A new energy grid-connected inverter with adaptive control parameter real-time optimization

Abstract

The application discloses a new energy grid-connected inverter with adaptive real-time optimization of control parameters, which comprises an inverter unit composed of a general control unit of the inverter, a capacitor C, a filter inductor L and a converter, and an adaptive control unit composed of an oscillation parameter detector, a control parameter calculation and evaluation unit, a line parameter adjuster and a measurable and controllable fast recovery protection circuit. f The application can adaptively adjust control parameters and grid-connected point circuit parameters, protect fast recovery operation, real-time optimize inertia, damping parameters and synchronization capability of the inverter, inhibit small amplitude oscillation of the power grid, maintain stable operation of the power grid and realize friendly access of new energy grid-connected power generation to the power system.

Description

Technical Field

[0001] This invention relates to the field of inverter control technology for grid-connected power generation of new energy sources, specifically a grid-connected inverter for new energy sources with adaptive real-time optimization of control parameters. This inverter suppresses small oscillations in the power grid and maintains stable grid operation through adaptive real-time optimization of control parameters. Background Technology

[0002] With rapid economic and social development, human demand for energy is constantly increasing, and fossil fuels will inevitably be depleted, posing a severe challenge to humanity's energy crisis. At the same time, the large-scale use of fossil fuels has led to global warming and excessive carbon emissions, drawing significant global attention. Therefore, controlling total fossil fuel consumption, implementing renewable energy substitution, and achieving carbon peaking and carbon neutrality have broad and profound socio-economic significance. Developing renewable energy and achieving sustainable energy development are crucial ways for humanity to address the energy crisis, environmental pollution, and global climate issues. New energy power generation, represented by wind power and photovoltaics, has received widespread attention both domestically and internationally, and renewable energy sources such as wind and solar power have been widely adopted worldwide. Most new energy power generation systems use grid-connected inverters as the interface to output power to the grid. Their basic function is similar to conventional hydroelectric and thermal synchronous generator sets, but their operating characteristics differ significantly from traditional rotating synchronous generators. This is mainly reflected in the low inertia, weak damping, and weak synchronization characteristics of grid-connected inverters. Furthermore, unlike traditional primary energy sources such as thermal, hydroelectric, and nuclear power, new energy sources like wind and solar power exhibit low spatial density dispersion and strong temporal random fluctuations. The large-scale integration of new energy power will cause both the "source" and "load" of the power system to exhibit strong randomness and volatility, posing significant challenges to grid operation and control. As the penetration rate of new energy in the public power grid continues to increase, the large-scale integration of grid-connected inverters characterized by low inertia and weak damping into the power system has gradually reduced the installed capacity of synchronous generator systems. This has led to a relative decrease in the spinning reserve capacity and rotational inertia of the grid, and the power system is gradually exhibiting a high proportion of power electronic grid-connected generation equipment, consequently reducing the grid's safe and stable operation capability. Power systems with a high proportion of renewable energy integration are constantly subject to minor disturbances during operation. A power system unstable due to even a minor disturbance is unlikely to operate normally in practice. In other words, a normally operating power system should first and foremost be stable under minor disturbances, which places higher demands on the grid-connected operation characteristics of renewable energy grid-connected inverters.

