Cooling System for Power Converter

Abstract

A power conversion device with improved cooling characteristics is disclosed. The device includes: an AC port; at least one DC port; a chassis; at least one power conversion module mounted in the chassis, the module being connectable to off-board conductors and the AC port and the at least one DC port; a module heat sink attached to each of the at least one power conversion module for cooling the module, wherein the off-board inductor is mounted in the chassis together with and separated from the module having one or more of an inductor heat sink and a cooling fluid circulator for cooling the inductor.

Description

[0001] This application claims priority to U.S. Provisional Patent Application No. 62 / 820,085, filed on March 18, 2019, which is incorporated herein by reference. Technical Field

[0002] The present invention relates to the field of power converters, such as rectifiers and inverters, which are used for different purposes, such as residential purposes. The present invention also relates to a cooling system used in a power converter. Background Art

[0003] The applicant has disclosed an example of a power converter in International PCT Patent Application No. PCT / CA2018 / 051291 (Publication No. WO2019 / 071359), which is capable of providing DC power for a home charging unit in addition to AC power.

[0004] Such a multilevel power conversion circuit uses a group of power semiconductor switches to perform power conversion, and the switches generate heat when undergoing a transition from off to on, and vice versa. In such a power conversion circuit, when the switching speed is increased, the size of the inductor and capacitor can be reduced, and the heat dissipated in such components can also be reduced. However, the heat generated by the power switch is proportional to the switching frequency.

[0005] Cooling of the power converter is important to prevent power converter failure. Summary of the Invention

[0006] The applicant has found that a power converter can be provided with a first cooling system for its power switches to manage the dissipation of the first-stage heat generation, and a second cooling system for its inductor and / or capacitor to manage the dissipation of the second-stage heat generation, wherein the switching frequency of the power switches in the power converter is selected to correspond to the heat dissipation capacity of the first cooling system, and the heat dissipation capacity of the second cooling system is selected to correspond to the second heat generation level under the condition of the selected switching frequency. The first-stage heat generation is usually much more than the second-stage heat generation. However, by reducing the switching frequency of the power switches, the second stage becomes important, and the first stage becomes easier to manage.

[0007] The present disclosure provides supplementary improvements that can be applied individually or in combination. These improvements relate to novel and innovative features, including a housing having a separate section for receiving filter components and non-board-mounted components, and an advanced cooling system for cooling the switches and non-board-mounted components.

[0008] In a broad aspect, the present disclosure provides a power conversion device that includes a housing and two or more electrical ports for receiving current from a power source and delivering it to a load, which can be an AC or DC load. The power conversion device also has: one or more power conversion circuits that can be connected to the electrical ports, the electrical ports having switches and being mounted within the housing; a compartment that is at least partially separated from the remainder of the housing for receiving non-on-board components of the at least one power conversion module; and a heat sink for attaching to at least one of the switches to transfer heat generated by the at least one switch, where the compartment allows the non-on-board components to be connected to at least one conversion module, and where the compartment has an additional cooling system for the non-on-board components.

[0009] In some embodiments, the additional cooling system can be any cooling system known in the art, such as an air cooling system, a fin cooling system, a phase change material cooling system, or a liquid cooling system.

[0010] In some embodiments, one or more of the power conversion circuits used in the converter can be a bidirectional power converter.

[0011] In some embodiments, the conversion circuit can be a multilevel circuit. In one embodiment, the converter circuit or module can be a multilevel converter topology, which includes a three-level, five-level, or seven-level topology. The applicant has disclosed the details of such a novel five-level topology in International PCT patent application No. PCT / CA2018 / 051291 and published as WO2019 / 071359.

[0012] The converter can be any type of conversion circuit, including AC-DC, DC-AC, or DC-DC, or an isolation circuit using switches.

[0013] In one example, the converter can include a connector backplane having a plurality of module connectors, and the power conversion circuit is a module converter directly connected to the module connectors or via a connecting device such as a cable or socket.

[0014] In some embodiments, the power conversion device can have a power conversion circuit that includes a buck / boost DC-to-DC converter circuit.

[0015] In an exemplary embodiment, the converter can have one or more baffles to redirect the flow from the liquid cooling system (such as a fan) to the non-on-board components, thereby assisting in cooling the components.

[0016] Those skilled in the art will understand that the converter can use a liquid cooling system to cool the converter, and the additional cooling system can be formed by concentrating air or liquid in a specific area.

[0017] In some embodiments, the compartment can be a designated portion of the housing of an additional cooling system with an extra fan. In one embodiment, a partition can separate the compartment from the at least one conversion circuit.

[0018] In other examples, the compartment can be a completely separate compartment with walls and partitions.

