Zero voltage ride through control method for power converter and related device

Abstract

The present disclosure provides a zero-voltage ride-through control method of a power converter and a related device, and relates to the technical field of power electronics. The zero-voltage ride-through control method can obtain a DC side electrical parameter of the power converter, and can adjust an AC side output phase angle of the power converter based on the DC side electrical parameter, so as to make the DC side power of the power converter equal to zero. When the DC side power of the power converter is zero, the AC side active power is also zero, and the AC side output impedance of the power converter is generally purely inductive. Therefore, the AC side output phase angle when the AC side active power is zero is the grid voltage phase. Thus, the obtained AC side output phase angle can be directly used as the grid voltage phase when the AC side active power is zero, and a control signal of the power converter can be generated. The present disclosure can control the DC side power to synchronize with the grid voltage phase, and the grid voltage does not need to be collected during the whole process. Therefore, the control accuracy during zero-voltage ride-through can be improved.

Description

Technical Field

[0001] This disclosure relates to the field of power electronics technology, and in particular to a zero-voltage ride-through control method and related apparatus for a power converter. Background Technology

[0002] In the control process of a power converter, the grid voltage phase needs to be obtained first through a phase-locked loop (PLL) based on the grid voltage, and then the corresponding control algorithm is executed based on this grid voltage phase. The voltage sampling circuit that implements the grid voltage acquisition function is typically designed to ensure voltage accuracy near the rated grid voltage. However, to meet the mandatory requirements of relevant standards, the power converter also needs to perform low-voltage ride-through (LVRT) under different grid voltage dip conditions, such as zero-voltage ride-through. The grid voltage during zero-voltage ride-through is often around 5% of its rated value, which leads to poor grid voltage acquisition accuracy, resulting in inaccurate grid voltage phase obtained by the PLL, and consequently affecting the control accuracy of the power converter. Summary of the Invention

[0003] In view of the above problems, this disclosure provides a zero-voltage ride-through control method and related apparatus for a power converter to improve the control accuracy during zero-voltage ride-through. The specific solution is as follows:

[0004] The first aspect of this disclosure provides a zero-voltage ride-through control method for a power converter, comprising:

[0005] Obtain the DC-side electrical parameters of the power converter;

[0006] Based on the DC-side electrical parameters, and with the goal of making the DC-side power of the power converter equal to zero, the AC-side output phase angle of the power converter is adjusted.

[0007] The AC side output phase angle is used as the grid voltage phase, and the control signal of the power converter is generated based on the grid voltage phase.

[0008] In one possible implementation, obtaining the DC-side electrical parameters of the power converter includes:

[0009] Obtain at least one of the DC-side voltage and DC-side current of the power converter.

[0010] In one possible implementation, obtaining the DC-side electrical parameters of the power converter includes obtaining the DC-side voltage and the DC-side current.

[0011] Based on the DC-side electrical parameters, and with the goal of making the DC-side power of the power converter equal to zero, the AC-side output phase angle of the power converter is adjusted, including:

[0012] Calculate the product of the DC-side voltage and the DC-side current;

[0013] The phase angle of the AC side output is adjusted with the goal of making the product equal to zero.

[0014] In one possible implementation, obtaining the DC-side electrical parameters of the power converter includes, in the case of obtaining the DC-side current,

[0015] Based on the DC-side electrical parameters, and with the goal of making the DC-side power of the power converter equal to zero, the AC-side output phase angle of the power converter is adjusted, including:

[0016] The AC output phase angle is adjusted with the goal of making the DC side current equal to zero.

[0017] In one possible implementation, obtaining the DC-side electrical parameters of the power converter includes, in the case of obtaining the DC-side voltage,

[0018] Based on the DC-side electrical parameters, and with the goal of making the DC-side power of the power converter equal to zero, the AC-side output phase angle of the power converter is adjusted, including:

[0019] The AC side output phase angle is adjusted with the goal of making the DC side voltage equal to the open-circuit voltage of the DC power supply connected to the DC side of the power converter.

[0020] A second aspect of this disclosure provides a controller for performing a zero-voltage ride-through control method for a power converter as described in the first aspect or any implementation thereof.

[0021] A third aspect of this disclosure provides a power converter, comprising: a controller, a sampling module, and a DC / AC conversion circuit; wherein,

[0022] The DC side of the DC / AC conversion circuit serves as the DC side of the power converter, and the AC side of the DC / AC conversion circuit serves as the AC side of the power converter.

