Linearization of power converters

Abstract

An apparatus includes a bidirectional DC-DC converter and a controller. The bidirectional DC-DC converter includes a plurality of switches configured to control power flow between a primary side and a secondary side. The controller is configured to generate a first control signal related to a desired phase shift angle between the primary side and the secondary side, apply a linear transformation to the first control signal to generate a second control signal, and control the plurality of switches to regulate power flow between the primary side and the secondary side in accordance with the second control signal. The second control signal is proportional to a desired power flow between the primary side and the secondary side.

Description

[0001] Cross-reference to related applications This application claims the benefit of U.S. Provisional Application No. 63 / 709,716, filed October 21, 2024, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] This invention relates to control technology for power converters, and more particularly to control technology for power converters used in grid support devices. Summary of the Invention

[0003] A grid support device manages the power transfer between a battery system, an AC input source (such as the power grid), and a power output unit to achieve various technical benefits. When connected to an input AC power source, the grid support device can use the input AC power to charge the battery system, and in some cases, simultaneously power any device connected to the power output unit. For example, when the demand from the connected device exceeds the capacity of the AC input or the power grid, the grid support device can discharge from the battery system to supplement the AC input, ensuring stable and continuous operation of the connected device. Furthermore, the grid support device can also be used as a portable power source, drawing power from the battery system to continue powering the connected device when external AC power is unavailable.

[0004] To achieve this functionality, grid support units can incorporate bidirectional power converters, which allow power to flow in both directions between the battery system, the AC input source, and the power output. This bidirectional power transfer allows the grid support unit to charge the battery system when connected to an AC power source and to discharge the battery system when the AC input power is insufficient or unavailable. A dual active bridge (DAB) converter is a specific type of bidirectional power converter and offers additional technical advantages that make it particularly effective in grid support or power supply operations. For example, the low inertia of a DAB converter helps in rapid response to dynamic load changes—when the input AC power fluctuates or a connected device suddenly increases its power demand, the DAB converter can quickly adjust to provide additional power from the battery system, ensuring uninterrupted and reliable operation.

[0005] The wide operating voltage range of the DAB converter offers additional technical advantages. For example, batteries can have varying voltage levels based on their state of charge, and devices connected to the grid can operate at different voltages. The DAB converter's ability to efficiently convert power over a wide voltage range ensures compatibility with different batteries at different states of charge and with diverse electrical loads from a range of connected devices.

[0006] The electronic controller can adjust the phase shift angle (such as the phase angle) between the primary and secondary sides of the power converter. To adjust the phase angle of the power converter (such as a DAB converter). This can represent the timing difference between the switching operations on the primary and secondary sides and / or correspond to the electrical phase difference between the resulting waveforms. Therefore, adjusting the phase angle... Controlling the electrical force transmitted between the two sides. However, although the electrical transmission P can be a phase angle... The function, but the phase angle The relationship between the power transfer P and the voltage transfer P is nonlinear. For example, the power transfer P between the primary and secondary sides of a DAB converter can be expressed by the following equation (1):

[0007] In the above equation (1), V p It can represent the voltage on the primary side of a transformer, V s N can represent the voltage on the secondary side of a transformer. p N can represent the number of turns on the primary side of a transformer. s It can represent the number of turns on the secondary side of a transformer, ω sw L can represent the angle switching frequency of a transformer. Lk,s This can represent the leakage inductance of the transformer secondary side. Thus, as shown in equation (1), when the phase angle... When the power transmission P changes linearly, the power transmission P changes nonlinearly.

[0008] Phase angle The nonlinear relationship between the power P transmitted by the DAB converter and the electronic controller—particularly those employing proportional-integral (PI) or proportional-integral-derivative (PID) control—can pose technical challenges to electronic controllers. For example, PI and PID controllers can adjust the phase angle. To minimize the difference between the desired setpoint (such as target power transmission) and the actual output (such as actual power transmission). However, the phase angle... - The nonlinear nature of the power transmission P relationship may imply that the phase angle Small adjustments can cause disproportionate changes in the actual power transmission P, especially near the extremes of the phase angle range. For example, with the phase angle... Approaching π / 2 (where the power delivery P reaches its peak), the electronic controller may experience overshoot or undershoot because it may not be able to accurately predict the effect of its regulation. Overshoot can occur when the delivered power exceeds the target before stabilizing. Undershoot can occur when the delivered power falls below the target before stabilizing. Therefore, the electronic controller may overcalibrate or take too long to reach the setpoint.

[0009] The systems, devices, methods, and techniques described in this patent specification apply linearization functions to, for example, phase angles. The control signals are linearized to provide a technical solution to these challenges (and others). The electronic controller then uses the linearized control signals to adjust the operation of the power converter. Using linearized control signals to adjust the operation of the power converter simplifies control dynamics, allowing the electronic controller to maintain stable real-time control while reducing the risk of overshoot or undershoot. Linearized control signals mean that each incremental adjustment made by the electronic controller causes a proportional change in the power transmission P, improving the electronic controller's ability to efficiently minimize the error between the desired setpoint and the actual output. Using a linearized control system also ensures that the electronic controller's response bandwidth remains consistent, reducing or eliminating the variation with phase angle. Unpredictable and variable behavior. This enables electronic controllers to operate with higher accuracy and reliability, ensuring faster response times and improving the overall performance of power converters.

[0010] According to some examples, an apparatus includes a bidirectional DC-DC converter and a controller. The bidirectional DC-DC converter includes a plurality of switches configured to control the flow of power between the primary and secondary sides. The controller is configured to generate a first control signal, apply a linear transformation to the first control signal to generate a second control signal, and control the plurality of switches according to the second control signal to adjust the flow of power between the primary and secondary sides. The first control signal is related to a desired phase shift angle between the primary and secondary sides, and the second control signal is proportional to the desired flow of power between the primary and secondary sides.