[0019] In some embodiments, the off-board component can be a toroidal inductor for a converter circuit, a DC-DC converter, or any other part of the converter circuit, which may be considered to require additional cooling or need to be relatively spacious to be placed on the converter circuit.

[0020] In some examples of the present disclosure, a heat sink can be attached to one or more of the switches using a thermal interface material such as thermal epoxy.

[0021] In some examples of the present disclosure, the off-board component is connected to at least one auxiliary heat sink. The auxiliary heat sink can be the sole cooling mechanism for the off-board component or used in combination with any other cooling techniques disclosed herein. A thermal pad or thermal epoxy can also be used to complete the connection to the auxiliary heat sink.

[0022] In one embodiment, the power conversion circuit can be a rectifier circuit, which includes: an AC input terminal connected to the AC port; at least one high-voltage capacitor for storing power; an inductor connected in series with the AC input terminal; a low-voltage capacitor; two high-voltage switches connected between the first AC input terminal and opposite ends of the high-voltage capacitor; two intermediate low-voltage power switches connected between the opposite ends of the high-voltage capacitor and the opposite ends of the low-voltage capacitor; and two terminal low-voltage power switches connected between the opposite ends of the low-voltage capacitor and the second AC terminal, where a DC load can be connected to the opposite ends of the high-voltage capacitor; a modulator receiving a reference signal from a converter controller; a state selection circuit receiving the at least one comparison signal and outputting a state signal, and a switch pulse generator receiving the state signal and connected to the gates of the power switches. In one example of the converter circuit, the converter circuit is a rectifier circuit, and the two high-voltage switches can be diodes.

[0023] In another example, the conversion circuit can be a bidirectional rectifier / inverter circuit, where the inductor is in series with the following: the AC input terminals, the low-voltage capacitor, the two high-voltage power switches connected between the first AC end of the AC port and the opposite end of the high-voltage capacitor, the two intermediate low-voltage power switches connected between the opposite ends of the high-voltage capacitor and the opposite ends of the low-voltage capacitor, and the two terminal low-voltage power switches connected between the opposite ends of the low-voltage capacitor and the second AC end of the AC port; where each of the plurality of DC ports is connected to the opposite ends of the high-voltage capacitor; and where the controller operates in inverter mode to generate a signal waveform and apply the signal waveform to the two high-voltage power switches, the two intermediate low-voltage power switches, and the two terminal low-voltage power switches, the signal waveform including: a first control signal for connecting the low-voltage capacitor in series with the DC port and the AC port and charging it to a predetermined value proportional to the voltage of the DC port; and a second control signal for disconnecting the low-voltage capacitor from the DC port and connecting it in series with the AC port, thereby discharging the low-voltage capacitor.

[0024] In some embodiments, the connector backplane can provide one or more connections between the conversion circuit and off-board components. This can be achieved by using a series of internal switches.

[0025] In another improvement, the present disclosure provides a converter device with improved cooling capabilities, thanks to its innovative off-board inductor supported by an independent cooling system. The circuit board can support the power conversion circuit, where the power switches are mounted along the edge of the circuit board and in thermal contact with a heat exchanger, such as a heat sink with a fin. Mounting the power inductor on such a circuit board creates problems of mechanically supporting the weight of the inductor and cooling it. Placing the inductor in an independent area within the housing of the converter device can be a suitable solution. In some embodiments, an independent compartment in the housing can allow for more effective and better control of the cooling of the inductor.

[0026] In addition, each individual converter card or module can be equipped with additional cooling equipment, such as a heat sink, which also provides additional cooling for the on-board electronic components on the converter card. Air or liquid cooling can be used, although air cooling is simpler. Heat pipes can also be used if needed.

[0027] Furthermore, the present disclosure provides for the use of toroidal inductors with a five-level converter circuit, which benefits from the low-noise characteristics of the five-level circuit to reduce the size of the filtering equipment and the inductor and generate less heat, thereby allowing for the use of a more basic cooling system in the converter and reducing the size of the converter.

[0028] In a broad aspect, the present disclosure provides a power conversion device that includes an AC port, at least one DC port, a chassis, and at least one power conversion module or card having power switches. The power conversion module is mounted on the chassis and is connected to off-board inductors as well as the AC and DC ports. The device also has a heat sink connected to the power conversion module for cooling the power switches. The off-board inductors are mounted in the chassis together with and separately from the module, and the module is provided with a heat sink and / or a cooling fluid circulator for cooling them.

[0029] In one embodiment, they can be mounted on a separate heat sink that has a fan for cooling them. In the chassis or enclosure, the inductors can be placed in a separate compartment that has its own air flow or cooling means.

[0030] In some embodiments, the module can be connected to the module heat sink via its switches. This means that one or more of the switches in the circuit can be connected to the heat sink to improve the cooling effect of the heat sink.