[0023] The DC / AC conversion circuit is controlled by the controller;

[0024] The sampling module is configured to: collect the DC-side electrical parameters of the power converter;

[0025] The controller includes: a power control module and a control algorithm module;

[0026] The power control module is configured to adjust the AC output phase angle of the power converter based on the DC-side electrical parameters, with the goal of making the DC-side power of the power converter equal to zero.

[0027] The control algorithm module is configured to generate a control signal for the power converter by using the AC side output phase angle as the grid voltage phase.

[0028] In one possible implementation, the DC-side electrical parameters include: the DC-side voltage and DC-side current of the power converter; the sampling module includes: a voltage sampling module for acquiring the DC-side voltage, and a current sampling module for acquiring the DC-side current;

[0029] The power control module includes: a power calculation module, a first error calculation module, and a power regulator;

[0030] The power calculation module is configured to calculate the product of the DC-side voltage and the DC-side current;

[0031] The first error calculation module is configured to: calculate a first error between the product and zero;

[0032] The power regulator is configured to generate the AC-side output phase angle with the goal of adjusting the first error to zero.

[0033] In one possible implementation, the DC-side electrical parameters include: the DC-side current of the power converter; the sampling module includes: a current sampling module for acquiring the DC-side current;

[0034] The power control module includes: a second error calculation module and a current regulator;

[0035] The second error calculation module is configured to: calculate the second error between the DC-side current and zero;

[0036] The current regulator is configured to generate the AC-side output phase angle with the goal of adjusting the second error to zero.

[0037] In one possible implementation, the DC-side electrical parameters include: the DC-side voltage of the power converter; the sampling module includes: a voltage sampling module for acquiring the DC-side voltage;

[0038] The power control module includes: a third error calculation module and a voltage regulator;

[0039] The third error calculation module is configured to calculate the third error between the DC side voltage and the open-circuit voltage of the DC power supply connected to the DC side of the power converter.

[0040] The voltage regulator is configured to generate the AC-side output phase angle with the goal of adjusting the third error to zero.

[0041] The zero-voltage ride-through control method for power converters disclosed herein obtains the DC-side electrical parameters of the power converter. Based on these parameters, the AC-side output phase angle of the power converter is adjusted to achieve a DC-side power of zero. Since the AC-side active power is also zero when the DC-side power is zero, and the AC-side output impedance of the power converter is generally purely inductive, the AC-side output phase angle at which the AC-side active power is zero is the grid voltage phase. Therefore, the obtained AC-side output phase angle can be directly used as the grid voltage phase at which the AC-side active power is zero, thereby generating the control signal for the power converter. This disclosure achieves phase synchronization with the grid by controlling the DC-side power, without requiring grid voltage acquisition throughout the process, thus improving the control accuracy during zero-voltage ride-through. Attached Figure Description

[0042] The features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and elements and actual parts are not necessarily drawn to scale.

[0043] Figure 1 A schematic diagram of a control scheme for a power converter provided for related technologies;

[0044] Figure 2 A flowchart of a zero-voltage ride-through control method for a power converter provided in an embodiment of this disclosure;

[0045] Figure 3 A schematic diagram of a first structure of a power converter and its controller provided in an embodiment of this disclosure;

[0046] Figure 4 A second structural schematic diagram of the power converter and its controller provided in the embodiments of this disclosure;

[0047] Figure 5 A schematic diagram of a third structure of a power converter and its controller provided in an embodiment of this disclosure;

[0048] Figure 6 This is a schematic diagram of a fourth structure of a power converter and its controller provided in an embodiment of this disclosure. Detailed Implementation

[0049] The embodiments of this disclosure are described below with reference to the accompanying drawings. The terminology used in the Description of Embodiments section of this disclosure is for illustrative purposes only and is not intended to limit the scope of this disclosure.

[0050] The embodiments of this disclosure are described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure. Those skilled in the art will understand that with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of this disclosure are also applicable to similar technical problems.

[0051] The terms “first,” “second,” etc., used in this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the description of embodiments of this disclosure. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of units is not necessarily limited to those units, but may include other units not expressly listed or inherent to those processes, methods, products, or apparatuses.

