LC inverter control method and system based on time delay feedback PID control

Abstract

This invention provides a control method and system for an LC inverter based on time-delay feedback PID control. The method includes: acquiring a current signal from the system output side and using it as a system state variable; comparing the current signal with a preset reference current signal to obtain an error signal; inputting the error signal to a PID control module, performing proportional, integral, and derivative operations to generate a basic modulation signal; performing time-delay processing on the current signal to obtain a delayed state signal; generating a time-delay feedback correction term based on the current signal and the delayed state signal; superimposing the basic modulation signal and the time-delay feedback correction term to generate a final control signal; inputting the final control signal to a pulse width modulation module to generate a PWM drive signal; and controlling the operating state of the power switching unit according to the PWM drive signal. Based on this, this invention can improve the reliability and robustness of system operation.

Description

Technical Field

[0001] This invention relates to the field of inverter control technology, and in particular to a control method and system for an LC inverter based on time-delay feedback PID control. Background Technology

[0002] Inverters, as key power electronic devices for converting DC power to AC power, are widely used in new energy power generation, distributed power sources, AC motor drives, power regulation, and aerospace power supply. LC inverters, due to their simple structure, good filtering effect, and ease of engineering implementation, are widely used in low-to-medium power applications.

[0003] In actual operation, LC inverters typically employ pulse width modulation (PWM) control, with their power devices operating at high-frequency switching, resulting in significant nonlinear characteristics. To achieve stable regulation of the output current or voltage, proportional-integral-derivative (PID) control strategies are widely used in existing engineering projects. PID controllers are simple in structure, have clearly defined physical meanings for their parameters, and are easy to tune, thus finding widespread application in inverter control systems.

[0004] However, under actual operating conditions, inverter system parameters (such as input voltage, load impedance, filter inductor and capacitor) often change, and control parameter tuning is usually based on linearized models or empirical methods. When system parameters change or control parameters are not set properly, the inverter is prone to problems such as low-frequency oscillation, output distortion, and dynamic instability. In severe cases, it may even cause overstress of power devices or system protection activation, affecting the reliability and robustness of system operation. Summary of the Invention

[0005] This invention provides a control method and system for an LC inverter based on time-delay feedback PID control. Without changing the main circuit structure of the inverter, it can effectively suppress unstable oscillations during system operation, significantly broaden the stable operating range of the inverter, and improve the reliability and robustness of system operation by introducing a time-delay feedback control mechanism.

[0006] In a first aspect, embodiments of the present invention provide a control method for an LC inverter based on time-delay feedback PID control, applied to an LC inverter control system. The LC inverter control system includes a main circuit module, a PID control module, a time-delay feedback control module, and a pulse width modulation module. The main circuit module consists of a DC voltage source, a power switching unit, and an LC filter load. The method includes: Acquire the current signal from the output side of the system; The current signal is compared with a preset reference current signal to obtain an error signal; The error signal is input to the PID control module, and after proportional, integral and derivative operations, a basic modulation signal is generated. The current signal is subjected to time delay processing to obtain a delayed state signal; A time delay feedback correction term is generated based on the current signal and the delay state signal, wherein the time delay feedback correction term is zero when the current signal is equal to the delay state signal; The time delay feedback control module superimposes the basic modulation signal with the time delay feedback correction term to generate the final control signal. The final control signal is input to the pulse width modulation module to generate a PWM drive signal; The operating state of the power switching unit is controlled according to the PWM drive signal.

[0007] In some embodiments, generating a time delay feedback correction term based on the current signal and the delay state signal includes: A feedback signal is constructed based on the difference between the current signal and the delayed state signal; The time delay feedback correction term is generated based on the feedback signal and the adjustable gain coefficient of the feedback signal.

[0008] In some embodiments, the main circuit module is used to convert DC power to AC power. The H-bridge power switching unit includes a first switch, a second switch, a third switch, and a fourth switch. The first switch and the third switch are connected in series to form a first branch, and the second switch and the fourth switch are connected in series to form a second branch. The first branch and the second branch are connected in parallel.

