Inverter bus voltage adjustment method, device, controller and storage medium

Abstract

The present invention discloses a method, device, controller and storage medium for adjusting the bus voltage of an inverter. The method comprises: obtaining the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current; obtaining the estimated value of the bus voltage based on the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current; adjusting the estimated value of the bus voltage to determine the target bus voltage; adjusting the duty cycle of the DC / DC converter in the inverter based on the target bus voltage so that the output bus voltage is consistent with the target bus voltage. The technical solution of the present invention adjusts the output bus voltage of the inverter to be consistent with the target bus voltage, and obtains an accurate and reasonable output bus voltage that can be stably output, thereby improving the inverter efficiency.

Description

Technical Field

[0001] The present invention relates to the field of inverters, and in particular to an inverter bus voltage adjustment method, device, controller and storage medium. Background Art

[0002] In photovoltaic power generation or energy storage systems, grid-connected inverters usually adopt a two-stage structure, with the front stage being a DC / DC converter and the back stage being an inverter circuit. The DC / DC converter needs to control the output bus voltage above the voltage required by the inverter circuit according to the preset bus voltage reference value, so that the inverter circuit can output the output bus voltage to the grid, but an excessively high output bus voltage will reduce the efficiency of the grid-connected inverter.

[0003] In the prior art, VBUS=Vmax+α(Vout)+β(Iout), where VBUS is the estimated value of the bus voltage, Vmax is the peak voltage of the grid, Vout is the grid voltage, Iout is the inverter output current, α(Vout) is the grid voltage increment, β(Iout) is the inverter output current increment, if the grid voltage is DC, the grid voltage peak is the grid voltage, if the grid voltage is AC, the grid voltage peak is the product of the grid voltage value and 1.414. When the inverter is working, as the grid voltage Vout and the inverter output current Iout change, the estimated value of the bus voltage VBUS is adjusted in real time to obtain the estimated value of the bus voltage VBUS=Vmax+α(Vout)+β(Iout).

[0004] The prior art only considers the impact of changes in the grid voltage value Vout and the grid-connected current value Iout on the output bus voltage, and does not consider factors such as the maximum duty cycle of the subsequent inverter circuit. The applicable scope of the output bus voltage estimation is narrow. When the maximum duty cycle setting of the inverter is changed, it is impossible to obtain an accurate and reasonable output bus voltage, which may cause the inverter waveform to be distorted, thereby reducing the inverter efficiency. Summary of the invention

[0005] The embodiments of the present invention provide an inverter bus voltage adjustment method, device, controller and storage medium to solve the problem that an accurate and reasonable output bus voltage cannot be obtained, thereby reducing the inverter efficiency.

[0006] A method for adjusting an inverter bus voltage, comprising:

[0007] Obtain the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current;

[0008] Obtaining a bus voltage estimation value based on the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current;

[0009] Adjusting the estimated bus voltage value to determine the target bus voltage at the current moment;

[0010] The duty cycle of the DC / DC converter in the inverter is adjusted based on the target bus voltage at the current moment, so that the output bus voltage is consistent with the target bus voltage at the current moment.

[0011] Further, the obtaining of the bus voltage estimation value based on the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current includes:

[0012] The bus voltage estimation formula is used to calculate the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current to obtain the bus voltage estimation value, wherein the bus voltage estimation formula is U bus =(a / m)*(U max +bI out )+c, where m is the maximum duty cycle of the inverter, a is the correction coefficient of the maximum duty cycle of the inverter, and U max is the peak voltage of the power grid, I out is the inverter output current, b is the adjustment coefficient of the inverter output current, and c is the correction coefficient of the bus voltage.

[0013] Furthermore, the adjusting process of the estimated bus voltage value to determine the target bus voltage at the current moment includes:

[0014] The bus voltage estimation value is subjected to anti-shake processing to determine the target bus voltage at the current moment.

[0015] Furthermore, the anti-shake processing is performed on the estimated bus voltage value to determine the target bus voltage at the current moment, including:

[0016] Obtain an estimated voltage change value based on the estimated bus voltage value at the current moment and the target bus voltage at the previous moment;

[0017] If the estimated voltage change value is a negative value, the change state corresponding to the estimated bus voltage value is a decreasing state, and the target bus voltage at the current moment is determined based on the comparison result between the absolute value of the estimated voltage change value and the preset voltage change value;

[0018] If the estimated voltage change value is a positive value, the change state corresponding to the estimated bus voltage value is an increasing state, and the estimated bus voltage value at the current moment is determined as the target bus voltage at the current moment.

[0019] Further, the determining the target bus voltage at the current moment based on the comparison result of the absolute value of the estimated voltage change value and the preset voltage change value includes:

[0020] If the absolute value of the estimated voltage change value is less than the preset voltage change value, the target bus voltage at the previous moment is determined as the target bus voltage at the current moment;

[0021] If the absolute value of the estimated voltage change value is greater than the preset voltage change value, the estimated bus voltage value at the current moment is determined as the target bus voltage at the current moment.

[0022] Furthermore, the adjusting process of the estimated bus voltage value to determine the target bus voltage at the current moment also includes:

[0023] The estimated bus voltage value is subjected to limit processing to determine the target bus voltage at the current moment.