[0031] In some embodiments, the power conversion module can be a bidirectional power conversion module that can be used as a rectifier and an inverter to provide AC and DC outputs. This enables the unit to have the possibility of receiving DC current from an automotive or solar panel or any other DC power source and converting it to AC for use, in addition to charging.

[0032] In some embodiments, the conversion device has more than one DC port. This can be achieved by having a conversion card or multiple cards with multiple outputs within the chassis.

[0033] In one embodiment, the inductor has a compartment separated from the rest of the device to allow for easier circulation of a coolant, such as air, by using a separate fan dedicated to cooling the inductor compartment.

[0034] In some embodiments, the power conversion card may be a multilevel rectifier / inverter circuit. In one embodiment, the power conversion module includes a high-voltage capacitor and circuitry for storing boost power. The circuitry includes: an inductor connected in series with an AC port, a low-voltage capacitor, two high-voltage switches connected between a first AC input terminal and an opposite end of the high-voltage capacitor, two intermediate low-voltage switches connected between the opposite ends of the high-voltage capacitor and the opposite ends of the low-voltage capacitor, and two terminal low-voltage switches connected between the opposite ends of the low-voltage capacitor and a second AC terminal, where a DC load may be connected to the opposite ends of the high-voltage capacitor; and a controller having at least one sensor for sensing current and / or voltage in the circuitry and connected to the gate inputs of the two intermediate low-voltage switches and the two terminal low-voltage power switches. Those skilled in the art will understand that any power conversion system including any multilevel conversion circuit may be used alternatively.

[0035] In one embodiment, the controller of the multilevel rectifier / inverter circuit is operable to operate the rectifier / inverter circuit in a boost mode, where the voltage of the high-voltage capacitor is higher than the peak voltage of the AC input, and the two intermediate low-voltage power switches and the two terminal low-voltage power switches are switched in redundant switching states in response to a measured value of the voltage present at the low-voltage capacitor so as to maintain the low-voltage capacitor at a predetermined fraction of a desired voltage of the high-voltage capacitor and thus maintain the high-voltage capacitor at a desired high voltage, where the rectifier circuit supplies the DC load and absorbs power as a five-level active rectifier having low harmonics on the AC input.

[0036] In some embodiments, the chassis includes a connector backplane having a plurality of module sockets and at least one power conversion module connected in the module sockets.

[0037] In some embodiments, baffles are used in the converter to redirect the flow from a cooling fluid circulator or fan onto the inductor. This will provide better cooling for the inductor. In one embodiment, the conversion device may further include a partition plate separating the inductor from the module. In some embodiments, the inductor used may be a toroidal inductor.

[0038] In one embodiment, the power conversion device may further include a buck / boost converter circuit for converting DC power having a buck / boost inductor.

[0039] In one example, the buck / boost inductor is mounted in the chassis together with the conversion circuit inductor.

[0040] In some embodiments, the power conversion device may have a module heat sink, and a fan may be used to cool the module and attached to the power conversion module using a thermal interface material that facilitates heat transfer between the module and the heat sink.

[0041] In some embodiments, the inductors, including the conversion module inductor and the buck / boost inductor, may be connected to the inductor heat sink with thermal pads and / or using thermal epoxy.

[0042] In some embodiments, a fan can be used to cool the module and the inductor. In some embodiments, separate fans can be used for the module and the inductor.

[0043] In a broader aspect, the present disclosure provides a method for providing a power converter having at least one power conversion module including at least one off-board component and a number of semiconductor power switches. The method includes selecting a switching frequency for the number of semiconductor power switches of the at least one power conversion module, providing a first cooling system having a first cooling capacity for the switches based on heat generated by the switches at the selected switching frequency, and providing a second cooling system having a second cooling capacity for the off-board component based on heat generated by the at least one off-board component at the selected switching frequency.

[0044] In some examples, the method may further include adjusting the first cooling capacity of the first cooling system based on the first temperature of the switch.

[0045] In some examples, the method may further include adjusting the second cooling capacity and the second cooling capacity based on a second temperature of the at least one off-board component.

[0046] Systems, methods, and broader techniques described herein and claimed below are provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] This example will be better understood with reference to the following figures:

[0048] Figure 1A Figure 1 is a diagram of the physical installation of a home EV charging system, which includes: a pole-top transformer; a residential electrical inlet with load sensors and a main circuit breaker panel; a 240V AC power line between the panel and the unit; two cable connections running between the unit and the electric vehicle (EV); a CAN bus connection between the EV and the unit; and a solar panel connection.

[0049] Figure 1B is a block diagram illustrating a power conversion apparatus having multiple DC and AC ports and an off-board component panel according to one embodiment of the present disclosure.

[0050] Figure 2A The circuit diagram of a conversion circuit with a 5-level topology circuit operating in a rectifier mode is shown according to a specific example of an embodiment.