[0003] Currently, the control parameters of traditional renewable energy grid-connected inverters are not adjustable. For different grid conditions, these parameters cannot be dynamically adjusted, and the control parameters cannot be adjusted according to the real-time operating conditions of the grid to provide support for grid stability, such as participating in grid frequency and voltage regulation. Simultaneously, renewable energy power supply is highly random, and renewable energy grid-connected inverters exert extremely frequent disturbances on the grid. Early traditional renewable energy grid-connected inverters operated in maximum power point tracking (MPPT) mode at the DC input end to maximize system power generation efficiency. These inverters exhibited current source characteristics on the grid, almost completely disregarding the disturbance impact on the grid due to the randomness of the input power. At some weak grid connection points, the operation of renewable energy grid-connected inverters can cause small oscillations in the grid at the connection point, making it difficult for the connection point to recover stability. To address this, some grid-connected inverters install filters with fixed parameters at the inverter's AC output port. However, due to the significant differences in grid parameters and characteristics at different connection points, fixed-parameter filters are insufficient to optimize the grid characteristics of various connection points. When the protection circuit of a traditional grid-connected inverter for new energy is triggered (usually a transient overcurrent fault), in order to protect the switching devices of the converter, the inverter will exit the operating state after the protection is triggered and then restart. This restart time after protection is generally between several seconds and tens of seconds. The process of the inverter shutting down and restarting under protection causes impact and disturbance to the grid output, affecting the stability of the grid.

[0004] Therefore, conducting small-disturbance stability analysis of power systems with a high proportion of power electronics access, determining whether the system is stable under specified operating conditions, and improving the control strategies and control circuits of existing grid-connected inverters for new energy sources based on this analysis are among the most fundamental and urgent tasks for power systems with a high proportion of new energy generation access.

[0005] Currently, researchers often optimize system design parameters based on specific renewable energy power generation conditions, achieving certain research results. For example, some renewable energy grid-connected inverters have added fault ride-through capabilities, enabling them to maintain grid-connected operation for a period of time when the grid experiences severe voltage drops. However, because the control parameters cannot be modified, they cannot provide the grid with necessary inertia, damping, and other support in a timely manner, nor can they participate in grid frequency and voltage regulation. Renewable energy power generation is geographically distributed and temporally random; therefore, a fixed set of optimized control parameters is difficult to adapt to the differences in inverters across time and space scales, causing numerous negative impacts on the power system. As the proportion of renewable energy generation connected to the grid increases year by year, its impact on the power grid cannot be ignored.

[0006] Therefore, it is urgent to study the dynamic stability mechanism of new energy grid-connected power generation systems and optimize the control parameters and control circuit structure of new energy grid-connected inverters in order to achieve friendly and compatible grid connection of new energy. Summary of the Invention

[0007] The purpose of this invention is to address the stability issues of renewable energy grid-connected power generation systems by proposing a renewable energy grid-connected inverter and its control method with adaptive real-time optimization of control parameters. Based on the general control system of traditional inverters, this invention can optimize and adjust control parameters and auxiliary grid line parameters in real time according to the actual operating conditions of the grid at the renewable energy grid connection point. This alters the grid-connected operating characteristics of the renewable energy grid-connected inverter, suppressing small grid oscillations, improving the stability of the grid at the connection point, and ultimately achieving a high proportion of renewable energy generation connected to the power system.

[0008] The technical solution of this invention is:

[0009] This invention provides a new energy grid-connected inverter with adaptive real-time optimization of control parameters, comprising:

[0010] The inverter consists of a general-purpose control unit, capacitor C, and filter inductor L. f The inverter unit consists of a converter; and the adaptive control unit consists of an oscillation parameter detector, a control parameter calculation and evaluation unit, a line parameter adjuster, and a measurable and controllable fast recovery protection circuit.

[0011] The detection signal terminal of the oscillation parameter detector is connected to the output terminal of the power grid voltage sensor, and the detection signal output terminal of the oscillation parameter detector is connected to the input terminal of the control parameter calculation and evaluation unit.

[0012] The two signal input terminals of the control parameter calculation and evaluation unit are connected to the output terminal of the grid voltage sensor to obtain the voltage and current signals of the grid. The other two input terminals are connected to the output terminal of the oscillation parameter detector to obtain the frequency and voltage change. The control signal output terminal of the control parameter calculation and evaluation unit is connected to the control signal input terminal of the line parameter adjuster. The communication signal terminal of the control parameter calculation and evaluation unit is connected to the communication port of the inverter general control unit.

