Dynamic response optimization regulation method for three-phase voltage-source PWM rectifier

Abstract

The present invention discloses a dynamic response optimization and regulation method for a three-phase voltage-type PWM rectifier; the present invention adopts a load power feedforward strategy of feeding forward the active power on the machine side to a given value of the active power on the grid side, and introduces a load power feedforward strategy to realize coordinated control of dual PWM frequencies, which can not only reduce the harmonics of the grid-side current, but also better suppress the fluctuation of the DC voltage when the load suddenly changes, accelerate the dynamic response of the rectifier side and the inverter side, and significantly enhance the anti-interference ability of the system; the present invention monitors the temperature changes of each divided area of ​​the PWM rectifier in real time and analyzes them, and constructs a temperature evaluation model for each divided area according to the analysis results of each divided area, so as to realize targeted regional analysis, and triggers a corresponding early warning signal based on the temperature evaluation model of each divided area and sends it to the mobile terminal of the technician, thereby improving the phase response speed while ensuring the reliability and life of the PWM rectifier.

Description

Technical Field

[0001] The invention relates to the technical field of power electronics, and in particular to a dynamic response optimization regulation method for a three-phase voltage-type PWM rectifier. Background Art

[0002] In modern power systems, rectifiers, as key equipment for power conversion, are widely used in many fields such as motor drive, power supply, and power transmission. Traditional rectifiers usually adopt uncontrolled rectification or phase-controlled rectification, which have some inherent defects. In order to solve these problems, pulse width modulation (PWM) technology has been introduced into rectifier design. PWM technology can achieve stable and adjustable DC voltage by adjusting the width of the pulse, reduce the harmonic content of the input current, and improve the power factor of the system.

[0003] However, the existing PWM rectifiers may affect the reliability, life and performance of the equipment due to the increase in temperature. The intelligence level of PWM rectifier temperature detection is low and it is impossible to respond and optimize quickly when the PWM rectifier temperature is abnormal.

[0004] Therefore, a dynamic response optimization regulation method for three-phase voltage-source PWM rectifier is proposed. Summary of the invention

[0005] In view of this, the present invention provides a dynamic response optimization adjustment method for a three-phase voltage-source PWM rectifier to solve the problems raised by the above background technology.

[0006] The object of the present invention can be achieved by the following technical solution: A dynamic response optimization adjustment method for a three-phase voltage-type PWM rectifier, comprising:

[0007] Dual closed-loop control: Adopting dual closed-loop control strategy of voltage outer loop and current inner loop to realize precise control of rectifier;

[0008] Load power feedforward control: Introduce load power feedforward control strategy in the current inner loop to feed forward the machine-side active power to the grid-side active power set value;

[0009] Temperature response processing: monitor the temperature change of the PWM rectifier in real time and analyze it to obtain the temperature evaluation model of the PWM rectifier within the set time period. Based on the temperature evaluation model of the PWM rectifier within the set time period, trigger the corresponding early warning signal;

[0010] Simulation verification: Build a simulation model to simulate load mutation, test the fluctuation of DC side voltage when the load changes, and verify the effectiveness of the control strategy.

[0011] In some embodiments, the temperature change of the PWM rectifier is monitored in real time and analyzed, specifically:

[0012] Get the temperature value of the corresponding divided area of ​​the PWM rectifier at each time point within the set time period. The corresponding divided area is represented by a number m, where m=1,2...g, and g is the total number of divided areas;

[0013] Thus, a temperature change line graph of the corresponding divided area of ​​the PWM rectifier is constructed, and the numerical points corresponding to the temperature values ​​of the divided area at each time point are plotted in the line graph, and the adjacent numerical points are connected to obtain the numerical line, and the slope of each numerical line and the angle with the vertical line are calculated. If the angle between one of the numerical lines and the vertical line is an obtuse angle, the slope of the numerical line is marked as an upward slope, and if the angle between one of the numerical lines and the vertical line is an acute angle, the slope of the numerical line is marked as a downward slope;

[0014] After marking is completed, the rising slopes of each group in the corresponding divided area are added together to obtain the total rising value, and the falling slopes of each group are added together and the absolute value is taken to obtain the total falling value. The ratio between the total rising value and the total falling value is calculated as the trend index of the corresponding divided area.

