A DC / DC converter and a voltage conversion method and device thereof, and a storage medium

Abstract

The embodiment of the application discloses a DC / DC converter and a voltage conversion method and device thereof and a storage medium, the method comprises the following steps: acquiring a current input voltage of the DC / DC converter, a last beat output voltage sample value, a last beat output current sample value and a reference voltage; determining a current feedforward control current of the DC / DC converter according to the current input voltage; determining a reference current based on voltage PI regulation according to the last beat output voltage sample value and the reference voltage; determining a current feedback current according to the last beat output current sample value; determining a current output current of an output end of the DC / DC converter based on current PI regulation according to the reference current, the current feedforward control current and the current feedback current; and determining a current output voltage of the DC / DC converter according to the current output current. The application solves the problem that the energy recovery caused by frequent start and stop of a vehicle leads to overvoltage damage of a high-voltage side of the DC / DC converter due to the failure of voltage conversion of the high-voltage side in time, and reduces the damage of high-voltage impact to the whole vehicle electrical system.

Description

TECHNICAL FIELD

[0001] The embodiment of the application relates to the field of vehicles, in particular to a DC / DC converter and a voltage conversion method and device thereof and a storage medium. BACKGROUND

[0002] The hybrid electric vehicle has the characteristics of long endurance and convenient refueling of a fuel vehicle and also has the advantages of a new energy vehicle, and occupies an important position in the new energy vehicle market. The complex road conditions in large cities require frequent start-stop or acceleration-deceleration operations of the vehicle, so that the instantaneous energy recovery of the system of the hybrid electric vehicle causes a high-voltage impact at the DC / DC converter of the power battery and the low-voltage storage battery, and the high-voltage impact can cause damage to the electrical system of the vehicle.

[0003] In the prior art, the low-voltage side overvoltage protection is usually configured at the DC / DC converter, but for the high-voltage side overvoltage, only a fault alarm strategy can be realized, and no explicit solution and specific implementation measures can be given. Once the high-voltage side overvoltage occurs, the vehicle will inevitably be damaged. SUMMARY

[0004] The embodiment of the application provides a DC / DC converter and a voltage conversion method and device thereof and a storage medium, so that the voltage of the high-voltage side of the DC / DC converter is timely changed, and the damage of the high-voltage impact to the electrical system of the vehicle is reduced.

[0005] In a first aspect, the embodiment of the application provides a voltage conversion method of a DC / DC, which comprises the following steps: acquiring a current input voltage, a last beat output voltage sample value, a last beat output current sample value and a reference voltage of the DC / DC converter;

[0006] determining a current feedforward control current of the DC / DC converter according to the current input voltage;

[0007] determining a reference current based on voltage PI adjustment according to the last beat output voltage sample value and the reference voltage;

[0008] determining a current feedback current according to the last beat output current sample value;

[0009] determining a current output current of an output end of the DC / DC converter based on current PI adjustment according to the reference current, the current feedforward control current and the current feedback current;

[0010] determining a current output voltage of the DC / DC converter according to the current output current.

[0011] Optionally, a current input voltage average value is determined according to the current input voltage.

[0012] According to the current output voltage and the input voltage average value, a first calculation formula is used to determine the current feed-forward current calculation value; the first calculation formula is: ; wherein, K is a feed-forward adjustment coefficient, Vin is the current input voltage, and Vavg is the current input voltage average value;

[0013] It is determined whether the current feed-forward current calculation value is within a current preset range.

[0014] If yes, the current feed-forward current calculation value is determined as the current feed-forward control current.

[0015] Alternatively, if the current feed-forward current calculation value is not within the current preset range, it is determined whether the current feed-forward current calculation value is greater than or equal to an upper limit value of the current preset range.

[0016] If yes, the upper limit value of the current preset range is determined as the current feed-forward control current.

[0017] Alternatively, if the current feed-forward current calculation value is not within the current preset range, it is determined whether the current feed-forward current calculation value is less than or equal to a lower limit value of the current preset range.

[0018] If yes, the lower limit value of the current preset range is determined as the current feed-forward control current.

[0019] Alternatively, an input voltage average value calculated in a previous beat is obtained.

[0020] According to the input voltage average value calculated in the previous beat and the current input voltage, a second calculation formula is used to determine the current input voltage average value.

[0021] The second calculation formula is: ; wherein, k is an average value coefficient, is the input voltage average value calculated in the previous beat.

[0022] Alternatively, according to the output voltage sampling value in the previous beat, a current feedback voltage is determined.

[0023] According to the current feedback voltage and the reference voltage, a current voltage deviation value is determined.

[0024] The current voltage deviation value is used as an input quantity of voltage PI adjustment, and an output quantity of the voltage PI adjustment is determined as the reference current based on the voltage PI adjustment.