[0051] Figure 2B The circuit diagram of a battery device converter with a 5-level topology circuit operating in an inverter mode is shown according to an embodiment of the present disclosure.

[0052] Figure 3 It is a schematic diagram of a power converter module according to an embodiment of the present disclosure.

[0053] Figure 4 It is a schematic diagram of two power converter modules according to an embodiment of the present disclosure, and their switches are connected to the module heat sinks.

[0054] Figure 5 It is according to an embodiment of the present disclosure and Figure 3 A schematic diagram of a backplane working together with the power converter module shown.

[0055] Figure 6 It is a schematic diagram of a non-onboard component panel according to an embodiment of the present disclosure.

[0056] Figure 7 It is a perspective view of a power conversion device according to an embodiment of the present invention, and its non-onboard components are located on the top of the chassis / enclosure.

[0057] Figure 8 It is Figure 7 A perspective view of the power conversion device shown, which has the conversion module and the inductor heat sink exposed.

[0058] Figure 9 It is according to an embodiment Figure 7 A top perspective view of the power conversion device shown, which has a baffle and a separation panel, and the inductor heat sink is exposed from the back of the device.

[0059] Figure 10 It is a flowchart showing the steps taken to operate a power converter according to an embodiment of the present disclosure. Detailed Description

[0060] References throughout the specification to "an embodiment", "embodiment", or similar language mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the phrases "in an embodiment", "in embodiments", and similar language that appear throughout the specification may, but do not necessarily, all refer to the same embodiment.

[0061] In addition, the features, structures or characteristics of the present invention may be combined in one or more embodiments in any suitable manner. It will be apparent to those skilled in the art that various modifications and variations may be made to the present invention without departing from the scope of the invention. Therefore, the present invention is intended to cover modifications and variations provided by the present invention, as long as they fall within the scope of the appended claims and their equivalents. Reference will now be made in detail to preferred embodiments of the present invention.

[0062] Figure 1A The physical environment of an embodiment is shown, in which split single-phase main power is delivered from a transformer on a utility pole, which is the most common type of power delivery in North America. The transformer typically receives 14.4kV or 25kV single-phase power from the distribution line, and the transformer can handle approximately 50kVA to 167kVA of power as split-phase 240VAC delivered to a small number of homes or electrical inlets. Each electrical inlet is typically configured to handle 100A to 200A of power at 240VAC, i.e., approximately 24kVA to 48kVA (usually assuming 1kVA is equivalent to 1kW). As shown, the conversion device or apparatus is connected to the network via an AC connection and can be connected to multiple vehicles and / or solar panels. This can be achieved by the bidirectional (rectifier / inverter) nature of the device, which is provided by the ability to receive AC or DC power from one port and provide AC or DC from the other port.

[0063] Those skilled in the art will appreciate that although a single phase inlet is shown, the embodiments of the present disclosure are not limited to separate single phase 240VAC power systems and any of the embodiments disclosed herein may be adapted to operate with different power grids delivering AC voltage.

[0064] An electrical inlet typically includes: an electricity meter; a main circuit breaker rated for the total allowable load (e.g., 100A or 200A); and a panel with circuit breakers for each household circuit, which can receive either 240VAC power or 120VAC power from a split-phase 240VAC input. While most circuit breakers have a capacity between 15A and 30A, some can be lower (i.e., 10A) for larger appliances, and some can be higher, such as 40A. In some countries, electrical inlets have a lower capacity, such as 40A to 60A, and in countries where all household circuits are 240VAC, the power is not split-phase, but rather common single-phase 240VAC (the voltage levels used can vary from approximately 100V to 250V).

[0065] As shown in Figure 1, the conversion device / converter is connected to the circuit breaker of the main panel through a circuit breaker with a relatively large rated current (such as 40A to 80A). However, if necessary, the disclosed device can consume more than 100A. The requirement for a device-specific circuit breaker is determined by the electrical code. The cable connecting the device to the panel has a relatively high rated current. The connection to the power board can be direct fixed wiring, or a high-voltage socket can be installed and connected to the power board so that the device is connected to the power board using a cable and a plug. For example, those similar to the cables and plugs used for appliances such as ovens or dryers. The device is shown connected to a single load sensor that senses the load borne by the entire power board including the device. The device cable can be a conventional device cable and plug known in the prior art.

[0066] In addition, as Figure 1A shown, the converter can be connected to a solar panel and one or more electric vehicles.

[0067] Figure 1B is a block diagram showing an exemplary power conversion device 10, which has an AC port 18, a plurality of DC and EV / DC ports 12 and 14, a DC / EV input port 16, and a non-onboard component panel 20. As Figure 1A shown, ports 12 and 14 can be connected to EV1 and EV2, while the DC / EV port 16 can be connected to a solar panel to use the DC energy generated by the panel.

