Techniques for power conversion in single-phase and multi-phase power supply networks

Abstract

The invention relates to a power converter arrangement (100) for power conversion in a single-phase power supply network. The power converter device comprises: an input filter (120) coupled to a first phase terminal (111) to receive a first AC voltage (112), the input filter (120) for filtering the first AC voltage (112) to provide an input voltage (121); an electrical switching network (130), the electrical switching network (130) comprising a bidirectional switch array (131) for generating a switching voltage (151) at the output terminals from the input voltage, and output terminals (145), the electrical switching network comprising a decoupling capacitor (140) for reducing undesirable oscillations at the output terminals; and a resonant circuit (150) for converting the switching voltage into a supply voltage to supply power to a load (160). The invention also relates to a power converter arrangement (200) for power conversion in a multi-phase power supply network in which at least one phase terminal is inoperative.

Description

Technical Field

[0001] The present invention relates to the field of power conversion in single-phase and multi-phase power supply networks. In particular, the present invention relates to a power conversion device and a corresponding method for power conversion in a single-phase power supply network and a power conversion device and a corresponding method for power conversion in a multi-phase power supply network in which at least one phase terminal is not operational. More specifically, the present invention relates to a device and an operating method of a single-phase direct resonant converter. Background Art

[0002] Direct resonant converters based on matrix converters and resonant tanks are gaining popularity due to their ability to provide single-stage AC / DC conversion and reduced switching losses when operated with model predictive control. In some applications such as on-board chargers, the input can be either three-phase or single-phase. When the input is single-phase, the double-line frequency ripple from the grid (typically 100Hz in a 50Hz system) is delivered to the load. In the case of electric vehicles (EVs), this is unacceptable as it can compromise the health of the battery. Other strategies are needed to prevent this double-line frequency ripple from appearing in the power delivered to the load. Summary of the invention

[0003] The present invention provides a solution for power conversion in the above applications but without the above mentioned disadvantages.

[0004] In particular, the present invention provides a power conversion device in which no harmful double-line frequency ripple is transmitted to the load, or the double-line frequency ripple is at least significantly attenuated.

[0005] The above and other objects are achieved by the features of the independent claims. Other implementations are apparent from the dependent claims, the description and the drawings.

[0006] The present invention provides a novel apparatus and control method for direct AC / DC conversion compatible with both three-phase and single-phase grid inputs. The topology is a single-phase to single-phase direct matrix resonant converter operated with model predictive control. By adding switch branches, the voltage on the decoupling capacitor can be controlled to absorb the dual line frequency ripple on the DC side. The additional switches can be operated under soft switching conditions, thereby improving performance. In addition, the converter can be connected to a three-phase grid. In this case, the input filter capacitor can play the role of a decoupling capacitor. The control strategy can always produce a sinusoidal input current and a constant output power.

[0007] The present invention provides an apparatus and control method for direct AC / DC conversion by a single-phase direct resonant converter operating with a novel control algorithm. The main features are as follows: (1) A power decoupling circuit with two bidirectional switches and a capacitor is added to store the dual-line frequency power ripple at the output caused by single-phase operation. (2) The control strategy calculates the voltage required to store the power ripple at the capacitor and makes the capacitor follow this reference value. (3) The control strategy can achieve soft switching operation in all matrix switches and additional power decoupling switches. (4) The additional branch together with the capacitor can be used to operate the converter under three-phase grid input. In this case, the input filter capacitor can be used as a decoupling element.

[0008] To describe the present invention in detail, the following terms, abbreviations and symbols are used:

[0009] EV Electric Vehicle

[0010] DC Direct Current

[0011] AC

[0012] DRC Direct Matrix Resonant Converter

[0013] MPC Model Predictive Control

[0014] ZCS Zero Current Switching

[0015] PWM Pulse Width Modulation

[0016] In the present invention, a power supply network or grid is described. Such a power supply network or grid is an interconnected network for transmitting or distributing electricity from producers to consumers. It may include power stations that generate electricity, substations that step up the voltage for transmission or step down the voltage for distribution, high-voltage transmission lines that transport electricity from distant sources to demand centers, and distribution lines that connect individual users.

[0017] The power converters and power converter devices described in the present invention are used to convert electrical energy from one form to another, for example, for converting between AC and DC. The power converter device can also change the voltage or frequency or some combination of voltage or frequency. The power converter device is based on power electronic switches that can be actively controlled by applying ON / OFF logic (i.e. PWM operation, usually commanded by a closed-loop control algorithm).

[0018] The controller or control device described in the present invention is any device that can be used to regulate the voltage, current or power of a power converter device. The controller or control device can be a single microcontroller or processor or a multi-core processor, or can include a group of microcontrollers or processors, or can include means for controlling and / or processing. The controller can perform specific control tasks, such as controlling a converter, based on software, hardware or firmware applications.

[0019] In the present invention, a Direct Matrix Resonant Converter (DRC) using Model Predictive Control (MPC) is described.

[0020] Direct resonant converters based on matrix converters and resonant tanks provide single-stage AC / DC conversion and reduce switching losses when operated with model predictive control. In some applications such as on-board chargers, the input can be three-phase or single-phase. When the input is single-phase, the dual-line frequency ripple from the grid is delivered to the load.

[0021] In MPC operation, the control evaluates all possible switch states, such as Figure 6 As shown, and select the switch state that minimizes the predetermined cost function, as shown below in combination Figure 2 Different cost functions can be applied to the MPC strategy by considering the error between reference and measured values ​​of input current, output current, or both.

[0022] Taking a three-phase MPC as an example, there can be six possible active states and three zero states. The current circulating through the switch is the current through the resonant tank. By performing a switching event every time the tank current crosses zero, zero current switching is achieved, thereby reducing switching losses. Each selected state is maintained during half of the resonant period of the resonant tank. In this way, the resonant tank operates at its resonant frequency and the current through the resonant tank can be assumed to be sinusoidal.

[0023] The discrete form of the state space equations for the input filter and the resonant circuit is used to estimate the change in input and output currents when the selected state is applied. The optimal state for each sampling time is selected according to a cost function that evaluates the deviation of the predicted current from a reference value (obtained from the power balance). The cost function can consider only the input current, only the output current, or both. When both reference values ​​are considered, a weighting factor is applied to adjust the relevance of each reference parameter. This control strategy and architecture can produce sinusoidal input current and constant power transfer. "Input + Output" control produces excellent performance: less input and output ripple.

[0024] During the operation of a single-phase DRC, no matter which control method is used, dual-line frequency ripple will appear at the output, such as Figure 7a In addition, the input current is also easily distorted, such as Figure 7b shown.

[0025] In the present invention, a single-phase converter and control method are provided that can achieve soft switching in all devices while avoiding the generation of dual line frequency ripple in the output. More details are provided in the following embodiments.

[0026] According to a first aspect, the present invention relates to a power converter device for performing power conversion in a single-phase power supply network, the single-phase power supply network comprising a first phase terminal, the first phase terminal being used to provide a first AC voltage, the power converter device comprising: an input filter, the input filter being coupled to the first phase terminal of the single-phase power supply network to receive the first AC voltage, the input filter being used to filter the first AC voltage to provide an input voltage; an electrical switch network, the electrical switch network comprising a bidirectional switch array and an output terminal, the bidirectional switch array being used to generate a switching voltage at the output terminal according to the input voltage, wherein the electrical switch network comprises a decoupling capacitor for reducing undesirable oscillations at the output terminal; and a resonant circuit, the resonant circuit being used to convert the switching voltage into a supply voltage to supply power to a load.