[0025] Alternatively, a sum of the reference current and the current feed-forward control current is used as a current current reference value.

[0026] determining a current current deviation value according to the current current reference value and the current feedback current;

[0027] taking the current current deviation value as an input quantity of a current PI regulation, and determining an output quantity of the current PI regulation based on the current PI regulation;

[0028] processing the output quantity of the current PI regulation through PWM wave generation, to determine a current output current of the DC / DC converter output end.

[0029] In a second aspect, the embodiment of the present application further provides a voltage conversion device of a DC / DC converter, comprising: a voltage and current parameter acquisition module, configured to acquire a current input voltage of the DC / DC converter, a previous beat output voltage sample value, a previous beat output current sample value, and a reference voltage;

[0030] a feedforward control current determination module, configured to determine a current feedforward control current of the DC / DC converter according to the current input voltage;

[0031] a reference current determination module, configured to determine a reference current based on voltage PI regulation according to the previous beat output voltage sample value and the reference voltage;

[0032] a feedback current determination module, configured to determine a current feedback current according to the previous beat output current sample value;

[0033] an output current determination module, configured to determine a current output current of the DC / DC converter output end based on current PI regulation according to the reference current, the current feedforward control current and the current feedback current;

[0034] an output voltage determination module, configured to determine a current output voltage of the DC / DC converter according to the current output current.

[0035] In a third aspect, the embodiment of the present application further provides a DC / DC converter, comprising: a processor, configured to implement the voltage conversion method of the DC / DC converter provided by any of the embodiments of the present application.

[0036] In a fourth aspect, the embodiment of the present application further provides a computer readable storage medium, which stores computer instructions, and the computer instructions are used to make the processor implement the voltage conversion method of the DC / DC converter provided by any of the embodiments of the present application when executed.

[0037] The current input voltage of the DC / DC converter is used to determine the current feedforward control current, and the current feedforward control current, the current reference current and the current feedback current are used to determine the current output current after current PI adjustment, and the current output voltage is determined according to the current output current. The technical scheme of the application solves the problem that the energy recovery caused by frequent start and stop of the vehicle leads to overvoltage damage of the high-voltage side of the DC / DC converter due to the failure of the voltage of the high-voltage side to be converted in time, and reduces the damage of high-voltage impact to the vehicle electrical system. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0039] Figure 1 is a flowchart of a voltage conversion method of a DC / DC converter according to the first embodiment of the application;

[0040] Figure 2 is a flowchart of a voltage conversion method of a DC / DC converter according to the second embodiment of the application;

[0041] Figure 3 is a flowchart of a voltage conversion method of a DC / DC converter according to the third embodiment of the application;

[0042] Figure 4 is a flowchart of a voltage conversion method of a DC / DC converter according to the fourth embodiment of the application;

[0043] Figure 5 is a flowchart of a voltage conversion method of a DC / DC converter according to the fifth embodiment of the application;

[0044] Figure 6 is a structure diagram of another voltage conversion control of a DC / DC converter according to the sixth embodiment of the application;

[0045] Figure 7 is a structure diagram of a 48V hybrid power system of a DC / DC converter according to the sixth embodiment of the application;

[0046] Figure 8 is a structure diagram of a voltage conversion device of a DC / DC converter according to the seventh embodiment of the application. DETAILED DESCRIPTION

[0047] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application in order to make the technical personnel in the technical field better understand the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by the ordinary technical personnel in the technical field without creative labor should belong to the protection scope of the present application.

[0048] It should be noted that the terms "first", "second" and the like in the description and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a list of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0049] Embodiment one

[0050] Figure 1 is a flowchart of a voltage conversion method of a DC / DC converter according to the embodiment one of the present application. The method can be executed by a DC / DC converter device, which can be composed of hardware and / or software. The voltage conversion method of the DC / DC converter provided by the embodiment of the present application includes the following steps:

[0051] S110, obtaining the current input voltage of the DC / DC converter, the last beat output voltage sample value, the last beat output current sample value, and the reference voltage.

[0052] The DC / DC converter can convert the input voltage, and is also a DC power converter. The DC / DC converter can be divided into three types: boost type, buck type, and boost-buck type. Preferably, the DC / DC converter in the embodiment is of the buck type, and is arranged in the vehicle power system of the new energy vehicle to realize conversion from high voltage to low voltage. When the vehicle is ready to start or needs the DC / DC converter to work, the DC / DC converter can complete self-detection, which is referred to as self-detection. After the self-detection is completed and a enable signal is sent by the vehicle control system, the DC / DC converter starts to work according to the enable signal, and outputs a low voltage signal from the output end after converting the high voltage signal at the input end. The reference voltage of the DC / DC converter can be preset as needed. When the DC / DC converter is initially working, the output voltage sampling value of the last beat and the current value of the output current of the last beat are initial values, which can be zero. When the DC / DC converter is working in a cycle, the output voltage sampling value of the last beat and the output current sampling value of the last beat can change as needed. The current input voltage specifically refers to the voltage at the high voltage side of the DC / DC converter. For example, the current input voltage can be the voltage on both sides of the 48V lithium battery, and the 48V lithium battery provides the required power for the engine of the vehicle.