[0052] like Figure 1 As shown, the AC side of the power converter is connected to the power grid via a grid-connected relay K. Related technologies typically involve setting up a voltage sampling circuit on the side of the grid-connected relay K connected to the power grid to acquire the grid voltage. Then, a phase-locked loop is used to obtain the grid voltage phase θg, and based on this phase θg, a corresponding control algorithm is executed to obtain the control signal for the power converter.

[0053] However, this voltage sampling circuit can only guarantee the voltage accuracy near the rated value of the grid voltage. The grid voltage during zero voltage crossing is often around 5% of its rated value, which leads to poor grid voltage acquisition accuracy, making the grid voltage phase obtained by the phase-locked loop inaccurate, and thus affecting the control accuracy of the power converter.

[0054] Therefore, this disclosure provides a zero-voltage ride-through control method for a power converter to improve control accuracy during zero-voltage ride-through. The specific solution is as follows:

[0055] Considering that the reactive current of the power converter will be fully generated during three-phase zero-voltage ride-through, and the active power on the AC side of the power converter will be zero, it is necessary to control the active current output of the power converter on the AC side to be zero. Since the AC output impedance of the power converter is generally purely inductive, the formula for calculating the active current Id on the AC side of the power converter is as follows:

[0056] ;

[0057] Where E is the AC output voltage amplitude of the power converter, Z is the AC output impedance of the power converter, θ is the AC output phase angle of the power converter, and θg is the grid voltage phase.

[0058] Therefore, the AC output phase angle θ of the power converter can be directly controlled, thereby controlling the AC output active current Id of the power converter; when Id=0, we have:

[0059] ;

[0060] Based on this, it can be concluded that when the power converter is performing three-phase zero voltage ride-through, directly controlling the AC side output phase angle θ of the power converter to make Id=0 will make the AC side active power of the power converter zero. At this time, the AC side output phase angle θ of the power converter is the grid voltage phase θg.

[0061] Furthermore, since sampling errors in the grid voltage can also lead to errors in the active power output on the AC side of the power converter, this embodiment uses DC power control; for example... Figure 2 As shown, the zero-voltage ride-through control method of this power converter includes:

[0062] S11. Obtain the DC-side electrical parameters of the power converter.

[0063] The specific optional forms of the DC side electrical parameters can be found in the following description.

[0064] S12. Based on the DC-side electrical parameters, adjust the AC-side output phase angle of the power converter with the goal of making the DC-side power of the power converter equal to zero.

[0065] Since the DC-side power of the power converter is zero, the AC-side active power is also zero. As can be seen from the above analysis, the AC-side output phase angle θ at this time is the grid voltage phase θg. Therefore, S13 can be executed.

[0066] S13. The AC side output phase angle is used as the grid voltage phase, and the control signal of the power converter is generated based on the grid voltage phase.

[0067] When the active power on the AC side is zero, the obtained AC side output phase angle θ can be directly used as the grid voltage phase θg; the control algorithm for generating the subsequent control signal can be found in relevant technologies, which will not be elaborated here.

[0068] The zero-voltage ride-through control method for the power converter provided in this embodiment synchronizes the DC-side power with the grid phase. The grid voltage does not need to be collected during the entire process, thus improving the control accuracy during zero-voltage ride-through.

[0069] Based on the previous embodiment, this embodiment provides some specific optional methods for the zero-voltage ride-through control method of the power converter, such as:

[0070] S11. Obtain the DC-side electrical parameters of the power converter, which may specifically include obtaining at least one of the DC-side voltage and DC-side current of the power converter. That is, in practical applications, only the DC-side voltage can be obtained, only the DC-side current can be obtained, or both the DC-side voltage and DC-side current can be obtained simultaneously; it depends on the specific application environment, and is not limited here.

[0071] In one example, if S11 includes obtaining the DC-side voltage and DC-side current, then S12, based on the DC-side electrical parameters, aims to make the DC-side power of the power converter equal to zero, adjusting the AC-side output phase angle of the power converter. Specifically, this may include: calculating the product of the DC-side voltage and DC-side current; and adjusting the AC-side output phase angle with the goal of making the product equal to zero.