[0009] In some embodiments, the PID control module is used to generate a basic modulation signal based on the error between the reference current signal and the current signal output by the LC inverter. The PID control module employs bipolar SPWM modulation. During SPWM modulation, the LC inverter control system has the following two operating states: When the basic modulation signal is less than the preset triangular carrier wave, the first switch and the fourth switch are turned on, and the second switch and the third switch are turned off, the load current rises, and the LC inverter control system is in the first working state. When the basic modulation signal is greater than the preset triangular carrier wave, the first switch and the fourth switch are turned off, and the second switch and the third switch are turned on, the load current decreases, and the LC inverter control system is in the second working state.

[0010] In some embodiments, the state equations of the LC inverter control system are expressed as follows:

[0011] in, i For load current, v c This is the load voltage. d n Duty cycle, R For resistance, L For inductance, C For capacitors, E The source is a DC voltage source, and t is time; the LC inverter control system is in its first operating state. μ =1; The LC inverter control system is in the second operating state. μ =0.

[0012] In some embodiments, the input variables and output variables of the PID control module are respectively and ,in, , , The expression is:

[0013] in, , ,

[0014] Among them, duty cycle d n The expression is:

[0015] The discrete iterative model of the LC inverter control system under PID regulation is as follows:

[0016] After introducing time delay feedback control, the duty cycle d n The expression is updated to: .

[0017] Secondly, embodiments of the present invention also provide an LC inverter control system based on time-delay feedback PID control. The system is used to implement the LC inverter control method based on time-delay feedback PID control as described in the first aspect. The system includes a main circuit module, a PID control module, a time-delay feedback control module, and a pulse width modulation module. The main circuit module is used to convert DC power to AC power. The PID control module is used to generate a basic modulation signal based on the error between a reference current signal and the actual output current signal. The time-delay feedback control module is used to delay the system state variables and generate a time-delay feedback correction term. The pulse width modulation module is used to generate a PWM drive signal based on the final control signal to control the on / off state of the power switching unit.

[0018] Thirdly, embodiments of the present invention also provide an LC inverter control device based on time-delay feedback PID control, the device comprising: The acquisition module is used to acquire the current signal from the system output side; The comparison module is used to compare the current signal with a preset reference current signal to obtain an error signal; The PID module is used to perform proportional, integral, and derivative operations on the error signal to generate a basic modulation signal; The time delay module is used to perform time delay processing on the current signal to obtain a delayed state signal; The correction module is used to generate a time delay feedback correction term based on the current signal and the delay state signal, wherein when the current signal is equal to the delay state signal, the time delay feedback correction term is zero; The superposition module is used to superimpose the basic modulation signal and the time delay feedback correction term to generate the final control signal; The modulation module is used to perform pulse width modulation on the final control signal to generate a PWM drive signal; The control module is used to control the operating state of the inverter power switching unit according to the PWM drive signal.

[0019] Fourthly, embodiments of the present invention also provide an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, when the processor executes the computer program, it implements the LC inverter control method based on time-delay feedback PID control as described in the first aspect.

[0020] Fifthly, embodiments of the present invention also provide a computer-readable storage medium storing computer-executable instructions for executing the LC inverter control method based on time-delay feedback PID control as described in the first aspect.

[0021] According to embodiments of the present invention, an LC inverter control method and system based on time-delay feedback PID control are provided. The LC inverter control method based on time-delay feedback PID control is applied to an LC inverter control system. The LC inverter control system includes a main circuit module, a PID control module, a time-delay feedback control module, and a pulse width modulation module. The main circuit module consists of a DC voltage source, a power switching unit, and an LC filter load. The method includes: acquiring a current signal from the system output side; comparing the current signal with a preset reference current signal through the main circuit module to obtain an error signal; inputting the error signal to the PID control module, and generating a basic modulation signal after proportional, integral, and derivative operations; performing time-delay processing on the current signal to obtain a delayed state signal; generating a time-delay feedback correction term based on the current signal and the delayed state signal, wherein the time-delay feedback correction term is zero when the current signal and the delayed state signal are equal; superimposing the basic modulation signal and the time-delay feedback correction term through the time-delay feedback control module to generate a final control signal; inputting the final control signal to the pulse width modulation module to generate a PWM drive signal; and controlling the operating state of the power switching unit according to the PWM drive signal. Compared to existing LC inverters that only employ traditional PID control, this invention introduces a time-delay feedback control mechanism on top of PID control. This allows the control system to utilize historical system state information to correct the current operating state, thereby effectively suppressing unstable oscillations under conditions of system parameter changes or disturbances. This invention significantly widens the inverter's stable operating range and improves the system's adaptability to input voltage and load variations without altering the inverter's main circuit structure or incurring additional hardware costs. Therefore, this embodiment of the invention, without changing the inverter's main circuit structure, effectively suppresses unstable oscillations during system operation by introducing a time-delay feedback control mechanism, significantly widening the inverter's stable operating range and improving the system's reliability and robustness. Attached Figure Description

