonly 10 bits or 12V); ΔADC is the binary number collected by the chip.

[0010] According to the formula, the better the consistency between the sensor power supply and the ADC module power supply, the higher the ADC signal sampling accuracy (does not change with power supply fluctuations).

[0011] In order to prevent the external sensor from short-circuiting and other faults that may damage the internal controller main chip, two independent power supplies are usually used for the ADC module and sensor of the main chip.

[0012] Current thermal management controllers often use a separate LDO low-dropout regulator to power the sensor, which cannot be consistent with the power supply of the ADC module of the main control chip. When the two power supplies fluctuate inconsistently due to load changes, the software sampling accuracy is greatly reduced.

[0013] Some thermal management controllers use LDO chips with tracking functions to power sensors. The output voltage can be adjusted according to the changes in the power supply voltage of the main controller, thereby solving the problem of poor sampling accuracy. However, the price of using such LDO chips with tracking functions is higher than that of ordinary chips, which weakens the market competitiveness of the product. Summary of the invention

[0014] The present invention provides a collection voltage compensation circuit of a whole vehicle thermal management controller and a vehicle, which are used to solve the problem of poor sampling accuracy of the output voltage of a sensor by the thermal management controller due to inconsistency between the power supply of the sensor and the power supply of an ADC module.

[0015] The technical solution of the present invention is:

[0016] On the one hand, the present application provides a collection voltage compensation circuit of a vehicle thermal management controller, including: a controller including an ADC module and a main control chip, a first buck module, a second buck module, a pressure difference processing module and a sensor;

[0017] The first step-down module steps down the low-voltage power supply of the vehicle to power the main control chip, the second step-down circuit steps down the low-voltage power supply of the vehicle to power the sensor, and the pressure difference processing module amplifies the pressure difference between the power supply voltage of the controller and the power supply voltage of the sensor;

[0018] The main control chip of the controller compensates the output voltage of the sensor according to the pressure difference amplification value output by the pressure difference processing module and the power supply voltage of the controller to obtain a compensation voltage;

[0019] The ADC module of the controller converts the compensation voltage and the power supply voltage of the controller to obtain a sampled binary number;

[0020] The ADC module of the controller determines a sampling voltage used for software processing by a main control chip according to the sampled binary number and the power supply voltage of the controller.

[0021] Furthermore, the voltage difference processing module includes: a differential amplifier and a bias circuit;

[0022] The first step-down module is connected to the inverting input terminal of the differential amplifier and the bias circuit;

[0023] The second step-down module and the bias circuit are connected in parallel and then connected to the in-phase input terminal of the differential amplifier;

[0024] The output end of the differential amplifier is connected to the ADC module of the controller;

[0025] The value output by the differential amplifier is a voltage difference amplified N times according to the amplification factor N of the differential amplifier, and the voltage difference is the difference between the output voltage of the first buck module and the output voltage of the second buck module.

[0026] Furthermore, the bias circuit includes: a third resistor, a fourth resistor and a fifth resistor;

[0027] The output end of the differential amplifier is connected to the inverting input end of the differential amplifier through a first resistor, and the first step-down module is connected to the inverting input end of the differential amplifier through a second resistor;

[0028] The first step-down module is connected to the non-inverting input terminal of the differential amplifier through a third resistor and a fourth resistor connected in series, and a fifth resistor connected to ground is further connected between the third resistor and the fourth resistor;

[0029] The second step-down module is connected to the non-inverting input terminal of the differential amplifier via a sixth resistor, and the sixth resistor is connected in parallel with the fourth resistor;

[0030] The output end of the differential amplifier is also connected to the ADC module of the controller through a seventh resistor, and a grounded capacitor is also connected between the seventh resistor and the ADC module of the controller.

[0031] Furthermore, the first buck module and the buck chip used in the first buck module are different.

[0032] Furthermore, the compensation voltage is given by the formula:

[0033]

[0034] Calculated, VI′ is the compensation voltage; VI is the output voltage of the sensor; V sensor is the power supply voltage of the sensor; V ADC is the power supply voltage of the controller; K is the coefficient of the sensor, K is a known value; V diff It is the value obtained by amplifying the pressure difference output by the pressure difference processing module.

[0035] Furthermore, the binary number collected by the ADC module of the main control chip is calculated by the formula:

[0036]

[0037] It is obtained by calculation, ΔADC′ is the binary number collected by the ADC module of the main control chip; and n is the resolution of the ADC module of the main control chip.

[0038] Furthermore, the sampled voltage for controller software processing is given by the formula:

[0039]

[0040] Calculated, V is the sampling voltage used by the main control chip for software processing.

[0041] On the other hand, the present application also provides a vehicle, including the above-mentioned acquisition voltage compensation circuit of the vehicle thermal management controller.