[0027] Since such distortion is suppressed or mitigated by the decoupling capacitors, such a power converter arrangement can advantageously suppress the transfer of the double line frequency ripple to the load.

[0028] By adding switch branches, the voltage on the decoupling capacitor can be controlled to absorb the double line frequency ripple on the DC side. The additional switch can be operated under soft switching conditions, thereby improving performance, etc. The converter has a flexible form factor and can also be connected to a three-phase grid, as described in the second aspect below. In this case, the input filter capacitor can play the role of a decoupling capacitor. This control strategy can always produce a sinusoidal input current and a constant output power.

[0029] In an exemplary implementation of the power converter device, the power converter device includes: a controller, which is used to provide a switching signal to the bidirectional switch array of the electrical switch network based on electrical measurement values ​​at the first phase terminal of the single-phase power supply network, electrical measurement values ​​of components of the input filter, electrical measurement values ​​on the resonant circuit, electrical measurement values ​​at the input of the switch network and voltage measurement values ​​on the decoupling capacitor, wherein the controller ensures that the voltage and current of the power converter device associated with the measurement values ​​follow predefined reference values.

[0030] This provides an advantage that the controller can ensure that the state variables (voltage and / or current) of the system follow their predefined reference values, thereby improving the efficiency of the power conversion.The electrical measurements as described above include voltage and / or current measurements.

[0031] In an exemplary implementation of the power converter device, the decoupling capacitor and the switches of the switch network are used to reduce dual line frequency harmonics from the single-phase power supply network, which operates at line frequency. Line frequency here refers to the frequency of the power grid (i.e., the power supply network).

[0032] This provides an advantage in that undesirable oscillations at the output terminals can be reduced efficiently and reliably.

[0033] In an exemplary implementation of the power converter device, the controller is used to provide the switching signal so as to turn on / off the bidirectional switch array during the zero crossing of the switching voltage or the zero crossing of the corresponding current of the resonant circuit, thereby reducing or eliminating the switching loss of the switch array.

[0034] This provides an advantage in that soft switching can be enabled, which reduces switching losses and enables devices with higher efficiency and lower thermal stress.

[0035] In an exemplary implementation of the power converter device, the switch network includes a plurality of bidirectional switch branches, wherein the branches are connected in parallel to form branches of the switch network, and the decoupling capacitor is connected to a midpoint of one of the branches of the switch network.

[0036] This provides an advantage in that the decoupling capacitor can effectively balance the two terminals of the switching network to mitigate undesirable oscillations.

[0037] In an exemplary implementation of the power converter device, the branch among the plurality of branches to which the decoupling capacitor is connected forms a decoupling branch for decoupling undesirable oscillations at the output terminal.

[0038] This provides an advantage that undesirable oscillations can be decoupled by the decoupling branch without affecting the switching behavior of other branches.

[0039] In an exemplary implementation of the power converter device, the switch network includes: a first input node and a second input node for receiving the input voltage; a first output node and a second output node for providing the switching voltage; a first bidirectional switch branch and a second bidirectional switch branch connected in parallel between the first output node and the second output node; and a bidirectional switch decoupling branch connected in parallel with the first bidirectional switch branch and the second bidirectional switch branch between the first output node and the second output node, wherein the decoupling capacitor is connected to the decoupling branch.

[0040] This offers the advantage of a symmetrical structure which facilitates decoupling of undesirable oscillations.

[0041] In an exemplary implementation of the power converter device, each bidirectional switch branch includes two bidirectional switches, which are connected to the intermediate nodes of the corresponding branches, wherein the intermediate node of the first branch is connected to the first input node of the switch network; wherein the intermediate node of the second branch is connected to the second input node of the switch network; wherein the decoupling capacitor is connected between the intermediate node of the decoupling branch and a ground terminal.

[0042] According to a second aspect, the present invention relates to a power converter device for performing power conversion in a multi-phase power supply network, the multi-phase power supply network comprising a plurality of phase terminals, each phase terminal being used to provide an AC voltage with a different voltage phase, wherein at least one phase terminal of the multi-phase power supply network is not working, the power converter device comprising: an input filter, the input filter being coupled to the plurality of phase terminals of the multi-phase power supply network to receive corresponding AC voltages, the input filter being used to filter the corresponding AC voltages to provide corresponding input voltages; an electrical switch network, the electrical switch network comprising a bidirectional switch array and an output terminal, the bidirectional switch array being used to generate a switching voltage at the output terminal according to the corresponding input voltage, wherein the input filter comprises an input filter capacitor, the input filter capacitor having an additional function of reducing undesirable oscillations at the output terminal of the electrical switch network; a resonant circuit, the resonant circuit being used to convert the switching voltage into a supply voltage to supply power to a load.

[0043] Since such distortion is suppressed or mitigated by the input filter capacitor, such a power converter device can advantageously suppress the double line frequency ripple from being transferred to the load. The converter is compatible with both single-phase and three-phase grid connections. Therefore, the operational flexibility is high, making the converter suitable for applications such as on-board chargers.

[0044] Compared with the single-phase power supply network defined in the first aspect above, in the multi-phase power supply network, the switch network has no decoupling branch. The switch used in the decoupling branch of the single-phase power supply network is no longer used as a decoupling circuit, but can be used as the third switch branch required for the three-phase input system.

[0045] The controller may remain the same as in the first aspect described above.

[0046] It may be necessary to add additional components to the input filter to cover all input phases.

[0047] When operating under three-phase input, the capacitor no longer acts as a decoupling capacitor, but rather as an input filter capacitor. When one or more phases are not operating, the capacitor acts similarly to the decoupling capacitor of the first aspect described above.

[0048] In an exemplary implementation of the power converter device, the power converter device includes: a controller, which is used to provide a switching signal to the bidirectional switch array of the electrical switch network based on electrical measurement values ​​at at least one of the phase terminals of the multi-phase power supply network, electrical measurement values ​​of components of the input filter, electrical measurement values ​​on the resonant circuit, measurement values ​​of the input voltage at the input of the switch network, and voltage measurement values ​​on the input filter capacitor, and the controller ensures that the voltage and current of the power converter device associated with the measurement values ​​follow predefined reference values.

[0049] This provides an advantage that the controller can ensure that the state variables (voltage and / or current) of the system follow their predefined reference values, thereby improving the efficiency of the power conversion.The electrical measurements as described above include voltage and / or current measurements.

[0050] In an exemplary implementation of the power converter device, the input filter capacitor of the disconnected phase is used to reduce double line frequency harmonics from the at least one inoperative phase terminal of the multi-phase power supply network, wherein the multi-phase power supply network operates at the line frequency.

[0051] This provides an advantage in that undesirable oscillations at the output terminals can be reduced efficiently and reliably.

[0052] For example, phase A is working and phase C is disconnected, so the capacitor of phase C can be a decoupling capacitor. It should be understood that other implementations can also be used, for example, if phase A is not working, its capacitor will be a decoupling capacitor.

[0053] In an exemplary implementation of the power converter arrangement, the input filter comprises a respective input filter capacitor for each phase terminal.

[0054] Such a power converter arrangement offers the advantage of high flexibility in case one or more phases fail.

[0055] In an exemplary implementation of the power converter apparatus, the input filter capacitors of each phase terminal are interconnected in a Y configuration or in a Delta configuration.