[0022] Figure 1A This is the main flowchart of an LC inverter control method based on time-delay feedback PID control provided in an embodiment of the present invention; Figure 1B This is an LC inverter control system provided in one embodiment of the present invention; Figure 2(a) shows the PID control of an LC inverter based on time-delay feedback with a proportional gain. k p Bifurcation diagram as a bifurcation parameter; Figure 2(b) shows the PID control of an LC inverter based on time-delay feedback with differential gain. k d Bifurcation diagram as a bifurcation parameter; Figure 2(c) shows the bifurcation diagram of a PID-controlled LC inverter based on time-delay feedback with DC input voltage E as the bifurcation parameter. Figure 2(d) shows the bifurcation diagram of a PID-controlled LC inverter based on time-delay feedback with load resistance R as the bifurcation parameter. Figure 2(e) shows the bifurcation diagram of a PID-controlled LC inverter based on time-delay feedback with load inductance L as the bifurcation parameter. Figure 3(a) shows a PID-controlled LC inverter without time-delay feedback control, operating at a proportional gain. k p Bifurcation diagram as a bifurcation parameter; Figure 3(b) shows the PID-controlled LC inverter without time-delay feedback control, operating at a differential gain. k d Bifurcation diagram as a bifurcation parameter; Figure 3(c) shows the bifurcation diagram of a PID-controlled LC inverter without time-delay feedback control, with the DC input voltage E as the bifurcation parameter. Figure 2(d) shows the bifurcation diagram of a PID-controlled LC inverter without time delay feedback control, with the load resistance R as the bifurcation parameter. Figure 3(e) shows the bifurcation diagram of a PID-controlled LC inverter without time delay feedback control, with the load inductance L as the bifurcation parameter. Figure 4 This is a schematic diagram of the structure of an LC inverter control device based on time-delay feedback PID control according to an embodiment of the present invention; Figure 5 This is a schematic diagram of an electronic device provided in one embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] It should be noted that although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, and the following drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0025] In this embodiment of the invention, the terms "furthermore," "exemplarily," or "optionally" are used as examples, illustrations, or descriptions and should not be construed as being more preferred or advantageous than other embodiments or designs. The use of the terms "furthermore," "exemplarily," or "optionally" is intended to present the relevant concepts in a specific manner.

[0026] To facilitate a more convenient description of the working principle of the embodiments of the present invention, the following introduction of relevant technical scenarios is given first.

[0027] Inverters, as key power electronic devices for converting DC power to AC power, are widely used in new energy power generation, distributed power sources, AC motor drives, power regulation, and aerospace power supply. LC inverters, due to their simple structure, good filtering effect, and ease of engineering implementation, are widely used in low-to-medium power applications.

[0028] In actual operation, LC inverters typically employ pulse width modulation (PWM) control, with their power devices operating at high-frequency switching, resulting in significant nonlinear characteristics. To achieve stable regulation of the output current or voltage, proportional-integral-derivative (PID) control strategies are widely used in existing engineering projects. PID controllers are simple in structure, have clearly defined physical meanings for their parameters, and are easy to tune, thus finding widespread application in inverter control systems.

[0029] However, under actual operating conditions, inverter system parameters (such as input voltage, load impedance, filter inductor and capacitor) often change, and control parameter tuning is usually based on linearized models or empirical methods. When system parameters change or control parameters are not set properly, the inverter is prone to problems such as low-frequency oscillation, output distortion, and dynamic instability. In severe cases, it may even cause overstress of power devices or system protection activation, affecting the reliability and robustness of system operation.

