A sampling current correction method, system, device and storage medium

Abstract

The present application discloses a sampling current correction method, system, device and storage medium, which are applied in the field of power electronics technology, including: determining the current working mode and working duty cycle of the DC converter; the working mode includes the boost mode and the buck mode; determining the first sampling current and the second sampling current of the specified phase in the DC converter; based on the working mode, the working duty cycle, the first sampling current and the second sampling current, determining the average current of the specified phase in the DC converter in the current switching cycle as the working current of the specified phase in the current switching cycle. Applying the scheme of the present application, the current correction of the DC converter can be effectively realized, the accuracy of the sampling current of the DC converter is improved, and the implementation is simple and convenient, the cost is low, which is conducive to ensuring the accuracy and reliability of the current sharing control.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to a sampling current correction method, system, device and storage medium. Background Art

[0002] A DC converter, also known as a DC-DC converter, can convert a certain voltage level of DC power into another voltage level of DC power. Figure 1 , which is a schematic diagram of the structure of a multi-phase interleaved parallel DC converter. Currently, high-power DC converters usually use Figure 1 Such a topology, combined with phase-shift control, can reduce output current ripple, alleviate current stress on switching devices, and extend the service life of power electronic devices. Figure 1 Such a multi-phase interleaved parallel DC converter has high requirements for the current equalization control between phases. If there is uneven current between phases, the current ripple will increase, the service life of the switching device will be reduced, and in severe cases, it will cause phase circulation and damage the machine.

[0003] When performing current sharing control, it is necessary to sample the working current of each phase, that is, to sample the inductor current at the inductor position of each phase. One current solution is to use a voltage-type Hall sensor, which can be found in Figure 2 , is a schematic diagram of the transmission principle of the sampling signal. The sampled current signal is converted into a voltage signal, and then the data is transmitted to the control end after passing through the signal processing circuit and the ADC conversion circuit. It can be seen that there will be delays in the hardware circuit. At the same time, there is also a certain data transmission waiting time when the software processes the data. These delays will cause the software to shift its position when collecting current. The sampling method commonly used at present is single sampling, that is, only one sampling is performed in a switching cycle, and the sampling value is used as the average current in the switching cycle. However, due to the influence of the delay error, the actual sampling position is moved backward, which makes the BOOST mode. Please refer to Figure 3 , is a schematic diagram of the current sampling effect. The sampling current will be larger than the theoretical value. In BUCK mode, please refer to Figure 4 , the sampled current will be smaller than the theoretical value. When the sampled value is inaccurate, it is not conducive to ensuring the reliability of current sharing control.

[0004] In summary, how to effectively improve the accuracy of the sampling current of the DC converter is a technical problem that those skilled in the art urgently need to solve. Summary of the invention

[0005] The object of the present invention is to provide a sampling current correction method, system, device and storage medium to effectively improve the accuracy of the sampling current of a DC converter.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a current correction method for a DC converter, comprising:

[0008] Determine the current working mode and working duty cycle of the DC converter; wherein the working mode includes a boost mode and a buck mode;

[0009] Determining a first sampling current and a second sampling current of a specified phase in the DC converter;

[0010] The first sampling current is the working current of the designated phase sampled for the first time in a single switching cycle, and the second sampling current is the working current of the designated phase sampled for the second time in the same switching cycle; in the same switching cycle, the first sampling moment is the default sampling moment, and the second sampling moment differs from the first sampling moment by half a switching cycle;

[0011] Based on the working mode, the working duty cycle, the first sampling current and the second sampling current, an average current of a designated phase in the DC converter in a current switching cycle is determined as the working current of the designated phase in the current switching cycle.

[0012] In one implementation, determining the current operating mode of the DC converter includes:

[0013] The current operation mode of the DC converter is determined based on the current direction of the DC converter, or the current operation mode of the DC converter is determined based on the received mode selection instruction.

[0014] In one implementation, determining the current operating duty cycle of the DC converter includes:

[0015] The proportion of the low-voltage side voltage of the DC converter to the high-voltage side voltage is used as the working duty cycle of the DC converter.

[0016] In one embodiment, the DC converter is a multi-phase interleaved parallel DC converter, and the current correction method of the DC converter further includes:

[0017] Based on the operating current of each phase of the multi-phase interleaved parallel DC converter in the current switching cycle, current sharing control of the multi-phase interleaved parallel DC converter is performed.

[0018] In one implementation, based on the working mode, the working duty cycle, the first sampled current, and the second sampled current, determining an average current of a specified phase in the DC converter in a current switching cycle as the working current of the specified phase in the current switching cycle includes:

[0019] According to the principle that the deviation duration of the first sampling current is the same as the deviation duration of the second sampling current, based on the working mode and the working duty cycle, a first deviation amount between the first sampling current and the average current and / or a second deviation amount between the second sampling current and the average current are determined;

[0020] Determine the average current of the specified phase in the DC converter in the current switching cycle by using the first sampled current and the first deviation, or determine the average current of the specified phase in the DC converter in the current switching cycle by using the second sampled current and the second deviation;

[0021] The determined average current is used as the operating current of the designated phase in the current switching cycle.