[0053] S120, determining a current feedforward control current of the DC / DC converter according to the current input voltage.

[0054] The current feedforward control current of the DC / DC converter can be determined by the current input voltage. The feedforward control current and the current input voltage can have a corresponding relationship, a relationship table or a relationship curve, so that the current feedforward control current can be determined correspondingly after the current input voltage is obtained, that is, the current feedforward control current changes with the change of the current input voltage.

[0055] S130, determining a reference current based on voltage PI regulation according to the reference voltage and the output voltage sampling value of the last beat.

[0056] During the actual working process of the DC / DC converter, there is a difference between the actual output voltage and the expected voltage converted by the DC / DC converter. The reference voltage can be the expected voltage converted by the DC / DC converter. At this time, the current output voltage of the DC / DC converter can be adjusted according to the reference voltage and the output voltage sampling value of the last beat. Generally, the reference voltage and the output voltage sampling value of the last beat are used to convert the voltage to the current based on voltage PI regulation to determine the current reference current.

[0057] Optionally, the current feedback voltage is determined according to the last beat output voltage sample value; the current voltage deviation value is determined according to the current feedback voltage and the reference voltage; the current voltage deviation value is taken as an input quantity of voltage PI adjustment, and an output quantity of the voltage PI adjustment is determined as the reference current based on the voltage PI adjustment. Exemplarily, the reference current and the voltage deviation value have a corresponding relationship, that is where i is the iteration number, is the reference current, is the current voltage deviation value after iteration i times. After a period of iteration, the reference current is finally calculated according to the above formula. The specific number of iterations is not limited here, and can be adaptively adjusted according to the actual iteration situation.

[0058] S140, the current feedback current is determined according to the last beat output current sample value.

[0059] where the last beat output current sample value is the actual output current of the DC / DC converter last time, and the actual output current can be determined after corresponding proportional change. Exemplarily, where, is the current feedback current, is the last beat output current sample value, is the current sampling proportional coefficient, is the current sampling first-order lag model, and the current feedback current can be determined according to the above formula.

[0060] S150, the current output current of the DC / DC converter output end is determined based on the current feedback current, the current feedforward control current and the reference current based on the current PI adjustment.

[0061] where the current output current of the DC / DC converter output end is determined based on the reference current, the current feedforward control current, the current feedback current and the current PI adjustment.

[0062] Optionally, the sum of the reference current and the current feedforward control current is taken as the current reference value, the current current deviation value is determined according to the current reference value and the current feedback current, the current deviation value is taken as the input quantity of the current PI adjustment, and the output quantity of the current PI adjustment is determined based on the current PI adjustment. The current output current of the DC / DC converter output end is determined after the output quantity of the current PI adjustment is processed by PWM wave generation. Further, the current deviation value is determined based on the current reference value and the current feedback current, and the current deviation value and the current PI adjustment output quantity have a corresponding relationship. Exemplarily, the relationship can be where j is the iteration number, is the current deviation value after iteration j times, The current PI regulation output quantity is outputted, and the specific number of iterations is not limited here, and can be adaptively adjusted according to the actual iteration condition. The output quantity after current PI regulation is subjected to PWM wave generation processing, and the current output current of the corresponding output DC / DC converter.

[0063] S160, determine the current output voltage of the DC / DC converter according to the current output current.

[0064] According to the Ohm's law formula, when the current output current is known, the current output voltage of the DC / DC converter can be calculated through a specific load, i.e. a known resistance value.

[0065] The current feedforward control current is determined by obtaining the current input voltage of the DC / DC converter, and the current feedforward control current, the current reference current and the current feedback current are subjected to current PI regulation to determine the current output current, and the current output voltage is determined according to the current output current. The technical scheme of the application solves the problem that the energy recovery caused by frequent start and stop of the vehicle causes the voltage on the high-voltage side of the DC / DC converter to be unable to be converted in time, resulting in overvoltage damage on the high-voltage side, and reduces the damage to the vehicle electrical system caused by high-voltage impact.

[0066] Embodiment two

[0067] Figure 2 is a flowchart of a voltage conversion method of a DC / DC converter according to embodiment two of the application, and the specific scheme for determining the current feedforward control current of the DC / DC converter is specifically provided on the basis of the above embodiment. The technical scheme of the embodiment comprises:

[0068] S210, obtain the current input voltage of the DC / DC converter, the last beat output voltage sample value, the last beat output current sample value and the reference voltage.