[0030] Based on this, the present invention provides a control method and system for an LC inverter based on time-delay feedback PID control. The LC inverter control method based on time-delay feedback PID control is applied to an LC inverter control system, which includes a main circuit module, a PID control module, a time-delay feedback control module, and a pulse width modulation module. The main circuit module consists of a DC voltage source, a power switching unit, and an LC filter load. The method includes: acquiring the current signal from the system output side; comparing the current signal with a preset reference current signal to obtain an error signal; inputting the error signal to the PID control module, and generating a basic modulation signal after proportional, integral, and derivative operations; performing time-delay processing on the current signal to obtain a delayed state signal; generating a time-delay feedback correction term based on the current signal and the delayed state signal, wherein the time-delay feedback correction term is zero when the current signal and the delayed state signal are equal; superimposing the basic modulation signal and the time-delay feedback correction term through the time-delay feedback control module to generate a final control signal; inputting the final control signal to the pulse width modulation module to generate a PWM drive signal; and controlling the operating state of the power switching unit according to the PWM drive signal. Compared to existing LC inverters that only employ traditional PID control, this invention introduces a time-delay feedback control mechanism on top of PID control. This allows the control system to utilize historical system state information to correct the current operating state, thereby effectively suppressing unstable oscillations under conditions of system parameter changes or disturbances. This invention significantly widens the inverter's stable operating range and improves the system's adaptability to input voltage and load variations without altering the inverter's main circuit structure or incurring additional hardware costs. Therefore, this embodiment of the invention, without changing the inverter's main circuit structure, effectively suppresses unstable oscillations during system operation by introducing a time-delay feedback control mechanism, significantly widening the inverter's stable operating range and improving the system's reliability and robustness.

[0031] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0032] like Figure 1A As shown, Figure 1A This is a flowchart of an LC inverter control method based on time-delay feedback PID control provided in an embodiment of the present invention. The LC inverter control method based on time-delay feedback PID control is applied to an LC inverter control system. The LC inverter control system includes a main circuit module, a PID control module, a time-delay feedback control module, and a pulse width modulation module. The main circuit module consists of a DC voltage source, a power switching unit, and an LC filter load. The LC inverter control method based on time-delay feedback PID control may include, but is not limited to, steps S101 to S108.

[0033] Step S101: Acquire the current signal from the system output side; Step S102: Compare the current signal with a preset reference current signal to obtain an error signal; Step S103: The error signal is input to the PID control module, and after proportional, integral and derivative operations, a basic modulation signal is generated. Step S104: Perform time delay processing on the current signal to obtain a delayed state signal; Step S105: Generate a time delay feedback correction term based on the current signal and the delay state signal, wherein when the current signal and the delay state signal are equal, the time delay feedback correction term is zero. Step S106: The basic modulation signal and the time delay feedback correction term are superimposed by the time delay feedback control module to generate the final control signal; Step S107: Input the final control signal to the pulse width modulation module to generate a PWM drive signal; Step S108: Control the operating state of the power switching unit according to the PWM drive signal.

[0034] Understandably, the LC inverter control system, such as Figure 1B As shown, the LC inverter control system includes: a main circuit module for converting DC power to AC power, comprising a DC power supply, power switching units, and an LC filter load; a PID control module for generating a basic control signal based on the error between the reference signal and the actual output signal; a time-delay feedback control module for delaying the current signal as a system state variable and generating a feedback correction; and a pulse-width modulation (PWM) module for generating a PWM drive signal based on the final control signal to control the on / off state of the power switching units. These modules work together through signal connections to form a complete LC inverter control system.

[0035] Understandably, in Time Delay Feedback Control (TDFC), the control signal consists of a base modulation signal and a time delay feedback correction term. The base modulation signal uses an error signal (such as...). Figure 1B Mean error signal i e = i ref – i The time delay feedback correction term is introduced. η [ i (t)- i (t The difference structure of τ), where τ is the delay time. η This is an adjustable gain coefficient. The control mechanism of this method lies in: when the current signal... i (t) and its delay i (t When τ) is equal, the time delay feedback correction term is zero, meaning the time delay feedback correction term disappears naturally, and the system stabilizes on the target periodic orbit. It should be noted that the selection of the delay time τ is based on the unstable periodic orbit characteristics of the target system, and is usually taken as an integer multiple of the orbit period. This ensures both control timing matching and effective suppression of chaotic oscillations.

[0036] It is understandable that, such as Figure 1B As shown, the LC inverter control system includes a main circuit and a control circuit. The main circuit consists of a DC voltage source E, switching transistors S1, S2, S3, and S4, and an RLC load (resistor R, inductor L, and capacitor C). The control circuit uses bipolar SPWM modulation: output current... i With reference current i ref The error signal is obtained by comparison. i e After PID control, a modulation signal is generated. i con Then with triangular carrier i tri Compare and generate PWM drive signals u It controls the on / off state of the switch tube.

