Inverter circuit and four-quadrant control method therefor, and energy storage inverter device

Abstract

The present application discloses an inverter circuit and a four-quadrant control method therefor. The inverter circuit comprises a primary side circuit and a secondary side circuit, the primary side circuit is connected to the secondary side circuit by means of a resonant inductor, the primary side circuit is used for connecting to a direct current side of the inverter circuit, and the secondary side circuit is used for connecting to an alternating current side of the inverter circuit. The four-quadrant control method comprises: on the basis of a target angle at which an inverter circuit operates in four quadrants, obtaining a target current on an alternating current side of the inverter circuit; obtaining an instantaneous voltage value on the alternating current side; and adjusting the inverter circuit on the basis of the target current and the instantaneous voltage value, so that the inverter circuit operates in the four quadrants at the target angle. According to the present application, the inverter circuit is allowed to operate over the full four-quadrant range.

Description

Inverter circuits and their four-quadrant control methods and energy storage inverter equipment

[0001] This application claims priority to Chinese Patent Application No. 202411467868.2, filed on October 18, 2024, entitled "Inverter Circuit and Four-Quadrant Control Method Thereof and Energy Storage Inverter Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of power conversion circuit technology, specifically to an inverter circuit and its four-quadrant control method and energy storage inverter device. Background Technology

[0003] Currently, inverter circuits, as an important component of energy storage inverter equipment, face increasingly stringent performance requirements. For different applications, inverter circuits not only need to stably convert DC to AC, but also need to adjust their operating conditions to grid fluctuations and load changes.

[0004] In existing technologies, the inverter circuits of energy storage inverter devices cannot achieve full-range operation in all four quadrants, thus having low adaptability to grid fluctuations and load changes, which in turn affects the stability of the inverter circuits. Summary of the Invention

[0005] In view of this, this application provides an inverter circuit, a four-quadrant control method thereof, and an energy storage inverter device, enabling the inverter circuit to operate in the full four-quadrant range. The technical solution of this application is as follows:

[0006] This application provides a four-quadrant control method for an inverter circuit, the inverter circuit including a primary circuit and a secondary circuit, the primary circuit being connected to the secondary circuit via a resonant inductor, the primary circuit being connected to the DC side of the inverter circuit, and the secondary circuit being connected to the AC side of the inverter circuit; the four-quadrant control method includes: obtaining a target current on the AC side of the inverter circuit based on a target angle for the inverter circuit to operate in four quadrants; obtaining an instantaneous voltage value on the AC side; and adjusting the inverter circuit according to the target current and the instantaneous voltage value, so that the inverter circuit operates in four quadrants at the target angle.

[0007] In one embodiment of this application, obtaining the target current on the AC side of the inverter circuit based on the target angle of the inverter circuit operating in four quadrants includes: obtaining the AC current and AC voltage on the AC side; obtaining the peak value of the AC side current based on the AC current; obtaining the lag angle of the AC current lagging behind the AC voltage; and obtaining the target current based on the peak value of the AC side current, the lag angle, and the target angle.

[0008] In one embodiment of this application, adjusting the inverter circuit according to the target current and the instantaneous voltage value so that the inverter circuit operates in four quadrants at the target angle includes: obtaining the target outward phase angle between the primary circuit and the secondary circuit according to the target current and the instantaneous voltage value; and adjusting the inverter circuit according to the target outward phase angle so that the inverter circuit operates in four quadrants at the target angle.

[0009] In one embodiment of this application, obtaining the target outward phase shift angle between the primary circuit and the secondary circuit based on the target current and the instantaneous voltage value includes: constructing an instantaneous power expression for the inverter circuit based on the phase shift angle parameter; and obtaining the target outward phase shift angle based on the instantaneous power expression, the target current, and the instantaneous voltage value.

[0010] In one embodiment of this application, constructing the instantaneous power expression of the inverter circuit based on the phase shift angle parameter includes: obtaining the inner phase shift angle of the primary circuit and the outer phase shift angle between the primary circuit and the secondary circuit; obtaining the DC voltage on the DC side and the AC voltage on the AC side; constructing a primary voltage expression based on the inner phase shift angle and the DC voltage; constructing a secondary voltage expression based on the outer phase shift angle and the AC voltage; and obtaining the instantaneous power expression based on the primary voltage expression and the secondary voltage expression.