[0069] S220, determine the current input voltage average value according to the current input voltage.

[0070] The current input voltage is the voltage between the two ends of the high-voltage side, and there is a slight fluctuation in the current input voltage obtained each time. The current input voltage average value is calculated by using an iterative calculation method.

[0071] S230, determine the current feedforward current calculation value according to the current output voltage and the input voltage average value by using a first calculation formula.

[0072] The determination of the current feedforward current calculation value is related to the current output voltage and the input voltage average value, and the first calculation formula is: ; wherein, K is a feed-forward adjustment coefficient, Vin is a current input voltage, and Vavg is a current input voltage average value. After the current input voltage average value is calculated based on iterative calculation, the current feed-forward current calculation value can be calculated using the first calculation formula.

[0073] S240, determining whether the current feed-forward current calculation value is within the current preset range, and if so, performing S250.

[0074] S250, determining the current feed-forward current calculation value as the current feed-forward control current.

[0075] The current feed-forward current calculation value can be calculated according to the first calculation formula, and the size relationship between the current feed-forward current calculation value and the current preset range is further determined. There are two cases corresponding to the size relationship, the current feed-forward current calculation value exceeds the current preset range or the current feed-forward current calculation value does not exceed the current preset range. When the current feed-forward current value does not exceed the current preset range, the current feed-forward current calculation value is the current feed-forward control current under the above condition.

[0076] S260, determining a reference current based on voltage PI regulation according to the last beat output voltage sample value and the reference voltage.

[0077] S270, determining a current feedback current according to the last beat output current sample value.

[0078] S280, determining a current output current of the DC / DC converter output end based on current PI regulation according to the reference current, the current feed-forward control current and the current feedback current.

[0079] S290, determining a current output voltage of the DC / DC converter according to the current output current.

[0080] In the embodiment of the application, when the current input voltage of the DC / DC converter is obtained to determine the current feed-forward control current, the current input voltage average value is determined using the current input voltage, and the current feed-forward current calculation value is calculated according to the formula of the current input voltage, the current input voltage average value and the current feed-forward current calculation value. In addition, it is determined whether the current feed-forward current calculation value exceeds the current preset range, and the current feed-forward control current is determined as the current feed-forward current calculation value that does not exceed the current preset range. The technical scheme of the application solves the problem that the energy recovery caused by frequent start and stop of the vehicle leads to overvoltage damage of the high-voltage side of the DC / DC converter due to the failure of the voltage of the high-voltage side to be converted in time, and reduces the damage to the vehicle electrical system caused by high-voltage impact.

[0081] Embodiment three

[0082] Figure 3is a flowchart of a voltage conversion method of a DC / DC converter according to Embodiment Three of the present application. Based on the above-mentioned embodiments, the present embodiment specifically provides a scheme in which the DC / DC converter determines whether the current feedforward control current is within a preset current range. The technical solution of the present embodiment includes:

[0083] S301, obtaining a current input voltage of the DC / DC converter, a previous beat output voltage sample value, a previous beat output current sample value, and a reference voltage.

[0084] S302, determining a current input voltage average value according to the current input voltage.

[0085] S303, determining a current feedforward current calculation value according to the current output voltage and the input voltage average value by using a first calculation formula.

[0086] S304, determining whether the current feedforward current calculation value is within a preset current range. If yes, performing S305; if no, performing S306.

[0087] S305, determining the current feedforward current calculation value as the current feedforward control current.

[0088] S306, determining whether the current feedforward current calculation value is greater than or equal to an upper limit value of the preset current range. If yes, performing S307.

[0089] S307, determining the upper limit value of the preset current range as the current feedforward control current.

[0090] The preset current range is a limitation on the calculation range of the current feedforward current calculation value, and includes an upper limit value and a lower limit value of the preset current range. When the calculated current feedforward current calculation value exceeds the upper limit value of the preset current range, the current feedforward control current is the upper limit value of the preset current range. For example, the upper limit value and the lower limit value of the preset current range are 5A and 15A respectively, the current feedforward current calculation value is 10A, and the determined current feedforward control current is 10A. When the current feedforward current calculation value is 20A and exceeds the upper limit value of the preset current range, the determined current feedforward control current is 15A. Here, only an example is provided, and the upper limit value and the lower limit value of the preset current range are not specifically limited.