[0042] The beneficial effects of the present invention are:

[0043] The circuit of the present invention can improve the accuracy of the thermal management controller in collecting sensor signals, improve the efficiency of the thermal management controller, and reduce the cost of using traditional power chips. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the first step-down module in the prior art stepping down the low-voltage power supply of the whole vehicle and outputting it to the thermal management controller;

[0045] Figure 2 It is a schematic diagram of the second step-down module in the prior art stepping down the low-voltage power supply of the vehicle and outputting it to the sensor;

[0046] Figure 3 This is a schematic diagram of a pressure difference processing module in an embodiment of the present application;

[0047] Figure 4 This is a logical diagram of the voltage collection compensation for the vehicle thermal management controller implemented in the embodiment of the present application. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0049] Reference Figure 1In the existing thermal management controller power supply circuit, a 12V rated voltage is input from the outside of the system (such as a low-voltage power supply of the entire vehicle), and a 5V voltage is output through a first-level DCDC step-down power supply chip U1 (the circuit where the first-level DCDC step-down power supply chip U1 is located constitutes a first step-down module) to power the controller.

[0050] Reference Figure 2 In the sensor power supply circuit of the existing thermal management system, a 12V rated voltage is input from the outside of the system (such as a low-voltage power supply of the whole vehicle), and a 5V voltage is output through a separate LDO step-down voltage chip U22 (the loop where the LDO step-down voltage chip U22 is located constitutes a second step-down module) to power the external sensors of the thermal management controller.

[0051] Since the two 5V outputs are connected to different loads and the output accuracy of the two power chips is also different, this will cause the signal voltage level collected by the software through the ADC to be unstable, which will ultimately be reflected in the poor sampling accuracy of the thermal management controller for the external sensor.

[0052] To this end, the embodiment of the present application provides a collection voltage compensation circuit of a vehicle thermal management controller, referring to Figure 4 , the circuit includes: a controller including an ADC module and a main control chip, a first step-down module, a second step-down module, a pressure difference processing module and a sensor;

[0053] The first step-down module steps down the low-voltage power supply of the vehicle to power the main control chip, the second step-down circuit steps down the low-voltage power supply of the vehicle to power the sensor, and the pressure difference processing module processes the power supply voltage V ADC and the sensor supply voltage V Sensor Amplify the pressure difference;

[0054] The main control chip of the controller outputs the pressure difference amplification value V according to the pressure difference processing module. diff , the controller supply voltage V ADC Compensating the output voltage VI of the sensor to obtain a compensated voltage VI';

[0055] The ADC module of the controller is based on the compensation voltage VI' and the power supply voltage V ADC The conversion results in a sampled binary number ΔADC′;

[0056] The ADC module of the controller generates a signal according to the sampled binary number ΔADC′ and the power supply voltage V ADC , determine the sampling voltage V used by the main control chip for software processing.

[0057] Reference Figure 3 ,In the embodiment of the present application, the voltage difference processing module includes: a differential amplifier and a bias circuit;

[0058] The first step-down module is connected to the inverting input terminal of the differential amplifier and the bias circuit;

[0059] The second step-down module and the bias circuit are connected in parallel and then connected to the in-phase input terminal of the differential amplifier;

[0060] The output end of the differential amplifier is connected to the ADC module of the controller;

[0061] The value output by the differential amplifier is a voltage difference amplified N times according to the amplification factor N of the differential amplifier, and the voltage difference is the difference between the output voltage of the first buck module and the output voltage of the second buck module.

[0062] The differential amplifier is used to amplify the voltage difference between two input terminals (the inverting input terminal and the non-inverting input terminal). The voltage at its output terminal is proportional to the voltage difference at the input terminals, and the proportionality factor is determined by the gain of the differential amplifier (or the amplification factor N).

[0063] The bias circuit is used to adjust the input bias of the differential amplifier to ensure that the differential amplifier can work stably when there is no voltage difference input and to avoid unnecessary output offset.

[0064] When there is a difference in the output voltage of the first buck module and the second buck module, the difference is amplified N times by the differential amplifier and then output; the bias circuit ensures that when there is no voltage difference, the output of the differential amplifier is at a stable reference point, avoiding unnecessary offset; the amplified voltage difference signal is filtered, collected by the ADC module, and converted into a digital signal for processing by the controller.

[0065] The differential amplifier is used to amplify the voltage difference between the two input terminals (the inverting input terminal and the non-inverting input terminal). The voltage at its output terminal is proportional to the voltage difference at the input terminal, and the proportionality factor is determined by the gain of the differential amplifier (or called the amplification factor N). The amplification factor can be configured by external resistors and R2 = R6, R1 = R4, R3 = R5. The bias circuit is used to adjust the input bias of the differential amplifier to ensure that the differential amplifier can work stably when there is no voltage difference input and avoid unnecessary output offset.

