Switching module for power electronic switching assembly

Abstract

We provide switching modules for power electronic switching assemblies. [Solution] The switching module 1 comprises an H-bridge circuit 2 having four switching assemblies and an active clamp circuit 6 having four controllable semiconductor switches (S5~S8). Each switching assembly comprises a pair of controllable semiconductor switches (S1~S4 and S9~S12) electrically connected in reverse series. The H-bridge circuit 2 comprises first and second AC bridge terminals (AC1, AC2) electrically connectable to each coil 4, and first and second DC bridge terminals (DC1, DC2) electrically connectable to a DC current source or a DC bridge terminal of another switching module. The active clamp circuit 6 comprises first and second DC clamp terminals DC3, DC4 to which an energy storage device C is electrically connected.

Description

Technical Field

[0001] The present invention relates to a switching module for a power electronics switching assembly.

[0002] The power electronics switching assembly may comprise a plurality of switching modules.

[0003] The power electronics switching assembly may be part of a direct current (DC) electric machine comprising a stator having a plurality of stator coils, each stator coil being electrically connected to a respective switching module. The power electronics switching assembly may also be part of a power converter in which each switching module is electrically connected to a respective coil of a transformer assembly.

Background Art

[0004] European Patent No. 23155859 describes a switching module that can be used to provide active commutation and energy recovery processes. In one configuration, the power electronics switching assembly comprises a plurality of switching modules and can be used, for example, to provide energy-efficient commutation for a direct current (DC) electric machine.

[0005] Referring to FIG. 1, each switching module 100 first and second AC bridge terminals AC1, AC2 electrically connectable to a respective coil 104, for example a stator coil of a DC electric machine, first and second DC bridge terminals DC1, DC2 electrically connectable to a DC current source, a first switch S1 electrically connected between the first AC bridge terminal AC1 and the first DC bridge terminal DC1, a second switch S2 electrically connected between the first AC bridge terminal AC1 and the second DC bridge terminal DC2, A third switch S3 is electrically connected between the second AC bridge terminal AC2 and the first DC bridge terminal DC1, A fourth switch S4 is electrically connected between the second AC bridge terminal AC2 and the second DC bridge terminal DC2. Includes an H-bridge circuit 102 equipped with

[0006] Each switching module 100 also includes an active clamp circuit 106. The active clamp circuit 106 of each switching module 100 is A first AC clamp terminal AC3 is electrically connected to the first AC bridge terminal AC1, The second AC clamp terminal AC4 is electrically connected to the second AC bridge terminal AC2, The first and second DC clamp terminals DC3, DC4, A fifth switch S5 is electrically connected between the first AC clamp terminal AC3 and the first DC clamp terminal DC3, A sixth switch S6 is electrically connected between the first AC clamp terminal AC3 and the second DC clamp terminal DC4, A seventh switch S7 is electrically connected between the second AC clamp terminal AC4 and the first DC clamp terminal DC3, An eighth switch S8 is electrically connected between the second AC clamp terminal AC4 and the second DC clamp terminal DC4, An energy storage device (e.g., capacitor C) is electrically connected between the first and second DC clamp terminals DC3 and DC4. It is equipped with.

[0007] In each H-bridge circuit 102, the first and second switches S1 and S2 are electrically connected in series between the first and second DC bridge terminals DC1 and DC2, which serve as the first bridge legs. The third and fourth switches S3 and S4 are electrically connected in series between the first and second DC bridge terminals DC1 and DC2, which serve as the second bridge legs. The DC terminals of the first and second bridge legs are electrically connected in parallel. The junction (or connection point) between the first and second switches S1 and S2 defines the first AC bridge terminal AC1, and the junction between the third and fourth switches S3 and S4 defines the second AC bridge terminal AC2.

[0008] In each active clamp circuit, the fifth and sixth switches S5 and S6 are electrically connected in series between the first and second DC clamp terminals DC3 and DC4, which serve as the first clamp legs. The seventh and eighth switches S7 and S8 are electrically connected in series between the first and second DC clamp terminals DC3 and DC4, which serve as the second clamp legs. The first and second clamp legs are electrically connected in parallel. The junction between the fifth and sixth switches S5 and S6 defines the first AC clamp terminal AC3, and the junction between the seventh and eighth switches S7 and S8 defines the second AC clamp terminal AC4. An energy storage device (i.e., capacitor C) is electrically connected in parallel with the first and second clamp legs between the first and second DC clamp terminals DC3 and DC4.

[0009] Each switch S1, S2, ..., S8 in the H-bridge circuit 102 and the active clamp circuit 106 may include one or more controllable semiconductor switches. Any suitable controllable semiconductor switch or combination of switches, such as metal oxide semiconductor field-effect transistors (MOSFETs), vertical junction field-effect transistors (VJFETs), insulated-gate bipolar transistors (IGBTs), and gate commutation thyristors can be used. Separate diodes may be electrically connected in antiparallel to each semiconductor switch, or the antiparallel diodes may be the intrinsic features of the semiconductor switch itself, such as the body diode of a MOSFET structure. Each controllable semiconductor switch is typically switched on and off by a gate drive signal generated by a gate driver.

[0010] In the H-bridge circuit 102, each switch S1, S2, ..., S4 may be a bidirectional switch, that is, each switch may provide gate-controlled bidirectional voltage blocking capability with unidirectional current. Each bidirectional switch may consist of (a) a pair of controllable semiconductor switches as shown in Figure 1, or (b) a controllable semiconductor switch and a diode, the pair of semiconductor devices being electrically connected in reverse series (or back-to-back), that is, one of the pair of semiconductor devices blocking voltage in a first direction, and the other semiconductor device blocking voltage in a second direction opposite to the first direction. (As used herein, the term “semiconductor device” may refer to a semiconductor switch or a diode as necessary.) When current flows through one of the semiconductor switches in a particular direction, the current may also flow through the antiparallel diode of the other reverse series-connected semiconductor switch. For example, if each semiconductor switch is a MOSFET, the body diode acts essentially as an antiparallel diode, as shown in Figure 1.

[0011] In one actual configuration of the switching module 100 shown in Figure 1, each switch S1, S2, ..., S4 of the H-bridge circuit 102 is implemented as a pair of MOSFETs electrically connected in reverse series (i.e., arranged to conduct in opposite directions), and each switch S5, S6, ..., S8 of the active clamp circuit 106 is implemented as IGBTs with antiparallel diodes D5a, D6a, ..., D8a. However, this requires the use of custom pre-packaged modules in the H-bridge circuit, as opposed to conventional "off-the-shelf" pre-packaged modules in which controllable semiconductor switches are electrically connected to conduct in the same direction. In particular, each pre-packaged module features a common source configuration and a pair of MOSFETs electrically connected in reverse series. Such custom pre-packaged modules are typically more expensive than conventional pre-packaged modules and are available from a limited number of suppliers. As used herein, the term “pre-packaged module” refers to a power module in which semiconductor devices and optionally other electronic components (e.g., temperature sensors) are packaged together in a suitable housing. The module may also include a pre-applied thermal interface material to dissipate heat generated by, for example, semiconductor devices. Such pre-packaged modules are often used in wind and solar power generation, energy storage, transmission and distribution, and towing applications.