[0068] In some embodiments, the device 10 can be adapted to receive DC current from a first port (such as the EV / DC port 12) among a plurality of DC ports and deliver a variable voltage to a second port (such as the EV / DC port 14). This can be achieved by using a plurality of switches, which can be located on the backplane 22 of the conversion circuit module 100, or on a separate switch module that can be connected to the backplane or directly connected to the conversion circuit module 100.

[0069] Those skilled in the art will understand that although the module 100 is shown as a bidirectional conversion module, any other type of module such as a rectifier, an inverter, a DC-DC, a buck-boost module, and a surge protector module can be used in the converter device as needed.

[0070] As Figure 8 shown, in one example, the first port 12 and the second port 14 are located on the same power conversion circuit 100, while in other examples, they can be located on different power conversion circuits or on the backplane 22 of the device.

[0071] Return to reference Figure 1B, the converter module 100 can be connected to the backplane 22 using connectors 114 (shown here as connectors 114a, 114b, 114c, 114d, 114e, each connected to a module 100). The converter 10 can also benefit from a non-onboard component board 20, which in this embodiment is used for the purpose of accommodating inductors.

[0072] Figures 2A to 2B Details of an example of a type conversion circuit module 100 according to a specific example of an embodiment are shown, which can be used in a conversion device or apparatus 10 for an electric vehicle.

[0073] As Figure 2A shown, an exemplary conversion circuit 100 operating in rectifier mode includes an AC input 105, an inductive filter 110 connected in series with the AC input 105, and a five-level topology circuit 115.

[0074] In some examples, the inductive filter 110 in this non-limiting example can be a 2.5 mH inductor. Conveniently, partly due to the small size of the inductive filter 110, this design allows for a small geometry of the entire power conversion circuit 100. The inductive filter 110 can vary according to a design selected based on applications, rated power, grid voltage harmonics, switching frequency, etc. While the simplest such filter is a single inductor, in alternative embodiments, the inductive filter 110 can include a combination of an inductor and a capacitor, such as an inductor (e.g., 2 mH) connected to a capacitor (e.g., 30 F), which is itself grounded. The choice of filter has an impact on the overall size and losses of the design, where a larger filter increases the size of the overall design and generally results in more losses.

[0075] The five-level circuit can include: a high-voltage capacitor 120; at least one low-voltage capacitor 125; two high-voltage power switches 130a, 130b connected between a first terminal 135 and respective opposite ends 145a, 145b of the high-voltage capacitor 120; two intermediate low-voltage power switches 140a, 140b each connected between a respective one of the two opposite ends 145a, 145b of the high-voltage capacitor 120 and respective opposite ends 155a, 155b of the low-voltage capacitor; and two terminal low-voltage power switches 150a, 150b each connected between a second input terminal 160 and a respective one of the opposite ends 155a, 155b of the low-voltage capacitor 125.

[0076] As Figure 2B shown, the power conversion module 100 can operate using power in a bi-directional state. This means that the five-level circuit must have high-voltage power switches 130a, 130b and cannot replace them with two diodes in order to use an AC load 202 and a DC source 206 as in Figure 2A Converts voltage / current from AC to DC in the rectifier mode shown, or in Figure 2B The inverter mode shown converts the voltage / current from DC to AC.

[0077] Details of the converter module (module 100), its operating principle and its switching details have been disclosed by the applicant in the international PCT patent application with serial number PCT / CA2018 / 05129 and publication number WO / 2019 / 071359.

[0078] For practical implementation, a power conversion apparatus including the power conversion circuit 100 may include a user-interchangeable DC vehicle charging cable and charging plug, for example, having a compatible format for fitting a standardized plug / socket (ie, SAE J1772, ChaDeMo, or other) in an EV.

[0079] Those skilled in the art will understand that any type of connector can be used as a backplane, and the purpose of the modular connector is only to facilitate and simplify the installation process for the user, and any type of connector can be used as a backplane.

[0080] Furthermore, those skilled in the art will appreciate that a power conversion device can benefit from a user interface, which can have a screen and be connected to a terminal device such as a computer or mobile phone via an application, either wired or wirelessly, to allow a user to manually adjust variables through such an interface. Such adjustments can prioritize charging of the device, provide a charging schedule, manage how solar panel DC is consumed and distributed, or any other functions desired by the user in terms of adjusting the input and output of the device throughout the day.

[0081] Furthermore, those skilled in the art will appreciate that the AC and DC outputs may use separate or the same physical receptacles or cables. In some embodiments, the receptacle may be capable of communicating with the vehicle's charging controller.