[0011] In other features, the controller employs a proportional-integral (PI) controller to generate the first control signal. In other features, the controller employs a proportional-integral-derivative (PID) controller to generate the first control signal. In other features, the change in the desired phase shift angle is not linearly proportional to the change in the desired electrical flow between the primary and secondary sides. In other features, the change in the second control signal is linearly proportional to the change in the electrical flow between the primary and secondary sides.

[0012] Among other features, the primary side includes a voltage source configured to receive DC power, a first capacitor connected in parallel with the voltage source, and a first bridge connected in parallel with the voltage source and the first capacitor. The first bridge includes a first plurality of switches and a first plurality of diodes. Among other features, the secondary side includes a second bridge, which includes a second plurality of switches and a second plurality of diodes, a second capacitor connected in parallel with the second bridge, and a voltage output section connected in parallel with the second capacitor and the second bridge.

[0013] Among other features, the device includes an inductor located between the first bridge and the second bridge, and a transformer located between the first bridge and the second bridge. Among other features, the controller is configured to control a first plurality of switches to generate an AC waveform. The AC waveform is transmitted to the second bridge via the transformer. Among other features, the controller is configured to control a second plurality of switches to rectify the AC waveform into a DC output.

[0014] Other examples provide a method for operating a bidirectional DC-DC converter, comprising generating a first control signal, applying a linear transformation to the first control signal to generate a second control signal, and controlling a plurality of switches of the bidirectional DC-DC converter according to the second control signal to adjust the power flow between the primary and secondary sides of the bidirectional DC-DC converter. The first control signal is related to a desired phase shift angle between the primary and secondary sides. The second control signal is proportional to the desired power flow between the primary and secondary sides.

[0015] In other features, the first control signal is generated by a proportional-integral controller. In other features, the first control signal is generated by a proportional-integral-derivative controller. In other features, the change in the desired phase shift angle is not linearly proportional to the change in the desired electric current flow between the primary and secondary sides. In other features, the change in the second control signal is linearly proportional to the change in the electric current flow between the primary and secondary sides.

[0016] Among other features, the primary side includes a voltage source configured to receive DC power, a first capacitor connected in parallel with the voltage source, and a first bridge connected in parallel with the voltage source and the first capacitor, the first bridge including a first plurality of switches and a first plurality of diodes. Among other features, the secondary side includes a second bridge, a second capacitor connected in parallel with the second bridge, and a voltage output section connected in parallel with the second capacitor and the second bridge, the second bridge including a second plurality of switches and a second plurality of diodes.

[0017] Among other features, an inductor is located between the first bridge and the second bridge, and a transformer is located between the first bridge and the second bridge. Among other features, the method includes controlling a first plurality of switches to generate an AC waveform and transmitting the AC waveform to the second bridge via the transformer. Among other features, the method includes controlling a second plurality of switches to rectify the AC waveform into a DC output.

[0018] Before explaining any implementation in detail, it should be understood that the implementation, in its application, is not limited to the details of the configuration and arrangement of the components described in the following description or shown in the drawings. The implementation can be practiced or implemented in various ways. Furthermore, it should be understood that the wording and terminology used in this invention are for illustrative purposes and should not be considered limiting. The use of “comprising,” “including,” or “having,” and variations thereof is intended to cover the items listed thereafter and their equivalents, as well as additional items. Unless otherwise stated or limited, the terms “mounted,” “connected,” “supported,” and “coupled,” and variations thereof are used broadly and cover direct and indirect mounting, connection, support, and coupling.

[0019] Furthermore, it should be understood that implementations may include hardware, software, and electronic components or modules, which, for the purposes of discussion, may be illustrated and described as if most components were implemented solely in hardware. However, those skilled in the art will recognize from this detailed description that, in at least one implementation, the electronic aspects may be implemented as software (e.g., stored on a non-transitory computer-readable medium) executable by one or more processing units (such as microprocessors and / or application-specific integrated circuits (“ASICs”)). Therefore, it should be noted that various implementations may be implemented using a plurality of hardware and software-based devices and a plurality of different structural components. For example, “server,” “computing device,” “controller,” “processor,” etc., described in the specification may include one or more processing units, one or more computer-readable medium modules, one or more input / output interfaces, and various connectors (e.g., system buses) for connecting components.

[0020] Related terms used in conjunction with quantities or conditions, such as “about,” “approximately,” “generally,” etc., will be understood by a person skilled in the art to include the value and have a meaning defined by the context (e.g., the term includes at least the degree of error associated with measurement accuracy, the tolerance associated with a particular value [e.g., manufacturing, assembly, use, etc.]). Such terms should also be considered to disclose a range defined by the absolute values ​​of two endpoints. For example, the expression “about 2 to about 4” also discloses the range “2 to 4.” Relative terms may refer to a percentage added to or subtracted from the indicated value (e.g., 1%, 5%, 10% or more).

[0021] It should be understood that although some figures illustrate hardware and software within a particular device, these depictions are for illustrative purposes only. Functions described herein as being performed by a single component can be performed by multiple components in a distributed manner. Similarly, functions performed by multiple components can be combined and performed by a single component. In some embodiments, the components shown may be combined or divided into separate software, firmware, and / or hardware. For example, logic and processing may be distributed among multiple electronic processors, rather than residing within and being performed by a single electronic processor. Regardless of how the hardware and software components are combined or divided, they may reside on the same computing device or be distributed among different computing devices connected via one or more networks or other suitable communication links. Similarly, components described as performing specific functions may also perform additional functions not described herein. For example, a device or structure "configured" in a certain way is at least configured in that manner, but may also be configured in a manner not explicitly listed.