[0066] When there is a difference in the output voltage of the first buck module and the second buck module, the difference is amplified N times by the differential amplifier and then output; the bias circuit ensures that when there is no voltage difference, the output of the differential amplifier is at a stable reference point, avoiding unnecessary offset; the amplified voltage difference signal is filtered, collected by the ADC module, and converted into a digital signal for processing by the controller.

[0067] Reference Figure 3, the bias circuit includes: a third resistor R3, a fourth resistor R4 and a fifth resistor R5;

[0068] The output end of the differential amplifier is connected to the inverting input end of the differential amplifier through the first resistor R1, and the first step-down module is connected to the first resistor R1 through the second resistor R2;

[0069] The first step-down module is connected to the non-inverting input terminal of the differential amplifier through a third resistor R3 and a fourth resistor R4 connected in series, and a grounded fifth resistor R5 is further connected between the third resistor R4 and the fourth resistor R4;

[0070] The second step-down module is connected to the non-inverting input terminal of the differential amplifier via a sixth resistor R6, and the sixth resistor R6 is connected in parallel with the fourth resistor R4;

[0071] The output end of the differential amplifier is also connected to the ADC module of the controller via a seventh resistor R7, and a grounded capacitor C1 is also connected between the seventh resistor R7 and the ADC module of the controller.

[0072] The first step-down module is connected to the inverting input terminal of the differential amplifier through the second resistor R2, and is also connected to the non-inverting input terminal of the differential amplifier (providing bias voltage) through the fourth resistor R4 after voltage division through the third resistor R3 and the fifth resistor R5 in series. This connection method allows the output voltage of the first step-down module to affect the two input terminals of the differential amplifier at the same time, but the influence methods are different.

[0073] The second step-down module is directly connected to the non-inverting input terminal of the differential amplifier through the sixth resistor R6, so that the output voltage of the second step-down module directly contributes to the total voltage of the non-inverting input terminal.

[0074] The fifth resistor R5 is grounded and forms a voltage divider network with the third resistor R3 to adjust the voltage reference (bias voltage) of the differential amplifier. The output of the differential amplifier is connected to the inverting input terminal through the first resistor R1 to form negative feedback, which helps to stabilize the gain of the differential amplifier and reduce nonlinear distortion.

[0075] The output end of the differential amplifier is connected to the ADC module of the controller through the seventh resistor R7. At the same time, a grounded capacitor C1 is connected between the seventh resistor R7 and the ADC module. The resistor R7 and the capacitor C1 form a low-pass filter circuit, which plays a filtering role, smoothes the output voltage, and reduces the influence of noise on ADC sampling.

[0076] Combination Figures 1 to 4The voltage difference processing module first collects the power supply voltage VADC output to the controller by the first step-down module where the first-level DCDC step-down power chip U1 is located, and amplifies it by A times through the differential amplifier of the voltage difference processing module to obtain the voltage value V that can be accurately recognized by the main control chip of the controller. diff , the main control chip can obtain the actual voltage difference V between the controller power supply voltage and the sensor power supply voltage through reverse calculation. diff / A.

[0077] Then when the external sensor is sampling, the main control chip can obtain the output voltage VI of the sensor. At this time, the output voltage VI of the sensor can be compensated by the following formula to obtain the compensation voltage VI′;

[0078]

[0079] Furthermore, the binary number ΔADC′ collected by the ADC module of the controller can be obtained as:

[0080]

[0081] Then, the final sampling voltage of the ADC module of the main controller is determined

[0082] The difference between the final output voltage V of the ADC module of the controller before and after the improvement is compared through actual assignment:

[0083] Assume that the coefficient k of the pressure sensor at the current pressure is 0.3 and the resolution of the ADC module is n=12.

[0084] 1) Ideally, the sensor input voltage V sensor No fluctuation occurs, that is, V ADC =V sensor =5V, V diff =0;

[0085] At this time, the output voltage VI of the sensor is 1.5V, ΔADC is 1228 (rounded), and the final sampling voltage of the ADC module recognized by the main control chip software is 1.499V.

[0086] 2) If the sensor supply voltage V sensor Fluctuations occur, assuming V sensor =4.9V, then the output voltage VI of the sensor is 1.47V. At this time, before the output voltage VI of the sensor is compensated, VI is calculated according to the prior art solution to be 1.47V, ΔADC = 1203 (rounded), and the final sampling voltage V of the ADC module recognized by the main control chip software is 1.469V. When compensating the output voltage VI of the sensor according to the improved technical solution of the embodiment of the present application, substitute the formula The compensation voltage VI'=1.5V is obtained after compensating the output voltage VI of the sensor, and then it can be determined that the binary number ΔADC'=1228 (rounded) collected by the ADC module after correction, and the final sampling voltage V of the ADC module recognized by the main control chip software is 1.499V.