[0013] The measurable and controllable fast recovery protection circuit is connected in series between the inverter general control unit and the converter. The current input terminal of the measurable and controllable fast recovery protection circuit is connected to the filter inductor L. f The current sensor output terminal is connected, the PWM input terminal of the controllable fast recovery protection circuit is connected to the PWM output terminal of the inverter general control unit, the PWM output terminal of the controllable fast recovery protection circuit is connected to the drive terminal of the converter, and the status output terminal and reset input terminal of the controllable fast recovery protection circuit are respectively connected to the digital input and output terminals of the inverter general control unit.

[0014] The control signal input terminal of the line parameter adjuster is connected to the control signal output terminal of the control parameter calculation and evaluation unit, and the compensation terminal of the line parameter adjuster is connected to the grid connection point of the inverter unit.

[0015] Furthermore, the oscillation parameter detector includes a low-frequency discriminator and a detector connected in parallel. The input terminals of the low-frequency discriminator and the detector are both connected to the output terminal of the power grid voltage sensor. The output terminals of the low-frequency discriminator and the detector respectively output the frequency change Δf and the voltage change ΔV to the AD input terminal of the control parameter calculation and evaluation unit.

[0016] Furthermore, the control parameter calculation and evaluation unit includes a high-performance embedded microprocessor. The multiple input ports of the processor's AD conversion module are connected to the output terminals of the grid voltage and current sensors, the Δf and ΔV output terminals of the oscillation parameter detector, respectively, and are connected to the three control terminals of the grid connection point line parameter adjuster SSR through three digital pins. The control parameter calculation and evaluation unit is connected to the communication port of the inverter general control unit through a digital communication port.

[0017] Furthermore, the measurable and controllable fast recovery protection circuit includes a comparator, a bistable trigger, and a PWM buffer;

[0018] One input terminal of the comparator serves as the current input of the controllable fast recovery protection circuit, and is connected to the filter inductor L. f The current sensor output terminal is connected, the other input terminal of the comparator is connected to the reference signal, and the output terminal of the comparator is connected to one input terminal of the bistable trigger.

[0019] The other input terminal of the bistable trigger is connected to the reset signal output terminal of the inverter general control unit, the state output terminal of the bistable trigger is connected to the digital input terminal of the inverter general control unit, and the buffer enable terminal of the bistable trigger is connected to the enable control terminal of the PWM buffer.

[0020] The PWM input terminal of the PWM buffer is connected to the PWM output terminal of the inverter general control unit, and the PWM output terminal of the PWM buffer is connected to the drive terminal of the converter.

[0021] Furthermore, the line parameter adjuster includes three sets of capacitors C1, C2, and C3 connected in parallel. Solid-state relays SSR1, SSR2, and SSR3 are respectively connected in series with each of the capacitors C1, C2, and C3. The compensation port of the line parameter adjuster is connected to the filter inductor L. f Equivalent inductance L of the power grid line g The common connection point between the solid-state relays SSR1, SSR2 and SSR3 is connected to the corresponding digital control port of the control parameter calculation and evaluation unit.

[0022] Furthermore, the capacitor satisfies: C3 = 2C2 = 4C1.

[0023] A control method for a new energy grid-connected inverter with adaptive real-time optimization of control parameters, the method comprising:

[0024] The oscillation parameter detector acquires the voltage signal from the grid voltage sensor and outputs the frequency change Δf and the voltage change ΔV.

[0025] The control parameter calculation and evaluation unit calculates the grid demand ratio of the inverter's inertia, damping, active power and reactive power based on the actual operating conditions of the grid at the grid connection point and the detected frequency and voltage changes. It then dynamically controls the inverter's converter control parameters and the switching status of the capacitor bank of the line parameter regulator to maximize the adjustment of the grid at the grid connection point to the expected operating state.