[0037] During SPWM modulation, the inverter system operates in two states: when i con < i tri When S1 and S4 are on and S2 and S3 are off, the load current... i As the voltage rises, μ=1, and the inverter system is in mode one. when i con > i tri When S1 and S4 are off and S2 and S3 are on, the load current... i The value decreases, at which point μ=0, and the inverter system is in mode two.

[0038] The system state equations are as follows:

[0039] In the formula, i For load current, v c This is the load voltage. d n Duty cycle, R For resistance, L For inductance, C For capacitors, E Here, t represents a DC voltage source, and t represents time.

[0040] Understandably, LC type inverters, such as Figure 1B As shown in the main circuit section, the state variables are taken. X = [ iv c ] T The state equations for the two modes of the system are as follows:

[0041] In the formula, , , .

[0042] Based on the stroboscopic iterative mapping theory, the discrete iterative model of the main circuit is obtained as follows:

[0043] In the formula, It is a second-order identity matrix. This represents the duty cycle.

[0044] It is understandable that, under PID control, an LC inverter, such as Figure 1B The control circuit is shown in the diagram. k p , k d and k i These are the proportional, integral, and derivative adjustment factors, respectively. and These are the input and output variables of the PID controller, respectively. , , As shown in the following formula:

[0045] in, , , .

[0046] The expression for duty cycle dn is:

[0047] Based on the discrete iterative model of the main circuit, the discrete iterative model of the LC inverter under PID control can be derived as follows:

[0048] As can be understood, time-delay feedback control is a nonlinear control strategy based on historical system state information, primarily used to suppress chaotic oscillations or stabilize periodic trajectories. Its core idea is to construct a feedback signal using the difference between the current state and the delayed state, and by adjusting the gain parameter of this signal, to make the system converge to the desired dynamic behavior. In time-delay feedback control, the control signal consists of a reference control quantity and a time-delay correction term. The reference control quantity uses an error signal (such as...) Figure 1B Mean error signal i e = i ref – i The time delay feedback correction term is introduced. η [ i (t)- i (t The difference structure of τ), where τ is the delay time. η This is an adjustable gain coefficient. The control mechanism of this method lies in: when the current signal... i (t) and its delay i (t When τ) is equal, the time delay feedback correction term is zero, meaning the time delay feedback correction term disappears naturally, and the system stabilizes on the target periodic orbit. It should be noted that the selection of the delay time τ is based on the unstable periodic orbit characteristics of the target system, and is usually taken as an integer multiple of the orbit period. This ensures both control timing matching and effective suppression of chaotic oscillations.

[0049] After introducing time-delay feedback control, the system duty cycle update is as follows:

[0050] Understandably, based on the discrete iterative model of this inverter, its bifurcation and chaotic characteristics under PID control are systematically studied using numerical simulation methods. The simulation parameter settings are shown in Table 1 below: Table 1. Parameter values ​​for LC inverter system with PID control based on time-delay feedback.

[0051] Set the reference current to the actual operating environment of the LC inverter. The default values ​​for each system parameter are shown in Table 1.

[0052] Bifurcation analysis, as an important tool in nonlinear dynamics research, can effectively reveal the evolution of a system's steady-state characteristics as parameters change. In inverter control systems, when the control gain exceeds a certain threshold, the system may experience abrupt changes in stability or structural characteristics, i.e., bifurcation occurs. Through bifurcation diagram analysis, a deeper understanding of the inverter's dynamic behavior under different operating conditions can be achieved, which has significant theoretical guiding value for optimizing system performance.

[0053] Based on the discrete iterative model of the LC inverter under PID regulation with time-delay feedback control established by the stroboscopic mapping theory, and combined with the system's state equation and duty cycle expression, the system parameters are selected to be consistent with those in Table 1. The feedback gain coefficient η = 0.05 is selected according to the time-delay feedback control law, and the system stability is verified using bifurcation diagram analysis.