[0087] Therefore, the sampling accuracy of the output voltage of the sensor by the ADC module can be effectively improved through algorithmic compensation without adding additional costs.

[0088] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0089] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0090] It should also be noted that, in this article, the orientation or position relationship indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, which is for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, relational terms such as "first" and "second" are used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations, nor can they be understood as indicating or implying relative importance. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements does not include those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such a process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0091] The technical solution provided by the present invention is described in detail above. The principle and implementation mode of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the present invention, and the content of this specification should not be understood as limiting the present invention. At the same time, for those skilled in the art, according to the present invention, there will be different forms of changes in the specific implementation mode and application scope. It is not necessary and impossible to list all the implementation modes here, and the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A collection voltage compensation circuit for a vehicle thermal management controller, characterized in that: include: A controller including an ADC module and a main control chip, a first step-down module, a second step-down module, a pressure difference processing module and a sensor; The first step-down module steps down the low-voltage power supply of the vehicle to power the main control chip, the second step-down circuit steps down the low-voltage power supply of the vehicle to power the sensor, and the pressure difference processing module amplifies the pressure difference between the power supply voltage of the controller and the power supply voltage of the sensor; The main control chip of the controller compensates the output voltage of the sensor according to the pressure difference amplification value output by the pressure difference processing module and the power supply voltage of the controller to obtain a compensation voltage; The ADC module of the controller converts the compensation voltage and the power supply voltage of the controller to obtain a sampled binary number; The ADC module of the controller determines a sampling voltage used for software processing by a main control chip according to the sampled binary number and the power supply voltage of the controller.

2. The acquisition voltage compensation circuit of the vehicle thermal management controller according to claim 1 is characterized in that: The voltage difference processing module includes: a differential amplifier and a bias circuit; The first step-down module is connected to the inverting input terminal of the differential amplifier and the bias circuit; The second step-down module and the bias circuit are connected in parallel and then connected to the in-phase input terminal of the differential amplifier; The output end of the differential amplifier is connected to the ADC module of the controller; The value output by the differential amplifier is a voltage difference amplified N times according to the amplification factor N of the differential amplifier, and the voltage difference is the difference between the output voltage of the first buck module and the output voltage of the second buck module.

3. The acquisition voltage compensation circuit of the vehicle thermal management controller according to claim 2 is characterized in that: The bias circuit comprises: a third resistor, a fourth resistor and a fifth resistor; The output end of the differential amplifier is connected to the inverting input end of the differential amplifier through a first resistor, and the first step-down module is connected to the inverting input end of the differential amplifier through a second resistor; The first step-down module is connected to the non-inverting input terminal of the differential amplifier through a third resistor and a fourth resistor connected in series, and a fifth resistor connected to ground is further connected between the third resistor and the fourth resistor; The second step-down module is connected to the non-inverting input terminal of the differential amplifier via a sixth resistor, and the sixth resistor is connected in parallel with the fourth resistor; The output end of the differential amplifier is also connected to the ADC module of the controller through a seventh resistor, and a grounded capacitor is also connected between the seventh resistor and the ADC module of the controller.

4. The acquisition voltage compensation circuit of the vehicle thermal management controller according to claim 1, characterized in that: The first buck module and the buck chip used in the first buck module are different.

5. The acquisition voltage compensation circuit of the vehicle thermal management controller according to claim 1, characterized in that: The compensation voltage is given by the formula: Calculated, VI′ is the compensation voltage; VI is the output voltage of the sensor; V sensor is the power supply voltage of the sensor; V ADC is the power supply voltage of the controller; K is the coefficient of the sensor, K is a known value; V diff It is the value obtained by amplifying the pressure difference output by the pressure difference processing module.

6. The acquisition voltage compensation circuit of the vehicle thermal management controller according to claim 5, characterized in that: The binary number collected by the ADC module of the main control chip is calculated by the formula: It is obtained by calculation, ΔADC′ is the binary number collected by the ADC module of the main control chip; and n is the resolution of the ADC module of the main control chip.

7. The acquisition voltage compensation circuit of the vehicle thermal management controller according to claim 6, characterized in that: The sampled voltage for controller software processing is given by the formula: Calculated, V is the sampling voltage used by the main control chip for software processing.

8. A vehicle, characterized in that: A collection voltage compensation circuit comprising the vehicle thermal management controller as described in any one of claims 1 to 7.

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