[0026] Furthermore, the measurable and controllable fast recovery protection circuit performs the following steps:

[0027] When the inverter is running normally, the PWM signal of the general control unit is buffered to the inverter drive end through the measurable and controllable fast recovery protection circuit;

[0028] When the inverter filter inductor L f When the current exceeds the limit, the comparator of the controllable fast recovery protection circuit outputs an edge-jumping signal to the bistable trigger. The bistable trigger outputs a level signal to block the PWM buffer and turn off the PWM drive output, protecting the switching device. It also outputs a protection status signal through the status pin for query by the general control unit.

[0029] When the inverter filter inductor L f Once the current recovers to the safe threshold, the general control unit enables the buffer output through the reset pin of the controllable fast recovery protection circuit, thereby controlling the inverter to resume operation.

[0030] Furthermore, the general control unit receives parameter corrections from the control parameter calculation and evaluation unit and performs real-time corrections to the inverter's control parameters and power.

[0031] Furthermore, the control parameter calculation and evaluation unit sends the switching status of the capacitor bank of the power grid line parameter regulator to the three SSR control terminals of the power grid line parameter regulator through three digital control ports, thereby realizing the switching operation of the capacitor compensation port of the power grid line parameter regulator to the grid at the connection point.

[0032] The beneficial effects of this invention are:

[0033] The new energy grid-connected inverter of the present invention adaptively optimizes control parameters in real time. According to the actual operating conditions of the grid at the inverter connection point, the inverter’s inertia, damping and synchronization capability are dynamically adjusted by adjusting and evaluating control parameters in real time. This meets the time-varying requirements of different grid connection points for the inverter’s output characteristics at different times, and maintains and improves the stability of the grid.

[0034] This invention employs a power grid line parameter adjuster, which can realize the auxiliary dynamic adjustment function of the grid parameters at the grid connection point. At certain weak grid connection points, it can effectively suppress the small oscillations of the grid at the grid connection point caused by the operation of the grid-connected inverter. It can also provide auxiliary compensation to the grid according to the actual needs of the grid at the grid connection point, and adjust the grid at the grid connection point to the expected operating state to the maximum extent.

[0035] This invention features a measurable and controllable fast recovery protection circuit. While protecting the inverter switching devices, their status can be queried. The reset enable pin allows the general control unit to make a decision and quickly reset and restart, ensuring that the inverter continues to operate after the current recovers to the safe threshold range. This achieves an "unnecessary shutdown" operation control strategy, minimizing the negative disturbance of the inverter to the power grid.

[0036] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0037] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0038] Figure 1 This is a schematic diagram of the overall structure of the new energy grid-connected inverter control system of the present invention;

[0039] Figure 2 This is a structural diagram of the power grid line parameter adjuster of the present invention;

[0040] Figure 3 This is a structural diagram of the power grid oscillation parameter detector of the present invention;

[0041] Figure 4 This is a structural diagram of the measurable and controllable fast recovery protection circuit of the present invention. Detailed Implementation

[0042] Preferred embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0043] This invention provides a new energy grid-connected inverter with adaptive real-time optimization of control parameters, comprising:

[0044] The inverter consists of a general-purpose control unit, capacitor C, and filter inductor L. fThe inverter unit consists of a converter; and the adaptive control unit consists of an oscillation parameter detector, a control parameter calculation and evaluation unit, a line parameter adjuster, and a measurable and controllable fast recovery protection circuit.

[0045] The detection signal terminal of the oscillation parameter detector is connected to the output terminal of the power grid voltage sensor, and the detection signal output terminal of the oscillation parameter detector is connected to the input terminal of the control parameter calculation and evaluation unit.

[0046] The two signal input terminals of the control parameter calculation and evaluation unit are connected to the output terminals of the grid voltage and current sensors to obtain the grid voltage and current signals. The other two input terminals are connected to the output terminal of the oscillation parameter detector to obtain the frequency and voltage change. The control signal output terminal of the control parameter calculation and evaluation unit is connected to the control signal input terminal of the line parameter adjuster. The communication signal terminal of the control parameter calculation and evaluation unit is connected to the communication port of the inverter general control unit.