[0054] Specifically, select the proportional gain k p Differential gain k d The DC input voltage E, load resistance R, and load inductance L are used as bifurcation parameters, and the inverter output current i is used as the state response quantity. After the system reaches quasi-steady state, the system state variables are periodically sampled based on stroboscopic mapping at a fixed phase point where the peak value of the sinusoidal reference current is located, and sampling points are retained within multiple consecutive fundamental frequency periods to construct a bifurcation diagram for analyzing the nonlinear dynamic behavior of the system under different parameter variation conditions, as shown in Figure 2.

[0055] When the bifurcation diagram presents a single continuous curve, it indicates that the system is in a stable single-cycle operating state; when the bifurcation diagram shows multiple branches, it indicates that the system has bifurcerated; when the bifurcation diagram presents irregularly dense sampling points, it indicates that the system has entered a chaotic state. Both bifurcation and chaos belong to the unstable operating states of the system.

[0056] For comparative analysis, while keeping the other system parameters the same, bifurcation diagrams of the LC inverter under PID regulation without time delay feedback control were drawn under the same parameter variation conditions, as shown in Figure 3.

[0057] A comparative analysis of Figures 2 and 3 reveals the following results: A comparison of Figure 2(a) and Figure 3(a) shows that as the proportional gain... k p With the increase of the proportional gain, the stable state range of the LC inverter based on PID control under time delay feedback is [1.11, 2.49], while the stable state range of the LC inverter using only PID control is [1.02, 1.89]. The inverter's stable domain is significantly expanded, indicating that the time delay feedback control effectively suppresses the unstable oscillations caused by the change in proportional gain.

[0058] A comparison of Figure 2(b) and Figure 3(b) shows that, in the differential gain... k d During the change process, the stable state range of the LC inverter based on PID control with time delay feedback is [0.00052, 0.00156], while the stable state range of the LC inverter using only PID control is [0.00071, 0.00158]. The inverter's stable domain is significantly expanded, indicating that the time delay feedback control effectively suppresses the unstable oscillations caused by the change in proportional gain.

[0059] Comparing Figure 2(c) and Figure 3(c), it can be seen that as the DC input voltage E increases, the stable operating range of the LC inverter based on PID control with time delay feedback is [0V, 997V], while the stable operating range of the LC inverter using only PID control is [0V, 665V]. The inverter's stable domain has been significantly expanded, indicating that the time delay feedback control effectively suppresses the unstable oscillations caused by the change in proportional gain.

[0060] Comparing Figure 2(d) and Figure 3(d), it can be seen that as the load resistance R changes, the stable state range of the LC inverter based on PID control with time delay feedback is [5.2Ω, 15.7Ω], while the stable state range of the LC inverter using only PID control is [7.2Ω, 15.7Ω]. The inverter's stable domain has been significantly expanded, indicating that time delay feedback control effectively suppresses the unstable oscillations caused by the change in proportional gain.

[0061] Comparing Figure 2(e) and Figure 3(e), it can be seen that as the load inductance L changes, the steady-state range of the LC inverter based on PID control with time delay feedback is [6.0mH, 20mH], while the steady-state range of the LC inverter using only PID control is [6.3mH, 20mH]. The inverter's stable domain is significantly expanded, indicating that the time delay feedback control effectively suppresses the unstable oscillations caused by the change in proportional gain.

[0062] The bifurcation diagram comparison and analysis above show that the PID control method based on time-delay feedback proposed in this invention can effectively suppress bifurcation and chaotic behavior in LC inverters under various parameter variation conditions, and significantly broaden the stable operating range of the system.

[0063] In summary, compared with the prior art, the present invention has at least the following beneficial effects: (1) Effectively suppress unstable oscillations without changing the main circuit structure of the inverter; (2) Significantly broadens the range of stable operating parameters for LC inverters; (3) The control structure is simple, easy to implement in engineering, and does not increase the additional hardware cost; (4) It has good robustness to changes in system parameters and is suitable for various operating conditions.

[0064] It should be noted that, without departing from the core technical concept of this invention, the technical solution of this invention can also have various alternative implementation methods. Specifically, the proportional, integral, and derivative parameters in the PID control module can be set using different tuning methods, including but not limited to empirical tuning methods, adaptive adjustment methods, or online adjustment methods based on operating status; the delay time in the time delay feedback control module is not limited to one switching cycle, but can also be set to an integer multiple of the switching cycle or adaptively adjusted according to the system operating characteristics; the time delay feedback gain parameter can also be adjusted according to the inverter's input voltage, load conditions, or output status. In addition, the system state variable is not limited to the output current signal, but can also be the output voltage signal or a combination of current and voltage signals; the control method is not only applicable to single-phase LC inverters, but also to multi-phase inverters or inverter systems with other filtering structures.