[0011] A second aspect of this application provides an inverter circuit, including a primary circuit, a secondary circuit, a transformer, a resonant inductor, a resonant capacitor, and a controller. The primary circuit is connected to the secondary circuit through the transformer and the resonant inductor. The resonant inductor is connected in series with the secondary circuit, and the resonant capacitor is connected in parallel with the secondary circuit. The primary circuit is used to connect to the DC side, and the secondary circuit is used to connect to the power grid through the AC side. The controller is connected to the primary circuit and the secondary circuit. The controller is used to obtain a target current on the AC side of the inverter circuit based on a target angle for the inverter circuit to operate in four quadrants at the target angle, obtain an instantaneous voltage value on the AC side, and adjust the inverter circuit according to the target current and the instantaneous voltage value so that the inverter circuit operates in four quadrants at the target angle.

[0012] In one embodiment of this application, the controller is further configured to obtain a target outward phase angle between the primary circuit and the secondary circuit based on the target current and the instantaneous voltage value, and adjust the inverter circuit according to the target outward phase angle so that the inverter circuit operates in all four quadrants at the target angle.

[0013] In one embodiment of this application, the primary-side circuit is a full-bridge circuit, including a first switch, a second switch, a third switch, a fourth switch, a primary-side inductor, and a primary-side capacitor; the first terminal of the first switch is connected to the positive terminal of the DC side, and the second terminal of the first switch is connected to the first terminal of the second switch; the second terminal of the second switch is connected to the negative terminal of the DC side; the first terminal of the third switch is connected to the first terminal of the first switch, and the second terminal of the third switch is connected to the first terminal of the fourth switch; the second terminal of the fourth switch is connected to the second terminal of the second switch; the first input terminal of the transformer is connected to the second terminal of the first switch, and the second input terminal of the transformer is connected to the second terminal of the third switch; the primary-side inductor is connected in parallel with the input terminal of the transformer; and the primary-side capacitor is connected in parallel with the DC side.

[0014] In one embodiment of this application, the secondary circuit is a half-bridge circuit, including a fifth switch, a sixth switch, a seventh switch, and an eighth switch, and the resonant capacitor includes a first capacitor and a second capacitor; the fifth switch, the sixth switch, the seventh switch, the eighth switch, the second capacitor, and the first capacitor are connected in series in sequence; the first output terminal of the transformer is connected between the sixth switch and the seventh switch through the resonant inductor, and the second output terminal of the transformer is connected between the first capacitor and the second capacitor.

[0015] This application provides a third aspect of an energy storage inverter device, including the aforementioned inverter circuit.

[0016] This application obtains a given target current on the AC side of the inverter circuit based on the target angle of the inverter's four-quadrant operation, and then adjusts the inverter circuit according to the target current and the instantaneous voltage value of the inverter to make the inverter circuit operate in the four quadrant at the target angle, thereby realizing the full range of four-quadrant operation of the inverter circuit and improving the stability of the inverter circuit. Attached Figure Description

[0017] Figure 1 is an equivalent schematic diagram of an inverter circuit provided in an embodiment of this application;

[0018] Figure 2 is a flowchart illustrating a four-quadrant control method for an inverter circuit provided in an embodiment of this application;

[0019] Figure 3 is a flowchart illustrating a method for obtaining a target current according to an embodiment of this application;

[0020] Figure 4 is a flowchart illustrating an adjustment inverter circuit according to an embodiment of this application;

[0021] Figure 5 is a schematic diagram of a process for obtaining the target outward phase angle according to an embodiment of this application;

[0022] Figure 6 is a schematic flowchart of constructing an instantaneous power expression provided by an embodiment of this application;

[0023] Figure 7 is a schematic block diagram of an inverter circuit provided in an embodiment of this application;

[0024] Figure 8 is a circuit diagram of an inverter circuit provided in an embodiment of this application. Detailed Implementation

[0025] It should be noted that in the embodiments of this application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone, where A and B can be singular or plural. The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and drawings of this application are used to distinguish similar objects, not to describe a specific order or sequence.

[0026] It should also be noted that the methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchanged, and some steps can also be deleted.

[0027] Currently, inverter circuits, as an important component of energy storage inverter equipment, face increasingly stringent performance requirements. For different applications, inverter circuits not only need to stably convert DC to AC, but also need to adjust their operating conditions to grid fluctuations and load changes.