[0022] Other examples, implementations, features, and aspects will become apparent from the detailed description and accompanying drawings. Attached Figure Description

[0023] Figure 1 This is a block diagram illustrating an exemplary power grid support device according to some embodiments.

[0024] Figure 2A This is an isometric view of an exemplary grid support device configured as a portable power source according to some embodiments.

[0025] Figure 2B This is an isometric view of an exemplary grid support device configured as a portable power source according to some embodiments.

[0026] Figure 3 This is a block diagram illustrating a control system for a power grid support device according to some embodiments.

[0027] Figure 4A and Figure 4B This is a schematic diagram illustrating an exemplary DAB converter that can be used in a power converter according to some embodiments.

[0028] Figure 5 This is a flowchart illustrating an exemplary process for controlling the operation of a power converter according to some embodiments.

[0029] Figure 6 This is a block diagram illustrating an exemplary control loop according to some implementations.

[0030] Figure 7 This is a block diagram illustrating the operation performed by an electronic controller according to some embodiments for implementing a linearizer module.

[0031] In the accompanying drawings, reference numerals may be used repeatedly to identify similar and / or identical elements. Detailed Implementation

[0032] Figure 1 This is a block diagram illustrating an exemplary grid support device 100 according to some embodiments. The grid support device 100 may include a battery system 110, an AC power input 120, a power output 130, and a power converter 140. The power converter 140 may be electrically connected between the battery system 110, the AC power input 120, and the power output 130, and manages the power flow between the battery system 110, the AC power input 120, and the power output 130. The AC power input 120 may be connected to an external power source, such as an AC power supply 125. In various embodiments, the AC power supply 125 is a power grid, such as a residential or commercial 120-volt or 240-volt grid. In some examples, the AC power input 120 is connected to the AC power supply 125 via a power cord.

[0033] The power output unit 130 may include a combination of AC and / or DC power outlets, which can supply power to an external load 135. For example, the load 135 may include an electrical load from any connected external electronic device. In various embodiments, the power output unit 130 also supplies power to internal components of the grid support device 100, such as motors, heating devices, or other components. The power converter 140 allows the grid support device 100 to manage the flow of power between the battery system 110, the AC power input unit 120, and / or the power output unit 130 by converting between different forms of power. For example, depending on the requirements of the grid support device 100, the power converter 140 can convert DC to AC (DC-AC), AC to DC (AC-DC), DC to DC (DC-DC), and / or AC to AC (AC-AC).

[0034] In various embodiments, the power converter 140 converts DC power supplied from the battery system 110 to AC power output via the power output unit 130. In some examples, the power converter 140 converts DC power from the battery system 110 to DC power output via the power output unit 130. In various embodiments, the power converter 140 converts AC power from the AC power input unit 120 to DC power to charge the battery system 110. In some examples, the power converter 140 supports pass-through power, allowing AC power from the AC power input unit 120 to be supplied to the power output unit 130.

[0035] In operation, when AC power 125 is available, AC power input 120 can receive AC power, supply AC power to power converter 140, and power converter 140 converts the AC power to DC power to charge battery system 110, ensuring that battery system 110 is charged and ready for future use. When AC power 125 is unavailable or when load 135 exceeds the power that AC power 125 can provide, power converter 140 can convert DC power from battery system 110 into AC power, which can be delivered to power output 130 to supplement or replace the power supplied from AC power input 120. This capability ensures that any device connected to power output 130 can continue to operate uninterruptedly, even without AC power 125 or when load 135 exceeds the limits of AC power 125. In various embodiments, when the power output from power output 130 is below a threshold, power converter 140 charges one or more batteries of battery system 110 without reducing the power supplied by power output 130.

[0036] The power converter 140 may include one or more bidirectional converters and / or multiple unidirectional converters. A unidirectional converter allows power conversion in one direction—from AC to DC or from DC to AC. In contrast, a bidirectional converter can manage power flow in both directions. Implementing the power converter 140 by including a bidirectional converter simplifies the design of the grid support device 100 by eliminating the need for separate charging and discharging circuits, thereby reducing the overall cost and complexity of the grid support device 100. Furthermore, implementing the power converter 140 by including a bidirectional converter improves the reliability of the grid support device 100, reduces the number of required components, and simplifies the maintenance and troubleshooting process.

[0037] In various embodiments, the power grid support device 100 includes one or more sensors positioned to detect and monitor the power level of the load 135. For example, one or more sensors may measure the output current supplied to the load 135 via the power output unit 130, and the sensor data may be used to calculate the power consumption at the power output unit 130. In various embodiments, the power grid support device 100 monitors the power level of the load 135 for real-time adjustments to optimize power delivery and ensure effective management of both external loads such as the load 135 and the battery system 110.

[0038] Figure 2A This is an isometric view of an exemplary power grid support device 100 configured as a portable power supply 100A according to some embodiments. Figure 2AIn the example, the portable power supply 100A includes a housing 205, which includes an internal battery module 210. An input / output panel 215 may be disposed on the exterior of the housing 205. The input / output panel 215 may include a power input section 220 and one or more power outlets 225. The power output section 225 may include one or more AC outlets designed to power AC electronic devices and / or one or more DC outlets designed to power DC electronic devices.