[0012] While it is possible to implement the H-bridge circuit 102 using a single or individual controllable semiconductor switch instead of a custom pre-packaged module, the voltage and current ratings of such a single switch are typically either too low or too high for implementation in a real switching module where the current rating may need to be, for example, in the range of approximately 200–500A. On the other hand, many conventional pre-packaged modules use controllable semiconductor switches with the required voltage and current ratings, such as 1200–1700V and 200–500A. Such “off-the-shelf” or conventional pre-packaged modules have the following advantages: Low cost, Available from a wide range of suppliers, Using a standardized structure, Available in a wide range of switch options (e.g., SiC MOSFETs and Si IGBTs) with the required voltage and current ratings.

[0013] Conventional pre-packaged modules (e.g., chopper modules) having electrically controllable semiconductor switches and diodes connected in reverse series are also available. [Overview of the project]

[0014] The present invention aims to address the problems identified above and provides an improved switching module that can be actually implemented using “off-the-shelf” or conventional pre-packaged modules to take advantage of the aforementioned cost and supply benefits. The present invention provides first and second AC bridge terminals electrically connectable to each coil, First and second DC bridge terminals that can be electrically connected to a DC current source or the DC bridge terminal of another switching module, A first switch assembly electrically connected between a first AC bridge terminal and a first DC bridge terminal, the first switch assembly comprising a first controllable semiconductor switch and a first semiconductor device (i.e., a controllable semiconductor switch or diode) electrically connected in series, A second switch assembly electrically connected between a first AC bridge terminal and a second DC bridge terminal, the second switch assembly comprising a second controllable semiconductor switch and a second semiconductor device (i.e., a controllable semiconductor switch or diode) electrically connected in series, A third switch assembly electrically connected between a second AC bridge terminal and a first DC bridge terminal, the third switch assembly comprising a third controllable semiconductor switch and a third semiconductor device (i.e., a controllable semiconductor switch or diode) electrically connected in series, A fourth switch assembly electrically connected between a second AC bridge terminal and a second DC bridge terminal, the fourth switch assembly comprising a fourth controllable semiconductor switch and a fourth semiconductor device (e.g., a controllable semiconductor switch or diode) electrically connected in series, and An H-bridge circuit equipped with, First and second DC clamp terminals, A first DC clamp terminal and a fifth controllable semiconductor switch electrically connected between the junction (or connection point) between the first controllable semiconductor switch and the first semiconductor device, A second DC clamp terminal and a sixth controllable semiconductor switch electrically connected between the junction between the second controllable semiconductor switch and the second semiconductor device, A first DC clamp terminal and a seventh controllable semiconductor switch electrically connected between the junction between the third controllable semiconductor switch and the third semiconductor device, A second DC clamp terminal and an eighth controllable semiconductor switch electrically connected between the junction between the fourth controllable semiconductor switch and the fourth semiconductor device, An energy storage device electrically connected between the first and second DC clamp terminals and An active clamp circuit equipped with We provide a switching module equipped with the following features.

[0015] The junction between the first and second controllable semiconductor switches defines a first AC bridge terminal, and the junction between the third and fourth controllable semiconductor switches defines a second AC bridge terminal.

[0016] The switch assembly of the H-bridge circuit comprises a pair of controllable semiconductor switches connected in series:

[0017] In one configuration, the first, second, third, and fourth semiconductor devices are controllable semiconductor switches; that is, each switch assembly in the H-bridge circuit may comprise a pair of controllable semiconductor switches. The pair of controllable semiconductor switches in each switch assembly are electrically connected in reverse series (i.e., arranged to conduct in opposite directions).

[0018] In this configuration, for convenience, the first semiconductor device is referred to as the ninth controllable semiconductor switch, the second semiconductor device as the tenth controllable semiconductor switch, the third semiconductor device as the eleventh controllable semiconductor switch, and the fourth semiconductor device as the twelfth controllable semiconductor switch.

[0019] The first and ninth controllable semiconductor switches may be electrically connected in reverse series. The first controllable semiconductor switch may be electrically connected to the first AC bridge terminal, and the ninth controllable semiconductor switch may be electrically connected to the first DC bridge terminal.

[0020] The second and tenth controllable semiconductor switches may be electrically connected in reverse series. The second controllable semiconductor switch may be electrically connected to the first AC bridge terminal, and the tenth controllable semiconductor switch may be electrically connected to the second DC bridge terminal.

[0021] The third and eleventh controllable semiconductor switches may be electrically connected in reverse series. The third controllable semiconductor switch may be electrically connected to the second AC bridge terminal, and the eleventh controllable semiconductor switch may be electrically connected to the first DC bridge terminal.

[0022] The fourth and twelfth controllable semiconductor switches may be electrically connected in reverse series. The fourth controllable semiconductor switch may be electrically connected to the second AC bridge terminal, and the twelfth controllable semiconductor switch may be electrically connected to the second DC bridge terminal.

[0023] All controllable semiconductor switches in a switching module may be of the same type. In particular, it will be understood that the same type of controllable semiconductor switch can be used to implement both H-bridge and active-clamp circuits. All controllable semiconductor switches may have the same ratings.

[0024] For example, any suitable fully controllable semiconductor switch can be used, such as metal oxide semiconductor field-effect transistors (MOSFETs), vertical junction field-effect transistors (VJFETs), insulated gate bipolar transistors (IGBTs), high electron mobility transistors (HEMTs), bipolar junction transitions (BJTs), and gate commutation thyristors (GCTs) or gate turn-off thyristors (GTOs). Separate diodes may be electrically connected in antiparallel to each semiconductor switch, or the antiparallel diodes may be the intrinsic features of the semiconductor switch itself, such as the body diode of a MOSFET structure.

[0025] Each controllable semiconductor switch is typically switched on and off by a gate drive signal generated by a gate driver.

[0026] In one particular configuration, all controllable semiconductor switches in the H-bridge circuit and the active clamp circuit may be implemented as MOSFETs. The first and ninth controllable semiconductor switches are preferably electrically connected in reverse series in a common drain configuration. The second and tenth controllable semiconductor switches are preferably electrically connected in reverse series in a common source configuration. The third and eleventh controllable semiconductor switches are preferably electrically connected in reverse series in a common drain configuration. The fourth and twelfth controllable semiconductor switches are preferably electrically connected in reverse series in a common source configuration.