[0015] In some embodiments, the temperature change of the PWM rectifier is monitored in real time and analyzed, and further:

[0016] The average value of the temperature values ​​at each time point in the corresponding divided area is taken as the average temperature value of the corresponding divided area, and the maximum value of the temperature values ​​at each time point in the corresponding divided area is taken as the peak temperature value of the corresponding divided area;

[0017] Based on the location of the corresponding divided area, the reference allowable values ​​of the trend index and the temperature mean of the corresponding divided area are preset and marked as the trend allowable index and the temperature mean, respectively.

[0018] In some embodiments, a temperature evaluation model of the PWM rectifier within a set time period is obtained, specifically:

[0019] The trend index of the corresponding divided area is calculated as the ratio of the trend index to the corresponding trend allowable index, which is used as the trend ratio of the corresponding divided area; that is, trend index / trend allowable index; further, the ratio of the temperature mean and temperature peak of the corresponding divided area to the temperature allowable mean is calculated as the mean ratio and peak ratio of the corresponding divided area; that is, temperature mean / temperature allowable mean, temperature peak / temperature allowable mean;

[0020] The trend ratio, mean ratio and peak ratio of the corresponding divided area are extracted and used as the length value, height value and width value of the three-dimensional rectangle respectively, thereby constructing the temperature assessment model of the corresponding divided area.

[0021] In some embodiments, based on the temperature evaluation model of the PWM rectifier within a set time period, a corresponding early warning signal is triggered, specifically:

[0022] Calculate the surface area of ​​the temperature assessment model of the corresponding divided area as the temperature warning index Wfm of the corresponding divided area;

[0023] Preset the threshold index of the temperature warning index Wfm of each divided area of ​​the PWM rectifier, if one group of temperature warning index Wfm is greater than the corresponding preset threshold index, then trigger the warning signal of the corresponding divided area;

[0024] First, the specific division area that triggers the early warning signal is obtained, and the PWM rectifier is optimized according to the preset optimization operation of the division area. After the optimization is completed, the temperature change of the division area within the set time period is continuously monitored and analyzed. If the analysis shows that the division area still triggers the early warning signal, the technician with the largest processing efficiency value TRe at the current time point is selected, and the early warning signal triggered by the division area is sent to the mobile terminal of the technician;

[0025] In some embodiments, the specific process of obtaining the processing efficiency value TRe of each technician is as follows:

[0026] Draw a circle with the current time point of the PWM rectifier as the center and the distance as the radius, select all technicians within the circle, and send a position feedback signal to their mobile terminals. After confirming the position feedback signal, each technician obtains the distance between each technician and the PWM rectifier at the current time point, and the distance is recorded as Eq1;

[0027] Further, the number of processing times is extracted from the work log of each technician, and the time taken in each processing process is obtained. The reference time taken by the PWM rectifier for a single processing of the divided area is set, and the time taken by each processing process of each technician is compared with the set reference time. If the time taken by one group of processing processes is longer than the set reference time, the processing process is marked as the number of times that takes a long time; if the time taken by one group of processing processes is lower than the set reference time, the processing process is marked as the number of times that takes a short time.

[0028] Calculate the ratio between the number of times each technician takes a shorter time and the number of times each technician takes a longer time, and use the calculated ratio as the processing speed value of each technician, and record the processing speed value as Eq2;

[0029] Finally, mark the number of times each technician processes as Eq3, and substitute the distance of each technician Eq1, the processing speed value Eq2, and the number of times each technician processes Eq3 into the formula A weighted calculation is performed to obtain the processing efficiency value TRe of each technician, wherein a1, a2 and a3 are the influencing weight factors of each technician's travel distance Eq1, processing speed value Eq2 and processing times Eq3 respectively.