[0022] In one embodiment, according to the principle that the deviation duration of the first sampling current is the same as the deviation duration of the second sampling current, based on the working mode and the working duty cycle, determining a first deviation amount between the first sampling current and the average current, and / or a second deviation amount between the second sampling current and the average current includes:

[0023] In the buck mode, a difference value obtained by subtracting the first sampling current from the second sampling current is determined as a first difference value, and a product of the first difference value and the working duty cycle D is used as a second deviation amount between the second sampling current and the average current; and / or, a difference value obtained by subtracting the first sampling current from the second sampling current is determined as a first difference value, a difference value obtained by subtracting the working duty cycle from 1 is determined as a second difference value, and a product of the first difference value and the second difference value is used as a first deviation amount between the first sampling current and the average current;

[0024] In the boost mode, a difference value obtained by subtracting the second sampling current from the first sampling current is determined as a third difference value, and a product of the third difference value and the working duty cycle is used as a second deviation amount between the second sampling current and the average current; and / or, a difference value obtained by subtracting the second sampling current from the first sampling current is determined as a third difference value, a difference value obtained by subtracting the working duty cycle from 1 is determined as a second difference, and a product of the third difference value and the second difference is used as the first deviation amount between the first sampling current and the average current.

[0025] In one embodiment, determining the average current of the specified phase in the DC converter in the current switching cycle by using the first sampled current and the first deviation, or determining the average current of the specified phase in the DC converter in the current switching cycle by using the second sampled current and the second deviation, includes:

[0026] In the step-down mode, the first sampled current is superimposed on the first deviation, and the result obtained is used as the determined average current of the specified phase in the DC converter in the current switching cycle, or the second sampled current is subtracted from the second deviation, and the result obtained is used as the determined average current of the specified phase in the DC converter in the current switching cycle;

[0027] In the boost mode, the first sampled current is subtracted from the first deviation, and the result obtained is used as the average current of the specified phase in the DC converter in the current switching cycle, or the second sampled current is superimposed with the second deviation, and the result obtained is used as the average current of the specified phase in the DC converter in the current switching cycle.

[0028] In a second aspect, the present invention provides a current correction system for a DC converter, comprising:

[0029] A parameter determination module, used to determine the current working mode and working duty cycle of the DC converter; wherein the working mode includes a boost mode and a buck mode;

[0030] A sampling module, used to determine a first sampling current and a second sampling current of a specified phase in the DC converter;

[0031] The first sampling current is the working current of the designated phase sampled for the first time in a single switching cycle, and the second sampling current is the working current of the designated phase sampled for the second time in the same switching cycle; in the same switching cycle, the first sampling moment is the default sampling moment, and the second sampling moment differs from the first sampling moment by half a switching cycle;

[0032] The correction module is used to determine the average current of the specified phase in the DC converter in the current switching cycle based on the working mode, the working duty cycle, the first sampling current and the second sampling current, as the working current of the specified phase in the current switching cycle.

[0033] In a third aspect, the present invention provides a current correction device for a DC converter, comprising:

[0034] Memory for storing computer programs;

[0035] A processor is used to execute the computer program to implement the steps of the current correction method of the DC converter as described above.

[0036] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the current correction method of the DC converter as described above are implemented.

[0037] Applying the technical solution provided by the embodiment of the present invention, considering that the sampling offset is affected by the working mode and the working duty cycle, the working mode includes the boost mode and the buck mode, so it is necessary to determine the current working mode and the working duty cycle of the DC converter. And in the present application scheme, it is necessary to adjust the single sampling to sample twice in each switching cycle, so as to determine the first sampling current and the second sampling current of the specified phase in the DC converter. The first sampling current is the working current of the specified phase sampled for the first time in a single switching cycle, and the second sampling current is the working current of the specified phase sampled for the second time in the same switching cycle. In the same switching cycle, the first sampling moment is the default sampling moment, and the second sampling moment differs from the first sampling moment by half a switching cycle. Ideally, the first sampling current and the second sampling current should be equal to the average current of the specified phase in the current switching cycle, but due to the sampling offset, both will have errors. Furthermore, the present application takes into account that although the first sampling current and the second sampling current both have errors compared to the average current in the current switching cycle, the offset duration of the two is consistent, and the offset conditions are affected by the working mode and the working duty cycle. Therefore, by combining the first sampling current and the second sampling current, through reasonable calculation, the average current of the specified phase in the DC converter in the current switching cycle can be obtained, the error can be eliminated, and the current correction of the DC converter can be effectively completed. And it can be seen that the present application scheme does not need to move the sampling moment or modify the hardware circuit to eliminate the sampling offset, and only needs to be based on the working mode, working duty cycle, the first sampling current and the second sampling current to determine the average current of the specified phase in the DC converter in the current switching cycle, which is simple and convenient to implement and has low cost.

[0038] In summary, the present application scheme can effectively realize the current correction of the DC converter, improve the accuracy of the sampling current of the DC converter, and is simple and convenient to implement with low cost, which is conducive to ensuring the accuracy and reliability of current sharing control. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 It is a structural schematic diagram of a multi-phase interleaved parallel DC converter;

[0041] Figure 2 Schematic diagram of the transmission principle of the sampling signal;

[0042] Figure 3 This is a schematic diagram of the sampling effect in the traditional solution under BOOST mode;

[0043] Figure 4 This is a schematic diagram of the sampling effect in the traditional solution under the BUCK mode;

[0044] Figure 5 A flowchart of a current correction method for a DC converter provided in a specific embodiment of the present invention;

[0045] Figure 6 A schematic diagram of the sampling effect in a boost mode in a specific embodiment of the present invention;

[0046] Figure 7 A schematic diagram of the sampling effect in a step-down mode in a specific embodiment of the present invention;

[0047] Figure 8 A schematic diagram of the structure of a current correction system for a DC converter provided in a specific embodiment of the present invention;

[0048] Fig. 9 A schematic structural diagram of a current correction device for a DC converter provided in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0049] The core of the present invention is to provide a current correction method for a DC converter, which can effectively realize the current correction of the DC converter, improve the accuracy of the sampling current of the DC converter, and is simple and convenient to implement, with low cost, which is conducive to ensuring the accuracy and reliability of current sharing control.