[0028] In existing technologies, the inverter circuits of energy storage inverter devices cannot achieve full-range operation in all four quadrants, thus having low adaptability to grid fluctuations and load changes, which in turn affects the stability of the inverter circuits.

[0029] This application provides an inverter circuit and its four-quadrant control method, which enables the inverter circuit to operate in the full range of the four quadrants.

[0030] Please refer to Figure 1, which is an equivalent schematic diagram of an inverter circuit provided in an embodiment of this application. The inverter circuit 100 includes a primary circuit 110, a secondary circuit 120, a resonant inductor 130, and a resonant capacitor 140.

[0031] In this embodiment, the primary circuit 110 is connected to the secondary circuit 120 through the resonant inductor 130, and the resonant capacitor 140 is connected in parallel with the secondary circuit 120. The primary circuit 110 is used to connect to the DC side, and the secondary circuit 120 is used to connect to the AC side.

[0032] It can be understood that when the inverter circuit 100 is operating, it receives the DC voltage from the DC side through the primary circuit 110, converts the DC voltage into a primary AC voltage, and then transmits it to the secondary circuit 120 through the resonant inductor 130. The secondary circuit 120 then adjusts the waveform of the primary AC voltage and finally outputs the AC voltage to the AC side. Alternatively, the secondary circuit 120 receives the AC voltage from the AC side, converts the AC voltage into a primary DC voltage, transmits it to the primary circuit 110 through the resonant inductor 130, and then the primary circuit 110 adjusts the waveform of the primary DC voltage and finally outputs the DC voltage to the DC side.

[0033] Next, referring to Figure 1, we will introduce a four-quadrant control method for an inverter circuit provided in an embodiment of this application. Please refer to Figure 2, which specifically includes the following steps:

[0034] Step S21: Obtain the target current on the AC side of the inverter circuit based on the target angle of the inverter circuit operating in four quadrants.

[0035] In the embodiments of this application, the inverter circuit can also be connected to a controller, which controls its operation and executes the various steps in this embodiment. For example, in an energy storage inverter device equipped with an inverter circuit, both the primary and secondary circuits of the inverter circuit can be connected to the main controller of the energy storage inverter device. The main controller of the energy storage inverter device controls the switching parameters of the primary and secondary circuits, thereby controlling the inverter circuit to operate.

[0036] It is understood that after controlling the inverter circuit to operate, the controller can also receive external commands to adjust the target angle of the inverter circuit's operation in the four quadrants according to the external commands, to correspond to the required operating conditions. The angle of the inverter circuit's operation in the four quadrants refers to the angle by which the output AC current lags behind the AC voltage. When this angle is in the first quadrant, it indicates that the inverter circuit is operating with both active and reactive power output; when the angle is in the second quadrant, it indicates that the inverter circuit is operating with both active and reactive power input; when the angle is in the third quadrant, it indicates that the inverter circuit is operating with both active and reactive power input; and when the angle is in the fourth quadrant, it indicates that the inverter circuit is operating with both active and reactive power input. Therefore, by controlling the angle of the inverter circuit's operation in the four quadrants, the inverter circuit can be controlled to operate under the corresponding operating conditions. In some embodiments, the controller can also receive externally transmitted operating condition control commands and obtain the corresponding target angle of operation in the four quadrants based on the operating condition control commands.

[0037] After obtaining the target angle, the controller will obtain the target current on the AC side of the inverter circuit based on the target angle, that is, it can calculate a given target current on the AC side based on the target angle.

[0038] Step S22: Obtain the instantaneous voltage value on the AC side.

[0039] In this embodiment, the controller can be connected to the AC side of the inverter circuit to obtain the AC voltage on the AC side, and thus obtain the instantaneous value of the AC voltage. In some embodiments, an AC voltage sampling circuit can be provided on the AC side to collect the AC voltage on the AC side and transmit it to the controller.

[0040] Step S23: Adjust the inverter circuit according to the target current and instantaneous voltage values ​​so that the inverter circuit operates in all four quadrants at the target angle.