[0030] In some embodiments, a dual closed-loop control strategy of a voltage outer loop and a current inner loop is adopted, specifically:

[0031] Voltage outer loop: A voltage regulator is used to process the difference between the DC voltage set value and the actual value to obtain the active power set value; the reactive power set value is set to zero to make the power factor 1;

[0032] Current inner loop: adopts feedforward decoupling control strategy and is realized through control equation and Decoupling control of

[0033] The digital model in the synchronous dq coordinate system is shown in formula (1): ,in , is the electromotive force of the three-phase power grid , as well as The d and q axis components obtained after 3s / 2r coordinate transformation, , Is the three-phase current , as well as The d and q axis components obtained after 3s / 2r coordinate transformation, the switching function =1 means the upper bridge arm is turned on and the lower bridge arm is turned off. =0, otherwise, K=d or q;

[0034] The control equation is as follows:

[0035] in the formula , They are The proportional and integral coefficients of the regulator, , They are Proportional and integral coefficients of the regulator.

[0036] In some embodiments, the load power feedforward control strategy specifically includes:

[0037] DC side voltage When the circuit loss is ignored, the input power on the grid side and the machine side is equal, that is, ;in is the active power input to the grid side, is the active power input to the generator side, , , They are the three-phase voltages of the motor and electronics, , , are the three-phase stator currents respectively; , , , , , , These 7 quantities are all instantaneous values; and When the power balance changes, ;in is the instantaneous power of the DC capacitor.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention monitors the temperature changes of each divided area of ​​the PWM rectifier in real time and analyzes them, and constructs a temperature evaluation model for each divided area according to the analysis results of each divided area, so as to achieve targeted regional analysis, and trigger corresponding early warning signals based on the temperature evaluation model of each divided area and send them to the mobile terminal of the technician, thereby improving the phase response speed while ensuring the reliability and life of the PWM rectifier;

[0040] The present invention adopts a load power feedforward strategy of feeding forward the active power on the machine side to a given value of the active power on the grid side, and introduces a load power feedforward strategy to realize coordinated control of dual PWM frequencies, which can not only reduce the harmonics of the grid-side current, but also better suppress the fluctuation of the DC voltage when the load changes suddenly, accelerate the dynamic response of the rectifier side and the inverter side, and significantly enhance the anti-interference ability of the system, thereby reducing the capacitor volume and reducing the cost;

[0041] The present invention realizes accurate control of DC voltage and current through double closed-loop control of voltage outer loop and current inner loop by the rectifier; setting the reactive power set value to zero ensures that the power factor is 1, thereby improving the energy efficiency of the system and reducing the reactive power burden of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Further details, features and advantages of the present application are disclosed in the following description of exemplary embodiments in conjunction with the accompanying drawings, in which:

[0043] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0044] Several embodiments of the present application will be described in more detail below with reference to the accompanying drawings so that those skilled in the art can implement the present application. The present application can be embodied in many different forms and purposes and should not be limited to the embodiments described herein. These embodiments are provided to make the present application comprehensive and complete, and to fully convey the scope of the present application to those skilled in the art. The embodiments do not limit the present application.

[0045] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the relevant art and / or the context of this specification, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such herein.

[0046] See also Figure 1 As shown, a dynamic response optimization adjustment method for a three-phase voltage-type PWM rectifier includes:

[0047] Dual closed-loop control: Adopting dual closed-loop control strategy of voltage outer loop and current inner loop to realize precise control of rectifier;

[0048] Specifically:

[0049] Voltage outer loop: A voltage regulator is used to process the difference between the DC voltage set value and the actual value to obtain the active power set value; the reactive power set value is set to zero to make the power factor 1;

[0050] Provide the expected value of active current of the current inner loop, and control the magnitude and direction of power by adjusting the active current;

[0051] Current inner loop: adopts feedforward decoupling control strategy and is realized through control equation and Decoupling control of

[0052] The digital model in the synchronous dq coordinate system is shown in formula (1): ,in , is the electromotive force of the three-phase power grid , as well as The d and q axis components obtained after 3s / 2r coordinate transformation, , Is the three-phase current , as well as The d and q axis components obtained after 3s / 2r coordinate transformation, the switching function =1 means the upper bridge arm is turned on and the lower bridge arm is turned off. =0, otherwise, K=d or q;