[0091] Further, the upper limit value and the lower limit value of the preset current range are and , the corresponding formula of the current feedforward current calculation value is , and the current feedforward control current is determined by comparing the size relationship between the current feedforward current calculation value and the upper limit value and the lower limit value of the preset current range. When is greater than or equal to If the current input voltage is greater than the current input voltage average value, and the current input voltage average value is greater than the current feedforward control current calculation value, then the current feedforward control current is If the current input voltage is less than the current input voltage average value, and the current input voltage average value is less than the current feedforward control current calculation value, then the current feedforward control current is If the current input voltage is less than or equal to the current input voltage average value, and the current input voltage average value is less than the current feedforward control current calculation value, then the current feedforward control current is If the current input voltage is greater than the current input voltage average value, and the current input voltage average value is greater than the current feedforward control current calculation value, then the current feedforward control current is If the current input voltage is less than the current input voltage average value, and the current input voltage average value is less than the current feedforward control current calculation value, then the current feedforward control current is If the current input voltage calculation value is within the current preset range, then the current feedforward control current is .

[0092] S308, determining a reference current based on voltage PI regulation according to the last beat output voltage sample value and the reference voltage.

[0093] S309, determining a current feedback current according to the last beat output current sample value.

[0094] S310, determining a current output current of the DC / DC converter output end based on current PI regulation according to the reference current, the current feedforward control current, and the current feedback current.

[0095] S311, determining a current output voltage of the DC / DC converter according to the current output current.

[0096] In the embodiment, the current input voltage of the DC / DC converter is acquired to determine the current feedforward control current, the current input voltage average value is determined based on the current input voltage, the current feedforward control current calculation value is calculated according to the formula of the current input voltage, the current input voltage average value, and the current feedforward current calculation value, the current feedforward control current calculation value is determined whether it exceeds the current preset range, the current feedforward control current calculation value which does not exceed the current preset range is taken as the current feedforward control current, and the current feedforward control current is determined by comparing the current feedforward control current calculation value which exceeds the current preset range with the upper limit of the current preset range. The technical scheme of the embodiment solves the problem that the energy recovery caused by frequent start and stop of the vehicle leads to overvoltage damage of the high-voltage side of the DC / DC converter due to the failure of the voltage of the high-voltage side to be converted in time, and reduces the damage of the high-voltage impact to the vehicle electrical system.

[0097] Embodiment four

[0098] Figure 4 is a flowchart of a voltage conversion method of a DC / DC converter according to the embodiment four of the application, and the DC / DC converter determines whether the current feedforward control current is in the current preset range based on the above embodiment. The technical scheme of the embodiment includes:

[0099] S401, acquiring the current input voltage of the DC / DC converter, the last beat output voltage sample value, the last beat output current sample value, and the reference voltage.

[0100] S402, determining a current input voltage average value according to the current input voltage.

[0101] S403, determining a current feed-forward current calculation value according to the current output voltage and the input voltage average value by using a first calculation formula.

[0102] S404, judging whether the current feed-forward current calculation value is within a current preset range, if yes, performing S405; if no, performing S406.

[0103] S405, determining the current feed-forward current calculation value as a current feed-forward control current.

[0104] S406, judging whether the current feed-forward current calculation value is less than or equal to a lower limit value of the current preset range, if yes, performing S407.

[0105] S407, determining the lower limit value of the current preset range as the current feed-forward control current.

[0106] The current preset range is a limitation on the calculation range of the current feed-forward current calculation value, and the current preset range includes an upper limit value and a lower limit value of the current preset range. When the calculated current feed-forward current is not less than or equal to the lower limit value of the current preset range, the current feed-forward control current is the lower limit value of the current preset range. For example, the upper limit value and the lower limit value of the current preset range are 5A and 15A respectively, the current feed-forward current calculation value is 2A, which is less than the lower limit value of the current preset range, and the determined current feed-forward control current is 5A. Here, only an example is given, and the upper limit value and the lower limit value of the current preset range are not limited.

[0107] S408, determining a reference current based on voltage PI regulation according to the last beat output voltage sample value and the reference voltage.

[0108] S409, determining a current feedback current according to the last beat output current sample value.

[0109] S410, determining a current output current of the DC / DC converter output end based on current PI regulation according to the reference current, the current feed-forward control current and the current feedback current.

[0110] S411, determining a current output voltage of the DC / DC converter according to the current output current.

[0111] The embodiment of the present application further determines the current input voltage average value after determining the current feed-forward control current according to the current input voltage of the DC / DC converter. The current feed-forward current calculation value is calculated based on the formula of the current input voltage, the current input voltage average value and the current feed-forward current calculation value. In addition, it is judged whether the current feed-forward current calculation value exceeds the current preset range. The current feed-forward control current is the current feed-forward current calculation value which does not exceed the current preset range. The current feed-forward control current is determined by comparing the current feed-forward current calculation value which exceeds the current preset range with the lower limit of the current preset range. The technical solution of the present application solves the problem that the energy recovery caused by the frequent start and stop of the vehicle leads to the overvoltage damage of the high-voltage side of the DC / DC converter due to the failure of the voltage transformation of the high-voltage side in time, and reduces the damage of the high-voltage impact to the vehicle electrical system.