[0047] The measurable and controllable fast recovery protection circuit is connected in series between the inverter general control unit and the converter. The current input terminal of the measurable and controllable fast recovery protection circuit is connected to the filter inductor L. f The current sensor output terminal is connected, the PWM input terminal of the controllable fast recovery protection circuit is connected to the PWM output terminal of the inverter general control unit, the PWM output terminal of the controllable fast recovery protection circuit is connected to the drive terminal of the converter, and the status output terminal and reset input terminal of the controllable fast recovery protection circuit are respectively connected to the digital input and output terminals of the inverter general control unit.

[0048] The control signal input terminal of the line parameter adjuster is connected to the control signal output terminal of the control parameter calculation and evaluation unit, and the compensation terminal of the line parameter adjuster is connected to the grid connection point of the inverter unit.

[0049] Furthermore, the oscillation parameter detector includes a low-frequency discriminator and a detector connected in parallel. The input terminals of the low-frequency discriminator and the detector are both connected to the grid voltage sensor. The output terminals of the low-frequency discriminator and the detector respectively output the frequency change Δf and the voltage change ΔV to the AD input terminal of the control parameter calculation and evaluation unit.

[0050] The control parameter calculation and evaluation unit includes a high-performance embedded microprocessor. The multiple input ports of the processor's AD conversion module are connected to the output terminals of the grid voltage and current sensors and the Δf and ΔV output terminals of the oscillation parameter detector, respectively. It is also connected to the three control terminals of the grid-connected line parameter adjuster SSR through three digital pins. The control parameter calculation and evaluation unit is connected to the communication port of the inverter general control unit through a digital communication port.

[0051] The measurable and controllable fast recovery protection circuit includes a comparator, a bistable trigger, and a PWM buffer; the input terminal of the comparator serves as the current input terminal of the measurable and controllable fast recovery protection circuit, and is connected to the filter inductor L. f The current sensor output is connected, the other input of the comparator is connected to the reference signal, and the output of the comparator is connected to one input of the bistable multivibrator; the other input of the bistable multivibrator is connected to the reset signal output of the inverter general control unit, the state output of the bistable multivibrator is connected to the digital input of the inverter general control unit, and the buffer enable of the bistable multivibrator is connected to the enable control of the PWM buffer; the PWM input of the PWM buffer is connected to the PWM output of the inverter general control unit, and the PWM output of the PWM buffer is connected to the drive of the converter.

[0052] The line parameter adjuster includes three sets of capacitors C1, C2, and C3 connected in parallel. Solid-state relays SSR1, SSR2, and SSR3 are connected in series with each of the capacitors C1, C2, and C3, respectively. The compensation port of the line parameter adjuster is connected to the filter inductor L. f Equivalent inductance L of the power grid line g The common connection point between the solid-state relays SSR1, SSR2 and SSR3 is connected to the corresponding digital control port of the control parameter calculation and evaluation unit.

[0053] Among them, the capacitor satisfies: C3 = 2C2 = 4C1.

[0054] Example:

[0055] Please see Figure 1-4 A new energy grid-connected inverter with adaptive real-time optimization of control parameters mainly consists of: a grid connection point line parameter adjuster, a grid oscillation parameter detector, a control parameter calculation and evaluation unit (the microprocessor model can be GigaDevice's domestic processor GD32F407), and a measurable and controllable fast recovery protection circuit (the comparator chip can be LM219, and the logic control chip with built-in bistable trigger can be XC9536).