[0050] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0051] Please refer to Figure 5 , Figure 5 The present invention provides a flow chart of a current correction method for a DC converter according to a specific embodiment of the present invention. The current correction method for a DC converter may include the following steps:

[0052] Step S501: Determine the current working mode and working duty cycle of the DC converter; wherein the working mode includes a boost mode and a buck mode.

[0053] The DC converter of the present application can usually be a multi-phase staggered parallel DC converter, which has high requirements for current sharing, so the current sampling value is required to be relatively accurate. The multi-phase staggered parallel DC converter has two working modes: boost mode (BOOST boost) and buck mode (BUCK buck). Of course, in other specific implementations, the DC converter used can be other types of DC converters.

[0054] by Figure 1 Taking the DC converter as an example, the boost mode and the buck mode are explained. Figure 1 The left side is the low voltage side, and the voltage on the low voltage side is denoted as U L , the right side is the high voltage side, the voltage on the high voltage side is denoted as U H For a multi-phase interleaved parallel DC converter, the specific number of parallel phases can be set according to actual needs, for example Figure 1 3 phases are shown, each phase is composed of an inductor and a bridge arm, and the two switch tubes in the bridge arm can usually be IGBTs. Of course, in practical applications, fuses and other components can also be provided in the DC converter according to actual needs, which will not be described in detail in this application.

[0055] In boost mode, current flows from the low voltage side to the high voltage side, that is, Figure 1The current flows from the left side to the right side, and the direction from left to right can usually be regarded as the positive direction of the current. In the boost mode, switches S1, S2 and S3 do not need to be on-off controlled, and the body diodes in these switches can be used for freewheeling. Switches S1, S2 and S3 can also be on-off controlled, and the on-off state is opposite to the on-off state of the switches in the corresponding lower bridge arm. Take one of the phases as an example. For example, during the period when S5 is on, S2 is off, and the current flowing through the inductor L2 increases linearly at a certain rate, and some energy is stored in the inductor L2. During the period when S5 is off, S2 can be turned on, and the current flows to the right side through switch S2, and the current on the inductor L2 gradually decreases. Here, the inductor L2 phase is taken as an example. The control logic of the other phases is the same. There are differences in phase. If it is three-phase, the phase difference is 120°.

[0056] In buck mode, current flows from the high voltage side to the low voltage side, that is, Figure 1 The current flows from the right side to the left side, so the direction from right to left is usually regarded as the positive direction of the current. Of course, a certain direction can also be uniformly regarded as the positive direction of the current. For the convenience of description, the currents in the various drawings of this application are all positive numbers, that is, in the corresponding working mode, the current flow direction is regarded as the positive direction so that the currents in each schematic diagram are all positive, or it can be understood that when the current is negative, its absolute value can be used.

[0057] In the buck mode, switches S4, S5 and S6 do not need to be on-off controlled, and the body diodes in these switches can be used for freewheeling. Switches S4, S5 and S6 can also be on-off controlled, and the on-off state is opposite to the on-off state of the switches in the corresponding upper bridge arm. Still taking the phase of inductor L2 as an example, for example, when S2 is on, S5 is off, and the current flowing through inductor L2 increases linearly at a certain rate, and some energy is stored in inductor L2. When S2 is off, S5 can be turned on, and through inductor L2, switch S5 or the body diode of switch S5 can form a freewheeling loop, and the current on inductor L2 gradually decreases. Here, the phase of inductor L2 is taken as an example, and the control logic of the other phases is the same.

[0058] In addition, the DC converter of the present application may be a DC converter having both a boost mode and a buck mode, or a DC converter having only a single working mode, that is, the present application is applicable to both unidirectional DC-DC converters and bidirectional DC-DC converters. If the DC converter has only a single working mode, it can be understood that when executing step S501, the working mode of the DC converter determined is fixed and will not change due to different scenarios. In the following text of the present application, Figure 1 Such a multi-phase interleaved parallel DC converter is used as an example for explanation, that is, it can support both the boost mode and the buck mode.

[0059] There may be multiple specific ways to determine the current working mode of the DC converter. In a specific implementation of the present invention, determining the current working mode of the DC converter may specifically include:

[0060] The current operating mode of the DC converter is determined based on the current direction of the DC converter, or the current operating mode of the DC converter is determined based on the received mode selection instruction.

[0061] This implementation takes into account that the current direction of the DC converter is different in different working modes. In the buck mode, the current flows from the high voltage side to the low voltage side, and in the boost mode, the current flows from the low voltage side to the high voltage side. Therefore, the current working mode of the DC converter can be determined based on the current direction of the DC converter. For example, three Hall sensors can be used to sample the current of three phases respectively, and the flow direction of the current sampling of each phase is consistent. Therefore, the current working mode of the DC converter can be determined by the current flow direction of any phase.

[0062] This implementation further takes into account that when using a DC converter, the user usually makes a mode selection in advance, so the current working mode of the DC converter can also be determined based on the received mode selection instruction, which is simpler and more convenient.