[0082] As described herein, in various embodiments, the power conversion circuit 100 may have off-board or on-board components, such as inductors and switching elements. Additionally, the power conversion circuit 100 may have a buck / boost circuit integrated therein.

[0083] Figure 3 The power converter module 100 is shown in an embodiment in which it has only one DC port and one AC port. Ports 812 and 814 can be used to connect the power converter module 100 to its off-board components, in this example, the off-board components are the inductive filter / inductor 110 and the buck / boost inductor 1012 for port 814.

[0084] Figure 5An example of the backplane 22 is shown, which can be used by the power converter module 100 in Figure 3 . As explained, in this embodiment, all switching can be done on the backplane 22 via the switch matrix 1302. Similarly, there are five series of connectors for cards 1 to 5, and each series of connectors has connectors 912, 910, 902, 908, and 914, which receive ports 812, 810, 802, 808, and 814 of the power converter module 100, as Figure 3 shown.

[0085] Now referring to Figure 4 , which shows an embodiment of the present disclosure where switches S1 to S8 of two modules 100 are connected to the module heat sink to provide better cooling for the modules, and the ports are on-board. The AC, DC, and data ports 808, 802, and 810 can be connected to the corresponding ports via cables instead of using the backplane 22. In addition, the controller 410 can have its own separate circuit that is connected to the module through ports (not shown in the drawings) on the back of the converter module / printed circuit board.

[0086] In some embodiments, the connection of the switches can use a thermal interface material to provide better cooling. The heating material can be any material known and used in the art, such as thermal epoxy resin.

[0087] Those skilled in the art will understand that although in this embodiment the switch matrix has been shown to exist on the backplane connector 22, in some embodiments, there may be no switch matrix, or additional switches may be beneficial to connect the ports to each other in different orders and combinations. These switches can be present on the module 100 or connected to the backplane as separate switches.

[0088] In some embodiments, the converter device does not have the backplane connector 22 for receiving the module. Ports 812, 810, 802, 804, 806, 808, and 814 can be directly connected to the AC and DC ports and the ports of the non-on-board inductors 110 and non-on-board inductor 16 on the panel 20.

[0089] Figure 6 An example of the non-on-board panel 20 is shown, which has enough space for the non-on-board components of five modules 100. In one embodiment, as Figure 10As shown, inductor 110 may be one or more toroidal inductors (here, three toroidal inductors are shown) connected to panel 20 via connector 1802, and buck / boost inductor 1012 may be a toroidal inductor connected to panel 20 via another connector 1802. Those skilled in the art will appreciate that panel 20 may have different connectors that may be used to connect different types of off-board components, including other types of inductors.

[0090] In some embodiments, panel 20 can be connected to one or more heat sinks that help cool the inductors. In some alternative embodiments, inductors 100 and 1012 can be placed in a sandwich of heat sinks, with two heat sinks placed on either side of the off-board components to provide cooling for the inductors.

[0091] The panel 20 may be directly connected to the backplane, or modularly connected to the backplane. Similarly, the non-board components may be permanently fixed to the panel, or have sockets / connectors that allow them to be replaced or changed.

[0092] In some embodiments, the panel 20 may be located separately from the converter module 100 .

[0093] like Figure 8 As shown, in one embodiment, the present disclosure provides a power conversion apparatus 1100 having a chassis or housing 1102. As shown, the panel 20 can be mounted on the chassis 1102 separately from the module 100 at the upper portion of the apparatus 1100.

[0094] Those skilled in the art will appreciate that the panel 20 operating as an off-board compartment may be an integral part of a housing or chassis dedicated to off-board components.

[0095] In one embodiment, the converter device 1100 has one or more specialized frames 1104 located in the rear portion of the chassis 1102 for an additional fluid cooling system (not shown). This may be a fluid circulation device, an air cooling system, a fin cooling system, a phase change material cooling system, or a liquid cooling system. In the illustrated embodiment, fans and liquid cooling systems may be used in addition to heat sinks. These additional fans may be dedicated to cooling off-board components (i.e., inductors) or shared with the rest of the converter, providing increased airflow or cooling for off-board components.

[0096] like Figure 7As shown, a (first) cooling system (in this example, fan 1808) can be used to cool the converter module, and a separate cooling system (in this example, fan 1810) can be used to cool the off-board components. Also as shown, the separation panel 1206 can be used to form a (second) separation compartment for the off-board components, here the inductors 1802 and 1804.

[0097] Those skilled in the art will understand that the cooling systems, here referred to as fans 1810 and 1808, can have variable cooling capabilities that can be adjusted based on the frequency at which the converter module 100 operates.

[0098] In addition, the converter can have a temperature sensor that can send the temperature of each part of the converter to a controller to control the cooling systems or directly control them.