[0056] This means that the input filter capacitor may be connected differently.

[0057] In an exemplary implementation of the power converter device, the controller is configured to determine a deviation of the measured value from a reference value thereof, and to determine the switching signal according to a cost function of the deviation.

[0058] This provides an advantage in that the state of the converter can be controlled efficiently and reliably.

[0059] In an exemplary implementation of the power converter device, the controller is configured to determine a configuration of the bidirectional switch array associated with a minimum value of the cost function, and to provide the switching signal according to the configuration associated with the minimum value of the cost function.

[0060] This provides an advantage in that the bidirectional switch can be controlled to achieve optimal performance for power conversion.

[0061] In an exemplary implementation of the power converter device, the controller is used to determine the reference value based on a balance of the power of the single-phase or multi-phase power supply network relative to the power at the load, the power on the decoupling capacitor, the power in the input filter, and the lost power.

[0062] This provides the advantage that power equations for determining the power balance can be derived and, by means of these power equations, the power converter arrangement can be optimally controlled.

[0063] For multiphase power supply networks, measurements must be performed on all three phases and reference values ​​determined for all three phases.

[0064] In an exemplary implementation of the power converter apparatus, the controller is configured to determine the power, the voltage and / or the current on the decoupling capacitor such that the power at the load remains constant.

[0065] This provides the advantage that all necessary states of the system are known and the power converter can be optimally controlled.

[0066] The resonant circuit may include a transformer and a rectification stage connecting the transformer to the load.

[0067] The input filter may comprise one of: a shunt RC damping network, a series damping resistor element with a parallel inductive element, a cascade filter with parallel RL damping in each section.

[0068] The resonant circuit may be of any type, for example: a series LC circuit, a series-parallel loaded LC circuit, a parallel LC circuit, an LCC circuit, etc.

[0069] The resonant circuit may include a transformer with an integrated resonant tank.

[0070] According to a third aspect, the present invention relates to a method for performing power conversion in a single-phase power supply network, the single-phase power supply network comprising a first phase terminal, the first phase terminal being used to provide a first AC voltage, the method comprising: filtering the first AC voltage of the first phase terminal of the single-phase power supply network to provide an input voltage; generating a switching voltage according to the input voltage by a bidirectional switch array of an electrical switching network, wherein the switching voltage is generated at an output terminal of the switching network; a decoupling capacitor of the switching network reduces undesirable oscillations at the output terminal; and converting the switching voltage into a supply voltage by a resonant circuit to supply power to a load.

[0071] This method provides the same advantages as the power converter device according to the first aspect. Since such distortion is suppressed or mitigated by the decoupling capacitor, the method can advantageously suppress the transfer of the double line frequency ripple to the load.

[0072] According to a fourth aspect, the present invention relates to a method for performing power conversion in a multi-phase power supply network, wherein the multi-phase power supply network comprises a plurality of phase terminals, each phase terminal being used to provide an AC voltage having a different voltage phase, wherein at least one phase terminal of the multi-phase power supply network is not working, and the method comprises: filtering the AC voltage received from the corresponding phase terminal of the multi-phase power supply network by an input filter to provide a corresponding input voltage; generating a switching voltage according to the corresponding input voltage by a bidirectional switch array of an electrical switching network, wherein the switching voltage is generated at an output terminal of the switching network; an input filter capacitor of the input filter reduces undesirable oscillations at the output terminal; and converting the switching voltage into a supply voltage by a resonant circuit to supply power to a load.

[0073] This method provides the same advantages as the power converter arrangement according to the second aspect. Since such distortion is suppressed or mitigated by the input filter capacitor, the method can advantageously suppress the transfer of double line frequency ripple to the load.

[0074] According to a fifth aspect, the present invention relates to a computer program product. The computer program product comprises computer executable code or computer executable instructions. When the computer executable code or computer executable instructions are executed, at least one computer executes the method according to the third aspect or the fourth aspect.

[0075] The computer program product may be used in a controller (e.g., Figure 1a and Figure 1b The controller 170 shown in the figure runs on the controller 170).

[0076] According to a sixth aspect, the present invention relates to a computer-readable medium. The computer-readable medium stores instructions, and when the instructions are executed by a computer, the computer executes the method according to the third aspect or the fourth aspect. Such a computer-readable medium may be a non-transitory readable storage medium. The instructions stored on the computer-readable medium may be stored by a computer-readable medium such as Figure 1a and Figure 1b The controller executes. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Other embodiments of the present invention will be described in conjunction with the following drawings, in which:

[0078] Figure 1a shows a block diagram of a power converter device 100 for power conversion in a single-phase power supply network according to a first embodiment;

[0079] Figure 1b shows a block diagram of a power converter device 200 for power conversion in a multi-phase network in which at least one phase terminal is inoperative according to a second embodiment;

[0080] Figure 2 Shows Figure 1a and Figure 1b A block diagram of an exemplary control strategy of the power converter apparatus 100, 200 shown in;

[0081] Figure 3 shows a block diagram of a power converter device 300 for power conversion in a single-phase power supply network according to a third embodiment;

[0082] Figure 4a Shows Figure 3 An equivalent circuit of a single-phase direct resonant converter shown in FIG. 1 , wherein the input and output of the matrix converter are shown;

[0083] Figure 4b Shows Figure 3 An equivalent circuit of a single-phase direct resonant converter shown in FIG. 1 , wherein an equivalent input filter circuit in the phase connected to the grid is shown;

[0084] Figure 4c Shows Figure 3 An equivalent circuit of a single-phase direct resonant converter shown in FIG. 1 , wherein an equivalent input filter circuit in a phase disconnected from the grid is shown;

[0085] Figure 4d Shows Figure 3 The equivalent circuit of the single-phase direct resonant converter shown in FIG. 1 , wherein the equivalent resonant circuit is shown;

[0086] Figure 5 Shows Figure 3 A schematic block diagram of a bridge and a resonant circuit 500 of a power converter device 300 is shown;

[0087] Figure 6 A switch diagram 600 is shown, in which Figure 3 The possible switching states of the power converter device shown in single-phase operation;

[0088] Figure 7a a performance graph showing power delivered to a load of the disclosed power converter apparatus compared to a conventional power converter;

[0089] Figure 7b a performance diagram showing grid current in a connected phase of the disclosed power converter arrangement compared to a conventional power converter;

[0090] Figure 7c a performance graph showing the voltage across the input filter capacitor of the disconnected branch of the disclosed power converter apparatus compared to a conventional power converter;

[0091] Figure 8 shows a block diagram of a power converter device 800 for power conversion in a multi-phase power supply network in which at least one phase terminal is inoperative according to a fourth embodiment;

[0092] Fig. 9 A block diagram showing different output configurations of an output voltage doubler;

[0093] Fig.10a shows a block diagram of a shunt RC damping network as an exemplary input filter topology for the disclosed power converter apparatus;

[0094] Fig.10b A block diagram of a damping network as an exemplary input filter topology of the disclosed power converter apparatus is shown, the damping network comprising a series damping R with a parallel connection L;

[0095] Fig.10cA block diagram of a damping network as an exemplary input filter topology of the disclosed power converter apparatus is shown, the damping network comprising a cascaded filter with parallel RL damping in each section;

[0096] Fig.11a , Fig.11b , Fig.11c and Fig.11d Examples of possible resonant tank configurations of the disclosed power converter apparatus with (a) series, (b) series-parallel loading, (c) parallel, and (d) LCC circuits are shown;

[0097] Fig.12 A circuit diagram showing a transformer with an integrated resonant tank of the disclosed power converter apparatus;

[0098] Fig.13 Schematic diagrams of methods 1300a and 1300b for power conversion in a single-phase power supply network or in a multi-phase power supply network in which at least one phase terminal is inoperative are shown. DETAILED DESCRIPTION

[0099] In the following detailed description, reference is made to the accompanying drawings which form a part of this specification, wherein specific aspects of the invention which may be practiced are illustrated by way of illustration. It should be understood that other aspects may be utilized and that structural or logical changes may be made without departing from the scope of the invention. Therefore, the following detailed description should not be understood in a restrictive sense, and the scope of the invention is defined by the appended claims.