[0039] Figure 2A The various components of the portable power supply 100A correspond to Figure 1 The previously described components of the power grid support device 100. In various embodiments, the internal battery module 210 corresponds to the battery system 110, the power input section 220 corresponds to the AC power input section 120, and the power socket 225 corresponds to the power output section 130. Therefore, in Figure 2A In the example, the power converter 140 is electrically connected between the internal battery module 210, the power input section 220, and the power socket 225. For example, in... Figure 1 In the example, the power converter 140 can perform power conversion tasks, such as converting DC power from the internal battery module 210 to AC power for the power socket 225, converting AC power from the power input section 220 to DC power to charge the internal battery module 210, and / or passing power directly from the power socket 225 to the power socket 225.

[0040] The power converter 140 can be designed to handle high amperage, making the portable power supply 100A suitable for powering a wide range of electronic devices, including those with high power demands. Therefore, the AC power outlet 225 can support devices such as power tools, appliances, and / or large electronic equipment. The high amperage capability of the power converter 140 ensures that the portable power supply 100A can deliver stable and reliable power to these connected devices, reducing or eliminating problems such as voltage drops or other forms of performance degradation. This capability can be particularly beneficial when connected power tools draw high current under heavy load conditions. In such cases, when directly connected to the grid, load spikes introduced by the power tools can cause circuit breakers to trip, interrupting work performed using the power tools. However, when the power tools are connected to the portable power supply 100A, the power converter 140 can supplement the grid power input via the power input section 220 using power from the internal battery module 210, reducing or eliminating interruptions caused by high current spikes.

[0041] Furthermore, the high amperage capacity of the power converter 140 allows for rapid charging of the internal battery module 210. When the portable power supply 100A is connected to the AC power source 125 via the power input section 220, the power converter 140 can operate to efficiently convert AC power into DC power, which facilitates rapid charging of the internal battery module 210. This rapid charging capability benefits users who may need to quickly charge their devices between uses or during short breaks in their work, ensuring that the portable power supply 100A remains ready for continuous operation.

[0042] The portable power bank 100A can incorporate additional features to enhance its functionality and user experience. For example, a display panel can be integrated into the housing 205 to provide the user with real-time information such as the charging level of the internal battery module 210, power output, output current, historical data, estimated remaining battery life, and other relevant data. These features improve usability and ensure the device is suitable for various scenarios. The high amperage capability of the power converter 140 also makes the portable power bank 100A suitable for a variety of applications, including outdoor events, emergencies, or as a backup power supply for homes and small businesses during temporary power outages, ensuring reliable power is available when needed.

[0043] Figure 2B This is an isometric view of an exemplary power grid support device 100 configured as a portable power supply 100A according to some embodiments. Figure 2B In the example, the portable power supply 100B includes a housing 230 having a first battery interface 235A and a second battery interface 235B. The first battery interface 235A can be configured to removably receive a first power tool battery pack 240A, and the second battery interface 235B can be configured to removably receive a second power tool battery pack 240B. The removable power tool battery packs 240A and 240B (collectively referred to as power tool battery pack 240) can be lithium-ion battery packs commonly used in cordless power tools. The power tool battery packs 240 can have (commonly or individually) a nominal voltage of about 12 volts, about 18 volts, about 24 volts, about 36 volts, about 54 volts, about 72 volts, about 90 volts, about 108 volts, etc., making them usable for powering a variety of indoor and outdoor cordless power tools. The portable power supply 100B may also include a power input section 245 and one or more power outlets 250. In various embodiments, power outlet 250 includes one or more AC outlets for supplying power to external AC electronic devices. In some examples, power outlet 250 includes one or more AC outlets for supplying power to external DC electronic devices.

[0044] Figure 2B The various components of the portable power supply 100B correspond to Figure 1The previously described components of the power grid support device 100. In various embodiments, the power tool battery pack 240 corresponds to the battery system 110, the power input 245 corresponds to the AC power input 120, and the power socket 250 corresponds to the power output 130. Therefore, a power converter 140 can be connected between the removable power tool battery pack 240, the power input 245, and the power socket 250. As in the example described above, the power converter 140 manages the flow of power to charge the power tool battery pack 240 by converting AC power from the power input 245 into DC power. The power converter 140 can also convert DC power from the battery pack 240 into AC power for the power socket 250 and / or provide AC power from the power input 245 to the power socket 250. In various embodiments, the portable power supply 100B includes a display for monitoring power usage and / or battery level.

[0045] Figure 3 This is a block diagram illustrating a control system 300 for a power grid support device 100 according to some embodiments. In various embodiments, the control system 300 may be integrated into or connected to a printed circuit board (PCB) and may include an electronic controller 305. The electronic controller 305 may be electrically and / or communicatively connected to various modules and / or components of the power grid support device 100. Figure 3 In the example, the electronic controller 305 is connected to the power converter 140, the user input section 310, other components 315 that may be applicable (such as a battery power meter and / or a working light (e.g., a light-emitting diode [LED]), one or more indicators 320 (e.g., LEDs), and one or more sensors 360 (such as current and / or voltage sensors).

[0046] The electronic controller 305 may include hardware and / or software designed to manage the operation of the power grid support device 100 (such as those combined with...). Figure 4A-7 As described in the detailed description). Electronic controller 305 may include various electrical and / or electronic components that provide power, operation control, and / or protection to components and / or modules within electronic controller 305 and / or power grid support device 100. For example, electronic controller 305 includes processing unit 325 (such as a microprocessor, microcontroller, or other suitable programmable device), memory 330, input unit 335, and / or output unit 340. Processing unit 325 may include control unit 345, arithmetic logic unit (ALU) 350, and / or a set of registers 355 (in... Figure 3 The processing unit 325 is a component (described as a set of registers). It can utilize computer architectures such as a modified Harvard architecture, von Neumann architecture, or other suitable architectures.