[0041] In this embodiment, after obtaining the target current and instantaneous voltage values, the controller adjusts the inverter circuit according to the instantaneous voltage value, ultimately enabling the inverter circuit to operate at the target angle in the four quadrants to correspond to the required operating conditions. For example, the controller can first control the inverter circuit to output the target current, and then adjust the operating parameters of the inverter circuit according to the instantaneous voltage value, ultimately making the angle by which the output current of the inverter circuit lags behind the output voltage the target angle, so that the inverter circuit operates at the target angle in the four quadrants.

[0042] It is understood that this application obtains a given target current on the AC side of the inverter circuit based on the target angle of the inverter's four-quadrant operation, and then adjusts the inverter circuit according to the target current and the instantaneous voltage value of the inverter to make the inverter circuit operate in the four quadrant at the target angle, thereby realizing the full range of four-quadrant operation of the inverter circuit and improving the stability of the inverter circuit.

[0043] In some embodiments, as shown in FIG3, obtaining the target current in step S21 above may specifically include the following steps:

[0044] Step S31: Obtain the AC current and AC voltage on the AC side.

[0045] In this embodiment, the inverter circuit may further include a current sampling circuit and a voltage sampling circuit. The current sampling circuit is used to collect the AC current on the AC side of the inverter circuit and transmit it to the controller. The voltage sampling circuit is used to collect the AC voltage on the AC side of the inverter circuit and transmit it to the controller.

[0046] Step S32: Obtain the peak value of the AC side current based on the AC current.

[0047] In this embodiment of the application, after the controller obtains the AC current through the current sampling circuit, it can obtain the peak current based on the AC current.

[0048] Step S33: Obtain the lag angle between the AC current and the AC voltage.

[0049] In this embodiment of the application, after the controller obtains the AC current through the current acquisition circuit and the AC voltage through the voltage acquisition circuit, it can obtain the lag angle of the current AC current lagging behind the AC voltage based on the current AC current and the AC voltage.

[0050] Step S34: Obtain the target current based on the peak value of the AC side current, the hysteresis angle, and the target angle.

[0051] In this embodiment, the controller can construct an expression for the target current based on the obtained AC side voltage peak value, hysteresis angle, and target angle, thereby obtaining the target current. The expression for the target current can be:

[0052] In the formula, i is the target current, and I m The peak value of the AC side current is given, and θ is the target angle. This is a lagging angle.

[0053] In some embodiments, as shown in FIG4, the step S23 above, which adjusts the inverter circuit according to the target current and instantaneous voltage value, may specifically include the following steps:

[0054] Step S41: Obtain the target outward phase angle between the primary circuit and the secondary circuit based on the target current and instantaneous voltage values.

[0055] Step S42: Adjust the inverter circuit according to the target outward phase angle so that the inverter circuit operates in all four quadrants at the target angle.

[0056] In this embodiment, the controller can calculate the target instantaneous power of the inverter circuit based on the target current and voltage instantaneous values, and then calculate the target outward phase angle based on the target instantaneous power. Subsequently, the controller adjusts the primary and secondary circuits in the inverter circuit based on the target outward phase angle so that the inverter circuit operates in all four quadrants at the target angle.

[0057] In some embodiments, as shown in FIG5, obtaining the target outward phase angle in step S41 above may specifically include the following steps:

[0058] Step S51: Construct the instantaneous power expression of the inverter circuit based on the phase shift angle parameter.

[0059] Step S52: Obtain the target outward phase angle based on the instantaneous power expression, the target current, and the instantaneous voltage value.

[0060] In this embodiment, the controller may also have a pre-built instantaneous power expression based on phase shift angle parameters, wherein the phase shift angle parameters include the inner phase shift angle of the primary circuit and the outer phase shift angle between the primary and secondary circuits. The controller can first calculate the target instantaneous power based on the instantaneous values ​​of the target current and voltage, and then substitute the target instantaneous power into the instantaneous power expression to calculate the corresponding target outer phase shift angle.

[0061] In some embodiments, as shown in FIG6, the construction of the instantaneous power expression in step S51 above may specifically include the following steps:

[0062] Step S61: Obtain the inner phase shift angle of the primary circuit and the outer phase shift angle between the primary circuit and the secondary circuit.