[0112] Embodiment five

[0113] Figure 5 The flowchart of the voltage transformation method of the DC / DC converter provided by the embodiment five of the present application is shown. The scheme for determining the current input voltage average value of the DC / DC converter is specifically provided based on the above-mentioned embodiments. The technical solution of the present embodiment includes:

[0114] S501, obtaining the current input voltage, the last sampling value of the output voltage, the last sampling value of the output current and the reference voltage of the DC / DC converter.

[0115] S502, obtaining the last calculated input voltage average value.

[0116] S503, determining the current input voltage average value according to the last calculated input voltage average value and the current input voltage by using the second calculation formula.

[0117] The last calculated input voltage average value is zero at the initial moment of the DC / DC converter. The last calculated input voltage average value is not zero when the DC / DC converter starts to work. The calculation formula of the last calculated input voltage average value, the current input voltage and the current input voltage average value determines the current input voltage average value. Specifically, the second calculation formula is: ; wherein k is the mean value coefficient, The last calculated input voltage average value is zero at the initial moment of the DC / DC converter. The last calculated input voltage average value is not zero when the DC / DC converter starts to work. The calculation formula of the last calculated input voltage average value, the current input voltage and the current input voltage average value determines the current input voltage average value. Specifically, the second calculation formula is:

[0118] S504, determining a current feed-forward current calculation value according to the current output voltage and the input voltage average value by using a first calculation formula.

[0119] S505, determining whether the current feed-forward current calculation value is within a preset current range, and if yes, performing S506.

[0120] S506, determining the current feed-forward current calculation value as a current feed-forward control current.

[0121] S507, determining a reference current according to the last beat output voltage sample value and the reference voltage based on voltage PI regulation.

[0122] S508, determining a current feedback current according to the last beat output current sample value.

[0123] S509, determining a current output current of the DC / DC converter output end according to the reference current, the current feed-forward control current and the current feedback current based on current PI regulation.

[0124] S510, determining a current output voltage of the DC / DC converter according to the current output current.

[0125] The embodiment of the application is based on the current input voltage, the last beat output voltage sample value, the last beat output current sample value and the reference voltage of the DC / DC converter, and determines the current input voltage average value by using the formula between the current input voltage, the last input voltage average value and the current input voltage average value. The technical scheme of the application solves the problem that the energy recovery caused by the frequent start and stop of the vehicle leads to the overvoltage damage of the high-voltage side of the DC / DC converter due to the failure of the voltage conversion of the high-voltage side in time, and reduces the damage of the high-voltage impact to the vehicle electrical system.

[0126] Embodiment six

[0127] Figure 6 is another structure schematic diagram of voltage conversion control of the DC / DC converter according to the embodiment six of the application. The embodiment is based on the above-mentioned embodiments and provides a specific embodiment.

[0128] Exemplary, Figure 7 is a structure schematic diagram of the 48V hybrid power system of the DC / DC converter according to the embodiment six of the application. Referring to Figure 7After the DC / DC converter is powered on, the initialization and self-check of the state are carried out by the DC / DC converter itself, and the normal state of the DC / DC converter is ensured. The vehicle controller sends an enable signal to the DC / DC converter, and the DC / DC converter starts to work. The power battery relay on the high-voltage side of the DC / DC converter is closed, the 48V lithium battery branch is turned on, and the engine BSG normally rotates to drive the vehicle to travel. When the vehicle is in the process of normal driving, frequent start-stop is required due to road conditions, and the hybrid power system of the vehicle needs to frequently recover energy. Strong instantaneous energy recovery pushes up the high-voltage side bus voltage of the DC / DC converter, and forms a high-voltage electric shock on the high-voltage side of the DC / DC converter. After passing through the DC / DC converter, the high-voltage electric shock can be converted into low-voltage electric shock. The 12V storage battery on the low-voltage side of the DC / DC converter can provide stable voltage support for the vehicle load. The DC / DC converter mainly converts the high-voltage electric shock on the high-voltage side into low-voltage electric shock, and takes away the high-voltage electric shock caused by the high-voltage electric shock to the hybrid power system.