[0072] like Figure 3 As shown, a voltage sampling module 132 is set to collect the DC-side voltage Vdc of the power converter, and a current sampling module 131 is set to collect the DC-side current Idc of the power converter. After the controller 102 obtains the DC-side voltage Vdc and the DC-side current Idc, it calculates the DC-side power P of the power converter through the power calculation module 211 according to P=Vdc×Idc. Then, using the DC-side power P as a feedback quantity and zero as a reference quantity, the first error calculation module 212 calculates the error between the two, which is recorded as the first error. The first error is input to the power regulator 213. The power regulator 213 directly controls the AC-side output phase angle θ according to the first error until the first error is adjusted to zero, that is, the DC-side power P is zero. Then, the control algorithm module 202 uses the AC-side output phase angle θ as the grid voltage phase θg, and performs coordinate transformation, current control and other algorithms based on the grid voltage phase θg, and finally generates a control signal to realize the control of the power converter.

[0073] In another example, if S11 includes obtaining the DC-side current, S12, based on the DC-side electrical parameters, adjusts the AC-side output phase angle of the power converter with the goal of making the DC-side power of the power converter equal to zero, including: adjusting the AC-side output phase angle with the goal of making the DC-side current equal to zero.

[0074] When the DC-side current Idc is zero, the DC-side power P is also zero; therefore, phase synchronization can also be performed based on the DC-side current Idc. For example... Figure 4As shown, a current sampling module 131 is set up to collect the DC-side current Idc of the power converter. After the controller 102 obtains the DC-side current Idc, it uses the DC-side current Idc as a feedback quantity and zero as a reference quantity, and calculates the error between the two through the second error calculation module 221, which is recorded as the second error. This second error is input to the current regulator 222. The current regulator 222 directly controls the AC-side output phase angle θ according to the second error until the second error is adjusted to zero, that is, the DC-side power P is zero. Then, the control algorithm module 202 uses the AC-side output phase angle θ as the grid voltage phase θg, and performs coordinate transformation, current control and other algorithms based on the grid voltage phase θg, and finally generates a control signal to realize the control of the power converter.

[0075] In another example, if S11 includes obtaining the DC-side voltage, S12, based on the DC-side electrical parameters, aims to make the DC-side power of the power converter equal to zero, and adjusts the AC-side output phase angle of the power converter, including: adjusting the AC-side output phase angle with the goal of making the DC-side voltage equal to the open-circuit voltage of the DC power supply connected to the DC side of the power converter.

[0076] In a photovoltaic power conversion system, the DC power supply is a single photovoltaic string or at least two photovoltaic strings connected in parallel. When the DC-side voltage Vdc is equal to the open-circuit voltage Vopen of the connected photovoltaic string, the DC-side power P of the power converter is also zero. Therefore, phase synchronization can also be performed based on the DC-side voltage Vdc in a photovoltaic power conversion system. Figure 5 As shown, a voltage sampling module 132 is set up to collect the DC-side voltage Vdc of the power converter. After the controller 102 obtains the DC-side voltage Vdc, it uses the DC-side voltage Vdc as a feedback quantity and the open-circuit voltage Vopen as a reference quantity. The third error calculation module 231 calculates the error between the two, which is recorded as the third error. This third error is input to the voltage regulator 232. The voltage regulator 232 directly controls the AC-side output phase angle θ based on the third error until the third error is adjusted to the open-circuit voltage Vopen, that is, the DC-side power P is zero. Then, the control algorithm module 202 uses the AC-side output phase angle θ as the grid voltage phase θg, and performs coordinate transformation, current control and other algorithms based on the grid voltage phase θg to finally generate a control signal to realize the control of the power converter.

[0077] S12 can be achieved through any of the above methods. This embodiment is not limited to any one of them and can be determined according to the specific application environment.

[0078] Another embodiment of this disclosure provides a controller for executing the zero-voltage ride-through control method for a power converter as described in any of the above embodiments. The specific process and principle of this zero-voltage ride-through control method can be found in the above embodiments, and will not be repeated here.

[0079] The controller provided in this disclosure may include software to implement the zero-voltage ride-through control method for the power converter described above. Alternatively, the controller provided in this disclosure may include hardware to implement the zero-voltage ride-through control method for the power converter described above. Or, the controller provided in this disclosure may include both software and hardware, using a combination of software and hardware to execute the zero-voltage ride-through control method for the power converter described above.

[0080] In practical applications, the controller can be integrated into the power converter or it can be independent of the power converter, depending on the specific application environment, and all of them are within the protection scope of this disclosure.