[0065] In addition, an embodiment of the present invention discloses an LC inverter control system based on time-delay feedback PID control. This system is used to implement the LC inverter control method based on time-delay feedback PID control as described above. The system includes a main circuit module, a PID control module, a time-delay feedback control module, and a pulse width modulation module. The main circuit module is used to convert DC power to AC power. The PID control module is used to generate a basic modulation signal based on the error between a reference current signal and the actual output current signal. The time-delay feedback control module is used to delay the current signal and generate a time-delay feedback correction term. The pulse width modulation module is used to generate a PWM drive signal based on the final control signal to control the on and off of the power switching unit.

[0066] The LC inverter control system based on time-delay feedback PID control in this embodiment of the invention is used to implement the LC inverter control method based on time-delay feedback PID control in the above embodiments. Its specific processing procedure is the same as that of the LC inverter control method based on time-delay feedback PID control in the above embodiments, and will not be described in detail here.

[0067] In addition, such as Figure 4 As shown, one embodiment of the present invention also discloses an LC inverter control device based on time-delay feedback PID control, the device comprising: Acquisition module 110 is used to acquire the current signal from the system output side; The comparison module 120 is used to compare the current signal with a preset reference current signal to obtain an error signal; PID module 130 is used to perform proportional, integral and derivative operations on the error signal to generate a basic modulation signal; The time delay module 140 is used to perform time delay processing on the current signal to obtain a delayed state signal; The correction module 150 is used to generate a time delay feedback correction term based on the current signal and the delay state signal, wherein when the current signal and the delay state signal are equal, the time delay feedback correction term is zero. The superposition module 160 is used to superimpose the basic modulation signal and the time delay feedback correction term to generate the final control signal; The modulation module 170 is used to perform pulse width modulation on the final control signal to generate a PWM drive signal; The control module 180 is used to control the operating state of the inverter power switching unit according to the PWM drive signal.

[0068] The LC inverter control device based on time-delay feedback PID control in this embodiment of the invention is used to execute the LC inverter control method based on time-delay feedback PID control in the above embodiment. Its specific processing procedure is the same as that of the LC inverter control method based on time-delay feedback PID control in the above embodiment, and will not be described in detail here.

[0069] In addition, such as Figure 5 As shown, one embodiment of the present invention also discloses an electronic device, including: at least one processor 210; at least one memory 220 for storing at least one program; when the at least one program is executed by the at least one processor 210, it implements the LC inverter control method based on time-delay feedback PID control as in any of the preceding embodiments.

[0070] In addition, one embodiment of the present invention discloses a computer-readable storage medium storing computer-executable instructions for performing the LC inverter control method based on time-delay feedback PID control as described in any of the preceding embodiments.

[0071] The system architecture and application scenarios described in the embodiments of this invention are for the purpose of more clearly illustrating the technical solutions of the embodiments of this invention, and do not constitute a limitation on the technical solutions provided by the embodiments of this invention. As those skilled in the art will know, with the evolution of system architecture and the emergence of new application scenarios, the technical solutions provided by the embodiments of this invention are also applicable to similar technical problems.

[0072] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, as well as the functional modules / units in the systems and devices, can be implemented as software, firmware, hardware, or suitable combinations thereof.

[0073] In hardware implementations, the division between functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0074] The terms “component,” “module,” “system,” etc., used in this specification are used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, or a computer. As illustrated, applications running on computing devices and computing devices can both be components. One or more components may reside in a process or execution thread, and components may be located on a single computer or distributed among two or more computers. Furthermore, these components can be executed from various computer-readable media on which various data structures are stored. Components can communicate, for example, via local or remote processes based on signals having one or more data packets (e.g., data from two components interacting with another component between a local system, a distributed system, or a network, such as the Internet interacting with other systems via signals).