[0063] In this embodiment, the controller can also construct an instantaneous power expression in real time based on the operating parameters of the inverter circuit. Specifically, after controlling the inverter circuit to operate, the controller can obtain the inner phase shift angle of the primary circuit and the outer phase shift angle between the primary and secondary circuits. For example, after controlling the inverter circuit to operate, the controller can obtain the operating parameters such as the frequency and duty cycle of each switching device in the primary and secondary circuits, and calculate the current inner and outer phase shift angles of the inverter circuit based on the operating parameters of each switching device.

[0064] Step S62: Obtain the DC voltage on the DC side and the AC voltage on the AC side.

[0065] In this application, the controller can also be connected to the DC side and AC side of the resonant circuit to obtain the DC voltage on the DC side and the AC voltage on the AC side. In some embodiments, a DC voltage sampling circuit can be provided on the DC side and an AC voltage sampling circuit can be provided on the AC side. The DC voltage sampling circuit is used to collect the DC voltage on the DC side and transmit it to the controller, and the AC voltage sampling circuit is used to collect the AC voltage on the AC side and transmit it to the controller.

[0066] Step S63: Construct the primary voltage expression based on the inner phase shift angle and DC voltage, and construct the secondary voltage expression based on the outer phase shift angle and AC voltage.

[0067] In some embodiments, the primary-side voltage expression based on the fundamental wave analysis method can be obtained using the internal phase shift angle and the DC voltage. The primary-side voltage expression constructed based on the fundamental wave analysis method can be:

[0068] In the formula, v p V is the primary voltage. dcdenoted as DC voltage on the DC side, n is the turns ratio of the transformer between the primary voltage and the variable voltage, D1∈[0,0.5], 0.5*2πD1 is the internal phase shift angle, ω is the frequency, and t is the time.

[0069] Furthermore, the expression for the secondary voltage based on the fundamental wave analysis method is obtained using the external phase shift angle and AC voltage. Specifically, the expression for the secondary voltage constructed based on the fundamental wave analysis method can be:

[0070] In the formula, v s U is the secondary voltage. g Let D2 be the AC voltage on the AC side, D2∈[-0.5,0.5], and 2πD2 be the outward phase shift angle.

[0071] Step S64: Obtain the instantaneous power expression based on the primary side voltage expression and the secondary side voltage expression.

[0072] In this embodiment of the application, the instantaneous power expression can be further obtained based on the above-mentioned primary-side voltage expression and secondary-side voltage expression as follows:

[0073] In the formula, X eq This is the resonant impedance.

[0074] To achieve instantaneous power flow switching, the sign of D2 can be changed. Even if D2′=-D2, sin(2πD2')=-sin(2πD2), which means that the magnitude of the instantaneous power P remains unchanged, but the direction is reversed.

[0075] Please refer to Figure 7, a schematic block diagram of an inverter circuit provided in this application embodiment, wherein the inverter circuit 700 includes: a primary circuit 710, a secondary circuit 720, a transformer 730, a resonant inductor 740, a resonant capacitor 750, and a controller 760.

[0076] In this embodiment, the primary circuit 710 is connected to the secondary circuit 720 through the transformer 730 and the resonant inductor 740. The resonant inductor 740 is connected in series with the secondary circuit 720, and the resonant capacitor 750 is connected in parallel with the secondary circuit 720. The primary circuit 710 is used to connect to the DC side, and the secondary circuit 720 is used to connect to the AC side.

[0077] The controller 760 is connected to the primary circuit 710 and the secondary circuit 720. The controller 760 is used to obtain the target current on the AC side of the inverter circuit 700 based on the target angle of the inverter circuit 700 operating in four quadrants, obtain the instantaneous voltage value on the AC side, and adjust the inverter circuit 700 according to the target current and the instantaneous voltage value so that the inverter circuit 700 operates in four quadrants at the target angle.

[0078] In some embodiments, the controller 760 further obtains the target outward phase angle between the primary circuit 710 and the secondary circuit 720 based on the target current and instantaneous voltage values, and adjusts the inverter circuit 700 according to the target outward phase angle so that the inverter circuit 700 operates in all four quadrants at the target angle.

[0079] In some embodiments, the controller 760 is further configured to acquire the AC current and AC voltage on the AC side, obtain the peak value of the AC side current based on the AC current, acquire the lag angle of the AC current lagging behind the AC voltage, and obtain the target current based on the peak value of the AC side current, the lag angle and the target angle.