[0063] For example, in one case, when using a DC converter, after the user connects the DC converter to the battery and the load respectively, the user operates in the host computer so that the DC converter starts working. At this time, the battery can supply power to the load through the DC converter, and at this time, based on the mode selection instruction from the host computer, it can be determined that it is currently in the boost mode, and then the on-off control of the corresponding switch will be performed according to the boost mode. On the contrary, after the user connects the DC converter to the battery and the power supply respectively, the user operates in the host computer so that the DC converter starts working. At this time, the power supply can charge the battery through the DC converter, and at this time, based on the mode selection instruction from the host computer, it can be determined that it is currently in the buck mode, and then the on-off control of the corresponding switch will be performed according to the buck mode. For another example, in one case, although a DC converter supporting two working modes is used, the user locks the mode based on its actual needs, for example, locks it to the buck mode, then it can be directly determined that the current working mode of the DC converter is the buck mode.

[0064] There may be multiple specific implementations for determining the current working duty cycle of the DC converter. For example, in one implementation, different expressions are used to represent the current working duty cycle of the DC converter for different working modes. For example, for the buck mode, the current working duty cycle D of the DC converter can be represented as D=U L / U H , UL is the low voltage side voltage, U H is the high-voltage side voltage. At this time, the working duty cycle D in the buck mode is Figure 1 The conduction duty cycle of the upper bridge arm switch. The larger the duty cycle, the longer the conduction time of the upper bridge arm switch in a single switching cycle, and the lower the voltage reduction, that is, U L The closer to U H For the boost mode, the current duty cycle D of the DC converter can be expressed as D=1-(U L / U H ), at this time, the working duty cycle D in the buck mode is defined as Figure 1 The conduction duty cycle of the middle and lower bridge arm switches. The larger the duty cycle, the longer the conduction time of the lower bridge arm switch in a single switching cycle, and the higher the boost degree, that is, U L with U H The greater the difference.

[0065] In one implementation, the on-duty cycle of the upper bridge arm switch can be uniformly used as the working duty cycle of the DC converter for both the buck mode and the boost mode, and the on-duty cycle of the lower bridge arm switch can be uniformly used as the working duty cycle of the DC converter. For example, in a specific implementation of the present invention, determining the current working duty cycle of the DC converter can specifically include:

[0066] The proportion of the low-voltage side voltage of the DC converter to the high-voltage side voltage is taken as the working duty cycle of the DC converter. That is, in both the buck mode and the boost mode, in this implementation, the working duty cycle D of the DC converter is determined as D=U L / U H That is, no matter in buck mode or boost mode, the on-duty cycle of the upper arm switch is uniformly used as the working duty cycle of the DC converter to facilitate subsequent calculations.

[0067] Step S502: determining a first sampling current and a second sampling current of a specified phase in the DC converter.

[0068] Among them, the first sampling current is the working current of the specified phase sampled for the first time in a single switching cycle, and the second sampling current is the working current of the specified phase sampled for the second time in the same switching cycle; in the same switching cycle, the first sampling moment is the default sampling moment, and the second sampling moment differs from the first sampling moment by half a switching cycle.

[0069] Specifically, the DC converter can be a single-phase or multi-phase DC converter in parallel. The specified phase in the DC converter described in the present application can be any phase in the DC converter. That is to say, the present application scheme takes any phase in the DC converter as an example to illustrate current correction. For other phases, the principles of the present application scheme can be referred to to improve current accuracy.

[0070] For a specified phase in a DC converter, the present application requires sampling the working current of the phase twice in the same switching cycle, that is, sampling the inductor current of the phase twice, which are respectively called the first sampling current and the second sampling current. In addition, the first sampling time is the default sampling time, that is, in the same switching cycle, the default sampling time is the sampling time originally set by the software, and the second sampling time differs from the first sampling time by half a switching cycle.

[0071] For example, for Figure 6 In the boost mode, sampling will be performed on the falling edge of the trigger signal, which corresponds to the stage of the inductor current falling. Due to the influence of delay, when the controller receives the sampled current, the value of the sampled current will be higher than the actual inductor current at the current moment. Therefore, in the boost mode, the first sampled current obtained will be higher than the working current of the current switching cycle. In the boost mode, after the default sampling moment, sampling is required at the rising edge of the trigger signal to obtain the second sampled current, which corresponds to the stage of the inductor current rising. Due to the influence of delay, when the controller receives the sampled current, the value of the sampled current will be lower than the actual inductor current at the current moment. Therefore, in the boost mode, the second sampled current obtained will be lower than the working current of the current switching cycle.

[0072] Figure 6 In the figure, the first sampling current and the second sampling current are denoted as Ia and Ib respectively, and the average current of the current switching cycle is denoted as Imean. Imean is the sampling value that should be obtained under ideal conditions. However, due to the influence of sampling offset, it can be seen that Ia and Ib are not equal to Imean.

[0073] Similarly, for Figure 7In the buck mode, sampling will be performed on the rising and falling edges of the trigger signal, which corresponds to the rising stage of the inductor current. Due to the influence of delay, when the controller receives the sampled current, the value of the sampled current will be lower than the actual inductor current at the current moment. Therefore, in the buck mode, the first sampled current obtained will be lower than the working current of the current switching cycle. In the buck mode, after the default sampling moment, a second sampling is required at the falling edge of the trigger signal to obtain the second sampled current, which corresponds to the falling stage of the inductor current. Due to the influence of delay, when the controller receives the sampled current, the value of the sampled current will be higher than the actual inductor current at the current moment. Therefore, in the buck mode, the second sampled current obtained will be higher than the working current of the current switching cycle.

[0074] Figure 7 Similarly, the first sampling current and the second sampling current are respectively recorded as Ia and Ib, and the average current of the current switching cycle is recorded as Imean. Even though Imean is the sampling value that should be obtained under ideal conditions, due to the influence of sampling offset, it can be seen that Ia and Ib are not equal to Imean.