[0047] Processing unit 325, memory 330, input unit 335, output unit 340, and / or other modules connected to electronic controller 305 may be interconnected via one or more control and / or data buses, such as common bus 365. Although for illustrative purposes... Figure 3 These buses are roughly illustrated, but those skilled in the art will recognize, given the embodiments described herein, that one or more control and / or data buses are used for interconnection and communication between various modules and / or components.

[0048] Memory 330 may include non-transitory computer-readable media, including, for example, a program storage area and / or a data storage area. The program storage area and data storage area may include any combination of different types of memory, such as read-only memory (ROM), random access memory (RAM—such as, for example, dynamic RAM [DRAM], synchronous DRAM [SDRAM], etc.), electrically erasable programmable read-only memory (EEPROM), flash memory, one or more hard disk drives, one or more SD cards, and / or other suitable magnetic, optical, physical, and / or electronic memory devices. Processing unit 325 may be connected to memory 330 and may execute software instructions that can be stored in the RAM of memory 330 (such as during execution), the ROM of memory 330 (such as on a substantially permanent basis), and / or another non-transitory computer-readable medium such as another memory or disk.

[0049] The software stored in memory 330 can control various functions of the power grid support device 100. For example, the function blocks and flowchart elements described in this invention can be used as software specifications, which can be translated into computer programs through the daily work of a skilled technician or programmer. The software may include firmware, applications, program data, filters, rules, program modules, and / or other executable instructions. The electronic controller 305 can retrieve and execute these instructions to control the operation of the power grid support device 100. In other configurations, depending on the specific embodiment, the electronic controller 305 may include additional, fewer, and / or different components.

[0050] The grid support device 100 can be configured to operate in various modes according to power demand. For example, the grid support device 100 can operate in a charging-only mode, wherein the controller 305 controls the power converter 140 to convert AC power from the AC power input 120 into an appropriate level of DC power to charge the battery system 110. In various embodiments, the grid support device 100 operates in a discharging-only mode, during which the controller 305 manages the power converter 140 to convert DC power from the battery system 110 into AC power and / or DC power (e.g., at the same or different levels) for the power output 130.

[0051] In direct-only mode, controller 305 can disable power converter 140 and directly connect AC power input 120 to power output 130, which directly supplies input AC power from AC power source 125 (received via AC power input 120) to power output 130. In grid-supported mode, controller 305 can control power converter 140 to convert DC power from battery system 110 into AC power, which supplements the power received from AC power input 120 before the combined power is supplied to power output 130. This allows grid-supported device 100 to handle dynamic load changes and maintain reliable power output, even if load 135 exceeds the capacity of AC power source 125.

[0052] The grid support device 100 can operate in other modes, such as charge-discharge mode and / or charge-straight-through mode, where the controller 305 manages power flow based on current demand. In each of these modes, the controller 305 can control the operation of the power converter 140 to ensure efficient power delivery and management across all operating scenarios.

[0053] Figure 4A and Figure 4B This is a schematic diagram illustrating an exemplary DAB converter 400 that can be used in a power converter 140 according to some embodiments. Figure 4A and 4B In the example, the DAB converter 400 can be positioned between the battery system 110 and the DC bus to enable bidirectional power conversion between the battery system 110 and the DC bus. For example, the DAB converter 400 can convert power from a first voltage (e.g., 400 volts) from the DC bus to a second voltage at the battery system 110 (e.g., which may correspond to the charging voltage of the battery system 110) to charge the battery system 110. Similarly, the DAB converter 400 can convert power at a third voltage (e.g., the battery system voltage) to a first voltage at the DC bus, which can then be converted to AC power to supply power to the load 135. Figure 4A and Figure 4B In the example, the DAB converter 400 includes a first bridge 405A, a second bridge 405B, and a transformer 410 electrically connected between the first bridge 405A and the second bridge 405B.

[0054] The first bridge 405A can be connected to the first DC bus 415A (e.g., corresponding to battery system 110) and includes four switches 420A, 420B, 420C, and 420D arranged in an H-bridge configuration. High-side switches 420A and 420B can be electrically connected between the positive terminal of the first DC bus 415A and the first side 425 of the transformer 410. Low-side switches 420C and 420D can be electrically connected between the negative terminal of the first DC bus 415A and the first side 425 of the transformer 410.

[0055] Similarly, the second bridge 405B can be connected to the second DC bus 415B (e.g., the DC bus of the power grid support device 100) and includes four switches 420E, 420F, 420G, and 420H arranged in an H-bridge configuration. The high-side switches 420E and 420F can be electrically connected between the positive terminal of the second DC bus 415B and the second side 430 of the transformer 410, while the low-side switches 420G and 420H can be electrically connected between the negative terminal of the second DC bus 415B and the second side 430 of the transformer 410.

[0056] Switches 420A-420H can be implemented using metal-oxide-semiconductor field-effect transistors (MOSFETs) or wide-bandgap semiconductor field-effect transistors (FETs), such as gallium nitride (GaN) or silicon carbide (SiC) based FETs. In some configurations, a combination of MOSFETs and wide-bandgap FETs can be used. Switches 420A-H can be controlled by an electronic controller 305 (e.g., via a gate driver) to ensure precise switching and efficient power conversion.

[0057] Switches 420A-420D on the first side 425 of transformer 410 can be electrically connected to inductor 435. Transformer 410 can be a high-frequency transformer configured to step up, step down, or maintain the voltage between the first side 425 and the second side 430 of transformer 410.

[0058] In one direction, the DAB converter 400 converts a first voltage at a first DC bus 415A to a second voltage at a second DC bus 415B. In this configuration, the first side 425 of the transformer 410 can be referred to as the primary side, and the second side 430 can be referred to as the secondary side. The electronic controller 305 controls switches 420A-420D to convert the DC voltage at the first DC bus 415A to the AC voltage at the first side 425 of the transformer 410.