[0081] By executing the zero-voltage ride-through control method for the power converter described in the above embodiments, the controller can achieve power synchronization through any one of DC-side power, DC-side current, and DC-side voltage. This avoids the problem that the low grid voltage sampling accuracy during zero-voltage ride-through leads to low grid voltage phase accuracy, which in turn causes the control accuracy of the AC-side output current to fail to meet standard requirements.

[0082] Another embodiment of this disclosure also provides a power converter, such as Figure 6 As shown, it includes: a controller 102, a sampling module 103, and a DC / AC conversion circuit 101; wherein, the DC side of the DC / AC conversion circuit 101 serves as the DC side of the power converter, which is used to connect to a DC power supply, which may include one photovoltaic string or at least two photovoltaic strings connected in parallel; the AC side of the DC / AC conversion circuit 101 serves as the AC side of the power converter, and a grid-connected switch 104 may be provided on the AC side of the power converter, the other side of which is used to connect to the power grid.

[0083] The DC / AC conversion circuit 101 is controlled by the controller 102.

[0084] The sampling module 103 is configured to: acquire DC-side electrical parameters of the power converter; as previously described, the DC-side electrical parameters include at least one of DC-side voltage and DC-side current.

[0085] The controller 102 is configured to: adjust the AC output phase angle of the power converter based on the DC-side electrical parameters, with the goal of making the DC-side power of the power converter equal to zero; and generate a control signal for the power converter using the AC output phase angle as the grid voltage phase. Specifically, the controller 102 includes: a power control module 201 and a control algorithm module 202; wherein, the power control module 201 is configured to: adjust the AC output phase angle of the power converter based on the DC-side electrical parameters, with the goal of making the DC-side power of the power converter equal to zero; and the control algorithm module 202 is configured to: generate a control signal for the power converter using the AC output phase angle as the grid voltage phase.

[0086] The specific control principle can be found in the above embodiments, and will not be repeated here.

[0087] The power converter provided in this embodiment achieves phase synchronization with the grid voltage without sampling AC side voltage information through a DC power synchronization phase-locked loop control strategy, thus avoiding the problem of poor AC side output current control accuracy of the power converter during three-phase zero voltage ride-through.

[0088] Based on the above embodiments, this embodiment provides some optional examples of the specific implementation of the power control module 201 in the power converter, specifically:

[0089] In one example, the DC-side electrical parameters include: the DC-side voltage and DC-side current of the power converter; such as Figure 3 As shown, the sampling module 103 includes a voltage sampling module 132 for acquiring DC-side voltage and a current sampling module 131 for acquiring DC-side current. The power control module 201 includes a power calculation module 211, a first error calculation module 212, and a power regulator 213; wherein, the power calculation module 211 is configured to calculate the product of DC-side voltage and DC-side current; the first error calculation module 212 is configured to calculate a first error between the product and zero; and the power regulator 213 is configured to generate an AC-side output phase angle with the goal of adjusting the first error to zero.

[0090] In another example, the DC-side electrical parameters include: the DC-side current of the power converter; the sampling module 103 includes: a current sampling module 131 for acquiring the DC-side current. The power control module 201 includes: a first error calculation module 221 and a current regulator 222; wherein, the first error calculation module 221 is configured to: calculate a second error between the DC-side current and zero; the current regulator 222 is configured to: generate an AC-side output phase angle with the goal of adjusting the second error to zero.

[0091] In another example, the DC-side electrical parameters include: the DC-side voltage of the power converter; the sampling module 103 includes: a voltage sampling module 132 for acquiring the DC-side voltage. The power control module 201 includes: a third error calculation module 231 and a voltage regulator 232; wherein, the third error calculation module 231 is configured to: calculate the third error between the DC-side voltage and the open-circuit voltage of the DC power supply connected to the DC side of the power converter; the voltage regulator 232 is configured to: generate the AC-side output phase angle with the goal of adjusting the third error to zero.

[0092] This embodiment provides phase-locked loop control strategies for achieving synchronization based on DC-side power, DC-side current, or DC-side voltage. In specific practical applications, the appropriate method can be selected according to the application environment, and no limitation is made here.

[0093] Similar or identical parts between the various embodiments in this disclosure can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the description of the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment solution according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0094] Those skilled in the art will also recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this disclosure.