[0075] Step S503: Based on the working mode, the working duty cycle, the first sampled current and the second sampled current, determine the average current of the designated phase in the DC converter in the current switching cycle as the working current of the designated phase in the current switching cycle.

[0076] It can be seen from the above description that, ideally, the first sampling current and the second sampling current should be equal to the average current of the specified phase in the current switching cycle, but due to the sampling offset caused by the delay, there will be errors in both, and the present application takes into account that the offset duration of the two is consistent. Therefore, when the working mode and the working duty cycle are determined, the first sampling current and the second sampling current can be combined to obtain the average current of the specified phase in the DC converter in the current switching cycle, thereby achieving error elimination and effectively completing the current correction of the DC converter.

[0077] In a specific implementation of the present invention, step S503 may specifically include:

[0078] Step 1: According to the principle that the deviation duration of the first sampling current is the same as the deviation duration of the second sampling current, based on the working mode and the working duty cycle, determine a first deviation amount between the first sampling current and the average current, and / or a second deviation amount between the second sampling current and the average current;

[0079] Step 2: determining the average current of the specified phase in the DC converter in the current switching cycle by using the first sampled current and the first deviation, or determining the average current of the specified phase in the DC converter in the current switching cycle by using the second sampled current and the second deviation;

[0080] Step 3: Use the determined average current as the operating current of the specified phase in the current switching cycle.

[0081] This implementation takes into account that, since the deviation duration of the first sampling current is the same as the deviation duration of the second sampling current, a first deviation amount between the first sampling current and the average current and / or a second deviation amount between the second sampling current and the average current can be determined based on the operating mode and the operating duty cycle.

[0082] It can be seen that when the first deviation is obtained, the average current of the designated phase in the DC converter in the current switching cycle can be determined based on the working mode through the first sampled current and the first deviation. Correspondingly, when the second deviation is obtained, the average current of the designated phase in the DC converter in the current switching cycle can be determined based on the working mode through the second sampled current and the second deviation. And in this implementation, you can choose to calculate the first deviation, or you can choose to calculate the second deviation, which ensures the flexibility of the implementation of the solution. After the average current of the designated phase in the DC converter in the current switching cycle is obtained, it can be used as the working current of the designated phase in the current switching cycle.

[0083] When calculating the first deviation and / or the second deviation, there can be multiple specific calculation methods, as long as it can be ensured that the obtained first deviation can effectively reflect the deviation between the first sampled current and the average current. Similarly, it is necessary to ensure that the obtained second deviation can effectively reflect the deviation between the second sampled current and the average current.

[0084] For example, in a specific embodiment of the present invention, the above step 1 may specifically include:

[0085] In the buck mode, a difference value obtained by subtracting the first sampling current from the second sampling current is determined as the first difference value, and the product of the first difference value and the working duty cycle D is used as the second deviation amount between the second sampling current and the average current; and / or, a difference value obtained by subtracting the first sampling current from the second sampling current is determined as the first difference value, a difference value obtained by subtracting the working duty cycle from 1 is determined as the second difference value, and the product of the first difference and the second difference is used as the first deviation amount between the first sampling current and the average current;

[0086] In the boost mode, a difference value obtained by subtracting the second sampling current from the first sampling current is determined as a third difference value, and the product of the third difference value and the working duty cycle is used as a second deviation amount between the second sampling current and the average current; and / or, a difference value obtained by subtracting the second sampling current from the first sampling current is determined as the third difference value, a difference value obtained by subtracting the working duty cycle from 1 is determined as the second difference, and the product of the third difference and the second difference is used as the first deviation amount between the first sampling current and the average current.

[0087] In this implementation mode, first Figure 7 For example, the working duty cycle of the DC converter in the buck mode is D=U L / U H Therefore, in a single switching cycle T, the duration of the current rise is D×T, and correspondingly, the duration of the current fall is (1-D)×T. Figure 7 The peak-to-peak value of the current in is represented by P, and the deviation time of the first sampling current and the second sampling current is consistent, both represented by △t. It can be understood that in the buck mode, the first sampling current Ia is lower than the average current Imean, and the first deviation between the two can be expressed as , accordingly, the second sampling current Ib is higher than the average current Imean, and the second deviation between the two can be expressed as . So we can get: . Thus, it can be determined . Therefore, the first deviation can be expressed as (Ib-Ia)×(1-D), and the second deviation can be expressed as (Ib-Ia)×D. Therefore, in this embodiment, in the buck mode, the difference obtained by subtracting the first sampling current Ia from the second sampling current Ib is determined as the first difference (Ib-Ia), and the second deviation can be obtained by multiplying the first difference (Ib-Ia) by D, and the first deviation can be obtained by multiplying the first difference (Ib-Ia) by the second difference (1-D).

[0089] Then Figure 6 The boost mode is taken as an example to illustrate. For example, the working duty cycle D of the DC converter in the boost mode is also determined as D=U L / U H Therefore, in a single switching cycle T, the duration of the current drop is D×T, and correspondingly, the duration of the current rise is (1-D)×T. Figure 6 The peak current value in the boost mode is represented by P, and the deviation time of the first sampling current and the second sampling current is consistent, both represented by △t. It can be understood that in the boost mode, the first sampling current Ia is higher than the average current Imean, and the first deviation between the two can be expressed as , accordingly, the second sampling current Ib is lower than the average current Imean, and the second deviation between the two can be expressed as . So we can get: . Thus, it can be determined . Therefore, the first deviation can be expressed as (Ia-Ib)×(1-D), and the second deviation can be expressed as (Ia-Ib)×D. Therefore, in this embodiment, in the boost mode, the difference obtained by subtracting the second sampling current Ib from the first sampling current Ia is determined as the third difference (Ia-Ib). The second deviation can be obtained by multiplying the third difference (Ia-Ib) by D, and the first deviation can be obtained by multiplying the third difference (Ia-Ib) by the second difference (1-D).