[0056] The compensation terminal of the grid connection point line parameter adjuster is connected to the grid connection point of the grid-connected inverter, that is, connected to the inverter filter inductor L. f Equivalent inductance L of the power grid line gThe common connection point of the grid oscillation parameter detector is connected to the output of the grid voltage sensor. The multi-channel AD input of the control parameter calculation and evaluation unit is connected to the Δf and ΔV outputs of the grid oscillation parameter detector, and the outputs of the grid voltage and current sensors, respectively. The control parameter calculation and evaluation unit is connected to the control ports of the three SSRs of the grid connection point line parameter regulator through three digital control ports. The control parameter calculation and evaluation unit is connected to the communication port of the inverter general control unit through a digital communication port. The PWM input port, status pin, and reset pin of the measurable fast recovery protection circuit are connected to the PWM output port, digital input pin, and output pin of the inverter general control unit, respectively. The PWM output port of the measurable fast recovery protection circuit is connected to the converter drive terminal. The current input pin of the measurable fast recovery protection circuit is connected to the inverter filter inductor L. f Connect to the output terminal of the current sensor.

[0057] The general control unit in the grid-connected inverter for new energy uses conventional inverter devices, and its working process is not described in detail. Only the working process of real-time optimization of control parameters, adjustment of grid line parameters, and rapid recovery after protection, which is related to this invention, is described. The working process of this invention is as follows:

[0058] When the new energy grid-connected inverter is in grid-connected power generation operation, the grid oscillation parameter detector collects the output signal of the grid voltage sensor. The frequency discriminator inside the grid oscillation parameter detector detects the frequency change Δf of the grid voltage signal in real time, and the detector inside the grid oscillation parameter detector detects the amplitude change ΔV of the grid voltage signal in real time. These signals are then output to the control parameter calculation and evaluation unit from the Δf and ΔV output ports, respectively.

[0059] The control parameter calculation and evaluation unit uses multiple AD input ports to sample the output signals of the grid voltage and grid current sensors, as well as the Δf and ΔV output signals of the grid oscillation parameter detector, in real time at a certain sampling frequency (generally 10kHz to 20kHz). Based on the collected parameters, the control parameter calculation and evaluation unit evaluates the grid status and calculates the demand ratio of the grid at the grid connection point for the new energy grid-connected inverter in terms of inertia, damping, active power, and reactive power. It also determines the switching state of the capacitor bank of the optimal grid line parameter regulator. Then, it weighs and optimizes the above demands by combining the DC input of the new energy power generation system and the inverter's own capacity threshold. Based on this, it calculates the correction amount of the grid-connected power, outer loop voltage control parameters, and inner loop current control parameters of the grid-connected inverter in real time and sends it to the inverter general control unit through a digital communication interface (generally a multi-channel buffered serial port MCBSP). The inverter general control unit corrects the inverter's control parameters and power in real time according to the sent parameter correction amount.

[0060] Meanwhile, the control parameter calculation and evaluation unit sends the calculated switching status of the capacitor bank of the power grid line parameter regulator to the three SSR control terminals of the power grid line parameter regulator through three digital control ports, thereby realizing the switching operation of the capacitor compensation port of the power grid line parameter regulator to the grid connection point.

[0061] After the above corrections take effect, i.e. after the inverter's converter adjusts its operating status according to the corrections, the control parameter calculation and evaluation unit re-evaluates the grid status based on the latest collected grid parameters, compares the previous control parameter corrections before and after, evaluates the improvement performance of the previous corrections, and provides a basis for this parameter adjustment. If the grid operating status at the grid connection point has improved, the control parameters will continue to be corrected in the same direction; otherwise, they will be corrected in the opposite direction.