[0099] Figure 8 The back of the chassis or housing 1102 is shown, which provides a conductor heat sink exposure port 1202 for the panel 20, or, in some embodiments where the inductors are directly assembled on the heat sink, a heat sink 1304’ (not shown here) cools the off-board components.

[0100] In this embodiment, the module heat sink exposed frame 1204 can also allow the heat sink 1304 to be connected to the converter module 100 to be cooled. In one embodiment, the back of the chassis has a gap 1404 that allows the cooling heat sinks 1304 and 1304’.

[0101] It should be understood that the heat sinks 1304 and 1304’ and their respective frames can be the same size or different sizes.

[0102] As shown, in some embodiments, the separation panel 1206 can separate the compartment 20 from the conversion module 100. This can allow for better air circulation and cooling of the conductors.

[0103] Figure 9 Shown is how the converter device 1100 and the off-board components and panel / compartment 20 of the three modules 100 are located inside the chassis or housing 1102.

[0104] Figure 10 Shown is a method example for providing a power converter having at least one power conversion module that includes at least one off-board component and a plurality of semiconductor power switches.

[0105] As Figure 10As shown in block 1502, the switching frequency of multiple semiconductor power switches of the power conversion module can be selected. As in block 1504, based on the heat generated from the switches at the selected switching frequency, a first cooling system is provided, and the first cooling system can have a first cooling capacity for the switches of the converter. In some embodiments, the heat generated by the switches can increase as the operating frequency of the switches therein increases. As shown in block 1506, a second cooling system can be provided, and based on the heat generated by the at least one non-onboard component at the selected switching frequency, the second cooling system has a second cooling capacity for the non-onboard component. Similarly, the heat generated may depend on the frequency at which the capacitor operates.

[0106] Those skilled in the art will understand that the cooling capacity of the cooling system can be adjusted by different methods, for example, increasing or enhancing liquid or air circulation, opening more liquid channels, etc.

[0107] In one example, as shown in block 1506, the method can further include adjusting the heat capacity of the first and / or second cooling system to provide the required cooling to the switches and non-onboard components.

[0108] Those skilled in the art will understand that the adjustment to the heating system can be applied during design and production or during use by changing the cooling system or by activating or deactivating different elements and parts of the cooling system.

[0109] Those skilled in the art will understand that in some examples, the system can adjust the switching frequency based on non-onboard components (such as inductors) within an allowable range while using one or two cooling systems to provide sufficient cooling.

[0110] In some embodiments, as Figure 9 shown, a baffle 1402 can be added to the converter device 1100. The baffle 1402 directs the air circulation towards the inductor and provides better cooling for the inductor.

[0111] In one embodiment, the baffle 1402 can provide the additional cooling mass required for the non-onboard components of the module 100.

[0112] In an alternative embodiment, the compartment or panel 20 can be a completely separate space dedicated to cooling the inductor.

[0113] Those skilled in the art will understand that although air and ordinary fans have been used for cooling the inductor and / or module in the embodiments disclosed herein, any other type of fluid cooling system known in the art can be alternatively used without exceeding the scope of the present invention.

[0114] Those skilled in the art will understand that although, as described herein, the power conversion module may be the PUC5 topology disclosed by the applicant in the international PCT patent application serial number PCT / CA2018 / 051291 and publication number WO2019 / 071359, alternatively, any other type of power conversion circuit may also be used in combination with the heat sink and fluid cooling design disclosed herein.

[0115] Those skilled in the art will appreciate that any type of rectifier, inverter, or rectifier / inverter combination can be used to provide the desired AC and DC outputs described herein. An example of such a conversion circuit may be a multi-level rectifier / inverter circuit.

[0116] Those skilled in the art will understand that the power conversion devices and circuits described in this application, such as the 5-level rectifier circuit, can be used in any AC to DC conversion system, such as a DC power supply, other EV chargers, any other type of battery device, or any other implementation requiring AC to DC conversion.

[0117] Although the above description is provided with reference to specific examples, this is for the purpose of illustrating rather than limiting the invention.

Claims

1. A power conversion device, comprising: - an AC port; - at least one DC port; - a chassis; - at least one power conversion module mounted in the chassis and connected to at least one controller, the at least one power conversion module comprising: a certain number of semiconductor power switches driven by the at least one controller at a switching frequency, at least one on-board or off-board inductor, a connector for the AC port, and a connector for the at least one DC port; - a heat sink attached to each of the at least one power conversion module for cooling the power switches; - a first cooling system for dissipating heat from the power switches when driven at the switching frequency; and - a second cooling system for dissipating heat from at least the at least one inductor when the power switches are driven at the switching frequency, wherein the at least one controller is configured to adjust the switching frequency such that it corresponds to the heat dissipation capabilities of the first cooling system and the second cooling system and avoids exceeding the heat dissipation capabilities of the first cooling system and the second cooling system.