[0091] In a specific implementation of the present invention, the above step 2 may specifically include:

[0092] In the step-down mode, the first sampled current is superimposed on the first deviation, and the result obtained is used as the determined average current of the specified phase in the DC converter in the current switching cycle, or the second sampled current is subtracted from the second deviation, and the result obtained is used as the determined average current of the specified phase in the DC converter in the current switching cycle;

[0093] In the boost mode, the first sampled current is subtracted from the first deviation, and the result obtained is used as the average current of the specified phase in the current switching cycle of the determined DC converter, or the second sampled current is superimposed with the second deviation, and the result obtained is used as the average current of the specified phase in the current switching cycle of the determined DC converter.

[0094] This implementation takes into account that, since the first sampled current and the second sampled current are sampled, the average current of the designated phase in the DC converter in the current switching cycle can be effectively determined by either the first deviation or the second deviation.

[0095] In the buck mode, the first sampled current Ia is lower than the average current Imean, so it is necessary to superimpose the first sampled current and the first deviation. For example, in the above example, the first deviation can be expressed as (Ib-Ia)×(1-D). In the buck mode, Ia+(Ib-Ia)×(1-D) can be used as the average current Imean of the specified phase in the DC converter in the current switching cycle. Correspondingly, in the buck mode, the second sampled current Ib is higher than the average current Imean. In the above example, the second deviation can be expressed as (Ib-Ia)×D. In the buck mode, Ib-(Ib-Ia)×D can be used as the average current Imean of the specified phase in the DC converter in the current switching cycle. Since Ib-(Ib-Ia)×D is easier to calculate, in actual applications, in the buck mode, the average current Imean can usually be directly determined based on the calculation method of (Ib-Ia)×D as the working current of the specified phase of the DC converter in the current switching cycle.

[0096] In the boost mode, the first sampled current Ia is higher than the average current Imean, so the first deviation needs to be subtracted from the first sampled current. For example, in the above example, the first deviation can be expressed as (Ia-Ib)×(1-D), then in the boost mode, Ia-(Ia-Ib)×(1-D) can be used as the average current Imean of the specified phase in the DC converter in the current switching cycle. Correspondingly, in the boost mode, the second sampled current Ib is lower than the average current Imean. In the above example, the second deviation can be expressed as (Ia-Ib)×D, then in the boost mode, Ib+(Ia-Ib)×D can be used as the average current Imean of the specified phase in the DC converter in the current switching cycle.

[0097] In addition, it can be understood that, taking the boost mode of this embodiment as an example, Ia-(Ia-Ib)×(1-D) is used as the average current Imean of the specified phase in the DC converter in the current switching cycle. If the working duty cycle D of the boost mode adopts D=1-(U L / U H ), according to the same principle, we can get that in boost mode, the average current Imean=Ia-(Ia-Ib)×D, and we will not repeat the derivation and explanation.

[0098] In a specific embodiment of the present invention, the DC converter is a multi-phase interleaved parallel DC converter, and the current correction method of the DC converter further includes:

[0099] Based on the working current of each phase of the multi-phase interleaved parallel DC converter in the current switching cycle, the current sharing control of the multi-phase interleaved parallel DC converter is performed.

[0100] As described above, the DC converter of the present application can be a single-phase or multi-phase interleaved parallel DC converter, usually a multi-phase interleaved parallel DC converter, which has high requirements for current sharing control. Therefore, after the working current of each phase of the multi-phase interleaved parallel DC converter in the current switching cycle is obtained through sampling and correction, the current sharing control of the multi-phase interleaved parallel DC converter can be performed, that is, the current of each phase is adjusted by controlling the on and off of each phase switch to ensure the current balance of each phase.

[0101] Applying the technical solution provided by the embodiment of the present invention, considering that the sampling offset is affected by the working mode and the working duty cycle, the working mode includes the boost mode and the buck mode, so it is necessary to determine the current working mode and the working duty cycle of the DC converter. And in the present application scheme, it is necessary to adjust the single sampling to sample twice in each switching cycle, so as to determine the first sampling current and the second sampling current of the specified phase in the DC converter. The first sampling current is the working current of the specified phase sampled for the first time in a single switching cycle, and the second sampling current is the working current of the specified phase sampled for the second time in the same switching cycle. In the same switching cycle, the first sampling moment is the default sampling moment, and the second sampling moment differs from the first sampling moment by half a switching cycle. Ideally, the first sampling current and the second sampling current should be equal to the average current of the specified phase in the current switching cycle, but due to the sampling offset, both will have errors. Furthermore, the present application takes into account that although the first sampling current and the second sampling current both have errors compared to the average current in the current switching cycle, the offset duration of the two is consistent, and the offset conditions are affected by the working mode and the working duty cycle. Therefore, by combining the first sampling current and the second sampling current, through reasonable calculation, the average current of the specified phase in the DC converter in the current switching cycle can be obtained, the error can be eliminated, and the current correction of the DC converter can be effectively completed. And it can be seen that the present application scheme does not need to move the sampling moment or modify the hardware circuit to eliminate the sampling offset, and only needs to be based on the working mode, working duty cycle, the first sampling current and the second sampling current to determine the average current of the specified phase in the DC converter in the current switching cycle, which is simple and convenient to implement and has low cost.