[0100] It should be understood that comments related to the described method may also apply to the corresponding device or system for performing the method, and vice versa. For example, if a specific method step is described, the corresponding device may include a unit for performing the described method step, even if such a unit is not elaborated or illustrated in detail in the figure. In addition, it should be understood that unless otherwise explicitly stated, the features of the various exemplary aspects described herein may be combined.

[0101] Figure 1a A block diagram of a power converter arrangement 100 for power conversion in a single-phase power supply network according to a first embodiment is shown.

[0102] The first embodiment of the power converter device 100 corresponds to a single-phase direct resonant converter (DRC) with the addition of a decoupling circuit 138, which is composed of two additional bidirectional switches and a capacitor 140. Here, the grid is connected to a single-phase input filter 120, followed by a switch matrix. The power decoupling circuit 138 is connected to the output of the single-phase matrix converter. The circuit includes an additional switch branch 138, with a capacitor 140 interconnected between the midpoint 142 of the switch branch 138 and a ground terminal 143. The structure also includes a control block 170, which is responsible for power factor correction, voltage and power regulation, and power decoupling.

[0103] Figure 1a All individual switches described in 130 must allow current and voltage to flow in both directions, i.e., be bidirectional switches. The output of the single-phase matrix converter 130 is connected to any type of resonant tank 150, followed by a load 160. Depending on the requirements of the application, the load 160 can be AC ​​or DC, isolated or non-isolated. In the case of a DC load, any type of rectification stage can be used.

[0104] The controller 170 receives the measured values ​​171, 172, 173, 174 of the current and voltage from the grid side, at the input of the matrix converter 130, in the resonant tank 150 and on the decoupling capacitor 140, such as Figure 1a The operation of the control method is as follows Figure 2 The controlled variables when the DRC using MPC is running are not only the grid current and the current through the resonant tank or the voltage on the resonant tank (depending on the resonant circuit topology), but also the voltage on the additional capacitor used for power decoupling. During operation, the decoupling capacitor 140 is controlled to absorb the double line frequency ripple. The reference value of the voltage on the capacitor is calculated by applying the conditions of power balance and constant output power.

[0105] A detailed description of the power converter device 100 according to the first embodiment is provided below.

[0106] The power converter device 100 according to the first embodiment can be used for power conversion in a single-phase power supply network. The single-phase power supply network comprises a first phase terminal 111, and the first phase terminal 111 is used to provide a first AC voltage 112, such as Figure 1a shown.

[0107] The power converter arrangement 100 comprises an input filter 120 coupled to a first phase terminal 111 of a single-phase power supply network to receive a first AC voltage 112. The input filter 120 is used to filter the first AC voltage 112 to provide an input voltage 121.

[0108] The power converter device 100 includes an electrical switch network 130 including a bidirectional switch array 131 and an output terminal 145. The bidirectional switch array 131 is used to generate a switch voltage 151 at the output terminal 145 from an input voltage 121. The electrical switch network 130 includes a decoupling capacitor 140 for reducing undesirable oscillations at the output terminal 145.

[0109] The power converter device 100 comprises a resonant circuit 150 for converting a switching voltage 151 into a supply voltage to supply power to a load 160 .

[0110] The power converter device 100 may further include a controller 170 for providing a switching signal 175 to the bidirectional switch array 131 of the electrical switch network 130 based on an electrical measurement 171 at the first phase terminal 111 of the single-phase power supply network, electrical measurements of components of the input filter 120, electrical measurements 172 on the resonant circuit 150, electrical measurements 173 at the input of the switch network 130, and a voltage measurement 174 on the decoupling capacitor 140. The controller 170 ensures that the voltage and current of the power converter device 100 associated with the measurements 171, 172, 173, 174 follow predefined reference values.

[0111] Specifically, the controller 170 ensures that the state variables (voltage and / or current) of the system follow their predefined reference values.

[0112] Electrical measurements as described above include voltage and / or current measurements.

[0113] The decoupling capacitors 140 and the switches of the switching network 130 may be used to reduce dual line frequency harmonics from a single-phase power supply network that operates at line frequency.

[0114] Line frequency here refers to the frequency of the power grid (i.e. the power supply network).

[0115] The controller 170 may be configured to provide a switching signal 175 to switch the bidirectional switch array 131 during a zero crossing of the switch voltage 151 or a corresponding zero crossing of the current of the resonant circuit 150 , thereby reducing or eliminating switching losses of the switch array 131 .

[0116] The switch network 130 may include a plurality of bidirectional switch branches 136, 137, and 138. These branches 136, 137, 138 may be connected in parallel to form branches of the switch network 130. A decoupling capacitor 140 may be connected to a midpoint 142 of one of the branches of the switch network 130, here branch 138.

[0117] The branch 138 among the plurality of branches 136 , 137 , 138 to which the decoupling capacitor 140 is connected forms a decoupling branch for decoupling undesirable oscillations at the output terminal 145 .

[0118] The switch network 130 may include a first input node 132 and a second input node 133 for receiving an input voltage 121. The switch network 130 may include a first output node 134 and a second output node 135 for providing a switch voltage 151. The switch network 130 may include a first bidirectional switch branch 136 and a second bidirectional switch branch 137 connected in parallel between the first output node 134 and the second output node 135. The switch network 130 may include a bidirectional switch decoupling branch 138 connected in parallel with the first bidirectional switch branch 136 and the second bidirectional switch branch 137 between the first output node 134 and the second output node 135, wherein a decoupling capacitor 140 is connected to the decoupling branch 138.

[0119] Each bidirectional switch branch 136, 137, 138 includes two bidirectional switches connected to an intermediate node 139, 141, 142 of the corresponding branch 136, 137, 138. The intermediate node 139 of the first branch 136 may be connected to the first input node 132 of the switch network 130. The intermediate node 141 of the second branch 137 may be connected to the second input node 133 of the switch network 130. The decoupling capacitor 140 may be connected between the intermediate node 142 of the decoupling branch 138 and a ground terminal 143.

[0120] The controller 170 may be configured to determine the deviation of the measured values ​​171, 172, 173, 174 from their reference values ​​and determine the switch signal 175 based on a cost function of the deviation, as described below in conjunction with Figure 2 described.

[0121] The controller 170 may be configured to determine a configuration of the bidirectional switch array 131 that is associated with a minimum value of the cost function and to provide a switch signal 175 based on the configuration associated with the minimum value of the cost function.

[0122] The controller 170 may be used to determine the reference value based on the balance of the power of the single-phase or multi-phase power supply network relative to the power at the load 160 , the power on the decoupling capacitor 140 , the power in the input filter 120 , and the lost power.

[0123] The controller 170 may be used to determine the power, voltage, and / or current on the decoupling capacitor 140 to keep the power at the load 160 constant.