[0027] In one configuration of the switching module, the first and second controllable semiconductor switches may be of the same type and may be implemented as a pre-packaged module in which the first and second controllable semiconductor switches are arranged to conduct in the same direction. In other words, the first and second controllable semiconductor switches may be implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0028] The third and fourth controllable semiconductor switches may be of the same type and may be implemented as a pre-packaged module in which the third and fourth controllable semiconductor switches are arranged to conduct in the same direction. In other words, the third and fourth controllable semiconductor switches may be implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0029] The fifth and ninth controllable semiconductor switches may be of the same type and may be implemented as a pre-packaged module in which the fifth and ninth controllable semiconductor switches are arranged to conduct in the same direction. In other words, despite the fact that the fifth and ninth controllable semiconductor switches are used in the active clamp circuit and the H-bridge circuit respectively, they may be implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0030] The sixth and tenth controllable semiconductor switches may be of the same type and may be implemented as a pre-packaged module in which the sixth and tenth controllable semiconductor switches are arranged to conduct in the same direction. In other words, despite the fact that the sixth and tenth controllable semiconductor switches are used in the active clamp circuit and the H-bridge circuit respectively, they may be implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0031] The seventh and eleventh controllable semiconductor switches may be of the same type and may be implemented as a pre-packaged module in which the seventh and eleventh controllable semiconductor switches are arranged to conduct in the same direction. In other words, despite the fact that the seventh and eleventh controllable semiconductor switches are used in the active clamp circuit and the H-bridge circuit respectively, they may be implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0032] The eighth and twelfth controllable semiconductor switches may be of the same type and may be implemented as a pre-packaged module in which the eighth and twelfth controllable semiconductor switches are arranged to conduct in the same direction. In other words, despite the fact that the eighth and twelfth controllable semiconductor switches are used in the active clamp circuit and the H-bridge circuit respectively, they may be implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0033] The pre-packaged modules may be, for example, half-bridge modules. In other words, each pair of controllable semiconductor switches (e.g., first and second controllable semiconductor switches, third and fourth controllable semiconductor switches, fifth and ninth controllable semiconductor switches, etc.) may be implemented as a separate half-bridge module. In this configuration, six conventional or "off-the-shelf" pre-packaged half-bridge modules are required to implement each switching module. Such half-bridge modules may include a pair of controllable semiconductor switches defining a single leg. However, switching modules can also be implemented using other pre-packaged modules. For example, a pre-packaged module may have two or more pairs of controllable semiconductors defining two or more legs whose leg terminals are not electrically connected to each other (e.g., DC terminals are not connected to each other). This makes it possible to implement multiple pairs of controllable semiconductor switches of a switching module in the same pre-packaged module. For example, if each pre-packaged module includes a first pair of controllable semiconductor switches defining a first leg and a second pair of controllable semiconductor switches defining a second leg, then only three conventional or "off-the-shelf" pre-packaged modules are needed to implement each switching module. If each pre-packaged module also includes a third pair of controllable semiconductor switches defining a third leg, then only two conventional or "off-the-shelf" pre-packaged modules are needed to implement each switching module. This allows for more compact switching modules and reduces costs. Different combinations of pre-packaged modules can be used, but they preferably all use the same type of controllable semiconductor switches.

[0034] The switch assembly of an H-bridge circuit comprises controllable semiconductor switches connected in series and diodes.

[0035] In an alternative configuration, the first, second, third, and fourth semiconductor devices are diodes, and that is, each switch assembly in the H-bridge circuit may comprise controllable semiconductor switches and diodes that are electrically connected in series and arranged to conduct in the same direction.

[0036] In this configuration, for convenience, the first semiconductor device is referred to as the first diode, the second semiconductor device as the second diode, the third semiconductor device as the third diode, and the fourth semiconductor device as the fourth diode.

[0037] The first controllable semiconductor switch and the first diode may be electrically connected in series and arranged to conduct in the same direction. The first controllable semiconductor switch may be electrically connected to the first AC bridge terminal, and the first diode may be electrically connected to the first DC bridge terminal.

[0038] The second controllable semiconductor switch and the second diode may be electrically connected in series and arranged to conduct in the same direction. The second controllable semiconductor switch may be electrically connected to the first AC bridge terminal, and the second diode may be electrically connected to the second DC bridge terminal.

[0039] The third controllable semiconductor switch and the third diode may be electrically connected in series and arranged to conduct in the same direction. The third controllable semiconductor switch may be electrically connected to the second AC bridge terminal, and the third diode may be electrically connected to the first DC bridge terminal.

[0040] The fourth controllable semiconductor switch and the fourth diode may be electrically connected in series and arranged to conduct in the same direction. The fourth controllable semiconductor switch may be electrically connected to the second AC bridge terminal, and the fourth diode may be electrically connected to the second DC bridge terminal.

[0041] All controllable semiconductor switches may be of the same type. In particular, it will be understood that the same type of controllable semiconductor switch can be used to implement both H-bridge circuits and active clamp circuits. All controllable semiconductor switches may have the same ratings.

[0042] For example, any suitable fully controllable semiconductor switch can be used, such as vertical junction field-effect transistors (VJFETs), insulated-gate bipolar transistors (IGBTs), high-electron-mobility transistors (HEMTs), bipolar junction transitions (BJTs), and gate commutation thyristors (GCTs) or gate turn-off thyristors (GTOs). Separate diodes may optionally be electrically connected in antiparallel to each semiconductor switch.

[0043] Each controllable semiconductor switch is typically switched on and off by a gate drive signal generated by a gate driver.

[0044] In one particular configuration, all controllable semiconductor switches in the H-bridge and active-clamp circuits may be implemented as IGBTs, for example, with associated antiparallel diodes.

[0045] In one configuration of the switching module, the first and second controllable semiconductor switches may be of the same type and may be implemented as a pre-packaged module in which the first and second controllable semiconductor switches are arranged to conduct in the same direction. In other words, the first and second controllable semiconductor switches may be implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0046] The third and fourth controllable semiconductor switches may be of the same type and may be implemented as a pre-packaged module in which the third and fourth controllable semiconductor switches are arranged to conduct in the same direction. In other words, the third and fourth controllable semiconductor switches may be implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0047] The fifth controllable semiconductor switch and the first diode may be implemented as a pre-packaged module in which the fifth controllable semiconductor switch and the first diode are electrically connected in reverse series, i.e., arranged to conduct in opposite directions. In other words, despite the fact that the fifth controllable semiconductor switch and the first diode are used in an active clamp circuit and an H-bridge circuit, respectively, the controllable semiconductor switch and diode may be implemented using conventional pre-packaged modules packaged together.