[0080] In some embodiments, the controller 760 is further configured to construct an instantaneous power expression for the inverter circuit 700 based on the phase shift angle parameter, and obtain the target outer phase shift angle according to the instantaneous power expression, the target current, and the instantaneous voltage value.

[0081] In some embodiments, the controller 760 is further configured to obtain the inner phase shift angle of the primary circuit 710 and the outer phase shift angle between the primary circuit 710 and the secondary circuit 720, obtain the DC voltage on the DC side and the AC voltage on the AC side, construct a primary voltage expression based on the inner phase shift angle and the DC voltage, construct a secondary voltage expression based on the outer phase shift angle and the AC voltage, and obtain an instantaneous power expression based on the primary voltage expression and the secondary voltage expression.

[0082] Please refer to Figure 8, which is a circuit diagram of an inverter circuit 700 provided in an embodiment of this application. The primary-side circuit 710 is a full-bridge circuit, including a first switch S1, a second switch S2, a third switch S3, a fourth switch S4, a primary-side inductor Lm, and a primary-side capacitor Cdc.

[0083] In this embodiment, the first end of the first switch S1 is connected to the positive terminal of the DC side Vdc, and the second end of the first switch S1 is connected to the first end of the second switch S2; the second end of the second switch S2 is connected to the negative terminal of the DC side Vdc; the first end of the third switch S3 is connected to the first end of the first switch S1, and the second end of the third switch S3 is connected to the first end of the fourth switch S4; the second end of the fourth switch S4 is connected to the second end of the second switch S2.

[0084] The first input terminal of transformer 730 is connected to the second terminal of the first switching transistor S1, and the second input terminal of transformer 630 is connected to the second terminal of the third switching transistor; the primary inductor Lm is connected in parallel with the input terminal of transformer 730; the primary capacitor Cdc is connected in parallel with the DC side Vdc.

[0085] The secondary circuit 720 is a half-bridge circuit, including a fifth switch S5, a sixth switch S6, a seventh switch S7, and an eighth switch S8. The resonant capacitor 650 includes a first capacitor Cr1 and a second capacitor Cr2. The fifth switch S5, the sixth switch S6, the seventh switch S7, the eighth switch S8, the second capacitor Cr2, and the first capacitor Cr1 are connected in series. The first output terminal of the transformer 730 is connected between the sixth switch S6 and the seventh switch S7 through the resonant inductor 740, and the second output terminal of the transformer 730 is connected between the first capacitor Cr1 and the second capacitor Cr2.

[0086] It is understood that the beneficial effects achieved by the inverter circuit 700 in the embodiments of this application can be referred to the beneficial effects of the current control method in any of the foregoing embodiments, and will not be repeated here.

[0087] In this embodiment of the application, more detailed functional descriptions of the above modules can be found in the corresponding content of the foregoing section, and will not be repeated here.

[0088] This application also provides a computer storage medium storing a computer program that, when executed by a processor, causes the processor to perform the aforementioned four-quadrant control method.

[0089] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer storage medium or transmitted through the computer storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., digital versatile discs (DVDs)), or semiconductor media (e.g., solid-state disks (SSDs)).

[0090] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks. Unless otherwise specified, the technical features of this embodiment and its implementation can be combined arbitrarily.

[0091] The embodiments described above are merely preferred embodiments of this application and are not intended to limit the scope of this application. Any modifications and improvements made by those skilled in the art to the technical solutions of this application without departing from the spirit of this application should fall within the protection scope defined by the claims of this application.

Claims

1. A four-quadrant control method of an inverter circuit, characterized by, The inverter circuit includes a primary circuit and a secondary circuit. The primary circuit is connected to the secondary circuit through a resonant inductor. The primary circuit is used to connect to the DC side of the inverter circuit, and the secondary circuit is used to connect to the AC side of the inverter circuit. The four-quadrant control method includes: The target current on the AC side of the inverter circuit is obtained based on the target angle of the inverter circuit operating in four quadrants. Obtain the instantaneous voltage value on the AC side; The inverter circuit is adjusted according to the target current and the instantaneous voltage value so that the inverter circuit operates in four quadrants at the target angle.