[0124] The resonant circuit 150 may include a transformer and a rectification stage 160 connecting the transformer to a load.

[0125] The input filter 120 may include one of the following: a shunt RC damping network (eg Fig.10a As shown), a series damping resistor element with a parallel inductor element (such as Fig.10b As shown), each section has a cascade filter with parallel RL damping (such as Fig.10c shown).

[0126] The resonant circuit (150) may be of any type, for example, a series LC circuit (such as Fig.11a As shown), series-parallel loading LC circuit (as Fig.11b As shown), parallel LC circuit (as Fig.11c As shown), LCC circuit (as Fig.11d shown).

[0127] The resonant circuit (150) may include a transformer with an integrated resonant tank, such as Fig.12 shown.

[0128] Figure 1b A block diagram of a power converter arrangement 200 for power conversion in a multi-phase network with at least one phase terminal being inoperative according to a second embodiment is shown.

[0129] The power converter device 200 according to the second embodiment can be used for power conversion in a multi-phase power supply network. The multi-phase power supply network includes a plurality of phase terminals 211, 212 and 213, each of which is used to provide an AC voltage with a different voltage phase. Figure 1b As shown by the light grey line in FIG. , at least one phase terminal 212 , 213 of the multiphase power supply network is not working. Figure 1b Phase terminals 212 and 213 are shown as being inoperative, but it should be understood that any one or both of the phase terminals 211, 212, or 213 may be inoperative.

[0130] The power converter device 200 includes an input filter 220, which is coupled to a plurality of phase terminals 211, 212, and 213 of a multi-phase power supply network to receive corresponding AC voltages 112, 113, and 114. The input filter 220 is used to filter the corresponding AC voltages 112, 113, and 114 to provide corresponding input voltages 121, 122, and 123.

[0131] The power converter device 200 includes an electrical switch network 130 including a bidirectional switch array 131 and an output terminal 145. The bidirectional switch array 131 is used to generate a switch voltage 151 at the output terminal 145 from the corresponding input voltages 121, 122 and 123. The input filter 220 includes an input filter capacitor 240, which has the additional function of reducing undesirable oscillations at the output terminal 145 of the electrical switch network 130.

[0132] The power converter device 200 includes a resonant circuit 150 for converting a switching voltage 151 into a supply voltage to supply power to a load 160 .

[0133] The power converter device 200 may further include a controller 170 for providing a switching signal 175 to the bidirectional switch array 131 of the electrical switch network 130 based on an electrical measurement 171 at at least one of the phase terminals 211, 212, 213 of the multiphase power supply network, electrical measurements of components 221, 222, 223 of the input filter 220, electrical measurements 172 on the resonant circuit 150, measurements 173 of the input voltages 121, 122, 123 at the input of the switch network 130, and a voltage measurement 174 on the input filter capacitor 240. The controller 170 ensures that the voltages and currents of the power converter device 200 associated with the measurements 171, 172, 173, and 174 follow predefined reference values.

[0134] Electrical measurements as described above include voltage and / or current measurements.

[0135] Combined with the above Figure 1a Compared with the single-phase power network described above, in this multi-phase power network, the switch network has no decoupling branch. The switch used in the decoupling branch of the single-phase power network is no longer used as part of the decoupling circuit, but can be used as the third switch branch required for the three-phase input system. The controller 170 can remain unchanged.

[0136] It may be necessary to add additional components to the input filter to cover all input phases.

[0137] When operating under three-phase input, capacitor 240 no longer acts as a decoupling capacitor, but instead acts as an input filter capacitor. When one or more phases are not operating, capacitor 240 functions similarly to the above combined Figure 1a The role of the decoupling capacitor in the single-phase power supply network.

[0138] The disconnected phase input filter capacitor 240 may be used to reduce double line frequency harmonics from at least one inoperative phase terminal 212 , 213 of a multiphase power supply network operating at line frequency.

[0139] exist Figure 1b In the embodiment, phase A works and phase C is disconnected; therefore, capacitor 240 is a decoupling capacitor. It should be understood that other implementations may also be used, for example, if phase A is not working, its capacitor will be a decoupling capacitor.

[0140] The input filter 220 may include a corresponding input filter capacitor 240 for each phase terminal 211, 212, 213. Figure 1b In FIG. 2 , only the input filter capacitor 240 of the phase terminal 213 is shown. It should be understood that, for example, according to Figure 8 As shown in the illustration, the phase terminals 211 and 212 may also include respective input filter capacitors 242 , 241 .

[0141] The input filter capacitors 242, 241 and 240 (such as Figure 8 As shown) can be interconnected in a Y configuration or a triangle configuration.

[0142] The controller 170 may correspond to the above Figure 1a The controller 170 is implemented.

[0143] That is, the controller 170 may be configured to determine a reference value based on a balance of power of a single-phase or multi-phase power supply network relative to power at the load 160 , power on the decoupling capacitor 240 , power in the input filter 220 , and power losses.

[0144] For multiphase power supply networks, measurements must be performed on all three phases and reference values ​​determined for all three phases.

[0145] Figure 2 Shows Figure 1a and Figure 1b 2 is a block diagram of an exemplary control strategy for power converter devices 100 and 200 shown in FIG.

[0146] Depend on Figure 1a and Figure 1b The control strategy implemented by the controller 170 shown in FIG. Figure 1a and Figure 1b as well as Figure 2The measured values ​​171, 172, 173, 174 and the reference value 176 shown in the figure use MPC to determine the PWM signal 175 as the control signal. The control strategy includes the following: applying the model equation 170a according to the measured values ​​171, 172, 173, 174; calculating the deviation 170b from the reference value according to the reference value 176; evaluating 170c the cost function; selecting 170d the state with the minimum cost function; applying 170e the state for soft switching to determine the output PWM signal 175 corresponding to the selected state.

[0147] In MPC operation, the control strategy evaluates all switch states, such as Figure 6 As shown, and select the switch state that minimizes the predetermined cost function, as shown below in combination Figure 2 Different cost functions can be applied to the MPC strategy by considering the error between reference and measured values ​​of input current, output current, or both.

[0148] Depending on the filter and resonant circuit topology selected, the mathematical model used by the controller 170 will change. However, the process of deriving these expressions is always the same. First, the equivalent circuits of the input filter, resonant tank, and decoupling capacitor are obtained. The state space equations are derived and used in their discrete form to predict the values ​​of the controlled variables at each switching instant k for each possible switching state j.

[0149] Var j [k+1]=g(measured value [k], system parameter) (1)

[0150] In addition to the filter and resonant tank states, another required state is the voltage on the decoupling capacitor. The reference values ​​for all states are then obtained from the power balance equation. For the capacitor voltage, the power delivered to the load is forced to remain constant; that is:

[0151] P grid =P load +P capacitor +P loss (2)

[0152] P load (θ s )=P; in all cases, θ s ∈(0,2π) (3)

[0153] For each possible switching state, the deviation of each controlled variable from the reference value is calculated at the sampling instant.

[0154]

[0155] To select the optimal switching state, these deviations are combined in a cost function using the weighting factor λ i Each controlled variable i is given a different relevance. The state chosen will be the one that achieves the minimum value of the cost function. This sequence of steps is repeated in each switch instance.

[0156]

[0157] Figure 3 A block diagram of a power converter arrangement 300 for power conversion in a single-phase power supply network according to a third embodiment is shown.