[0059] This switching can be achieved by alternating the switching states of switches 420A-420D in a coordinated manner. For example, to create an AC waveform, electronic controller 305 can turn on switches 420A and 420D during a portion of the switching cycle, allowing current to flow through transformer 410 in one direction. In the second half of the cycle, switches 420B and 420C are turned on, reversing the current flowing through transformer 410, thereby generating an AC voltage across the first side 425. The timing and sequence of the switching are determined by the phase shift angle (e.g., phase angle). The phase shift angle is determined and controlled by electronic controller 305 to adjust the amount of power transmitted between the primary and secondary sides. A larger phase angle... Increased power transmission with a smaller phase angle Reduce power transmission.

[0060] Transformer 410 then generates a corresponding AC voltage on the second side 430. Electronic controller 305 controls switches 420E-420H to convert this AC voltage back to DC voltage at the second DC bus 415B. In this case, switches 420E-420H operate in a similar manner to rectify the AC voltage into DC voltage. For example, when switches 420E and 420H are turned on, current flows through the transformer in one direction, generating a positive output on the DC bus. In the next half-cycle, switches 420F and 420G are turned on, allowing current to flow in the opposite direction and completing the rectification process, resulting in DC voltage at the second DC bus 415B.

[0061] In reverse operation, electronic controller 305 controls switches 420E-420H to convert the DC voltage at the second DC bus 415B to AC voltage at the second side 430 of transformer 410, which is now used as the primary side. A similar principle applies, but the switching occurs at the second side 430. For example, electronic controller 305 can alternately switch switches 420E and 420H to allow current to flow through transformer 410 in one direction, and then switch switches 420F and 420G to reverse the current direction, thereby generating an AC voltage at the second side 430.

[0062] Transformer 410 generates a corresponding AC voltage on the first side 425, which is now used as the secondary side in this reverse mode. Electronic controller 305 then controls switches 420A-420D to convert the AC voltage to DC voltage at the first DC bus 415A. Similar to the previous operation, electronic controller 305 alternately switches 420A and 420D in one half-cycle and switches 420B and 420C in the next half-cycle, rectifying the AC voltage into DC voltage at the first DC bus 415A. The phase angle between the switching waveforms of bridges 405A and 405B during both directions of power transmission... It can be regulated by the controller 305, thereby allowing precise control of the transmitted electrical force and ensuring the effective operation of the DAB converter 400.

[0063] In various embodiments, each switch 420A-420H includes a corresponding diode connected in parallel, which helps reverse current flow and protects the respective switch during power transitions. For example, diode 440A may be connected in parallel with switch 420A, diode 440B may be connected in parallel with switch 420B, diode 440C may be connected in parallel with switch 420C, diode 440D may be connected in parallel with switch 420D, diode 440E may be connected in parallel with switch 420E, diode 440F may be connected in parallel with switch 420F, diode 440G may be connected in parallel with switch 420G, and diode 440H may be connected in parallel with switch 420H. Examples of suitable diodes include Schottky diodes, ultrafast recovery diodes, and SiC diodes.

[0064] In some examples, capacitors are connected in parallel with each of the DC buses 415A and 415B to achieve voltage smoothing and stability during operation. For example, capacitor 445A may be connected in parallel with DC bus 415A between DC bus 415A and the first H-bridge 405A, and capacitor 445B may be connected in parallel with DC bus 415B between DC bus 415B and the second H-bridge 405B. Examples of suitable capacitors include electrolytic capacitors, film capacitors, ceramic capacitors, and polymer capacitors.

[0065] Figure 5 This is a flowchart illustrating an exemplary process 500 for controlling the operation of a power converter 140 according to some embodiments. In the exemplary process 500, an electronic controller 305 may receive a setpoint corresponding to a desired power transfer between the primary and secondary sides of the power converter 140. The electronic controller 305 controls the operation of switches 420A-420H and / or other components of the power converter 140 and / or the power grid support device 100 to maintain the power transfer between the primary and secondary sides at the setpoint. Figure 6 This is a block diagram illustrating an exemplary control loop 600 of an exemplary implementation of an exemplary process 500 according to some embodiments.

[0066] See also Figure 5 and Figure 6In the exemplary process 500, electronic controller 305 generates a first control signal (at block 505). For example, electronic controller 305 receives or generates a reference signal 605 corresponding to a desired setpoint. Electronic controller 305 receives or generates a feedback signal 610 representing the actual power transfer 615 between the primary and secondary sides of power converter 140. Electronic controller 305 provides the reference signal 605 and the feedback signal 610 to error calculation block 620. Error calculation block 620 calculates and outputs an error signal 625 representing the difference between the reference signal 605 (which corresponds to the setpoint or desired power transfer) and the feedback signal 610 (which corresponds to the actual power transfer 615). Electronic controller 305 provides the error signal 625 to control loop 630. Control loop 630 generates and outputs a first control signal 635 corresponding to the phase angle between the primary and secondary sides of power converter 140. Or the phase angle between the primary and secondary sides of the power converter 140 Related.

[0067] In various embodiments, control loop 630 implements PI control. In an example where control loop 630 implements PI control, control loop 630 receives an error signal 625 representing the error between the desired power transmission and the actual power transmission. Control loop 630 applies proportional and integral control to adjust the current (or cumulative) error and generates a first control signal 635 to minimize the error. p Generate the proportional control term P(t), for example, according to the following equation (2):

[0068] As shown in equation (2) above, the proportional gain K p The control signal is adjusted directly in response to the magnitude of the error e(t) at the current time t. A larger error e(t) results in a larger adjustment, while a smaller error e(t) results in a smaller adjustment. Proportional gain K p Determine how strong the response of control loop 630 is to the current error e(t). A higher proportional gain K p This means that the control loop 630 responds more aggressively to the current error e(t), while the lower proportional gain K p This means that the control loop 630 is less responsive to the current error e(t).