[0095] The above description of the disclosed embodiments shows that the features described in the various embodiments of this disclosure can be substituted for or combined with each other, enabling those skilled in the art to implement or use this disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A zero-voltage ride-through control method for a power converter, characterized in that, include: Obtain the DC-side electrical parameters of the power converter; Based on the DC-side electrical parameters, and with the goal of making the DC-side power of the power converter equal to zero, the AC-side output phase angle of the power converter is adjusted. The AC side output phase angle is used as the grid voltage phase, and the control signal of the power converter is generated based on the grid voltage phase.

2. The zero-voltage ride-through control method for a power converter according to claim 1, characterized in that, Obtain the DC-side electrical parameters of the power converter, including: Obtain at least one of the DC-side voltage and DC-side current of the power converter.

3. The zero-voltage ride-through control method for a power converter according to claim 2, characterized in that, Obtaining the DC-side electrical parameters of the power converter, including the DC-side voltage and DC-side current, Based on the DC-side electrical parameters, and with the goal of making the DC-side power of the power converter equal to zero, the AC-side output phase angle of the power converter is adjusted, including: Calculate the product of the DC-side voltage and the DC-side current; The phase angle of the AC side output is adjusted with the goal of making the product equal to zero.

4. The zero-voltage ride-through control method for a power converter according to claim 2, characterized in that, Obtaining the DC-side electrical parameters of the power converter, including, in the case of obtaining the DC-side current. Based on the DC-side electrical parameters, and with the goal of making the DC-side power of the power converter equal to zero, the AC-side output phase angle of the power converter is adjusted, including: The AC output phase angle is adjusted with the goal of making the DC side current equal to zero.

5. The zero-voltage ride-through control method for a power converter according to claim 2, characterized in that, Obtaining the DC-side electrical parameters of the power converter, including, in the case of obtaining the DC-side voltage. Based on the DC-side electrical parameters, and with the goal of making the DC-side power of the power converter equal to zero, the AC-side output phase angle of the power converter is adjusted, including: The AC side output phase angle is adjusted with the goal of making the DC side voltage equal to the open-circuit voltage of the DC power supply connected to the DC side of the power converter.

6. A controller, characterized in that, A zero-voltage ride-through control method for a power converter as described in any one of claims 1 to 5.

7. A power converter, characterized in that, include: Controller, sampling module, and DC / AC conversion circuit; among which, The DC side of the DC / AC conversion circuit serves as the DC side of the power converter, and the AC side of the DC / AC conversion circuit serves as the AC side of the power converter. The DC / AC conversion circuit is controlled by the controller; The sampling module is configured to: collect the DC-side electrical parameters of the power converter; The controller includes: a power control module and a control algorithm module; The power control module is configured to adjust the AC output phase angle of the power converter based on the DC-side electrical parameters, with the goal of making the DC-side power of the power converter equal to zero. The control algorithm module is configured to generate a control signal for the power converter by using the AC side output phase angle as the grid voltage phase.

8. The power converter according to claim 7, characterized in that, The DC-side electrical parameters include: the DC-side voltage and DC-side current of the power converter; the sampling module includes: a voltage sampling module for acquiring the DC-side voltage, and a current sampling module for acquiring the DC-side current; The power control module includes: a power calculation module, a first error calculation module, and a power regulator; The power calculation module is configured to calculate the product of the DC-side voltage and the DC-side current; The first error calculation module is configured to: calculate a first error between the product and zero; The power regulator is configured to generate the AC-side output phase angle with the goal of adjusting the first error to zero.

9. The power converter according to claim 7, characterized in that, The DC-side electrical parameters include: the DC-side current of the power converter; the sampling module includes: a current sampling module for acquiring the DC-side current; The power control module includes: a second error calculation module and a current regulator; The second error calculation module is configured to: calculate the second error between the DC-side current and zero; The current regulator is configured to generate the AC-side output phase angle with the goal of adjusting the second error to zero.

10. The power converter according to claim 7, characterized in that, The DC-side electrical parameters include: the DC-side voltage of the power converter; the sampling module includes: a voltage sampling module for acquiring the DC-side voltage; The power control module includes: a third error calculation module and a voltage regulator; The third error calculation module is configured to calculate the third error between the DC side voltage and the open-circuit voltage of the DC power supply connected to the DC side of the power converter. The voltage regulator is configured to generate the AC-side output phase angle with the goal of adjusting the third error to zero.

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