[0158] For this third embodiment of the power converter device 300, a more detailed description is provided below, which applies to the exemplary case where the DRC 330 is followed by the series resonant tank 350. Here, two switches are used in each position. Figure 3 As shown, the bridge is connected by an inductor L f,a 、Capacitor C f,a and damping resistor R Lf,a The input filter 120 formed is connected to the grid 301. On the load side, a transformer 351 can (but not necessarily) be added to provide isolation. For this embodiment, the load 160 includes a rectifier stage 352, which connects the transformer 351 to the load 160 (e.g., the battery of the EV).

[0159] The equations and their derivations for the control algorithm are described in detail below for this embodiment without loss of generality. Similar derivations can be performed for other input filters and resonant tanks. The equivalent circuit of this embodiment is shown in FIG. Figures 4a to 4d As shown. Figure 5 and Figure 6 In the diagram, all possible switch states are provided.

[0160] The input current, the tank current, or both are controlled to follow a reference value. The input current variation is predicted according to the selected switch state using the discrete equations of the input filter. Based on the measured value at time [k] and the known system parameters (A p ) evaluates the input current at the next sampling time [k+1] as follows:

[0161]

[0162]

[0163] Where j∈(0…7) represents the state. The reference current is obtained according to the power balance equation:

[0164]

[0165] In a similar manner, the discrete equations of the resonant circuit are used to predict the change in output current according to the selected switching state. Based on the measured value at time [k] and the known system parameters (B p ) evaluates the current through the resonant tank at the next sampling time [k+1] cycle:

[0166]

[0167] Discrete equations can be used to predict the change in voltage across the decoupling capacitor depending on the selected switch state. p )Evaluate the voltage of the decoupling capacitor at the next sampling time [k+1]:

[0168]

[0169] The reference voltage is obtained based on the conditions of power balance and constant output power. The derivation of the reference voltage in the exemplary case of Embodiment 1 is described below.

[0170] The following provides a derivation of the reference magnitude and phase of the decoupling capacitor voltage.

[0171] The instantaneous power provided by phase a of the power grid can be expressed as:

[0172]

[0173] Among them, V s ,I s ,ω s are the peak voltage and current and frequency of the grid. For simplicity, losses are neglected, so the power balance is the following result:

[0174] P s (t) = P load (t)+P cf,a (t)+P cf,c (12)

[0175] Since the required load power is constant, the double line frequency supply ripple must be stored by capacitors:

[0176]

[0177] The capacitor voltage and current in phase a depend on the grid voltage and current waveforms and are therefore uncontrollable. Therefore, we define the converter input power Pin as the power directly entering the matrix converter from phase a, and the power balance results in:

[0178] P in (t) = P load (t)+P cap,C(t) = P + P cap,C (t)(14)

[0179] The voltage and current in this capacitor can be expressed as:

[0180]

[0181] Among them, P c =V c I c / 2,C f is the capacitance of the decoupling capacitor, is the phase angle of the voltage on the decoupling capacitor. The instantaneous power in capacitor C is:

[0182]

[0183] For the input power, the voltage drop on the filter inductor can be ignored, so the voltage on the filter capacitor of phase a can be considered to be approximately equal to the voltage v of phase a of the grid. s,A Then, the grid current i s,A The current i is divided into the current i for charging and discharging the filter capacitor cap ,a and the input converter current i in,a .

[0184] P in (t) = v cap,IB (t)i in,a (t)≈v s,a (t)(i s,a (t)-i cap,a (t))(18)

[0185]

[0186] Then, the instantaneous power in the load is:

[0187]

[0188] If the load power is constant, then equation (22) at every point in the cycle must evaluate to a constant value, P. Since the ripple doubles the grid frequency, it is sufficient to evaluate the expression at 0° and 45° of the grid cycle:

[0189]

[0190] Dividing (24) / (23) yields the second-order equation for the capacitor voltage phase angle tangent:

[0191]

[0192] Where K is defined as According to (23), we can obtain P c :

[0193]

[0194] For positive values ​​of Pc, the second solution of (25) is used, and the reference voltage that the filter capacitor of phase C must follow is defined in terms of its magnitude and phase angle as:

[0195]

[0196] During operation, the MPC strategy takes these reference values ​​into account. Considering the capacitor voltage and input current, a clear sinusoidal input current and output power are obtained with negligible ripple, such as Figures 7a to 7c Here, input control refers to a single-phase system where only the input current is controlled without decoupling. Input+output control refers to the use of decoupling capacitors but only the input and output currents are controlled. Finally, input+capacitor control regulates the voltage in the decoupling capacitor according to the reference values ​​in (27) and (28). The results achieved are superior to those of other techniques: the supply ripple is eliminated, and both the grid current and the capacitor voltage are sinusoidal.

[0197] The following advantages can be achieved by this third embodiment. In this embodiment, the input filter is a single-stage filter with a high-frequency zero point, which reduces the attenuation of high-frequency noise. However, the input filter has the advantages of a reduced number of components and a simple model, and a discrete state space equation for predictive control can be obtained.

[0198] For a resonant circuit, the distortion of the output current is affected by the quality factor of the resonant tank. In the case of parallel and series resonant parallel loading, the current circulating through the resonant component increases in proportion to the load current, and the increase is the quality factor. However, in the series resonant circuit selected for Example 1, the current through the resonant tank is equal to the load current, regardless of the quality factor. Therefore, the components of the resonant circuit can be selected with lower rated currents, and in the series case, the dissipated power of the parasitic resistors is lower.

[0199] Figure 8 A block diagram of a power converter arrangement 800 for power conversion in a multi-phase power supply network with at least one phase terminal being inoperative according to a fourth embodiment is shown.

[0200] In this fourth embodiment, the converter 800 can operate with a three-phase input grid having a first phase terminal 211, a second phase terminal 212, and a third phase terminal 213. In this illustration, the second phase and the third phase are not operational, as shown by the light gray lines. The switch of the power decoupling branch 138 can be used as a third phase branch switch. Therefore, the input filter capacitors 240, 241, 242 can play the role of decoupling capacitors. The connection of the capacitors 240, 241, 242 can be in a Y shape (such as Figure 8 The control algorithm can achieve single-phase or three-phase operation of the converter 800 by controlling or not controlling the voltage on the capacitor 240 of the C phase.

[0201] If the converter 800 is implemented for both single-phase input and three-phase input, the secondary side of the converter may include two transformers and a rectifier stage, such as Fig. 9 As shown, the two transformer and rectifier stages can be connected in series or in parallel, depending on the load and voltage input. This allows two different voltage levels to be achieved. This is very useful for extending the operating voltage range of the converter.

[0202] Figures 10a to 10c Different input filter topologies of the disclosed power converter arrangement are shown. Fig.10a A shunt RC damping network is shown as an example, Fig.10b shows a damping network comprising a series damper R with a parallel L, Fig.10c A damping network comprising cascaded filters with parallel RL damping in each section is shown.

[0203] like Figures 10a to 10c As shown, the topology of the input filter can be changed. Different filter architectures can be used to improve the performance of the converter in terms of power factor and harmonic injection into the grid. The input filter capacitors can also be connected in a delta or star configuration. Different filters involve different control strategy application equations, but the derivation of these equations is combined with the above Figure 3 The derivation described is the same.

[0204] Fig.11a , Fig.11b , Fig.11c and Fig.11d Examples of possible resonant tank configurations of the disclosed power converter apparatus with (a) series, (b) series-parallel loading, (c) parallel, and (d) LCC circuits are shown.