[0069] The control loop 630 can further generate an integral control term I(t) representing the accumulated error over a period of time. The integral control term I(t) helps to eliminate steady-state errors (e.g., long-term differences between the setpoint and the actual power transmission 615). For example, the control loop 630 can generate the integral control term I(t) as a tunable integral gain term K according to the following equation (3). i A function of the integral of the error e(τ) at each time point τ:

[0070] As shown in equation (3), the integral term increases with time until it reaches the error, ensuring that only the proportional control term is used. Small, persistent errors that could not be eliminated were resolved. Larger, time-accumulated errors were addressed. This results in larger adjustment and smaller cumulative error over time. This results in a smaller adjustment. Integral gain. Determine the control loop's response to accumulated errors over time. How strong is the response? High integral gain. This means that the control loop 630 responds more aggressively to the error accumulated over time. And lower integral gain This means that the control loop 630 is less responsive to the accumulated error over time. .

[0071] In the example of implementing proportional-integral (PI) control in control loop 630, control loop 630 generates the first control signal 635 by, for example, summing the proportional control term P(t) and the integral control term P(t) according to the following equation (4):

[0072] In various embodiments, control loop 630 implements proportional-integral-derivative (PID) control. In an example where control loop 630 implements PID control, control loop 630 receives an error signal 625 representing the difference between the desired power transmission and the actual power transmission, and applies proportional control to adjust the current error, integral control to adjust the accumulated error, and derivative control to adjust the rate of change of the error. Control loop 630 generates a first control signal 635 to minimize these errors.

[0073] As mentioned earlier, control loop 630 can generate a proportional control term P(t) and an integral control term I(t). Additionally, control loop 630 can generate a differential control term D(t) to address the rate of error change. The differential control term D(t) helps control loop 630 predict and address future error behavior and suppress oscillations, thus improving system stability. The differential control term D(t) can be calculated using the differential gain K.d The error e(t) is calculated using the rate of change of the error, for example, according to the following equation (4):

[0074] Differential control term Adjusting the control signal based on the rate of error change can provide suppression to prevent overshoot and oscillation. A larger rate of error change... This results in a larger adjustment and a smaller rate of error change. This results in a smaller adjustment. Differential gain. Determine the rate of change of the control loop error How strong is the response? A high differential gain. This means that the control loop 630 responds more aggressively to the rate of error change. And lower differential gain This means that the control loop 630 is less responsive to the rate of error change. .

[0075] In the example of implementing PID control in control loop 630, control loop 630 generates the first control signal 635 by, for example, summing the proportional control term P(t), integral control term P(t), and derivative control term D(t) according to the following equation (5):

[0076] In exemplary process 500, electronic controller 305 generates a second control signal (at block 510) by transforming a first control signal 635. For example, electronic controller 305 provides the first control signal 635 (which corresponds to a phase angle) to linearizer module 640. Furthermore, the power transmission between the primary and secondary sides of the power converter 140 has a nonlinear relationship. The linearizer module 640 applies a function to linearize this relationship and outputs a second control signal 645 that has a linear relationship with the power transmission.

[0077] In various embodiments, the linearizer module 640 applies the linearization function g(x) as defined by the following equation (6):

[0078] In equation (6) above, the variable k It can be initialized to the value π / 2, and the function sign(x) returns -1 when the input x is negative, 0 when the input x is zero, and 1 when the input x is positive.

[0079] Figure 7This is a block diagram illustrating the operation of an electronic controller 305 according to some embodiments to implement a linearizer module 640 based on a linearization function g(x). Figure 7 In the example, electronic controller 305 provides input signal 705 to linearizer module 640. In various embodiments, input signal 705 is a first control signal 635. In various embodiments, electronic controller 305 initializes variable 710 to k (e.g., the value π / 2), variable 715 to the value 1, and variable 720 to the value 1. Electronic controller 305 may provide input signal 705 to absolute value function 725, which generates output 730 corresponding to the absolute value of input signal 705. Electronic controller 305 may provide variable 720 and output 730 to subtraction function 735. Subtraction function 735 subtracts output 730 from variable 720 to generate output 740.

[0080] Electronic controller 305 can provide output 740 to square root function 745, which generates output 750 corresponding to the square root of output 740. Electronic controller 305 can provide variable 715 and output 750 to subtraction function 755. Subtraction function 755 subtracts output 750 from variable 715 to generate output 760. Electronic controller 305 can provide variable 710 and output 760 to multiplication function 765. Multiplication function 765 multiplies variable 710 with output 760 to generate output 770.

[0081] Electronic controller 305 can provide input signal 705 to sign function 775, which generates output 780, having a value of -1 when input signal 705 is negative, a value of 0 when input signal 705 is zero, and a value of 1 when input signal 705 is positive. Electronic controller 305 can provide outputs 770 and 780 to multiplication function 785. Multiplication function 785 multiplies outputs 770 and 780 to generate output signal 790. In various embodiments, output signal 790 is a second control signal 645.

[0082] In some examples, the electronic controller 305 implements the linearizer module 640 according to a lookup table, instead of applying the linearization function g(x) defined according to equation (6) above or performing a combination. Figure 7 The job described.