[0053] The above formula (1) shows and There is coupling;

[0054] The control equation is as follows:

[0055] in the formula , They are The proportional and integral coefficients of the regulator, , They are Proportional and integral coefficients of the regulator;

[0056] Ensure that the current value on the AC side can follow its expected value and achieve unity power factor operation;

[0057] Load power feedforward control: Introduce load power feedforward control strategy in the current inner loop to feed forward the machine-side active power to the grid-side active power set value;

[0058] The specific contents of the load power feedforward control strategy are:

[0059] DC side voltage When the circuit loss is ignored, the input power on the grid side and the machine side is equal, that is, ;in is the active power input to the grid side, is the active power input to the generator side, , , They are the three-phase voltages of the motor and electronics, , , are the three-phase stator currents respectively; , , , , , , These 7 quantities are all instantaneous values; and When the power balance changes, ;in is the instantaneous power of the DC capacitor; it can be seen that to stabilize , must be and Maintain dynamic balance;

[0060] The above-mentioned load power feedforward strategy of feeding forward the active power on the machine side to the given value of the active power on the grid side makes the active power on the grid side no longer indirectly regulated through the voltage outer loop, making the regulation process faster;

[0061] Temperature response processing: monitor the temperature change of the PWM rectifier in real time and analyze it to obtain the temperature evaluation model of the PWM rectifier within the set time period. Based on the temperature evaluation model of the PWM rectifier within the set time period, trigger the corresponding early warning signal;

[0062] Specifically:

[0063] Obtain the temperature value of the corresponding divided area at each time point of the PWM rectifier within the set time period, where the divided area includes the capacitor area, IGBT module, inductor and other key parts of the PWM rectifier, and the specific layout is set by the technical personnel; the corresponding divided area is represented by the number m, where m=1,2...g, where g is the total number of divided areas;

[0064] Thus, a temperature change line graph of the corresponding divided area of ​​the PWM rectifier is constructed, and the numerical points corresponding to the temperature values ​​of the divided area at each time point are plotted in the line graph, and the adjacent numerical points are connected to obtain the numerical line, and the slope of each numerical line and the angle with the vertical line are calculated. If the angle between one of the numerical lines and the vertical line is an obtuse angle, the slope of the numerical line is marked as an upward slope, and if the angle between one of the numerical lines and the vertical line is an acute angle, the slope of the numerical line is marked as a downward slope;

[0065] It should be noted that according to the figure As shown, rising slope and falling slope are classified.

[0066] After the marking is completed, the rising slopes of each group in the corresponding divided area are added together to obtain the total rising value, and the falling slopes of each group are added together and the absolute value is taken to obtain the total falling value. The ratio between the total rising value and the total falling value is calculated as the trend index of the corresponding divided area;

[0067] Further, the average value of the temperature values ​​at each time point of the corresponding divided area is taken as the temperature average value of the corresponding divided area, and the maximum value of the temperature values ​​at each time point of the corresponding divided area is taken as the temperature peak value of the corresponding divided area;

[0068] Based on the location of the corresponding divided area, the reference allowable values ​​of the trend index and the temperature mean of the corresponding divided area are preset and marked as the trend allowable index and the temperature allowable mean, respectively, and the trend index of the corresponding divided area and the corresponding trend allowable index are calculated as the trend ratio of the corresponding divided area; that is, trend index / trend allowable index;

[0069] Further, the ratios of the temperature mean and temperature peak of the corresponding divided area to the temperature allowable mean are calculated as the mean ratio and peak ratio of the corresponding divided area; that is, temperature mean / temperature allowable mean, temperature peak / temperature allowable mean;

[0070] The trend ratio, mean ratio and peak ratio of the corresponding divided area are extracted and used as the length value, height value and width value of the three-dimensional rectangle respectively, thereby constructing a temperature assessment model for the corresponding divided area;