[0048] The sixth controllable semiconductor switch and the second diode may be implemented as a pre-packaged module in which the sixth controllable semiconductor switch and the second diode are electrically connected in reverse series, i.e., arranged to conduct in opposite directions. In other words, despite the fact that the sixth controllable semiconductor switch and the second diode are used in the active clamp circuit and the H bridge circuit, respectively, the sixth controllable semiconductor switch and the second diode may be implemented using controllable semiconductor switches and diodes packaged together in a conventional pre-packaged module.

[0049] The seventh controllable semiconductor switch and the third diode may be implemented as a pre-packaged module in which the seventh controllable semiconductor switch and the third diode are electrically connected in reverse series, i.e., arranged to conduct in opposite directions. In other words, despite the fact that the seventh controllable semiconductor switch and the third diode are used in the active clamp circuit and the H bridge circuit, respectively, the seventh controllable semiconductor switch and the third diode may be implemented using controllable semiconductor switches and diodes packaged together in a conventional pre-packaged module.

[0050] The eighth controllable semiconductor switch and the fourth diode may be implemented as a pre-packaged module in which the eighth controllable semiconductor switch and the fourth diode are electrically connected in reverse series, i.e., arranged to conduct in opposite directions. In other words, despite the fact that the eighth controllable semiconductor switch and the fourth diode are used in the active clamp circuit and the H bridge circuit, respectively, they may be implemented using controllable semiconductor switches and diodes packaged together in a conventional pre-packaged module.

[0051] The pre-packaged modules for the first and second controllable semiconductor switches may be the first pre-packaged half-bridge module, and the pre-packaged modules for the third and fourth controllable semiconductor switches may be the second pre-packaged half-bridge module. Alternatively, the first, second, third, and fourth controllable semiconductor switches may be implemented as a single pre-packaged module having two pairs of controllable semiconductor switches defining two legs as described above. The remaining pre-packaged modules may be chopper modules, each chopper module comprising a controllable semiconductor switch (e.g., an IGBT and an antiparallel diode) electrically connected in anti-series with a diode. If each pre-packaged chopper module contains one controllable semiconductor switch and one diode, then five or six conventional or "off-the-shelf" pre-packaged modules are required to implement each switching module. If each pre-packaged chopper module contains two or more legs, and each leg contains a controllable semiconductor switch electrically connected in anti-series with a diode, then fewer pre-packaged modules are required.

[0052] However, in actual configurations, the remaining pre-packaged modules may be half-bridge modules, each comprising a first controllable semiconductor switch (e.g., an IGBT) and a first antiparallel diode electrically connected in inverse series to a second controllable semiconductor switch (e.g., an IGBT) and a second antiparallel diode. A pre-packaged half-bridge module may have two or more pairs of controllable semiconductors defining two or more legs as described above. This makes it possible to implement multiple pairs of controllable semiconductor switches in a switching module on the same pre-packaged module. One of the first and second controllable semiconductor switches in each half-bridge module (or each leg) can be disabled (e.g., by shorting the gate and emitter terminals in the case of an IGBT), thereby effectively making the switch redundant without affecting the respective antiparallel diodes. This makes it possible to implement a switching module using, for example, six (or fewer) identical pre-packaged modules, but in the case of a pre-packaged module with disabled controllable semiconductor switches, only the undisabled (or active) controllable semiconductor switches can be switched on and off. Other controllable semiconductor switches are disabled, but current can still flow through their respective antiparallel diodes. Different combinations of pre-packaged modules (e.g., half-bridge and chopper modules) can be used, but they preferably all use the same type of controllable semiconductor switch.

[0053] Implementing H-bridge and active-clamp circuits using MOSFETs minimizes conduction losses. Using IGBTs may be cheaper, but switching modules have higher conduction losses. Both configurations using MOSFETs and IGBTs require a total of six (or fewer) pre-packaged modules.

[0054] Compared to the actual configuration of the known switching module described above, in which each switch in the H-bridge circuit is implemented as a pair of MOSFETs electrically connected in reverse series (i.e., arranged to conduct in opposite directions) and each switch in the active clamp circuit is implemented as an IGBT with an antiparallel diode, implementing the H-bridge and active clamp circuits of the present invention using MOSFETs requires a slight increase in the number of gate drivers, namely 12 instead of 8, since in the known switching module a single gate driver can be used to control the switching of the pair of antiparallel MOSFETs of each switch on and off. The total chip area of ​​each switch remains the same. If the H-bridge and active clamp circuits are implemented using IGBTs with antiparallel diodes (or any other suitable type of controllable semiconductor device), only 8 gate drivers are required. This is also true when the switching module is implemented using six (or fewer) identical pre-packaged modules (e.g., half-bridge modules), and one of the four first and second controllable semiconductor switches of the pre-packaged module is disabled (e.g., by shorting the gate and emitter terminals of the IGBT, if used).

[0055] All controllable semiconductor switches are preferably of the same type (e.g., all MOSFETs or all IGBTs or other suitable fully controllable semiconductor switches) and preferably provided in pre-packaged modules, so they typically have the same voltage and current ratings. In other words, controllable semiconductor switches in active clamp circuits are rated to handle the total current flowing through the H-bridge circuit, although previously these switches had lower ratings. Controllable semiconductor switches in active clamp circuits do not require this high rating for normal operation, i.e., to provide energy recovery during the operation of the switching module, but higher ratings may be useful in certain situations such as fault conditions, high-frequency applications, or dynamic damping (see below) where higher currents may flow through the active clamp circuit.

[0056] The energy storage device may be a capacitor. Any suitable capacitor with any appropriate rating can be used. Alternatively, the energy storage device may be, for example, a battery or other suitable device.

[0057] The first and second AC terminals of the switching module may be electrically connectable to a single coil or to two or more coils electrically connected in series or parallel.

[0058] A switching module may be associated with one or more electronic circuits, such as a control circuit or a gate driver circuit for driving controllable semiconductor switches. These electronic circuits may communicate with a main controller, for example, by an optical fiber link or other galvanically isolated communication channel. The electronic circuits typically require a power supply. In one configuration, power for the electronic circuits may be provided by an energy storage device in the switching module, instead of being supplied by a separate power supply. Thus, the switching module may include a power supply circuit (e.g., a low-voltage power supply circuit) electrically connected in parallel with the energy storage device between first and second DC clamp terminals. The power supply circuit may be electrically connectable to one or more local electronic circuits. The power supply circuit may include a power converter, such as a step-down power converter, for deriving a suitable output voltage from the energy storage device voltage. A suitable power converter may be a DC / DC power converter, such as a forward converter or a flyback converter. The energy storage device can be charged by a DC current source through first and second DC bridge terminals, or by a current induced in coils electrically connected to first and second AC bridge terminals, in the latter case, the induced current flows through one or more semiconductor devices of the H-bridge circuit and clamp circuit. For example, once the energy storage device is charged by performing a pre-charge process, a power supply circuit can be used to provide power to one or more electronic circuits associated with the switching module.