[0102] In summary, the present application scheme can effectively realize the current correction of the DC converter, improve the accuracy of the sampling current of the DC converter, and is simple and convenient to implement with low cost, which is conducive to ensuring the accuracy and reliability of current sharing control.

[0103] Corresponding to the above method embodiment, an embodiment of the present invention further provides a current correction system for a DC converter, which can be referred to in correspondence with the above.

[0104] See also Figure 8 FIG. 1 is a schematic diagram of a current correction system for a DC converter according to the present invention, comprising:

[0105] The parameter determination module 801 is used to determine the current working mode and working duty cycle of the DC converter; wherein the working mode includes a boost mode and a buck mode;

[0106] A sampling module 802, configured to determine a first sampling current and a second sampling current of a specified phase in the DC converter;

[0107] The first sampling current is the working current of the designated phase sampled for the first time in a single switching cycle, and the second sampling current is the working current of the designated phase sampled for the second time in the same switching cycle; in the same switching cycle, the first sampling moment is the default sampling moment, and the second sampling moment differs from the first sampling moment by half a switching cycle;

[0108] The correction module 803 is used to determine the average current of the specified phase in the DC converter in the current switching cycle based on the working mode, the working duty cycle, the first sampling current and the second sampling current, as the working current of the specified phase in the current switching cycle.

[0109] In a specific embodiment of the present invention, the parameter determination module 801 includes an operating mode determination unit, which is used to: determine the current operating mode of the DC converter based on the current direction of the DC converter, or determine the current operating mode of the DC converter based on the received mode selection instruction.

[0110] In a specific implementation of the present invention, the parameter determination module 801 includes a duty cycle determination unit, which is used to:

[0111] The proportion of the low-voltage side voltage of the DC converter to the high-voltage side voltage is used as the working duty cycle of the DC converter.

[0112] In a specific embodiment of the present invention, the DC converter is a multi-phase staggered parallel DC converter, and further includes a current sharing control module for:

[0113] Based on the operating current of each phase of the multi-phase interleaved parallel DC converter in the current switching cycle, current sharing control of the multi-phase interleaved parallel DC converter is performed.

[0114] In a specific implementation of the present invention, the correction module 803 includes:

[0115] a deviation determination unit, configured to determine a first deviation between the first sampling current and the average current, and / or a second deviation between the second sampling current and the average current, based on the working mode and the working duty cycle, in accordance with the principle that the deviation duration of the first sampling current is the same as the deviation duration of the second sampling current;

[0116] An average current determination unit is used to determine the average current of the specified phase in the DC converter in the current switching cycle through the first sampling current and the first deviation, or to determine the average current of the specified phase in the DC converter in the current switching cycle through the second sampling current and the second deviation; and use the determined average current as the operating current of the specified phase in the current switching cycle.

[0117] In a specific implementation of the present invention, the deviation determination unit is specifically used to:

[0118] In the buck mode, a difference value obtained by subtracting the first sampling current from the second sampling current is determined as a first difference value, and a product of the first difference value and the working duty cycle D is used as a second deviation amount between the second sampling current and the average current; and / or, a difference value obtained by subtracting the first sampling current from the second sampling current is determined as a first difference value, a difference value obtained by subtracting the working duty cycle from 1 is determined as a second difference value, and a product of the first difference value and the second difference value is used as a first deviation amount between the first sampling current and the average current;

[0119] In the boost mode, a difference value obtained by subtracting the second sampling current from the first sampling current is determined as a third difference value, and a product of the third difference value and the working duty cycle is used as a second deviation amount between the second sampling current and the average current; and / or, a difference value obtained by subtracting the second sampling current from the first sampling current is determined as a third difference value, a difference value obtained by subtracting the working duty cycle from 1 is determined as a second difference, and a product of the third difference value and the second difference is used as the first deviation amount between the first sampling current and the average current.

[0120] In a specific implementation of the present invention, the average current determination unit is specifically used to:

[0121] In the step-down mode, the first sampled current is superimposed on the first deviation, and the result obtained is used as the determined average current of the specified phase in the DC converter in the current switching cycle, or the second sampled current is subtracted from the second deviation, and the result obtained is used as the determined average current of the specified phase in the DC converter in the current switching cycle;

[0122] In the boost mode, the first sampled current is subtracted from the first deviation, and the result obtained is used as the average current of the specified phase in the DC converter in the current switching cycle, or the second sampled current is superimposed with the second deviation, and the result obtained is used as the average current of the specified phase in the DC converter in the current switching cycle.

[0123] Corresponding to the above method and system embodiments, the embodiments of the present invention further provide a current correction device for a DC converter and a computer-readable storage medium, which can be referred to in correspondence with the above.

[0124] See also Fig. 9 As shown, the device may include:

[0125] Memory 901, used for storing computer programs;

[0126] The processor 902 is used to execute a computer program to implement the steps of the current correction method of the DC converter in any of the above embodiments.

[0127] The computer readable storage medium stores a computer program, and when the computer program is executed by the processor, the steps of the current correction method of the DC converter in any of the above embodiments are implemented. The computer readable storage medium mentioned here includes random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, register, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the technical field.