2. The four quadrant control method of claim 1, wherein, The step of obtaining the target current on the AC side of the inverter circuit based on the target angle of the inverter circuit operating in four quadrants includes: Obtain the AC current and AC voltage on the AC side; The peak value of the AC side current is obtained based on the AC current. Obtain the lag angle between the AC current and the AC voltage; The target current is obtained based on the peak value of the AC side current, the hysteresis angle, and the target angle.

3. The four quadrant control method of claim 1, wherein, The step of adjusting the inverter circuit according to the target current and the instantaneous voltage value to make the inverter circuit operate in four quadrants at the target angle includes: The target outward phase angle between the primary circuit and the secondary circuit is obtained based on the target current and the instantaneous voltage value. The inverter circuit is adjusted according to the target outward phase angle so that the inverter circuit operates in all four quadrants at the target angle.

4. The four quadrant control method of claim 3, wherein, The step of obtaining the target outward phase shift angle between the primary circuit and the secondary circuit based on the target current and the instantaneous voltage value includes: Construct the instantaneous power expression of the inverter circuit based on the phase shift angle parameter; The target outward phase angle is obtained based on the instantaneous power expression, the target current, and the instantaneous voltage value.

5. The four quadrant control method of claim 4, wherein, The instantaneous power expression based on the phase shift angle parameter for constructing the inverter circuit includes: Obtain the inner phase shift angle of the primary circuit and the outer phase shift angle between the primary circuit and the secondary circuit; Obtain the DC voltage on the DC side and the AC voltage on the AC side; The primary voltage expression is constructed based on the inner phase shift angle and the DC voltage, and the secondary voltage expression is constructed based on the outer phase shift angle and the AC voltage. The instantaneous power expression is obtained based on the primary-side voltage expression and the secondary-side voltage expression.

6. An inverter circuit, characterized by comprising: It includes a primary circuit, a secondary circuit, a transformer, a resonant inductor, a resonant capacitor, and a controller. The primary circuit is connected to the secondary circuit through the transformer and the resonant inductor. The resonant inductor is connected in series with the secondary circuit, and the resonant capacitor is connected in parallel with the secondary circuit. The primary circuit is used to connect to the DC side, and the secondary circuit is used to connect to the power grid through the AC side. The controller is connected to the primary circuit and the secondary circuit. The controller is used to obtain the target current on the AC side of the inverter circuit based on the target angle of the inverter circuit operating in four quadrants, obtain the instantaneous voltage value on the AC side, and adjust the inverter circuit according to the target current and the instantaneous voltage value so that the inverter circuit operates in four quadrants at the target angle.

7. The inverter circuit of claim 6, wherein The controller is also configured to obtain the target outward phase angle between the primary circuit and the secondary circuit based on the target current and the instantaneous voltage value, and adjust the inverter circuit according to the target outward phase angle so that the inverter circuit operates in all four quadrants at the target angle.

8. The inverter circuit of claim 6, wherein, The primary-side circuit is a full-bridge circuit, including a first switching transistor, a second switching transistor, a third switching transistor, a fourth switching transistor, a primary-side inductor, and a primary-side capacitor; The first terminal of the first switch is connected to the positive terminal of the DC side, and the second terminal of the first switch is connected to the first terminal of the second switch; the second terminal of the second switch is connected to the negative terminal of the DC side; the first terminal of the third switch is connected to the first terminal of the first switch, and the second terminal of the third switch is connected to the first terminal of the fourth switch; the second terminal of the fourth switch is connected to the second terminal of the second switch. The first input terminal of the transformer is connected to the second terminal of the first switching transistor, and the second input terminal of the transformer is connected to the second terminal of the third switching transistor; the primary inductor is connected in parallel with the input terminal of the transformer; and the primary capacitor is connected in parallel with the DC side.

9. The inverter circuit of claim 6, wherein, The secondary circuit is a half-bridge circuit, including a fifth switch, a sixth switch, a seventh switch, and an eighth switch, and the resonant capacitor includes a first capacitor and a second capacitor. The fifth switch, the sixth switch, the seventh switch, the eighth switch, the second capacitor, and the first capacitor are connected in series in sequence; the first output terminal of the transformer is connected between the sixth switch and the seventh switch through the resonant inductor, and the second output terminal of the transformer is connected between the first capacitor and the second capacitor.

10. An energy storage inverter apparatus, characterized by, Including the inverter circuit as described in any one of claims 6 to 9.

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