[0059] The switching module may further comprise a battery (or a battery bank comprising multiple electrically connected batteries) electrically connected between the first and second DC clamp terminals in parallel with the energy storage device. By integrating additional energy storage beyond what is required for energy recovery, a distributed energy storage network can be provided for a power electronic switching assembly comprising multiple switching modules. The distributed energy storage network may be used, for example, to black start an electromechanical or other load electrically connected to the switching module by controlling a controllable semiconductor device in an active clamp circuit to discharge the battery or battery bank, or for voltage regulation. The battery voltage and state of charge (SoC) of the battery may be controlled by the active clamp circuit. The active clamp circuit may be designed to match the battery voltage range over an acceptable variation in the battery's SoC. In some situations, the battery may also be used to absorb excess power induced in coils electrically connected to the first and second AC bridge terminals during overspeed conditions of a DC electromechanical machine, which comprises multiple switching modules, each of which is electrically connected to the stator coil of the DC electromechanical machine.

[0060] The switching module may further comprise a dynamic braking system electrically connected in parallel with the energy storage device between the first and second DC clamp terminals. The dynamic braking system may be of any suitable type. For example, the dynamic braking system may comprise a braking resistor and a controllable semiconductor switch electrically connected in series between the first and second DC clamp terminals. The dynamic braking system may also comprise a diode electrically connected in parallel with the braking resistor. The dynamic braking system can be used, for example, to provide short-term power dissipation during overspeed conditions of a DC electromachine.

[0061] The switching module may have one or more power supply circuits, batteries for distributed energy storage, dynamic braking systems, or any other suitable circuits electrically connected in parallel with the energy storage device.

[0062] The present invention A stator having multiple stator coils, Rotor and, DC current source and A power electronic switching assembly comprising the above-mentioned n switching modules, wherein n is an integer of 2 or more. The present invention provides a DC electromachine comprising the following: The first and second AC bridge terminals of each switching module are electrically connected to at least one respective stator coil. The first DC bridge terminal of the first switching module is electrically connected to a DC current source, the second DC bridge terminal of the nth switching module is electrically connected to a DC current source, and the first and second DC bridge terminals of the remaining switching modules are electrically connected in series. For example, the first DC bridge terminal of the first switching module is electrically connected to a DC current source (e.g., its first DC terminal), the second DC bridge terminal of the first switching module is electrically connected to the first DC bridge terminal of the second switching module, the second DC bridge terminal of the second switching module is electrically connected to the first DC bridge terminal of the third switching module, and so on until the second DC bridge terminal of the (n-1) switching module is electrically connected to the first DC bridge terminal of the nth switching module, and so on until the second DC bridge terminal of the nth switching module is electrically connected to a DC current source (e.g., its second DC terminal). In other words, the switching modules may be electrically connected in a series chain link structure between the DC terminals of the DC current source. Two or more sets of switching modules electrically connected in a series chain link structure may be electrically connected in parallel between the DC terminals of the DC current source. The switching modules may also be electrically connected to each other in other ways to define a power electronic switching assembly.

[0063] The stator coils may be housed in slots formed in the stator. The stator coils may be of any suitable type (e.g., single-layer, double-layer, etc.) and may be arranged around the stator to have any suitable winding topology. The rotor rotates relative to the stationary stator and is separated from the stator by an air gap. The rotor may be of any suitable type (e.g., permanent magnet type, or wound rotor type with field windings using slip rings, brushless, etc., with any suitable excitation). The rotor may be a synchronous rotor or an asynchronous / inductive rotor.

[0064] The DC current source may be a power converter, for example, an AC / DC power converter having first and second DC terminals electrically connected to first and nth switching modules of a power electronic switching assembly, and two or more AC terminals electrically connected to an AC circuit or power grid (e.g., a three-phase power grid). The AC / DC power converter may be, for example, a current source inverter or a thyristor converter (6p, 12p, etc.). The DC current source may also be a DC / DC power converter having first and second DC terminals electrically connected to first and nth switching modules of a power electronic switching assembly, and third and fourth DC terminals electrically connected to a DC circuit or a storage device such as a battery. The DC current source may also be another DC electromachine, for example, a generator that provides a DC output voltage.

[0065] Each switching module may further comprise a controller adapted to commutate its respective switching module according to a coil commutation process (i.e., the current flowing through the coil is reversed). Alternatively, one or more controllers may be associated with two or more switching modules, each controller adapted to commutate its respective switching module according to a coil commutation process. The coils of each switching module may be commutated, and each coil commutation process may be interleaved. The stator coils of a DC electromachine may be arranged around the stator to provide multiple phase-shifted coil voltages, typically having multiple phases. For example, a DC electromachine with p phases may include a first group of at least p stator coils, whose EMFs are phase-shifted from each other by 360 / p°, where p is an integer greater than or equal to 2, where one cycle of the stator fundamental frequency occupies 360°, and each EMF crosses zero twice per cycle. A DC electromachine according to the present invention may have any convenient number of stator coils and therefore may have more phases with smaller phase displacements between EMFs. The number of coil commutation events per cycle at the stator fundamental frequency is equal to twice the number of phases, and therefore consecutive coil commutations are interleaved. In the case of DC electromachines with many phases, several overlapping coil commutation events may be progressing in any given time.

[0066] The timing parameters for each coil commutation event can be modified or adjusted to provide closed-loop control of the voltage across the energy storage device in the active clamp circuit of each switching module.

[0067] The present invention also, A transformer assembly comprising multiple first coils, DC current source and A power electronic switching assembly comprising the above-mentioned n switching modules, wherein n is an integer of 2 or more. A power converter is provided, comprising: First and second AC bridge terminals of each switching module electrically connected to the respective first coils of the transformer assembly. The first DC bridge terminal of the first switching module is electrically connected to a DC current source, the second DC bridge terminal of the nth switching module is electrically connected to a DC current source, and the first and second DC bridge terminals of the remaining switching modules are electrically connected in series. For example, the first DC bridge terminal of the first switching module is electrically connected to a DC current source (e.g., its first DC terminal), the second DC bridge terminal of the first switching module is electrically connected to the first DC bridge terminal of the second switching module, the second DC bridge terminal of the second switching module is electrically connected to the first DC bridge terminal of the third switching module, and so on until the second DC bridge terminal of the (n-1) switching module is electrically connected to the first DC bridge terminal of the nth switching module, and so on until the second DC bridge terminal of the nth switching module is electrically connected to a DC current source (e.g., its second DC terminal). In other words, the switching modules may be electrically connected in a series chain link structure between the DC terminals of the DC current source. The switching modules may also be electrically connected to each other in other ways (e.g., in series, parallel, or series-parallel) to define a power electronic switching assembly.