[0062] Additionally, the PWM input of the controllable fast recovery protection circuit receives the PWM signal output from the general control unit. This signal is then output to its PWM output terminal via the internal PWM buffer. The PWM output terminal of the controllable fast recovery protection circuit then sends the PWM signal to the inverter's drive terminal via a ribbon cable to drive the inverter. The current input of the controllable fast recovery protection circuit acquires the current from the inverter's filter inductance L. f The current sensor output signal is converted into the inverter filter inductor L using a hysteresis comparator. f The current sensor output signal is compared with the reference signal. When the current exceeds the limit during the operation of the new energy grid-connected inverter due to its own reasons or grid reasons, the inverter filter inductor L... f When the current sensor output signal is greater than the reference signal, the hysteresis comparator outputs a fault signal to the bistable multivibrator. The bistable multivibrator outputs an enable signal level to the enable control terminal of the PWM buffer, controlling the PWM buffer to shut down the PWM output of the measurable fast recovery protection circuit to protect the switching devices of the inverter. Simultaneously, the status port of the measurable fast recovery protection circuit outputs a fault level to the digital input terminal of the general-purpose control unit. After the measurable fast recovery protection circuit generates a protection action, the general-purpose control unit repeatedly polls the inverter filter inductor L at high speed. f The current sensor outputs a signal when the inverter filter inductor L... f When the current drops to within the safe threshold range, the protection of the controllable fast recovery protection circuit is unlocked by controlling the reset input terminal of the controllable fast recovery protection circuit, and the inverter is quickly restored to grid-connected operation. This process generally lasts for 2 to 5 interrupt cycles, with a time of 0.1ms to 0.5ms. This can minimize the negative disturbance to the grid caused by the inverter's overcurrent protection and maintain the stability of the grid.

[0063] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A new energy grid-connected inverter with adaptive real-time optimization of control parameters, characterized in that... include: The inverter consists of a general-purpose control unit, capacitor C, and filter inductor L. f Inverter unit consisting of inverter and converter; And an adaptive control unit consisting of an oscillation parameter detector, a control parameter calculation and evaluation unit, a line parameter adjuster, and a measurable and controllable fast recovery protection circuit; The detection signal input terminal of the oscillation parameter detector is connected to the output terminal of the power grid voltage sensor, and the detection signal output terminal of the oscillation parameter detector is connected to the input terminal of the control parameter calculation and evaluation unit. The two signal input terminals of the control parameter calculation and evaluation unit are connected to the output terminal of the grid voltage sensor to obtain the voltage and current signals of the grid. The other two input terminals are connected to the output terminal of the oscillation parameter detector to obtain the frequency and voltage change. The control signal output terminal of the control parameter calculation and evaluation unit is connected to the control signal input terminal of the line parameter adjuster. The communication signal terminal of the control parameter calculation and evaluation unit is connected to the communication port of the inverter general control unit. The measurable and controllable fast recovery protection circuit is connected in series between the inverter general control unit and the converter. The current input terminal of the measurable and controllable fast recovery protection circuit is connected to the filter inductor L. f The current sensor output terminal is connected, the PWM input terminal of the controllable fast recovery protection circuit is connected to the PWM output terminal of the inverter general control unit, the PWM output terminal of the controllable fast recovery protection circuit is connected to the drive terminal of the converter, and the status output terminal and reset input terminal of the controllable fast recovery protection circuit are respectively connected to the digital input and output terminals of the inverter general control unit. The control signal input terminal of the line parameter adjuster is connected to the control signal output terminal of the control parameter calculation and evaluation unit, and the compensation terminal of the line parameter adjuster is connected to the grid connection point of the inverter unit.

2. A new energy grid-connected inverter with adaptive real-time optimization of control parameters according to claim 1, characterized in that: The oscillation parameter detector includes a low-frequency discriminator and a detector connected in parallel. The input terminals of the low-frequency discriminator and the detector are both connected to the grid voltage sensor. The output terminals of the low-frequency discriminator and the detector output the frequency change Δf and the voltage change ΔV to the AD input terminal of the control parameter calculation and evaluation unit, respectively.

3. A new energy grid-connected inverter with adaptive real-time optimization of control parameters according to claim 1, characterized in that: The control parameter calculation and evaluation unit includes a high-performance embedded microprocessor. The multiple input ports of the processor's AD conversion module are connected to the output terminals of the grid voltage sensor and the Δf and ΔV output terminals of the oscillation parameter detector, respectively. It is also connected to the three control terminals of the grid connection point line parameter adjuster SSR through three digital pins. The control parameter calculation and evaluation unit is connected to the communication port of the inverter general control unit through a digital communication port.