[0205] The resonant circuit can be changed to a parallel or series-parallel combination topology. Due to the change in the resonant circuit, the equations used to predict the value of the controlled variable at each sampling time are modified, but the derivation of these equations is combined with the above Figure 3 The derivation described is the same.

[0206] Fig.12 A circuit diagram of a transformer with an integrated resonant tank of the disclosed power converter arrangement is shown.

[0207] By adjusting the parasitic capacitance and leakage inductance, the resonant circuit can be integrated as part of the transformer. One of the resonant components can be integrated into the transformer, or both resonant components can be integrated into the transformer. In this case, the resonant circuit may not be visible, but the system behavior is the same. Therefore, the current or voltage at the matrix output is sinusoidal, and a switching event occurs at each zero crossing of this sinusoidal waveform. Each state of the matrix converter is maintained for the same amount of time.

[0208] Fig.13 Schematic diagrams of methods 1300a and 1300b for power conversion in a single-phase power supply network or in a multi-phase power supply network in which at least one phase terminal is inoperative are shown.

[0209] The method 1300a can be used to perform power conversion in a single-phase power network, as described above in conjunction with Figure 1a The single-phase power supply network comprises a first phase terminal, and the first phase terminal is used for providing a first AC voltage.

[0210] The method 1300 a comprises filtering 1301 a a first AC voltage 112 at a first phase terminal 111 of a single-phase power supply network to provide an input voltage 121 .

[0211] The method 1300 a includes generating 1302 a switching voltage 151 by a bidirectional switch array 131 of an electrical switching network 130 based on an input voltage 121 , wherein the switching voltage 151 is generated at an output terminal 145 of the switching network 130 .

[0212] The method 1300 a includes reducing 1303 a undesirable oscillation at the output terminal 145 of the switch network 130 by the decoupling capacitor 140 .

[0213] The method 1300 a includes converting 1304 a the switching voltage 151 to a supply voltage by the resonant circuit 150 to supply power to the load 160 .

[0214] The method 1300b may be used to perform power conversion in a multi-phase power network, as described above in conjunction with Figure 1b Such a multi-phase power supply network comprises a plurality of phase terminals 211, 212, 213, each phase terminal being used to provide an AC voltage with a different voltage phase, wherein at least one phase terminal 212, 213 of the multi-phase power supply network is inoperative.

[0215] The method 1300 b comprises filtering 1301 b , by an input filter 220 , AC voltages 112 , 113 , 114 received from respective phase terminals 211 , 212 , 213 of a multiphase power supply network to provide respective input voltages 121 , 122 , 123 .

[0216] The method 1300 b includes generating 1302 b a switching voltage 151 by a bidirectional switch array 131 of an electrical switching network 130 according to respective input voltages 121 , 122 , 123 , wherein the switching voltage 151 is generated at an output terminal 145 of the switching network 130 .

[0217] The method 1300 b includes reducing 1303 b undesirable oscillations at the output terminal 145 of the input filter 120 by the input filter capacitor 240 .

[0218] The method 1300 b includes converting 1304 b , by the resonant circuit 150 , the switching voltage 151 into a supply voltage to supply power to the load 160 .

[0219] The solution provided by the present invention is applicable to any application that requires single-stage AC / DC conversion and the output end must avoid double-line frequency ripple. Examples of these application scenarios are as follows:

[0220] (i) On-board and off-board chargers (OBC) for electric vehicles.

[0221] (ii) Uninterruptible Power Supply (UPS).

[0222] (iii) Solid State Transformer (SST).

[0223] The solution provided by the present invention can connect the device to a three-phase or single-phase grid input, maintaining a sinusoidal grid waveform and a constant output power in both operating modes.

[0224] The following advantages can be achieved:

[0225] (1) Single-stage AC-DC conversion. No DC link is required, so compactness and power density are high.

[0226] (2) Always use soft switching (ZCS) in the matrix switch and decoupling switch. When the current circulating through the bidirectional switch is zero, the bidirectional switch commutates, which can reduce switching losses, resulting in higher efficiency and lower thermal stress of the device.

[0227] (3) Compatible with both single-phase and three-phase connections to the grid. Therefore, the high operational flexibility makes the converter suitable for applications such as on-board chargers.

[0228] Although specific features or aspects of the present invention may have been disclosed with respect to only one of several implementations, such features or aspects may be advantageously combined with one or more other features or aspects of other implementations as desired and for any given or specific application. In addition, to a certain extent, the terms "include", "have", "have" or other variations of these words are used in the detailed description or claims, and such terms are similar to the term "include" and are both expressions of the meaning of inclusion. Similarly, the terms "exemplary" and "for example" are only represented as examples, rather than the best or optimal. The terms "coupled" and "connected" and derivatives may be used. It should be understood that these terms may be used to indicate that two elements cooperate or interact with each other, regardless of whether they are in direct physical contact or electrical contact, or they are not in direct contact with each other.

[0229] Although specific aspects have been illustrated and described herein, it will be understood by those skilled in the art that various alternative and / or equivalent implementations may be used to replace the specific aspects shown and described without departing from the scope of the present invention. This application is intended to cover any modifications or changes to the specific aspects discussed herein.

[0230] Although elements in the following claims are listed in a specific order with corresponding labels, these elements are not necessarily limited to being implemented in this specific order unless the claim recitation otherwise implies a specific order for implementing some or all of these elements.

[0231] According to the above guidance, many substitutions, modifications and changes are obvious to those skilled in the art. Of course, it is easy for those skilled in the art to recognize that, in addition to the applications described herein, there are many other applications of the present invention. Although the present invention has been described with reference to one or more specific embodiments, it is recognized by those skilled in the art that many changes may be made to it without departing from the scope of the present invention. Therefore, it should be understood that, as long as it is within the scope of the appended claims and their equivalents, the present invention may be practiced in a manner different from that specifically described herein.

Claims

1. A power converter device (100) for power conversion in a single-phase power supply network, characterized in that: The single-phase power supply network comprises a first phase terminal (111), the first phase terminal (111) is used to provide a first AC voltage, and the power converter device (100) comprises: an input filter (120), the input filter (120) being coupled to the first phase terminal (111) of the single-phase power supply network to receive the first AC voltage (112), the input filter (120) being configured to filter the first AC voltage (112) to provide an input voltage (121); An electrical switch network (130), the electrical switch network (130) comprising a bidirectional switch array (131) and an output terminal (145), the bidirectional switch array (131) being used to generate a switch voltage (151) at the output terminal (145) according to the input voltage (121), wherein the electrical switch network (130) comprises a decoupling capacitor (140) for reducing undesirable oscillations at the output terminal (145); A resonant circuit (150), the resonant circuit (150) is used to convert the switching voltage (151) into a supply voltage to supply power to a load (160).

2. The power converter device (100) according to claim 1, characterized in that: include: A controller (170) for providing a switching signal (175) to the bidirectional switch array (131) of the electrical switch network (130) based on electrical measurements (171) at the first phase terminal (111) of the single-phase power supply network, electrical measurements of components of the input filter (120), electrical measurements (172) on the resonant circuit (150), electrical measurements (173) at the input of the switch network (130) and voltage measurements (174) on the decoupling capacitor (140), wherein the controller (170) ensures that the voltage and current of the power converter device (100) associated with the measurements (171, 172, 173, 174) follow predefined reference values.