[0024] Furthermore, the limiting process is performed on the estimated bus voltage value to determine the target bus voltage at the current moment, including:

[0025] If the estimated bus voltage value is less than the bus voltage lower limit value, the bus voltage lower limit value is determined as the target bus voltage at the current moment;

[0026] If the estimated bus voltage value is greater than the bus voltage upper limit value, the bus voltage upper limit value is determined as the target bus voltage at the current moment;

[0027] If the estimated bus voltage value is between the bus voltage lower limit value and the bus voltage upper limit value, the estimated bus voltage value is determined as the target bus voltage at the current moment.

[0028] An inverter bus voltage adjustment device, comprising:

[0029] An acquisition module is used to obtain the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current;

[0030] A voltage estimation module, used for obtaining a bus voltage estimation value based on the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current;

[0031] A voltage adjustment processing module is used to adjust the bus voltage estimation value to determine the target bus voltage at the current moment;

[0032] The adjustment execution module is used to adjust the duty cycle of the DC / DC converter in the inverter based on the target bus voltage at the current moment, so that the output bus voltage is consistent with the target bus voltage at the current moment.

[0033] An inverter controller comprises a memory, a processor and an inverter controller program stored in the memory and executable on the processor. When the processor executes the inverter controller program, the inverter bus voltage adjustment method is implemented.

[0034] A computer-readable storage medium stores an inverter controller program, and when the inverter controller program is executed by a processor, the inverter bus voltage adjustment method is implemented.

[0035] The inverter bus voltage adjustment method, device, inverter controller and storage medium described above, the inverter controller can obtain the estimated bus voltage value based on the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current, dynamically analyze and adjust the estimated bus voltage value in real time, determine the target bus voltage at the current moment, and then adjust the duty cycle of the DC / DC converter in the inverter based on the target bus voltage at the current moment, so that the output bus voltage is consistent with the target bus voltage at the current moment. The purpose is to enable the inverter controller to adjust the output bus voltage of the inverter to be consistent with the target bus voltage at the current moment, to accurately adjust the inverter bus voltage to improve the grid-connected efficiency, to reasonably and stably output the output bus voltage, and to improve the inverter efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0037] Figure 1 is a flow chart of a method for adjusting the inverter bus voltage in one embodiment of the present invention;

[0038] Figure 2 is another flow chart of an inverter bus voltage adjustment method in one embodiment of the present invention;

[0039] Figure 3 is another flow chart of an inverter bus voltage adjustment method in one embodiment of the present invention;

[0040] Figure 4 is another flow chart of an inverter bus voltage adjustment method in one embodiment of the present invention;

[0041] Figure 5 is a schematic diagram of an inverter bus voltage adjustment device in one embodiment of the present invention;

[0042] Figure 6is a schematic diagram of an inverter controller in one embodiment of the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] This embodiment provides an inverter bus voltage adjustment method, which can be applied in an inverter controller. The inverter controller can obtain a bus voltage estimation value based on the maximum duty cycle of the inverter, the peak voltage of the power grid, and the inverter output current, dynamically analyze and adjust the bus voltage estimation value in real time, determine the target bus voltage at the current moment, and then adjust the duty cycle of the DC / DC converter in the inverter based on the target bus voltage at the current moment, so that the output bus voltage is consistent with the target bus voltage at the current moment. The purpose is to enable the inverter controller to adjust the output bus voltage of the inverter to be consistent with the target bus voltage at the current moment, to accurately adjust the inverter bus voltage to improve the grid-connected efficiency, to reasonably and stably output the output bus voltage, and to improve the inverter efficiency.

[0045] In one embodiment, if Figure 1 As shown, a method for adjusting the bus voltage of an inverter is provided, and the method is applied to an inverter controller as an example for explanation, and includes the following steps:

[0046] S10: Obtain the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current.

[0047] Among them, the maximum duty cycle of the inverter is the parameter of the inverter output waveform, which is set by the user. The peak voltage of the grid is the peak voltage of the grid external to the inverter, which can be determined by the effective voltage of the grid obtained by the inverter. The effective voltage of the grid is the effective voltage of the grid external to the inverter. It should be noted that when the external grid is DC, the peak voltage of the grid is equal to the effective voltage of the grid; when the external grid is AC, the peak voltage of the grid is equal to the effective voltage of the grid and The product of the grid peak voltage and the grid effective voltage is 1.414. The inverter output current is the current output by the inverter.

[0048] In this example, the inverter controller obtains the maximum duty cycle of the inverter input by the user, and collects the peak voltage of the power grid and the inverter output current in real time, so that the inverter controller can perform subsequent voltage adjustment processing according to the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current obtained in real time. It can be understood that the inverter controller can improve the reliability of the inverter bus voltage adjustment method by obtaining reliable and accurate parameters such as the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current in real time.

[0049] S20: Obtain a bus voltage estimation value based on the maximum duty cycle of the inverter, the peak voltage of the power grid, and the inverter output current.

[0050] The bus voltage estimation value is an estimation value of the output bus voltage of the inverter obtained by calculating the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current. It can be understood that the bus voltage estimation value can be used as a basis for the inverter controller to accurately and reliably adjust the output bus voltage of the inverter according to the bus voltage estimation value.