4. A new energy grid-connected inverter with adaptive real-time optimization of control parameters according to claim 1, characterized in that: The measurable and controllable fast recovery protection circuit includes a comparator, a bistable trigger, and a PWM buffer; One input terminal of the comparator serves as the current input of the controllable fast recovery protection circuit, and is connected to the filter inductor L. f The current sensor output terminal is connected, the other input terminal of the comparator is connected to the reference signal, and the output terminal of the comparator is connected to one input terminal of the bistable trigger. The other input terminal of the bistable trigger is connected to the reset signal output terminal of the inverter general control unit, the state output terminal of the bistable trigger is connected to the digital input terminal of the inverter general control unit, and the buffer enable terminal of the bistable trigger is connected to the enable control terminal of the PWM buffer. The PWM input terminal of the PWM buffer is connected to the PWM output terminal of the inverter general control unit, and the PWM output terminal of the PWM buffer is connected to the drive terminal of the converter.

5. A new energy grid-connected inverter with adaptive real-time optimization of control parameters according to claim 1, characterized in that: The line parameter adjuster includes three sets of capacitors C1, C2, and C3 connected in parallel. Solid-state relays SSR1, SSR2, and SSR3 are connected in series with each of the capacitors C1, C2, and C3, respectively. The compensation port of the line parameter adjuster is connected to the filter inductor L. f Equivalent inductance L of the power grid line g The common connection point between the solid-state relays SSR1, SSR2 and SSR3 is connected to the corresponding digital control port of the control parameter calculation and evaluation unit.

6. A new energy grid-connected inverter with adaptive real-time optimization of control parameters according to claim 1, characterized in that: The capacitor satisfies: C3 = 2C2 = 4C1.

7. A control method for a new energy grid-connected inverter with adaptive real-time optimization of control parameters as described in any one of claims 1-6, characterized in that... The method includes: The oscillation parameter detector acquires the voltage signal from the grid voltage sensor and outputs the frequency change Δf and the voltage change ΔV. The control parameter calculation and evaluation unit calculates the grid demand ratios of the inverter for inertia, damping, active power and reactive power based on the actual operating conditions of the grid at the grid connection point and the detected frequency and voltage changes. It then dynamically controls the inverter's control parameters and the switching status of the capacitor bank of the line parameter regulator to maximize the adjustment of the grid at the grid connection point to the expected operating state.

8. The control method for a new energy grid-connected inverter with adaptive real-time optimization of control parameters according to claim 7, characterized in that... The controllable fast recovery protection circuit performs the following steps: When the inverter is running normally, the PWM signal of the general control unit is buffered to the inverter drive end through the measurable and controllable fast recovery protection circuit; When the inverter filter inductor L f When the current exceeds the limit, the comparator of the controllable fast recovery protection circuit outputs an edge-jumping signal to the bistable trigger. The bistable trigger outputs a level signal to block the PWM buffer and turn off the PWM drive output, protecting the switching device. It also outputs a protection status signal through the status pin for query by the general control unit. When the inverter filter inductor L f Once the current recovers to the safe threshold, the general control unit enables the buffer output through the reset pin of the controllable fast recovery protection circuit, thereby controlling the inverter to resume operation.

9. The control method for a new energy grid-connected inverter with adaptive real-time optimization of control parameters according to claim 7, characterized in that: The general control unit receives parameter correction values ​​from the control parameter calculation and evaluation unit and performs real-time corrections on the inverter's control parameters and power.

10. The control method for a new energy grid-connected inverter with adaptive real-time optimization of control parameters according to claim 7, characterized in that: The control parameter calculation and evaluation unit sends the switching status of the capacitor bank of the power grid line parameter regulator to the three SSR control terminals of the power grid line parameter regulator through three digital control ports, thereby realizing the switching operation of the capacitor compensation port of the power grid line parameter regulator to the grid at the connection point.

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