[0068] Each switching module may be electrically connected to its respective first coil by a capacitor.

[0069] Each switching module can function as a DC / AC power converter, generating an output current waveform in each first coil. The output current waveform may have any suitable frequency, for example, approximately 1–10 kHz or higher. This allows for minimizing the size of the transformer assembly and achieving high power density.

[0070] The transformer assembly may further comprise a plurality of second coils, each second coil associated with a first coil (for example, having coupled primary and secondary coils). In other words, the transformer assembly may comprise a plurality of individual transformer units, each transformer unit comprising physically separated, electromagnetically coupled primary and secondary coils. Each second coil may be electrically connected to its respective AC / DC power converter. Any suitable AC / DC power converter can be used. For example, each AC / DC power converter may have two AC terminals electrically connected to its respective second coil and two DC terminals electrically connected to a DC circuit. Alternatively, the second coils may be electrically connected to, for example, a common AC / DC power converter.

[0071] Therefore, the power converter can provide medium-frequency galvanic isolation between the DC current source and the DC circuit. The DC circuit may include one or more energy storage devices, such as capacitors.

[0072] If an AC output voltage is required, this can be derived from a DC circuit using any suitable DC / AC power converter. For example, a DC / AC power converter may have two DC terminals electrically connected to a DC circuit and two or more AC terminals that provide the desired AC output voltage at the desired frequency (e.g., 60Hz).

[0073] Each switching module can also function as a switch-mode converter (e.g., forward or flyback converter, dual active bridge (DAB) converter, Cuk converter, single-ended primary inductor converter (SEPIC), etc.) or a resonant converter.

[0074] The switching modules of a power electronic switching assembly may be bypassed in the event of a failure in the H-bridge or active clamp circuit. A bypass switch (e.g., a mechanical switch or a controllable semiconductor switch) can be electrically connected between the first and second DC bridge terminals of each switching module. The bypass switch is normally switched off (or normally open to prevent current from flowing through the bypass circuit between the first and second DC bridge terminals), but can be selectively switched on (or closed) to bypass the H-bridge circuit. This allows the power electronic switching assembly to continue operating, possibly at a slightly reduced rating, if one or more switching modules fail and need to be bypassed. [Brief explanation of the drawing]

[0075] [Figure 1] This is a schematic circuit diagram showing a known switching module. [Figure 2] This is a schematic circuit diagram showing a first switching module according to the present invention. [Figure 3A] Figure 2 is a schematic circuit diagram of the first switching module. [Figure 3B] Figure 2 is a schematic circuit diagram of the first switching module. [Figure 3C] Figure 2 is a schematic diagram of a pre-packaged module that can be used to implement the first switching module shown in Figure 2. [Figure 4A] This is a schematic circuit diagram of the second switching module. [Figure 4B] This is a schematic circuit diagram of the second switching module. [Figure 4C] These are schematic circuit diagrams of pre-packaged modules that can be used to implement the second switching module shown in Figures 4A and 4B. [Figure 4D]These are schematic circuit diagrams of pre-packaged modules that can be used to implement the second switching module shown in Figures 4A and 4B. [Figure 4E] These are schematic circuit diagrams of pre-packaged modules that can be used to implement the second switching module shown in Figures 4A and 4B. [Figure 4F] These are schematic circuit diagrams of pre-packaged modules that can be used to implement the second switching module shown in Figures 4A and 4B. [Figure 5A] Figures 4A and 4B are schematic circuit diagrams showing the coil commutation process of the second switching module. [Figure 5B] Figures 4A and 4B are schematic circuit diagrams showing the coil commutation process of the second switching module. [Figure 5C] Figures 4A and 4B are schematic circuit diagrams showing the coil commutation process of the second switching module. [Figure 5D] Figures 4A and 4B are schematic circuit diagrams showing the coil commutation process of the second switching module. [Figure 5E] Figures 4A and 4B are schematic circuit diagrams showing the coil commutation process of the second switching module. [Figure 5F] Figures 4A and 4B are schematic circuit diagrams showing the coil commutation process of the second switching module. [Figure 6] Figures 4A and 4B show schematic circuit diagrams of the second switching module, which has a power supply circuit. [Figure 7] Figures 4A and 4B show schematic circuit diagrams of the second switching module, which has a battery for distributed energy storage. [Figure 8] Figures 4A and 4B show schematic circuit diagrams of the second switching module having a dynamic braking system. [Figure 9]This is a schematic circuit diagram of a DC (direct current) electromachine having a power electronic switching assembly with multiple switching modules. [Figure 10] This is a schematic circuit diagram of a power converter having a power electronic switching assembly with multiple switching modules. [Figure 11] Figure 10 shows a schematic circuit diagram of the switching module, transformer unit, and AC / DC power converter of the power converter. [Figure 12] Figures 4A and 4B are schematic circuit diagrams of the second switching module, which has a bypass switch. [Modes for carrying out the invention]

[0076] Referring to Figure 2, the switching module 1 according to the present invention includes an H-bridge circuit 2. The H-bridge circuit 2 is First and second AC bridge terminals AC1 and AC2, which can be electrically connected to each coil 4, First and second DC bridge terminals DC1 and DC2, which can be electrically connected to a DC current source or the DC bridge terminal of another switching module, A first switch assembly electrically connected between a first AC bridge terminal AC1 and a first DC bridge terminal DC1, the first switch assembly comprising a first controllable semiconductor switch S1 and a ninth controllable semiconductor switch S9 electrically connected in series, A second switch assembly electrically connected between a first AC bridge terminal AC1 and a second DC bridge terminal DC2, the second switch assembly comprising a second controllable semiconductor switch S2 and a tenth controllable semiconductor switch S10 electrically connected in series, A third switch assembly electrically connected between a second AC bridge terminal AC2 and a first DC bridge terminal DC1, the third switch assembly comprising a third controllable semiconductor switch S3 and an eleventh controllable semiconductor switch S11 electrically connected in series, A fourth switch assembly electrically connected between a second AC bridge terminal AC2 and a second DC bridge terminal DC2, wherein the fourth switch assembly comprises a fourth controllable semiconductor switch S4 and a twelfth controllable semiconductor switch S12 electrically connected in series. Includes.

[0077] The first and second AC terminals AC1 and AC2 of the switching module 1 are shown to be electrically connected to a single coil 4. However, the switching module 1 may be electrically connected to two or more coils that are electrically connected in series or in parallel.