[0051] It should be noted that when the maximum duty cycle of the inverter and the peak voltage of the power grid obtained remain unchanged, the estimated value of the bus voltage is dynamically adjusted according to the inverter output current obtained in real time. When the maximum duty cycle of the inverter and the inverter output current obtained remain unchanged, the estimated value of the bus voltage is dynamically adjusted according to the peak voltage of the power grid obtained in real time. When the peak voltage of the power grid and the inverter output current remain unchanged, the estimated value of the bus voltage can be dynamically adjusted according to the maximum duty cycle of the inverter obtained in real time.

[0052] S30: adjusting the estimated bus voltage value to determine the target bus voltage at the current moment.

[0053] The target bus voltage at the current moment is a reference voltage for adjusting the output bus voltage.

[0054] It can be understood that based on the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current, the bus voltage estimation value for estimating the output bus voltage is obtained. In order to make the output bus voltage stable and reasonably output. Therefore, the bus voltage estimation value is dynamically analyzed and adjusted in real time to determine the target bus voltage at the current moment, so that the inverter controller can adjust the output bus voltage of the inverter to be consistent with the target bus voltage at the current moment, so as to reasonably and stably output the output bus voltage and improve the inverter efficiency.

[0055] S40: adjusting the duty cycle of the DC / DC converter in the inverter based on the target bus voltage at the current moment, so that the output bus voltage is consistent with the target bus voltage at the current moment.

[0056] Among them, the DC / DC converter is a device in the inverter that steps up or down the voltage.

[0057] Specifically, the DC / DC converter compares the target bus voltage at the current moment with the output bus voltage to obtain the voltage difference between the target bus voltage at the current moment and the output bus voltage, and feeds back the voltage difference between the target bus voltage at the current moment and the output bus voltage to the inverter controller. Further, the inverter controller adjusts the duty cycle of the DC / DC converter according to the voltage difference between the target bus voltage at the current moment and the output bus voltage, so as to achieve the purpose of making the output bus voltage consistent with the target bus voltage at the current moment, so that the output bus voltage can be output stably.

[0058] In this embodiment, the inverter controller can obtain the estimated bus voltage value based on the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current, dynamically analyze and adjust the estimated bus voltage value in real time, determine the target bus voltage at the current moment, and then adjust the duty cycle of the DC / DC converter in the inverter based on the target bus voltage at the current moment, so that the output bus voltage is consistent with the target bus voltage at the current moment. The purpose is to enable the inverter controller to adjust the output bus voltage of the inverter to be consistent with the target bus voltage at the current moment, to accurately adjust the inverter bus voltage to improve the grid connection efficiency, to reasonably and stably output the output bus voltage, and to improve the inverter efficiency.

[0059] In one embodiment, in step S20, based on the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current, obtaining the estimated value of the bus voltage includes: using the bus voltage estimation formula to calculate the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current to obtain the estimated value of the bus voltage, wherein the bus voltage estimation formula is U bus =(a / m)*(U max +bI out )+c, where m is the maximum duty cycle of the inverter, a is the correction coefficient of the maximum duty cycle of the inverter, and U max is the peak voltage of the power grid, I out is the inverter output current, b is the adjustment coefficient of the inverter output current, and c is the correction coefficient of the bus voltage.

[0060] Among them, U bus is the estimated value of bus voltage, U max is the peak voltage of the power grid, I outis the inverter output current. The correction coefficient a of the inverter maximum duty cycle, the adjustment coefficient b of the inverter output current and the correction coefficient c of the bus voltage are user-defined parameters. The correction coefficient a of the inverter maximum duty cycle is used to correct the inverter maximum duty cycle. The adjustment coefficient b of the inverter output current is used to calculate the bus voltage increment corresponding to the inverter output current. The correction coefficient c of the bus voltage is used to correct the estimated bus voltage value so that the estimated bus voltage value is closer to the output bus voltage.

[0061] Specifically, based on the maximum duty cycle U of the inverter obtained in real time max , Grid peak voltage U max and inverter output current I out . Based on the bus voltage estimation formula U bus =(a / m)*(U max +bI out )+c,U bus =(a / m)*U max +(a / m)*bI out +c, the estimated value of bus voltage is (a / m)*U max 、(a / m)*bI out And c. It can be understood that when the maximum duty cycle m of the inverter and the peak voltage U of the grid are obtained max When the inverter output current I out When changing, according to ΔU bus =(a / m)*b*ΔI out , dynamically adjust the estimated value of the bus voltage. When the maximum duty cycle m of the inverter and the inverter output current I out When it remains unchanged, according to ΔU bus =(a / m)*ΔU max , dynamically adjust the estimated bus voltage value. When the maximum duty cycle m of the inverter changes to k, according to U bus =(a / k)*(U max +bI out ), dynamically adjust the estimated value of bus voltage. bus The difference between the estimated bus voltage at the current moment and the estimated bus voltage at the previous moment, ΔI out is the difference between the inverter output current at the current moment and the inverter output current at the previous moment, ΔU max The difference between the peak voltage of the power grid at the current moment and the peak voltage of the power grid at the previous moment, k is the maximum duty cycle of the inverter after the maximum duty cycle of the inverter m is changed.

[0062] As an example, the maximum duty cycle m of the inverter can be 0.96, the correction coefficient a of the maximum duty cycle of the inverter can be 1, the adjustment coefficient b of the inverter output current can be 0.5, and the correction coefficient c of the bus voltage can be 3. The above values ​​are only for illustration purposes, and the specific values ​​can be set according to the actual situation. max is 320V, inverter output current I out For 20A, U can be calculated bus =(1 / 0.96)*(320+0.5*20)+3=346.75V.