Claims

1. A control method for an LC inverter based on time-delay feedback PID control, applied to an LC inverter control system, wherein the LC inverter control system includes a main circuit module, a PID control module, a time-delay feedback control module, and a pulse width modulation module, the main circuit module consisting of a DC voltage source, a power switching unit, and an LC filter load, the method comprising: Acquire the current signal from the output side of the system; The current signal is compared with a preset reference current signal to obtain an error signal; The error signal is input to the PID control module, and after proportional, integral and derivative operations, a basic modulation signal is generated. The current signal is subjected to time delay processing to obtain a delayed state signal; A time delay feedback correction term is generated based on the current signal and the delay state signal, wherein the time delay feedback correction term is zero when the current signal is equal to the delay state signal; The time delay feedback control module superimposes the basic modulation signal with the time delay feedback correction term to generate the final control signal. The final control signal is input to the pulse width modulation module to generate a PWM drive signal; The operating state of the power switching unit is controlled according to the PWM drive signal.

2. The method according to claim 1, characterized in that, The step of generating a time delay feedback correction term based on the current signal and the delay state signal includes: A feedback signal is constructed based on the difference between the current signal and the delayed state signal; The time delay feedback correction term is generated based on the feedback signal and the adjustable gain coefficient of the feedback signal.

3. The method according to claim 1, characterized in that, The main circuit module is used to convert DC power to AC power. The power switching unit includes a first switch, a second switch, a third switch, and a fourth switch. The first switch and the third switch are connected in series to form a first branch, and the second switch and the fourth switch are connected in series to form a second branch. The first branch and the second branch are connected in parallel.

4. The method according to claim 3, characterized in that, The PID control module is used to generate a basic modulation signal based on the error between the reference current signal and the current signal output by the LC inverter. The PID control module adopts bipolar SPWM modulation. During SPWM modulation, the LC inverter control system has the following two operating states: When the basic modulation signal is less than the preset triangular carrier wave, the first switch and the fourth switch are turned on, and the second switch and the third switch are turned off, the load current rises, and the LC inverter control system is in the first working state. When the basic modulation signal is greater than the preset triangular carrier wave, the first switch and the fourth switch are turned off, and the second switch and the third switch are turned on, the load current decreases, and the LC inverter control system is in the second working state.

5. The method according to claim 4, characterized in that, The state equations of the LC inverter control system are expressed as follows: in, i For load current, v c This is the load voltage. d n Duty cycle, R For resistance, L For inductance, C For capacitors, E The source is a DC voltage source, and t is time; the LC inverter control system is in its first operating state. μ =1; The LC inverter control system is in the second operating state. μ =0.

6. The method according to claim 1, characterized in that, The input and output variables of the PID control module are respectively and ,in, , , The expression is: in, , , Among them, duty cycle d n The expression is: The discrete iterative model of the LC inverter control system under PID regulation is as follows: After introducing time delay feedback control, the duty cycle d n The expression is updated to: 。 7. A control system for an LC inverter based on time-delay feedback PID control, characterized in that, The system is used to implement the LC inverter control method based on time-delay feedback PID control as described in any one of claims 1 to 6. The system includes a main circuit module, a PID control module, a time-delay feedback control module, and a pulse width modulation module. The main circuit module is used to convert DC power to AC power. The PID control module is used to generate a basic modulation signal based on the error between the reference current signal and the actual output current signal. The time delay feedback control module is used to delay the current signal and generate a time delay feedback correction term; the pulse width modulation module is used to generate a PWM drive signal according to the final control signal to control the power switching unit to turn on and off.

8. A control device for an LC inverter based on time-delay feedback PID control, characterized in that, The device includes: The acquisition module is used to acquire the current signal from the system output side; The comparison module is used to compare the current signal with a preset reference current signal to obtain an error signal; The PID module is used to perform proportional, integral, and derivative operations on the error signal to generate a basic modulation signal; The time delay module is used to perform time delay processing on the current signal to obtain a delayed state signal; The correction module is used to generate a time delay feedback correction term based on the current signal and the delay state signal, wherein when the current signal is equal to the delay state signal, the time delay feedback correction term is zero; The superposition module is used to superimpose the basic modulation signal and the time delay feedback correction term to generate the final control signal; The modulation module is used to perform pulse width modulation on the final control signal to generate a PWM drive signal; The control module is used to control the operating state of the inverter power switching unit according to the PWM drive signal.

9. An electronic device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, when the processor executes the computer program, it implements the LC inverter control method based on time-delay feedback PID control as described in any one of claims 1 to 6.

10. A computer-readable storage medium storing computer-executable instructions for performing the LC inverter control method based on time-delay feedback PID control as described in any one of claims 1 to 6.

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