[0129] On the basis of the above hybrid power system, with reference to Figure 6, further illustrate the voltage conversion control process of the DC / DC converter. First, by obtaining the current input voltage Vin of the high voltage side of the DC / DC converter, the current feedforward current calculation value is determined by using the related formula. By comparing the current feedforward current calculation value with the current preset range, the current feedforward control current is determined after corresponding amplitude limiting control. In the voltage conversion control of the DC / DC converter, there are voltage control outer loop and current control inner loop. For the voltage control outer loop, the output voltage of the last time is output as the corresponding current feedback voltage Vf through the voltage sampling ring H1(s). The reference voltage Vref is subtracted from the current feedback voltage Vf, and then the current voltage deviation value verr is obtained. The current voltage deviation value verr is used as the input quantity of the voltage PI regulation, and the output quantity after the voltage PI regulation is used as the reference current Iref. The sum of the reference current Iref and the current feedforward control current is used as the current reference value. For the current control inner loop, the output current of the last time is output as the corresponding current feedback current If through the current sampling ring H2(s). The sum of the reference current Iref and the current feedforward control current is used as the current reference value, and the difference between the current reference value and the current feedback current If is used as the current deviation value ierr. The current deviation value ierr is used as the input quantity of the current PI regulation, and the current output current Io is determined after the current PI regulation and the PWM wave generation processing. The current output voltage Vo is calculated according to the current output current Io and the load Z(s), so as to realize the cycle control process of the entire DC / DC converter. The specific functions and beneficial effects of the corresponding function modules of the above-mentioned embodiment are not repeated here.

[0130] Embodiment seven

[0131] Figure 8 A structure diagram of a voltage conversion device of a DC / DC converter is provided for the seventh embodiment of the present application. The device can be composed of hardware and / or software. As shown in the figure, the device comprises: a voltage and current parameter acquisition module 810, a feedforward control current determination module 820, a reference current determination module 830, a feedback current determination module 840, an output current determination module 850, an output voltage determination module 860, a current feedforward current calculation value judgment module 870, and a current output voltage average value determination module 880. Figure 8

[0132] The voltage and current parameter acquisition module 810 is used to acquire the current input voltage, the last time output voltage sample value, the last time output current sample value, and the reference voltage of the DC / DC converter.

[0133] ​The feedforward control current determination module 820 is configured to determine a current feedforward control current of the DC / DC converter according to a current input voltage.

[0134] The reference current determination module 830 is configured to determine a reference current based on voltage PI adjustment according to a last beat output voltage sample value and a reference voltage.

[0135] The feedback current determination module 840 is configured to determine a current feedback current according to a last beat output current sample value.

[0136] The output current determination module 850 is configured to determine a current output current of an output end of the DC / DC converter based on current PI adjustment according to the reference current, the current feedforward control current and the current feedback current.

[0137] The output voltage determination module 860 is configured to determine a current output voltage of the DC / DC converter according to the current output current.

[0138] The current feedforward current calculation value judgment module 870 is configured to judge whether the current feedforward current calculation value is within a current preset range; if yes, the current feedforward current calculation value is determined as the current feedforward control current; if the current feedforward current calculation value is not within the current preset range, it is judged whether the current feedforward current calculation value is greater than or equal to an upper limit value of the current preset range; if yes, the upper limit value of the current preset range is determined as the current feedforward control current; if the current feedforward current calculation value is not within the current preset range, it is judged whether the current feedforward current calculation value is less than or equal to a lower limit value of the current preset range; if yes, the lower limit value of the current preset range is determined as the current feedforward control current.

[0139] The current output voltage average value determination module 880 is configured to obtain a last beat calculated input voltage average value; determine a current input voltage average value by using a second calculation formula according to the last beat calculated input voltage average value and a current input voltage; the second calculation formula is: ; wherein k is an average coefficient, is the last beat calculated input voltage average value.

[0140] Further, the feedforward control current determination module 820 is further configured to determine a current input voltage average value according to the current input voltage, and determine a current feedforward current calculation value by using a first calculation formula according to the current output voltage and the input voltage average value; the first calculation formula is: ; wherein K is a feedforward adjustment coefficient, Vin is the current input voltage, and Vavg is the current input voltage average value.

[0141] The reference current determination module 830 is further configured to determine a current feedback voltage according to the last beat output voltage sample value, determine a current voltage deviation value according to the current feedback voltage and a reference voltage, take the current voltage deviation value as an input of voltage PI adjustment, and determine an output of the voltage PI adjustment as the reference current based on the voltage PI adjustment.

[0142] The output current determination module 850 is further configured to take a sum of the reference current and the current feedforward control current as a current reference value, determine a current current deviation value according to the current reference value and a current feedback current, take the current current deviation value as an input of current PI adjustment, and determine an output of the current PI adjustment based on the current PI adjustment, and determine a current output current of the DC / DC converter through PWM wave generation processing of the output of the current PI adjustment.

[0143] The voltage conversion device of the DC / DC converter provided by the embodiment of the application determines the current feedforward control current by obtaining the current input voltage of the DC / DC converter, the last beat output voltage sample value, the last beat output current sample value and the reference voltage. The reference current and the current output current are determined based on the voltage PI and the current PI, respectively, and then the current output voltage of the DC / DC converter is determined according to the output current. The voltage conversion device of the DC / DC converter can perform the voltage conversion method of the DC / DC converter provided by any embodiment of the application, has the function modules and the beneficial effects corresponding to the execution method.