[0063] The maximum duty cycle m of the inverter is equal to 0.96 at the current moment and the previous moment, and the peak voltage of the grid is U max is 320V, inverter output current I out When the current changes from 20A at the previous moment to 40A at the current moment, according to ΔU bus =(a / m)*b*ΔI out , ΔU bus =(1 / 0.96)*0.5*(40-20)=10.42V. According to ΔU bus =10.42V, for U bus =346.75V, the estimated value of the adjusted bus voltage is ΔU bus +U bus =357.17V.

[0064] The maximum duty cycle m of the inverter at the current moment is equal to that of the previous moment, which is 0.96, and the inverter output current I out is 20A, the peak voltage of the power grid is U max When the voltage changes from 320V at the last moment to 300V at the current moment, according to ΔU bus =(a / m)*ΔU max , ΔU bus =(1 / 0.96)*(300-320)=-20.83V. According to ΔU bus =-20.83V, for U bus =346.75V, the estimated value of the adjusted bus voltage is ΔU bus +U bus =325.92V.

[0065] The peak voltage U of the power grid is equal at the current moment and the previous moment max is 320V, inverter output current I out When the inverter maximum duty cycle m is changed from 0.96 to k=0.90, the estimated bus voltage is U bus =(a / k)*(U max +bI out), U bus =(1 / 0.90)*(320+0.5*20)=366.67V.

[0066] In this embodiment, when the inverter controller obtains the maximum inverter duty cycle m and the grid peak voltage U max When the inverter output current I out When changing, according to ΔU bus =(a / m)*b*ΔI out , dynamically adjust the estimated value of the bus voltage. When the maximum duty cycle m of the inverter and the inverter output current I out When it remains unchanged, according to ΔU bus =(a / m)*ΔU max , dynamically adjust the estimated bus voltage value. When the maximum duty cycle m of the inverter changes to k, according to U bus =(a / k)*(U max +bI out ), dynamically adjust the estimated bus voltage value. The inverter controller adjusts the output bus voltage according to the estimated bus voltage value, thereby protecting the output bus voltage waveform from distortion or ensuring the output bus voltage has the best efficiency.

[0067] In one embodiment, in step S30, based on the estimated bus voltage value, the output bus voltage is adjusted to determine the target bus voltage at the current moment, including: anti-shaking processing of the estimated bus voltage value to determine the target bus voltage at the current moment.

[0068] Among them, anti-shake processing of the bus voltage estimation value refers to the process of making the bus voltage estimation value stably output according to a stable voltage value when the frequency or amplitude of the bus voltage estimation value rising or falling is too large, that is, preventing the output bus voltage from jumping with excessive frequency or amplitude.

[0069] Specifically, the inverter controller performs anti-shake processing on the output bus voltage through the bus voltage estimation value, specifically, by analyzing the frequency or amplitude of the rise or fall of the real-time bus voltage estimation value, the frequency or amplitude of the rise or fall of the output bus voltage can be analyzed. Further, according to the frequency or amplitude of the rise or fall of the bus voltage estimation value, the target bus voltage at the current moment is determined, so that the inverter controller adjusts the output bus voltage to be consistent with the target bus voltage at the current moment, so that the output bus voltage can be stably output.

[0070] In this embodiment, the inverter controller determines the target bus voltage at the current moment according to the frequency or amplitude of the bus voltage estimation value rising or falling, so that the inverter controller adjusts the output bus voltage to be consistent with the target bus voltage at the current moment. Further, the inverter controller performs anti-shake processing on the output bus voltage according to the target bus voltage at the current moment, so that the output bus voltage can be output stably.

[0071] In one embodiment, if Figure 2 As shown, the bus voltage estimation value is subjected to anti-shake processing to determine the target bus voltage at the current moment, including:

[0072] S311: Based on the estimated bus voltage at the current moment and the target bus voltage at the previous moment, an estimated voltage change value is obtained.

[0073] The current moment and the previous moment are two adjacent time points. The estimated voltage change value is the difference between the estimated bus voltage at the current moment and the target bus voltage at the previous moment after two adjacent time points.

[0074] Specifically, based on the estimated bus voltage at the current moment and the target bus voltage at the previous moment, the target bus voltage at the previous moment is subtracted from the estimated bus voltage at the current moment to obtain the difference between the estimated bus voltage at the current moment and the target bus voltage at the previous moment, and the estimated voltage change value is obtained based on the difference between the estimated bus voltage at the current moment and the target bus voltage at the previous moment.

[0075] As an example, the target bus voltage at the last moment is U bus1 , the estimated bus voltage at the current moment is U bus2 , then the estimated voltage change value ΔU bus =U bus2 -U bus1 .

[0076] S312: If the estimated voltage change value is a negative value, the change state corresponding to the estimated bus voltage value is a decreasing state, and the target bus voltage at the current moment is determined based on the comparison result between the absolute value of the estimated voltage change value and the preset voltage change value.

[0077] The preset voltage change value is a parameter set by the user, which is used as a parameter for comparing the estimated voltage change value. The target bus voltage at the current moment is the voltage obtained by passing the target bus voltage at the previous moment through two adjacent time points. The comparison result is the result obtained by comparing the estimated voltage change value corresponding to the output bus voltage with the preset voltage change value.