3. The power converter device (100) according to claim 1 or 2, characterized in that: The decoupling capacitor (140) and the switches of the switch network (130) are used to reduce dual line frequency harmonics from the single-phase power supply network, the single-phase power supply network operating at the line frequency.

4. The power converter device (100) according to claim 2, characterized in that: The controller (170) is used to provide the switching signal (175) so as to switch the bidirectional switch array (131) during the zero crossing of the switching voltage (151) or the zero crossing of the corresponding current of the resonant circuit (150), thereby reducing or eliminating the switching loss of the switch array (131).

5. The power converter device (100) according to any one of the preceding claims, characterized in that: The switch network (130) comprises a plurality of bidirectional switch branches (136, 137, 138), wherein the branches (136, 137, 138) are connected in parallel to form branches of the switch network (130), The decoupling capacitor (140) is connected to a midpoint of one of the branches of the switch network (130).

6. The power converter device (100) according to claim 5, characterized in that: The branch (138) among the plurality of branches (136, 137, 138) to which the decoupling capacitor (140) is connected forms a decoupling branch for decoupling undesirable oscillation at the output terminal (145).

7. The power converter device (100) according to any one of the preceding claims, characterized in that: The switch network (130) comprises: A first input node (132) and a second input node (133) for receiving the input voltage (121); A first output node (134) and a second output node (135) for providing the switch voltage (151); a first bidirectional switch branch (136) and a second bidirectional switch branch (137) connected in parallel between the first output node (134) and the second output node (135); a bidirectional switch decoupling branch (138) connected in parallel with the first bidirectional switch branch (136) and the second bidirectional switch branch (137) between the first output node (134) and the second output node (135), Wherein, the decoupling capacitor (140) is connected to the decoupling branch (138).

8. The power converter device (100) according to claim 7, characterized in that: Each bidirectional switch branch (136, 137, 138) includes two bidirectional switches connected to an intermediate node (139, 141, 142) of the corresponding branch (136, 137, 138), wherein the intermediate node (139) of the first branch (136) is connected to the first input node (132) of the switch network (130); wherein the intermediate node (141) of the second branch (137) is connected to the second input node (133) of the switch network (130); The decoupling capacitor (140) is connected between the middle node (142) of the decoupling branch (138) and a ground terminal (143).

9. A power converter device (200) for power conversion in a multi-phase power supply network, characterized in that: The multi-phase power supply network comprises a plurality of phase terminals (211, 212, 213), each phase terminal being used to provide an AC voltage having a different voltage phase, wherein at least one phase terminal (212, 213) of the multi-phase power supply network is not operational, and the power converter device (200) comprises: an input filter (220), the input filter (220) being coupled to the plurality of phase terminals (211, 212, 213) of the multi-phase power supply network to receive corresponding AC voltages (112, 113, 114), the input filter (220) being used for filtering the corresponding AC voltages (112, 113, 114) to provide corresponding input voltages (121, 122, 123); An electrical switch network (130), the electrical switch network (130) comprising a bidirectional switch array (131) and an output terminal (145), the bidirectional switch array (131) being configured to generate a switch voltage (151) at the output terminal (145) according to the corresponding input voltage (121, 122, 123), wherein the input filter (220) comprises an input filter capacitor (240), the input filter capacitor (240) having an additional function of reducing undesirable oscillations at the output terminal (145) of the electrical switch network (130); A resonant circuit (150), the resonant circuit (150) is used to convert the switching voltage (151) into a supply voltage to supply power to a load (160).

10. The power converter device (200) according to claim 9, characterized in that: include: A controller (170) for providing a switching signal (175) to the bidirectional switch array (131) of the electrical switch network (130) based on electrical measurements (171) at at least one of the phase terminals (211, 212, 213) of the multiphase power supply network, electrical measurements of components (221, 222, 223) of the input filter (220), electrical measurements (172) on the resonant circuit (150), measurements (173) of the input voltage (121, 122, 123) at the input of the switch network (130) and voltage measurements (174) on the input filter capacitor (240), the controller (170) ensuring that voltages and currents of the power converter device (200) associated with the measurements (171, 172, 173, 174) follow predefined reference values.

11. The power converter device (200) according to claim 9 or 10, characterized in that: The input filter capacitor (240) of the disconnected phase is used to reduce double line frequency harmonics from the at least one inoperative phase terminal (212, 213) of the multi-phase power supply network, Wherein, the multi-phase power supply network operates at the line frequency.

12. The power converter device (200) according to any one of claims 9 to 11, characterized in that: The input filter (220) includes a respective input filter capacitor (240) for each phase terminal (211, 212, 213).

13. The power converter device (200) according to claim 12, characterized in that: The input filter capacitors (242, 241, 240) of each phase terminal (211, 212, 213) are interconnected in a Y configuration or in a delta configuration.

14. The power converter device (100, 200) according to claim 2 or 10, characterized in that: The controller (170) is used to determine the deviation of the measured value (171, 172, 173, 174) from its reference value, and determine the switching signal (175) according to a cost function of the deviation.

15. The power converter device (100, 200) according to claim 14, characterized in that The controller (170) is configured to determine a configuration of the bidirectional switch array (131), the configuration associated with a minimum value of the cost function, and to provide the switch signal (175) according to the configuration associated with the minimum value of the cost function.

16. The power converter device (100, 200) according to claim 2 or 10, characterized in that: The controller (170) is used to determine the reference value based on a balance of the power of the single-phase or multi-phase power supply network relative to the power at the load (160), the power on the decoupling capacitor (240), the power in the input filter (120, 220) and the lost power.

17. The power converter device (100) according to claim 16, characterized in that The controller (170) is used to determine the power, the voltage and / or the current on the decoupling capacitor (240) so that the power at the load (160) remains constant.

18. A method (1300a) for power conversion in a single-phase power supply network, characterized in that: The single-phase power supply network comprises a first phase terminal for providing a first AC voltage, the method comprising: filtering (1301a) the first AC voltage (112) at the first phase terminal (111) of the single-phase power supply network to provide an input voltage (121); generating (1302a) a switching voltage (151) from the input voltage (121) by a bidirectional switch array (131) of an electrical switching network (130), wherein the switching voltage (151) is generated at an output terminal (145) of the switching network (130); The decoupling capacitor (140) of the switch network (130) reduces (1303a) undesirable oscillations at the output terminal (145); The switching voltage (151) is converted (1304a) into a supply voltage by the resonant circuit (150) to supply power to the load (160).

19. A method (1300b) for power conversion in a multi-phase power supply network, characterized in that: The multiphase power supply network comprises a plurality of phase terminals (211, 212, 213), each phase terminal being used to provide an AC voltage having a different voltage phase, wherein at least one phase terminal (212, 213) of the multiphase power supply network is inoperative, and the method comprises: The AC voltage (112, 113, 114) received from the corresponding phase terminals (211, 212, 213) of the multi-phase power supply network is filtered (1301b) by an input filter (220) to provide a corresponding input voltage (121, 122, 123); generating (1302b) a switching voltage (151) from the corresponding input voltage (121, 122, 123) by a bidirectional switch array (131) of an electrical switching network (130), wherein the switching voltage (151) is generated at an output terminal (145) of the switching network (130); An input filter capacitor (240) of the input filter (120) reduces (1303b) undesirable oscillations at the output terminal (145); The switching voltage (151) is converted (1304b) into a supply voltage by the resonant circuit (150) to supply power to the load (160).

Images