[0128] It should also be noted that, in the present application, relational terms such as first and second, etc. are only 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. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "comprise one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between each embodiment can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0129] Those skilled in the art may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in this application can be implemented by electronic hardware, computer software or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to the function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention. Specific examples are used in this application to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principles of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A current correction method for a DC converter, characterized in that: include: Determine the current working mode and working duty cycle of the DC converter; wherein the working mode includes a boost mode and a buck mode; Determining a first sampling current and a second sampling current of a specified phase in the DC converter; The first sampling current is the working current of the designated phase sampled for the first time in a single switching cycle, and the second sampling current is the working current of the designated phase sampled for the second time in the same switching cycle; in the same switching cycle, the first sampling moment is the default sampling moment, and the second sampling moment differs from the first sampling moment by half a switching cycle; Based on the working mode, the working duty cycle, the first sampling current and the second sampling current, an average current of a designated phase in the DC converter in a current switching cycle is determined as the working current of the designated phase in the current switching cycle.

2. The current correction method of the DC converter according to claim 1, characterized in that: Determine the current operating mode of the DC converter, including: The current operation mode of the DC converter is determined based on the current direction of the DC converter, or the current operation mode of the DC converter is determined based on the received mode selection instruction.

3. The current correction method of a DC converter according to claim 1, characterized in that: Determine the current operating duty cycle of the DC converter, including: The proportion of the low-voltage side voltage of the DC converter to the high-voltage side voltage is used as the working duty cycle of the DC converter.

4. The current correction method of a DC converter according to claim 1, characterized in that: The DC converter is a multi-phase staggered parallel DC converter, and the current correction method of the DC converter also includes: Based on the operating current of each phase of the multi-phase interleaved parallel DC converter in the current switching cycle, current sharing control of the multi-phase interleaved parallel DC converter is performed.

5. The sampling current calibration method according to any one of claims 1 to 4, characterized in that: Based on the working mode, the working duty cycle, the first sampling current and the second sampling current, determining an average current of a specified phase in the DC converter in a current switching cycle as the working current of the specified phase in the current switching cycle, including: According to the principle that the deviation duration of the first sampling current is the same as the deviation duration of the second sampling current, based on the working mode and the working duty cycle, a first deviation amount between the first sampling current and the average current and / or a second deviation amount between the second sampling current and the average current are determined; Determine the average current of the specified phase in the DC converter in the current switching cycle by using the first sampled current and the first deviation, or determine the average current of the specified phase in the DC converter in the current switching cycle by using the second sampled current and the second deviation; The determined average current is used as the operating current of the designated phase in the current switching cycle.

6. The sampling current correction method according to claim 5, characterized in that: According to the principle that the deviation duration of the first sampling current is the same as the deviation duration of the second sampling current, based on the working mode and the working duty cycle, determining a first deviation amount between the first sampling current and the average current, and / or a second deviation amount between the second sampling current and the average current, including: In the buck mode, a difference value obtained by subtracting the first sampling current from the second sampling current is determined as a first difference value, and a product of the first difference value and the working duty cycle D is used as a second deviation amount between the second sampling current and the average current; and / or, a difference value obtained by subtracting the first sampling current from the second sampling current is determined as a first difference value, a difference value obtained by subtracting the working duty cycle from 1 is determined as a second difference value, and a product of the first difference value and the second difference value is used as a first deviation amount between the first sampling current and the average current; In the boost mode, a difference value obtained by subtracting the second sampling current from the first sampling current is determined as a third difference value, and a product of the third difference value and the working duty cycle is used as a second deviation amount between the second sampling current and the average current; and / or, a difference value obtained by subtracting the second sampling current from the first sampling current is determined as a third difference value, a difference value obtained by subtracting the working duty cycle from 1 is determined as a second difference, and a product of the third difference value and the second difference is used as the first deviation amount between the first sampling current and the average current.

7. The sampling current correction method according to claim 5, characterized in that: Determining an average current of a specified phase in the DC converter in a current switching cycle by using the first sampled current and the first deviation, or determining an average current of a specified phase in the DC converter in a current switching cycle by using the second sampled current and the second deviation, comprises: In the step-down mode, the first sampled current is superimposed on the first deviation, and the result obtained is used as the determined average current of the specified phase in the DC converter in the current switching cycle, or the second sampled current is subtracted from the second deviation, and the result obtained is used as the determined average current of the specified phase in the DC converter in the current switching cycle; In the boost mode, the first sampled current is subtracted from the first deviation, and the result obtained is used as the average current of the specified phase in the DC converter in the current switching cycle, or the second sampled current is superimposed with the second deviation, and the result obtained is used as the average current of the specified phase in the DC converter in the current switching cycle.

8. A current correction system for a DC converter, characterized in that: include: A parameter determination module, used to determine the current working mode and working duty cycle of the DC converter; wherein the working mode includes a boost mode and a buck mode; A sampling module, used to determine a first sampling current and a second sampling current of a specified phase in the DC converter; The first sampling current is the working current of the designated phase sampled for the first time in a single switching cycle, and the second sampling current is the working current of the designated phase sampled for the second time in the same switching cycle; in the same switching cycle, the first sampling moment is the default sampling moment, and the second sampling moment differs from the first sampling moment by half a switching cycle; A correction module is used to determine the average current of the specified phase in the DC converter in the current switching cycle based on the working mode, the working duty cycle, the first sampling current and the second sampling current, as the working current of the specified phase in the current switching cycle.

9. A current correction device for a DC converter, characterized in that: include: Memory for storing computer programs; A processor, configured to execute the computer program to implement the steps of the current correction method for a DC converter according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the current correction method of the DC converter according to any one of claims 1 to 7 are implemented.

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