[0078] Specifically, if the estimated bus voltage at the current moment is less than the target bus voltage at the previous moment, the estimated bus voltage at the current moment is subtracted from the target bus voltage at the previous moment, and the estimated voltage change value is a negative value. At this time, the change state corresponding to the estimated bus voltage value obtained in real time is a decreasing state, and correspondingly, the change state of the output bus voltage corresponding to the estimated bus voltage value is also a decreasing state. In order to prevent the output bus voltage from frequently jumping, thereby affecting the performance of the inverter, the estimated voltage change value corresponding to the output bus voltage is compared with the preset voltage change value to obtain a comparison result. Based on the comparison result, the target bus voltage at the current moment is determined, so that the inverter controller adjusts the output bus voltage to be consistent with the target bus voltage at the current moment, so that the output bus voltage can be output stably, thereby protecting the waveform of the output bus voltage from frequent jumping.

[0079] S313: If the estimated voltage change value is a positive value, the change state corresponding to the estimated bus voltage value is an increasing state, and the estimated bus voltage value at the current moment is determined as the target bus voltage at the current moment.

[0080] Specifically, if the bus voltage estimate at the current moment is greater than the target bus voltage at the previous moment, the bus voltage estimate at the current moment minus the target bus voltage at the previous moment, the estimated voltage change value is a positive value. At this time, the change state corresponding to the bus voltage estimate obtained in real time is an upward state, and correspondingly, the change state of the output bus voltage corresponding to the bus voltage estimate is also an upward state. When the output bus voltage is in an upward state, in order to maintain the output efficiency of the output bus voltage, the bus voltage estimate at the current moment is determined as the target bus voltage at the current moment, so that the output bus voltage continues to output an increasing voltage, so that the inverter controller adjusts the output bus voltage to be consistent with the target bus voltage at the current moment, thereby ensuring the output efficiency of the output bus voltage.

[0081] In this embodiment, the inverter controller obtains the estimated voltage change value based on the bus voltage estimation value at the current moment and the target bus voltage at the previous moment. When the estimated voltage change value is a negative value, the output bus voltage change state is determined to be a decreasing state according to the change state corresponding to the estimated bus voltage being a decreasing state. The target bus voltage at the current moment is determined based on the comparison result between the absolute value of the estimated voltage change value and the preset voltage change value, so that the inverter controller adjusts the output bus voltage based on the target bus voltage at the current moment, so that the output bus voltage can be output stably, thereby protecting the waveform of the output bus voltage from frequent jumps. When the estimated voltage change value is a positive value, the output bus voltage change state is determined to be an increasing state according to the change state corresponding to the estimated bus voltage being an increasing state, and the bus voltage estimation value at the current moment is determined as the target bus voltage at the current moment, so that the output bus voltage continuously outputs an increasing voltage, so that the inverter controller adjusts the output bus voltage to be consistent with the target bus voltage at the current moment, ensuring that the inverter waveform is not distorted.

[0082] In one embodiment, if Figure 3 As shown, in step S312, based on the comparison result of the absolute value of the estimated voltage change value and the preset voltage change value, the target bus voltage at the current moment is determined, including:

[0083] S3121: If the absolute value of the estimated voltage change value is less than or equal to the preset voltage change value, the target bus voltage at the previous moment is determined as the target bus voltage at the current moment.

[0084] Specifically, when the absolute value of the estimated voltage change value is less than or equal to the preset voltage change value, the target bus voltage at the previous moment is determined as the target bus voltage at the current moment, so that the inverter controller adjusts the output bus voltage to be consistent with the target bus voltage at the current moment, so that the output bus voltage can be output stably, thereby ensuring that the waveform of the output bus voltage does not jump frequently.

[0085] As an example, the target bus voltage at the last moment is U bus1 , the estimated bus voltage at the current moment is U bus2 , then the absolute value of the estimated voltage change is ΔU bus =|U bus2 -U bus1 |, the preset voltage change value is ΔU set , when ΔU bus ≤ΔU set <ΔU set , then U bus1 Determined as the target bus voltage at the current moment.

[0086] As an example, when the absolute value of the estimated voltage change value is greater than the difference between the target bus voltage at the previous moment and the preset voltage change value, and is less than the target bus voltage at the previous moment, it can be understood that when the output bus voltage corresponding to the bus voltage estimation value frequently jumps between the difference between the target bus voltage at the previous moment and the preset voltage change value and the target bus voltage at the previous moment, the target bus voltage at the previous moment is determined as the target bus voltage at the current moment, so that the output bus voltage can be output stably, thereby ensuring that the waveform of the output bus voltage does not frequently jump. For example, the target bus voltage at the previous moment is U bus1 , the estimated bus voltage at the current moment is U bus2 , then the absolute value of the estimated voltage change is ΔU bus =|U bus2 -U bus1 |, the preset voltage change value is ΔU set , when (U bus1 -ΔU set )<ΔU bus ≦U bus1 When U bus1 Determined as the target bus voltage at the current moment.

[0087] S3122: If the absolute value of the estimated voltage change value is greater than the preset voltage change value, the estimated bus voltage value at the current moment is determined as the target bus voltage at the current moment.