2. The power conversion device according to claim 1, wherein the at least one power conversion module is a bidirectional power conversion module.

3. The power conversion device according to claim 1 or 2, wherein the at least one DC port is at least two DC ports.

4. The power conversion device according to any one of claims 1 to 3, wherein the at least one power conversion module is at least two conversion modules, and the conversion device provides DC to DC charging.

5. The power conversion device according to any one of claims 1 to 4, further comprising a compartment separated from the module, the compartment including the inductor and one or more of an inductor heat sink and a cooling fluid circulator.

6. The power conversion device according to any one of claims 1 to 5, wherein the at least one power conversion module is a multi-level rectifier / inverter circuit.

7. The power conversion device according to any one of claims 1 to 6, wherein the first cooling system includes at least one fan arranged to blow air over a finned bulk heat sink having the heat sink and is mounted in a first air duct.

8. The power conversion device according to claim 7, wherein the second cooling system includes at least one fan arranged to blow air over at least the inductor in a second air duct.

9. A power conversion device, comprising: a housing having a first cooling system; at least two electrical ports for sending and receiving current between the conversion device and at least one power source and one electrical load; at least one power conversion circuit connected to the at least two electrical ports, having switches and located within the housing, wherein the switches are controlled by a controller to operate at a switching frequency; a heat sink for attaching to at least one of the switches and transferring heat generated by at least one of the switches; and, a compartment at least partially separately located within the housing and for receiving off-board components of the at least one power conversion circuit, the compartment having an additional cooling system for cooling the off-board components; wherein the compartment allows connection between the at least one conversion circuit and the off-board components, and wherein the additional cooling system provides additional cooling for the off-board components, The controller is configured to adjust the switching frequency so as to correspond to the heat dissipation capacity of the first cooling system and the heat dissipation capacity of the additional cooling system and avoid exceeding the heat dissipation capacity of the first cooling system and the heat dissipation capacity of the additional cooling system. 10 . The power conversion apparatus according to claim 9 , wherein the additional cooling system is an air cooling system. 11 . The power conversion device according to claim 9 , wherein the additional cooling system is a fin cooling system. 12 . The power conversion apparatus according to claim 9 , wherein the additional cooling system is a phase change material cooling system. 13 . The power conversion apparatus according to claim 9 , wherein the additional cooling system is a liquid cooling system. 14 . The power conversion apparatus according to claim 9 , wherein the at least one power conversion circuit is a bidirectional power converter. 15 . The power conversion apparatus according to claim 9 , wherein the at least one power conversion circuit is a multi-level circuit. 16 . The power conversion apparatus according to claim 9 , further comprising a connector backplane having a plurality of module connectors, and wherein the at least one power conversion circuit is a conversion module connected to the module connectors. 17 . The power conversion apparatus of claim 16 , wherein the connector backplane provides connections between the at least one power conversion circuit and the off-board components. 18 . The power conversion apparatus according to claim 9 , wherein the at least one power conversion circuit comprises a buck / boost DC-to-DC converter circuit.

19. The power conversion apparatus of claim 10, further comprising a baffle to redirect flow from the air cooling system onto the off-board components. 20 . The power conversion device according to claim 9 , further comprising a partition plate that separates the compartment from the at least one conversion circuit. 21 . The power conversion apparatus according to claim 9 , wherein the off-board component is a toroidal inductor. 22 . The power conversion apparatus according to claim 9 , wherein the heat sink is attached to the at least one of the switches using a thermal interface material.

23. The power conversion apparatus according to any one of claims 9 to 22, wherein the off-board components are connected to at least one auxiliary heat sink. 24 . The power conversion apparatus according to claim 9 , wherein the off-board component is connected to the at least one auxiliary heat sink via a thermal pad.

25. A method for providing a power converter having at least one power conversion module, the at least one power conversion module including at least one off-board component and a number of semiconductor power switches, the method comprising: - selecting a switching frequency of the certain number of semiconductor power switches of the at least one power conversion module; - providing a first cooling system having a first heat dissipation capability for the number of semiconductor power switches based on the heat generated from the switches at the selected switching frequency; - providing a second cooling system having a second heat dissipation capacity for the at least one off-board component based on the heat generated by the at least one off-board component at the selected switching frequency; as well as - adjusting the switching frequency so as to correspond to the first heat dissipation capacity of the first cooling system and the second heat dissipation capacity of the second cooling system and avoid exceeding the first heat dissipation capacity of the first cooling system and the second heat dissipation capacity of the second cooling system.

26. The method according to claim 25 further comprises: The first cooling system is regulated based on a first temperature of the switch.

27. The method according to claim 25 further comprises: The second heat dissipation capability is adjusted based on a second temperature of the at least one off-board component.

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