[0071] Calculate the surface area of ​​the temperature assessment model of the corresponding divided area as the temperature warning index Wfm of the corresponding divided area;

[0072] Preset the threshold index of the temperature warning index Wfm of each divided area of ​​the PWM rectifier, if one group of temperature warning index Wfm is greater than the corresponding preset threshold index, then trigger the warning signal of the corresponding divided area;

[0073] First, the specific division area that triggers the early warning signal is obtained, and the PWM rectifier is optimized according to the preset optimization operation of the division area. After the optimization is completed, the temperature change of the division area within the set time period is continuously monitored and analyzed. If the analysis shows that the division area still triggers the early warning signal, the technician with the largest processing efficiency value TRe at the current time point is selected, and the early warning signal triggered by the division area is sent to the mobile terminal of the technician; the preset optimization operation is such as adjusting the load of the rectifier or reducing the output power;

[0074] The specific process of obtaining the processing efficiency value TRe of each technician is as follows:

[0075] Draw a circle with the current time point of the PWM rectifier as the center and the distance as the radius, select all technicians within the circle, and send a position feedback signal to their mobile terminals. After confirming the position feedback signal, each technician obtains the distance between each technician and the PWM rectifier at the current time point, and the distance is recorded as Eq1;

[0076] Further, the number of processing times is extracted from the work log of each technician, and the time taken in each processing process is obtained. The reference time taken by the PWM rectifier for a single processing of the divided area is set, and the time taken by each processing process of each technician is compared with the set reference time. If the time taken by one group of processing processes is longer than the set reference time, the processing process is marked as the number of times that takes a long time; if the time taken by one group of processing processes is lower than the set reference time, the processing process is marked as the number of times that takes a short time.

[0077] Calculate the ratio between the number of times each technician takes a shorter time and the number of times each technician takes a longer time, and use the calculated ratio as the processing speed value of each technician, and record the processing speed value as Eq2;

[0078] Finally, mark the number of times each technician processes as Eq3, and substitute the distance of each technician Eq1, the processing speed value Eq2, and the number of times each technician processes Eq3 into the formula Perform weighted calculation to obtain the treatment efficiency value TRe of each technician; a1, a2 and a3 are the influencing weight factors of the distance Eq1, the treatment speed Eq2 and the number of treatments Eq3 of each technician respectively;

[0079] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A dynamic response optimization adjustment method for a three-phase voltage-type PWM rectifier, characterized in that: include: Dual closed-loop control: Adopting dual closed-loop control strategy of voltage outer loop and current inner loop to realize precise control of rectifier; Load power feedforward control: Introduce load power feedforward control strategy in the current inner loop to feed forward the machine-side active power to the grid-side active power set value; Temperature response processing: monitor the temperature change of the PWM rectifier in real time and analyze it to obtain the temperature evaluation model of the PWM rectifier within the set time period. Based on the temperature evaluation model of the PWM rectifier within the set time period, trigger the corresponding early warning signal and execute the corresponding steps; The specific steps of temperature response processing are: Get the temperature value, trend index, temperature mean and temperature peak of the corresponding divided area of ​​the PWM rectifier at each time point in the set time period. The corresponding divided area is represented by the number m, where m=1,2...g, and g is the total number of divided areas; Based on the location of the corresponding divided area, the reference allowable values ​​of the trend index and the temperature mean of the corresponding divided area are preset and marked as the trend allowable index and the temperature allowable mean respectively; Calculate the ratio of the trend index of the corresponding divided area to the corresponding trend allowable index as the trend ratio of the corresponding divided area; That is, trend index / trend allowable index; further calculate the ratio of the temperature mean and temperature peak of the corresponding divided area to the temperature allowable mean, as the mean ratio and peak ratio of the corresponding divided area; that is, temperature mean / temperature allowable mean, temperature peak / temperature allowable mean; The trend ratio, mean ratio and peak ratio of the corresponding divided area are extracted and used as the length value, height value and width value of the three-dimensional rectangle respectively, thereby constructing a temperature assessment model for the corresponding divided area; Calculate the surface area of ​​the temperature assessment model of the corresponding divided area as the temperature warning index Wfm of the corresponding divided area; Preset the threshold index of the temperature warning index Wfm of each divided area of ​​the PWM rectifier, if one group of temperature warning index Wfm is greater than the corresponding preset threshold index, then trigger the warning signal of the corresponding divided area; Simulation verification: Build a simulation model to simulate load mutation, test the fluctuation of DC side voltage when the load changes, and verify the effectiveness of the control strategy.