[0088] Specifically, when the absolute value of the estimated voltage change value is greater than the preset voltage change value, it can be understood that at this time, the absolute value of the estimated voltage change value has exceeded the range of the preset voltage change value. The estimated value of the bus voltage at the current moment is determined as the target bus voltage at the current moment, so that the bus voltage output is more reasonable, the inverter efficiency is improved, and the inverter waveform is improved.

[0089] As an example, the target bus voltage at the last moment is U bus1 =330V, the estimated bus voltage at the current moment is U bus2 =310V, then the absolute value of the estimated voltage change is ΔU bus =|U bus2 -U bus1 |=|310-330|=20V, the preset voltage change value is ΔU set =1. ΔU bus >ΔU set , will U bus2 =310V is determined as the target bus voltage at the current moment.

[0090] In this embodiment, when the absolute value of the estimated voltage change value is less than the preset voltage change value, the target bus voltage at the previous moment is determined as the target bus voltage at the current moment; when the absolute value of the estimated voltage change value is greater than the preset voltage change value, the bus voltage estimation value is determined as the target bus voltage at the current moment, so that the bus voltage output is more reasonable, the inverter efficiency is improved, and the inverter waveform is improved.

[0091] In one embodiment, in step S30, based on the estimated value of the bus voltage, the output bus voltage is adjusted to determine the target bus voltage at the current moment, and it also includes: based on the estimated value of the bus voltage, the output bus voltage is limited to determine the target bus voltage at the current moment.

[0092] Among them, limiting the output bus voltage means that when the output bus voltage is too large or too small, the output bus voltage is maintained within a preset voltage range to prevent the output bus voltage from being too high to damage the device or the output bus voltage from being too low to cause an abnormally large current in the system.

[0093] Specifically, the inverter controller estimates the output bus voltage through the bus voltage estimation value, and by analyzing the magnitude of the bus voltage estimation value obtained in real time, the magnitude of the output bus voltage can be analyzed. Further, according to the magnitude of the bus voltage estimation value, the overly high or overly low bus voltage estimation value is restricted, and the target bus voltage at the current moment is determined, so as to enable the inverter controller to adjust the output bus voltage to be consistent with the target bus voltage at the current moment, so as to prevent the output bus voltage from being too high to damage the device or the output bus voltage from being too low to cause an abnormally large current in the system.

[0094] In this embodiment, the inverter controller can analyze the size of the output bus voltage by analyzing the size of the bus voltage estimate value obtained in real time, and limit the bus voltage estimate value that is too high or too low according to the size of the bus voltage estimate value, and determine the target bus voltage at the current moment. The purpose is to enable the inverter controller to adjust the output bus voltage to be consistent with the target bus voltage at the current moment, to prevent the output bus voltage from being too high to damage devices or the output bus voltage from being too low to cause abnormally large current in the system.

[0095] In one embodiment, if Figure 4 As shown, in step S30, based on the estimated value of the bus voltage, the output bus voltage is limited to determine the target bus voltage at the current moment, including:

[0096] S321: If the estimated bus voltage value is less than the bus voltage lower limit value, the bus voltage lower limit value is determined as the target bus voltage at the current moment.

[0097] The bus voltage lower limit is a user-defined voltage value, which is used to limit the bus voltage estimation value that is too small.

[0098] Specifically, it can be seen from P=U*I that when the inverter power remains unchanged, a lower output bus voltage will result in a larger DC side current. To prevent abnormally large current, when the bus voltage estimate is less than the bus voltage lower limit, the bus voltage lower limit is determined as the target bus voltage at the current moment, so that the inverter controller adjusts the output bus voltage to be consistent with the target bus voltage at the current moment, preventing the output bus voltage from being too low and causing abnormally large current in the system.

[0099] As an example, the bus voltage estimate is U bus The lower limit of bus voltage is U downlimit . When U bus downlimit When the bus voltage lower limit value U downlimit Determined as the target bus voltage at the current moment.

[0100] S322: If the estimated bus voltage value is greater than the upper limit value of the bus voltage, the upper limit value of the bus voltage is determined as the target bus voltage at the current moment.

[0101] The bus voltage lower limit is a user-defined voltage value, which is used to limit excessive bus voltage estimation values.

[0102] Specifically, in order to prevent excessively high output bus voltage from damaging devices, when the bus voltage estimate is greater than the bus voltage upper limit, the bus voltage upper limit is determined as the target bus voltage at the current moment, so that the inverter controller adjusts the output bus voltage to be consistent with the target bus voltage at the current moment, preventing the output bus voltage from being too high and damaging devices.

[0103] As an example, the bus voltage estimate is U bus The upper limit of bus voltage is U uplimit . When U bus >U uplimit When the bus voltage upper limit value U uplimit Determined as the target bus voltage at the current moment.

[0104] S323: If the estimated bus voltage value is between the lower limit value of the bus voltage and the upper limit value of the bus voltage, the estimated bus voltage value is determined as the target bus voltage at the current moment.

[0105] ​Specifically, when the bus voltage estimation value is between the bus voltage lower limit value and the bus voltage upper limit value, there is no possibility that the output bus voltage is too high to damage the device or the output bus voltage is too low to cause an abnormally large current in the system. The bus voltage estimation value is directly determined as the target bus voltage at the current moment, so that the inverter controller adjusts the output bus voltage to be consistent with the target bus voltage at the current moment, thereby ensuring the output efficiency of the output bus voltage.