[0078] Switching module 1 also, The first and second DC clamp terminals DC3, DC4, A first DC clamp terminal DC3 and a fifth controllable semiconductor switch S5 electrically connected between the junction (or connection point) between the first and ninth controllable semiconductor switches S1 and S9, A second DC clamp terminal DC4 and a sixth controllable semiconductor switch S6 electrically connected between the junctions of the second and tenth controllable semiconductor switches S2 and S10, A first DC clamp terminal DC3 and a seventh controllable semiconductor switch S7 electrically connected between the junctions of the third and eleventh controllable semiconductor switches S3 and S11, An eighth controllable semiconductor switch S8 is electrically connected between a second DC clamp terminal DC4 and the junction between the fourth and twelfth controllable semiconductor switches S4 and S12, An energy storage device (i.e., capacitor C) is electrically connected between the first and second DC clamp terminals DC3 and DC4. It includes an active clamp circuit 6 equipped with [the necessary components].

[0079] The junction between the first and second controllable semiconductor switches S1 and S2 defines a first AC bridge terminal AC1, and the junction between the third and fourth controllable semiconductor switches S3 and S4 defines a second AC bridge terminal AC2.

[0080] In the switching module 1 shown in Figure 2, each switch assembly of the H-bridge circuit 2 includes a pair of controllable semiconductor switches (e.g., the first and ninth controllable semiconductor switches S1 and S9). The pair of controllable semiconductor switches in each switch assembly are electrically connected in reverse series (i.e., arranged to conduct in opposite directions). In particular,

[0081] The first and ninth controllable semiconductor switches S1 and S9 are electrically connected in reverse series. The first controllable semiconductor switch S1 is electrically connected to the first AC bridge terminal AC1, and the ninth controllable semiconductor switch S9 is electrically connected to the first DC bridge terminal DC1.

[0082] The second and tenth controllable semiconductor switches S2 and S10 are electrically connected in reverse series. The second controllable semiconductor switch S2 is electrically connected to the first AC bridge terminal AC1, and the tenth controllable semiconductor switch S10 is electrically connected to the second DC bridge terminal DC2.

[0083] The third and eleventh controllable semiconductor switches S3 and S11 are electrically connected in reverse series. The third controllable semiconductor switch S3 is electrically connected to the second AC bridge terminal AC2, and the eleventh controllable semiconductor switch S11 is electrically connected to the first DC bridge terminal DC1.

[0084] The fourth and twelfth controllable semiconductor switches S4 and S12 are electrically connected in reverse series. The fourth controllable semiconductor switch S4 is electrically connected to the second AC bridge terminal AC2, and the twelfth controllable semiconductor switch S12 is electrically connected to the second DC bridge terminal DC2.

[0085] All controllable semiconductor switches S1, S2, ..., S12 in switching module 1 are of the same type and have the same ratings. In switching module 1 shown in Figure 2, all controllable semiconductor switches S1, S2, ..., S12 are MOSFETs. Each MOSFET includes a body diode as part of its MOSFET structure. It will be understood that other controllable semiconductor switches can also be used as needed.

[0086] The first and ninth controllable semiconductor switches S1 and S9 are electrically connected in reverse series in a common drain configuration. The second and tenth controllable semiconductor switches S2 and S10 are electrically connected in reverse series in a common source configuration. The third and eleventh controllable semiconductor switches S3 and S11 are electrically connected in reverse series in a common drain configuration. The fourth and twelfth controllable semiconductor switches S4 and S12 are electrically connected in reverse series in a common source configuration.

[0087] The same switching module 1 is shown in Figure 3A.

[0088] Referring to Figure 3B, the first and second controllable semiconductor switches S1 and S2 are of the same type and are implemented as a first pre-packaged module M1 in which the first and second controllable semiconductor switches S1 and S2 are arranged to conduct in the same direction. In other words, the first and second controllable semiconductor switches S1 and S2 are implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0089] The third and fourth controllable semiconductor switches S3 and S4 are of the same type and are implemented as a second pre-packaged module M2 in which the third and fourth controllable semiconductor switches S3 and S4 are arranged to conduct in the same direction. In other words, the third and fourth controllable semiconductor switches S3 and S4 are implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0090] The fifth and ninth controllable semiconductor switches S5 and S9 are of the same type and are implemented as a third pre-packaged module M3 in which the fifth and ninth controllable semiconductor switches S5 and S9 are arranged to conduct in the same direction. In other words, despite the fact that the fifth and ninth controllable semiconductor switches S5 and S9 are used in the active clamp circuit 6 and the H bridge circuit 2 respectively, they are implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0091] The sixth and tenth controllable semiconductor switches S6 and S10 are of the same type and are implemented as a fourth pre-packaged module M4 in which the sixth and tenth controllable semiconductor switches S6 and S10 are arranged to conduct in the same direction. In other words, despite the fact that the sixth and tenth controllable semiconductor switches S6 and S10 are used in the active clamp circuit 6 and the H bridge circuit 2 respectively, they are implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0092] The seventh and eleventh controllable semiconductor switches S7 and S11 are of the same type and are implemented as a fifth pre-packaged module M5, in which the seventh and eleventh controllable semiconductor switches S7 and S11 are arranged to conduct in the same direction. In other words, despite the fact that the seventh and eleventh controllable semiconductor switches S7 and S11 are used in the active clamp circuit 6 and the H-bridge circuit 2 respectively, they are implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0093] The eighth and twelfth controllable semiconductor switches S8 and S12 are of the same type and are implemented as a sixth pre-packaged module M6, which is arranged so that the eighth and twelfth controllable semiconductor switches S8 and S12 conduct in the same direction. In other words, despite the fact that the eighth and twelfth controllable semiconductor switches S8 and S12 are used in the active clamp circuit 6 and the H-bridge circuit 2 respectively, they are implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0094] In this configuration, six conventional or "off-the-shelf" pre-packaged modules M1, M2, ..., M6 are required to implement the switching module. The pre-packaged modules M1, M2, ..., M6 may be, for example, half-bridge modules. An example of a half-bridge module having a pair of MOSFETs electrically connected in series and arranged to conduct in the same direction is shown in Figure 3C. As described above, if each pre-packaged module has two or more pairs of controllable semiconductors defining two or more legs whose leg terminals are not electrically connected to each other (e.g., DC terminals are not connected to each other), the switching module may be implemented using fewer pre-packaged modules. This makes it possible to implement multiple pairs of controllable semiconductor switches of the switching module in the same pre-packaged module.