2. The dynamic response optimization adjustment method for a three-phase voltage-type PWM rectifier according to claim 1, characterized in that: Get the trend index, temperature mean and temperature peak of the corresponding divided area at each time point of the PWM rectifier within the set time period, specifically: Construct a temperature change line graph of the corresponding divided area of ​​the PWM rectifier, draw the numerical points corresponding to the temperature values ​​of the divided area at each time point in the line graph, connect adjacent numerical points to obtain numerical lines, calculate the slope of each numerical line and the angle with the vertical line, if the angle between one of the numerical lines and the vertical line is an obtuse angle, then mark the slope of the numerical line as an upward slope, if the angle between one of the numerical lines and the vertical line is an acute angle, then mark the slope of the numerical line as a downward slope; After the marking is completed, the rising slopes of each group in the corresponding divided area are added together to obtain the total rising value, and the falling slopes of each group are added together and the absolute value is taken to obtain the total falling value. The ratio between the total rising value and the total falling value is calculated as the trend index of the corresponding divided area; The average of the temperature values ​​at each time point in the corresponding divided area is taken as the temperature mean value of the corresponding divided area, and the maximum value of the temperature values ​​at each time point in the corresponding divided area is taken as the temperature peak value of the corresponding divided area.

3. The dynamic response optimization adjustment method for a three-phase voltage-type PWM rectifier according to claim 2, characterized in that: Trigger the corresponding warning signal and execute the corresponding steps, specifically: First, the specific divided area that triggers the early warning signal is obtained, and the PWM rectifier is optimized according to the preset optimization operation of the divided area. After the optimization is completed, the temperature change of the divided area within the set time period is continuously monitored and analyzed. If the analysis shows that the divided area still triggers the early warning signal, the technician with the largest processing effectiveness value TRe at the current time point is selected, and the early warning signal triggered by the divided area is sent to the technician's mobile terminal.

4. The dynamic response optimization adjustment method for a three-phase voltage-type PWM rectifier according to claim 3, characterized in that: The processing efficiency value TRe of each technician is obtained, which is specifically: Draw a circle with the current time point of the PWM rectifier as the center and the distance as the radius, select all technicians within the circle, and send position feedback signaling to their mobile terminals. After confirming the position feedback signaling, each technician obtains the distance between each technician and the PWM rectifier at the current time point, and the distance is recorded as Eq1; Further, the number of processing times is extracted from the work log of each technician, and the time taken in each processing process is obtained. The reference time taken by the PWM rectifier for a single processing of the divided area is set, and the time taken by each processing process of each technician is compared with the set reference time. If the time taken by one group of processing processes is longer than the set reference time, the processing process is marked as the number of times that takes a long time; if the time taken by one group of processing processes is lower than the set reference time, the processing process is marked as the number of times that takes a short time. The ratio between the number of times each technician takes a shorter time and the number of times each technician takes a longer time is calculated, and the calculated ratio is used as the processing speed value of each technician, and the processing speed value is recorded as Eq2.

5. The dynamic response optimization adjustment method for a three-phase voltage-type PWM rectifier according to claim 4, characterized in that: The processing efficiency value TRe of each technician is obtained, which also includes: Mark the number of times each technician processes as Eq3, and substitute the distance of each technician Eq1, the processing speed value Eq2, and the number of times each technician processes Eq3 into the formula A weighted calculation is performed to obtain the processing efficiency value TRe of each technician, wherein a1, a2 and a3 are the influencing weight factors of each technician's travel distance Eq1, processing speed value Eq2 and processing times Eq3 respectively.

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