[0106] As an example, the bus voltage estimate is U bus The upper limit of bus voltage is U uplimit The lower limit of bus voltage is U downlimit . When U uplimit >U bus >U downlimit When the bus voltage estimated value U bus Determined as the target bus voltage at the current moment.

[0107] In this embodiment, when the bus voltage estimation value is less than the bus voltage lower limit value, the inverter controller determines the bus voltage lower limit value as the target bus voltage at the current moment; when the bus voltage estimation value is greater than the bus voltage upper limit value, the bus voltage upper limit value is determined as the target bus voltage at the current moment; the bus voltage upper limit value and the bus voltage lower limit value are used to ensure that the target bus voltage at the current moment is within a reasonable range to ensure system reliability.

[0108] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0109] In one embodiment, an inverter bus voltage adjustment device is provided, and the inverter bus voltage adjustment device corresponds to the inverter bus voltage adjustment method in the above embodiment. Figure 5 As shown, the inverter bus voltage adjustment device includes an acquisition module 10, a voltage estimation module 20, a voltage adjustment processing module 30 and an adjustment execution module 40. The functional modules are described in detail as follows:

[0110] An acquisition module 10 is used to acquire the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current;

[0111] The voltage estimation module 20 is used to obtain a bus voltage estimation value based on the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current;

[0112] The voltage adjustment processing module 30 is used to adjust the bus voltage estimation value to determine the target bus voltage at the current moment;

[0113] The adjustment execution module 40 is used to adjust the duty cycle of the DC / DC converter in the inverter based on the target bus voltage at the current moment, so that the output bus voltage is consistent with the target bus voltage at the current moment.

[0114] Furthermore, the voltage estimation module 20 includes:

[0115] The estimation formula submodule is used to calculate the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current using the bus voltage estimation formula to obtain the estimated value of the bus voltage. The bus voltage estimation formula is U bus =(a / m)*(U max +bI out )+c, where m is the maximum duty cycle of the inverter, a is the correction coefficient of the maximum duty cycle of the inverter, and U max is the peak voltage of the power grid, I out is the inverter output current, b is the adjustment coefficient of the inverter output current, and c is the correction coefficient of the bus voltage.

[0116] Furthermore, the voltage adjustment processing module 30 includes:

[0117] The estimated value anti-shake submodule is used to perform anti-shake processing on the bus voltage estimated value to determine the target bus voltage at the current moment.

[0118] Furthermore, the voltage adjustment processing module 30 also includes:

[0119] The estimated change value submodule obtains the estimated voltage change value based on the bus voltage estimated value at the current moment and the target bus voltage at the previous moment;

[0120] A decreasing state submodule is used to determine the target bus voltage at the current moment based on the comparison result between the absolute value of the estimated voltage change value and the preset voltage change value when the estimated voltage change value is a negative value, and the change state corresponding to the estimated bus voltage value is a decreasing state;

[0121] The rising state submodule is used to determine the bus voltage estimate value as the target bus voltage at the current moment when the estimated voltage change value is a positive value and the change state corresponding to the bus voltage estimate value is a rising state.

[0122] Furthermore, the voltage adjustment processing module 30 also includes:

[0123] A first determination submodule, configured to determine the target bus voltage at the previous moment as the target bus voltage at the current moment when the absolute value of the estimated voltage change value is less than the preset voltage change value;

[0124] The second determination submodule is used to determine the target bus voltage at the previous moment as the target bus voltage at the current moment when the absolute value of the estimated voltage change value is greater than the target voltage difference value and less than the target bus voltage at the previous moment, and the target voltage difference value is the difference between the target bus voltage at the previous moment and the preset voltage change value;

[0125] The third determination submodule is used to determine the estimated bus voltage value at the current moment as the target bus voltage at the current moment when the absolute value of the estimated voltage change value is greater than the preset voltage change value.

[0126] Furthermore, the voltage adjustment processing module 30 also includes:

[0127] The estimation and limitation submodule is used to perform limit processing on the estimated value of the bus voltage and determine the target bus voltage at the current moment.

[0128] Furthermore, the voltage adjustment processing module 30 also includes:

[0129] The fourth determination submodule is used to determine the bus voltage lower limit as the target bus voltage at the current moment when the bus voltage estimation value is less than the bus voltage lower limit;

[0130] A fifth determination submodule, configured to determine the upper limit value of the bus voltage as the target bus voltage at the current moment when the estimated bus voltage value is greater than the upper limit value of the bus voltage;

[0131] The sixth determination submodule is used to determine the estimated bus voltage as the target bus voltage at the current moment when the estimated bus voltage is between the lower limit value of the bus voltage and the upper limit value of the bus voltage.

[0132] For the specific definition of the inverter bus voltage adjustment device, please refer to the definition of the inverter bus voltage adjustment method above, which will not be repeated here. Each module in the above-mentioned inverter bus voltage adjustment device can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the inverter controller in the form of hardware, or can be stored in the memory in the inverter controller in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0133] In one embodiment, an inverter controller is provided, whose internal structure diagram can be as follows: Figure 6As shown. The inverter controller includes a processor, a memory, a network interface and a database connected through a system bus. Among them, the processor of the inverter controller is used to provide computing and control capabilities. The memory of the inverter controller includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, an inverter control program and a database. The internal memory provides an environment for the operation of the operating system and the inverter control program in the non-volatile storage medium. The database of the inverter controller is used for inverter bus voltage adjustment (functional limitations are added to the database). The network interface of the inverter controller is used to communicate with an external terminal through a network connection. When the inverter control program is executed by the processor, a method for adjusting the inverter bus voltage is implemented.