[0083] Return to Figure 5 and Figure 6In exemplary flow 500, electronic controller 305 controls the operation of power converter 140 according to a second control signal 645 (at block 515). For example, electronic controller 305 provides the second control signal 645 as an input to switch control logic 650. In various embodiments, switch control logic 650 generates a gate signal 655, which can be used to control the operation of switches 420A-420H of power converter 140. In some examples, gate signal 655 is a timing signal that controls the opening and closing of various switches 420A-420H, defining the actual power transfer 615 between the primary and secondary sides of power converter 140.

[0084] Converting the first control signal 635 into a second control signal 645 with a linear relationship to the actual power transmission 615 provides various technical benefits related to the operation of the power converter 140. As previously described, in control loop 600, a linear change in the second control signal 645 corresponds to a linear change in the actual power transmission 615. The change in the actual power transmission 615 directly affects the feedback signal 610, which is used to calculate the error signal 625. This linearization simplifies the control dynamics of control loop 600, particularly in examples where control loop 630 is implemented according to PI or PID control. For example, this linearization allows control loop 630 to respond to the error signal more accurately and predictably, ensuring that each adjustment in the control signal results in a proportional change in power transmission. This leads to smoother system operation (e.g., by reducing the risk of overshoot or oscillation) and faster stabilization of power transmission to match the desired setpoint.

[0085] Furthermore, linearization makes the PI or PID control parameters (e.g., proportional gain K) more flexible. p Integral gain K i and differential gain K d The tuning of the PI or PID control parameters is more efficient because the system's response to these adjustments becomes more consistent and easier to optimize. Therefore, in various embodiments, the PI or PID control parameters are tuned when the linearizer module 640 is ready (or implemented). Thus, in general, linearizing the first control signal 635 and controlling the operation of the power converter 140 according to the linearized second control signal 645 enhances the performance and reliability of the control loop 630 in maintaining precise power regulation in the power converter 140.

[0086] Therefore, the embodiments described in this invention particularly provide systems and methods for controlling the operating sequence of power grid support devices. Various features and advantages are set forth in the appended claims.

Claims

1. An apparatus comprising: A bidirectional DC-DC converter, the bidirectional DC-DC converter including a plurality of switches configured to control the power flow between the primary and secondary sides; and The controller is configured as follows: A first control signal is generated, which is related to the desired phase shift angle between the primary edge and the secondary edge. A linear transformation is applied to the first control signal to generate a second control signal, the second control signal being proportional to the desired power flow between the primary and secondary sides. The plurality of switches are controlled according to the second control signal to adjust the power flow between the primary side and the secondary side.

2. The apparatus of claim 1, wherein, The controller employs a proportional-integral controller to generate the first control signal.

3. The apparatus of claim 1, wherein, The controller employs a proportional-integral-derivative controller to generate the first control signal.

4. The apparatus of claim 1, wherein, The change in the desired phase shift angle is not linearly proportional to the change in the desired electrical flow between the primary and secondary sides.

5. The apparatus of claim 1, wherein, The change in the second control signal is linearly proportional to the change in the power flow between the primary side and the secondary side.

6. The apparatus of claim 1, wherein, The primary edge includes: A voltage source configured to receive direct current power; A first capacitor, connected in parallel with the voltage source; and A first bridge is connected in parallel with the voltage source and the first capacitor, and the first bridge includes a first plurality of switches and a first plurality of diodes.

7. The apparatus of claim 6, wherein, The secondary edge includes: The second bridge includes a second plurality of switches and a second plurality of diodes; A second capacitor, which is connected in parallel with the second bridge; and A voltage output section is connected in parallel with the second capacitor and the second bridge.

8. The apparatus of claim 7, further comprising: An inductor located between the first bridge and the second bridge; and A transformer, located between the first bridge and the second bridge.

9. The apparatus of claim 8, wherein: The controller is configured to control the first plurality of switches to generate an AC waveform; and The AC waveform is transmitted to the second bridge through the transformer.

10. The apparatus of claim 9, wherein, The controller is configured to control the second plurality of switches to rectify the AC waveform into a DC output.

11. A method for operating a bidirectional DC-DC converter, comprising: A first control signal is generated, which is related to the desired phase shift angle between the primary and secondary sides of the bidirectional DC-DC converter; A linear transformation is applied to the first control signal to generate a second control signal, the second control signal being proportional to the desired power flow between the primary side and the secondary side; and The second control signal controls a plurality of switches of the bidirectional DC-DC converter to adjust the power flow between the primary side and the secondary side.

12. The method according to claim 11, wherein, The first control signal is generated by a proportional-integral controller.

13. The method according to claim 11, wherein, The first control signal is generated by a proportional-integral-derivative controller.

14. The method according to claim 11, wherein, The change in the desired phase shift angle is not linearly proportional to the change in the desired electrical flow between the primary side and the secondary side.

15. The method according to claim 11, wherein, The change in the second control signal is linearly proportional to the change in the power flow between the primary side and the secondary side.

16. The method according to claim 11, wherein, The primary edge includes: A voltage source configured to receive direct current power; A first capacitor, connected in parallel with the voltage source; and A first bridge is connected in parallel with the voltage source and the first capacitor, and the first bridge includes a first plurality of switches and a first plurality of diodes.

17. The method according to claim 16, wherein, The secondary edge includes: The second bridge includes a second plurality of switches and a second plurality of diodes; A second capacitor, which is connected in parallel with the second bridge; and A voltage output section is connected in parallel with the second capacitor and the second bridge.

18. The method of claim 17, wherein: The inductor is located between the first bridge and the second bridge; and The transformer is located between the first bridge and the second bridge.

19. The method of claim 18, further comprising: Control the first plurality of switches to generate an AC waveform; and The AC waveform is transmitted to the second bridge via the transformer.

20. The method of claim 19, further comprising: Control the second plurality of switches to rectify the AC waveform into DC output.

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