[0144] Embodiment eight

[0145] The embodiment eight of the application provides a DC / DC converter, which comprises a processor configured to perform the voltage conversion method of the DC / DC converter provided by any embodiment of the application, has the function modules and the beneficial effects corresponding to the execution method.

[0146] Embodiment nine

[0147] The computer readable storage medium of the embodiment nine of the application stores a computer program, and the computer program for implementing the method of the application can be written in any combination of one or more programming languages. The computer program can be provided to a processor of a general purpose computer, a special purpose computer, or other programmable data processing apparatus, so that the computer program, when executed by the processor, causes the functions / operations specified in the flowchart and / or block diagram to be implemented. The computer program can be executed completely on the machine, partially on the machine and partially on a remote machine, partially on the machine and partially on a remote machine as a separate software package, or completely on a remote machine or server.

[0148] In the context of the present application, a computer-readable storage medium can be a tangible medium that can contain or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. A computer-readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium can be a machine-readable signal medium. More specific examples of a machine-readable storage medium will include one or more lines of a program of instructions in a transitory signal, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0149] To provide for interaction with a user, the systems and techniques described here can be implemented on an electronic device having a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the electronic device. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0150] The systems and techniques described here can be implemented in a computing system that includes a back end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front end component (e.g., a user computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0151] The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system, to solve the defects of large management difficulty and weak business scalability in traditional physical host and VPS service.

[0152] It should be understood that the various forms of flow shown above can be used to reorder, add or delete steps. For example, each step described in the present application can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solutions of the present application can be achieved, which is not limited herein.

[0153] The above detailed description does not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A voltage conversion method of a DC / DC converter, characterized by, The method comprises: acquiring a current input voltage, a previous beat output voltage sample value, a previous beat output current sample value, and a reference voltage of the DC / DC converter; acquiring an input voltage average value calculated in a previous beat; According to the input voltage average value calculated in the last beat and the current input voltage, a second calculation formula is used to determine the current input voltage average value; the second calculation formula is: ; wherein k is a mean coefficient, is the input voltage average value calculated in the last beat. According to the current input voltage and the current input voltage average value, a first calculation formula is used to determine a current feedforward current calculation value; the first calculation formula is: ; wherein, K is a feedforward adjustment coefficient, Vin is the current input voltage, and Vavg is the current input voltage average value. determining whether the current feedforward current calculation value is within a current preset range; if yes, determining the current feedforward current calculation value as a current feedforward control current; if the current feedforward current calculation value is not within the current preset range, determining whether the current feedforward current calculation value is greater than or equal to an upper limit value of the current preset range; if yes, determining the upper limit value of the current preset range as the current feedforward control current; or, if the current feedforward current calculation value is not within the current preset range, determining whether the current feedforward current calculation value is less than or equal to a lower limit value of the current preset range; if yes, determining the lower limit value of the current preset range as the current feedforward control current; determining a current feedback voltage according to the previous beat output voltage sample value; determining a current voltage deviation value according to the current feedback voltage and the reference voltage; taking the current voltage deviation value as an input quantity of voltage PI regulation, and determining an output quantity of the voltage PI regulation as a reference current based on the voltage PI regulation; determining a current feedback current according to the previous beat output current sample value; taking a sum of the reference current and the current feedforward control current as a current current reference value; determining a current current deviation value according to the current current reference value and the current feedback current; taking the current current deviation value as an input quantity of current PI regulation, and determining an output quantity of the current PI regulation based on the current PI regulation; determining a current output current of the DC / DC converter output end through PWM wave generation processing of the output quantity of the current PI regulation; determining a current output voltage of the DC / DC converter according to the current output current.

2. A voltage conversion device of a DC / DC converter, characterized by comprising: The voltage conversion method for executing the DC / DC converter of claim 1, wherein the voltage conversion device of the DC / DC converter comprises: a voltage and current parameter acquisition module, configured to acquire a current input voltage, a previous beat output voltage sample value, a previous beat output current sample value, and a reference voltage of the DC / DC converter; a feedforward control current determination module, configured to determine a current feedforward control current of the DC / DC converter according to the current input voltage; a reference current determination module, configured to determine a reference current based on voltage PI regulation according to the previous beat output voltage sample value and the reference voltage; a feedback current determination module, configured to determine a current feedback current according to the previous beat output current sample value; an output current determination module, configured to determine a current output current of the DC / DC converter output end based on current PI regulation according to the reference current, the current feedforward control current, and the current feedback current; an output voltage determination module, configured to determine a current output voltage of the DC / DC converter according to the current output current.

3. A DC / DC converter, characterized by The method comprises: A processor is configured to execute the voltage conversion method of the DC / DC converter as claimed in claim 1.

4. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer instructions for causing a processor to implement the voltage conversion method of the DC / DC converter as claimed in claim 1 when executed.

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