[0134] In one embodiment, an inverter controller is provided, including a memory, a processor, and an inverter control program stored in the memory and executable on the processor. When the processor executes the inverter control program, the steps of the inverter bus voltage adjustment method in the above embodiment are implemented, such as steps S10 to S40. Alternatively, when the processor executes the inverter control program, the functions of each module / unit in the inverter bus voltage adjustment device in this embodiment are implemented, such as the functions of modules 10 to 40. To avoid repetition, it will not be repeated here.

[0135] In one embodiment, a computer-readable storage medium is provided, on which an inverter control program is stored. When the inverter control program is executed by a processor, the steps of the inverter bus voltage adjustment method in the above embodiment are implemented, such as steps S10 to S40. To avoid repetition, they are not described here. Alternatively, when the inverter control program is executed by a processor, the functions of each module / unit in the above embodiment of the inverter bus voltage adjustment device are implemented, such as the functions of modules 10 to 40. To avoid repetition, they are not described here.

[0136] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through the inverter control program, and the inverter control program can be stored in a non-volatile computer-readable storage medium. When the inverter control program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0137] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0138] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for adjusting the inverter bus voltage, characterized in that: include: Obtain the maximum duty cycle of the inverter, the peak voltage of the grid and the inverter output current; Based on the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current, a bus voltage estimation formula is used to obtain a bus voltage estimation value, wherein the bus voltage estimation formula is: , is the maximum duty cycle of the inverter, is the correction factor of the maximum duty cycle of the inverter, is the peak voltage of the power grid, is the inverter output current, is the regulation coefficient of the inverter output current, is the correction factor of bus voltage; Adjusting the estimated bus voltage value to determine the target bus voltage at the current moment; The duty cycle of the DC / DC converter in the inverter is adjusted based on the target bus voltage at the current moment, so that the output bus voltage is consistent with the target bus voltage at the current moment.

2. The inverter bus voltage adjustment method according to claim 1, characterized in that: The adjusting process of the estimated bus voltage value to determine the target bus voltage at the current moment includes: The bus voltage estimation value is subjected to anti-shake processing to determine the target bus voltage at the current moment.

3. The inverter bus voltage adjustment method according to claim 2, characterized in that: The anti-shake processing is performed on the estimated bus voltage value to determine the target bus voltage at the current moment, including: Obtain an estimated voltage change value based on the estimated bus voltage value at the current moment and the target bus voltage at the previous moment; If the estimated voltage change value is a negative value, the change state corresponding to the estimated bus voltage value is a decreasing state; if the absolute value of the estimated voltage change value is less than or equal to the preset voltage change value, the target bus voltage at the previous moment is determined as the target bus voltage at the current moment; if the absolute value of the estimated voltage change value is greater than the preset voltage change value, the estimated bus voltage at the current moment is determined as the target bus voltage at the current moment; If the estimated voltage change value is a positive value, the change state corresponding to the estimated bus voltage value is an increasing state, and the estimated bus voltage value at the current moment is determined as the target bus voltage at the current moment.

4. The inverter bus voltage adjustment method according to claim 1, characterized in that: The adjusting process of the estimated bus voltage value to determine the target bus voltage at the current moment also includes: The estimated bus voltage value is subjected to limit processing to determine the target bus voltage at the current moment.

5. The inverter bus voltage adjustment method according to claim 4, characterized in that: The limiting process is performed on the estimated bus voltage value to determine the target bus voltage at the current moment, including: If the estimated bus voltage value is less than the bus voltage lower limit value, the bus voltage lower limit value is determined as the target bus voltage at the current moment; If the estimated bus voltage value is greater than the bus voltage upper limit value, the bus voltage upper limit value is determined as the target bus voltage at the current moment; If the estimated bus voltage value is between the bus voltage lower limit value and the bus voltage upper limit value, the estimated bus voltage value is determined as the target bus voltage at the current moment.

6. An inverter bus voltage adjustment device, characterized in that: include: An acquisition module is used to obtain the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current; A voltage estimation module is used to obtain a bus voltage estimation value based on the maximum duty cycle of the inverter, the peak voltage of the power grid and the inverter output current using a bus voltage estimation formula, wherein the bus voltage estimation formula is: , is the maximum duty cycle of the inverter, is the correction factor of the maximum duty cycle of the inverter, is the peak voltage of the power grid, is the inverter output current, is the regulation coefficient of the inverter output current, is the correction factor of bus voltage; A voltage adjustment processing module is used to adjust the bus voltage estimation value to determine the target bus voltage at the current moment; The adjustment execution module is used to adjust the duty cycle of the DC / DC converter in the inverter based on the target bus voltage at the current moment, so that the output bus voltage is consistent with the target bus voltage at the current moment.

7. An inverter controller, comprising a memory, a processor, and an inverter controller program stored in the memory and executable on the processor, characterized in that: When the processor executes the inverter controller program, the inverter bus voltage adjustment method according to any one of claims 1 to 5 is implemented.

8. A computer-readable storage medium storing an inverter controller program, characterized in that: When the inverter controller program is executed by the processor, the inverter bus voltage adjustment method according to any one of claims 1 to 5 is implemented.

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