[0095] Referring to Figure 4A, the alternative switching module 10 according to the present invention includes an H-bridge circuit 12. The H-bridge circuit 12 is First and second AC bridge terminals AC1 and AC2, which can be electrically connected to each coil 14, First and second DC bridge terminals DC1 and DC2, which can be electrically connected to a DC current source or the DC bridge terminal of another switching module, A first switch assembly electrically connected between a first AC bridge terminal AC1 and a first DC bridge terminal DC1, the first switch assembly comprising a first controllable semiconductor switch S1 and a first diode D1 electrically connected in series, A second switch assembly electrically connected between a first AC bridge terminal AC1 and a second DC bridge terminal DC2, the second switch assembly comprising a second controllable semiconductor switch S2 and a second diode D2 electrically connected in series, A third switch assembly electrically connected between a second AC bridge terminal AC2 and a first DC bridge terminal DC1, the third switch assembly comprising a third controllable semiconductor switch S3 and a third diode D3 electrically connected in series, A fourth switch assembly electrically connected between a second AC bridge terminal AC2 and a second DC bridge terminal DC2, the fourth switch assembly comprising a fourth controllable semiconductor switch S4 and a fourth diode D4 electrically connected in series Includes.

[0096] The first and second AC terminals AC1 and AC2 of the switching module 10 are shown to be electrically connected to a single coil 14. However, the switching module 10 may be electrically connected to two or more coils that are electrically connected in series or in parallel.

[0097] The switching module 10 also, The first and second DC clamp terminals DC3, DC4, A first DC clamp terminal DC3 and a fifth controllable semiconductor switch S5 electrically connected between the junction (or connection point) between the first controllable semiconductor switch S1 and the first diode D1, A second DC clamp terminal DC4 and a sixth controllable semiconductor switch S6 electrically connected between the junction between the second controllable semiconductor switch S2 and the second diode D2, A first DC clamp terminal DC3 and a seventh controllable semiconductor switch S7 electrically connected between the junction between the third controllable semiconductor switch S3 and the third diode D3, A second DC clamp terminal DC4 and an eighth controllable semiconductor switch S8 electrically connected between the junction between the fourth controllable semiconductor switch S4 and the fourth diode D4, An energy storage device (i.e., capacitor C) is electrically connected between the first and second DC clamp terminals DC3 and DC4. Includes an active clamp circuit 16 equipped with

[0098] The junction between the first and second controllable semiconductor switches S1 and S2 defines a first AC bridge terminal AC1, and the junction between the third and fourth controllable semiconductor switches S3 and S4 defines a second AC bridge terminal AC2.

[0099] The first controllable semiconductor switch S1 and the first diode D1 are electrically connected in series and arranged to conduct in the same direction. The first controllable semiconductor switch S1 is electrically connected to the first AC bridge terminal AC1, and the first diode D1 is electrically connected to the first DC bridge terminal DC1.

[0100] The second controllable semiconductor switch S2 and the second diode D2 are electrically connected in series and arranged to conduct in the same direction. The second controllable semiconductor switch S2 is electrically connected to the first AC bridge terminal AC1, and the second diode D2 is electrically connected to the second DC bridge terminal DC2.

[0101] The third controllable semiconductor switch S3 and the third diode D3 are electrically connected in series and arranged to conduct in the same direction. The third controllable semiconductor switch S3 is electrically connected to the second AC bridge terminal AC2, and the third diode D3 is electrically connected to the first DC bridge terminal DC1.

[0102] The fourth controllable semiconductor switch S4 and the fourth diode D4 are electrically connected in series and arranged to conduct in the same direction. The fourth controllable semiconductor switch S4 is electrically connected to the second AC bridge terminal AC2, and the fourth diode D4 is electrically connected to the second DC bridge terminal DC2.

[0103] All of the controllable semiconductor switches S1, S2, ..., S8 in the switching module are of the same type and have the same ratings. In the switching module 10 shown in Figure 4A, all of the controllable semiconductor switches S1, S2, ..., S8 are IGBTs. Each IGBT is associated with an antiparallel diode (i.e., diodes D1a, D2a, ..., D8a). It will be understood that other controllable semiconductor switches can also be used.

[0104] Referring to Figure 4B, the first and second controllable semiconductor switches S1 and S2 are of the same type and are implemented as a first pre-packaged module M1 in which the first and second controllable semiconductor switches S1 and S2 are arranged to conduct in the same direction. In other words, the first and second controllable semiconductor switches S1 and S2 are implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0105] The third and fourth controllable semiconductor switches S3 and S4 are of the same type and are implemented as a second pre-packaged module M2 in which the third and fourth controllable semiconductor switches S3 and S4 are arranged to conduct in the same direction. In other words, the third and fourth controllable semiconductor switches S3 and S4 are implemented using a pair of controllable semiconductor switches packaged together in a conventional pre-packaged module.

[0106] The fifth controllable semiconductor switch S5 and the first diode D1 are implemented as a third pre-packaged module M3 in which the fifth controllable semiconductor switch S5 and the first diode D1 are electrically connected in reverse series, i.e., arranged to conduct in opposite directions. In other words, despite the fact that the fifth controllable semiconductor switch S5 and the first diode D1 are used in the active clamp circuit 16 and the H bridge circuit 12, respectively, they are implemented using controllable semiconductor switches and diodes packaged together in a conventional pre-packaged module.

[0107] The sixth controllable semiconductor switch S6 and the second diode D2 are implemented as a fourth pre-packaged module M4, in which the sixth controllable semiconductor switch S6 and the second diode D2 are electrically connected in reverse series, i.e., arranged to conduct in opposite directions. In other words, despite the fact that the sixth controllable semiconductor switch S6 and the second diode D2 are used in the active clamp circuit 16 and the H-bridge circuit 12, respectively, they are implemented using controllable semiconductor switches and diodes packaged together in a conventional pre-packaged module.

[0108] The seventh controllable semiconductor switch S7 and the third diode D3 are implemented as a fifth pre-packaged module M5, in which the seventh controllable semiconductor switch S7 and the third diode D3 are electrically connected in reverse series, i.e., arranged to conduct in opposite directions. In other words, despite the fact that the seventh controllable semiconductor switch S7 and the third diode D3 are used in the active clamp circuit 16 and the H-bridge circuit 12, respectively, they are implemented using controllable semiconductor switches and diodes packaged together in a conventional pre-packaged module.

[0109] The eighth controllable semiconductor switch S8 and the fourth diode D4 are implemented as a sixth pre-packaged module M6, in which the eighth controllable semiconductor switch S8 and the fourth diode D4 are electrically connected in reverse series, i.e., arranged to conduct in opposite directions. In other words, the eighth controllable semiconductor switch S8 and the fourth diode D4 are implemented using controllable semiconductor switches and diodes packaged together in a conventional pre-packaged module, despite the fact that they are used in the active clamp circuit 16 and the H-bridge circuit 12, respectively.

[0110] In this configuration, six conventional or "off-the-shelf" pre-packaged modules are required to implement the switching module. The first and second pre-packaged modules M1, M2 may be, for example, half-bridge modules. An example of a half-bridge module having a pair of IGBTs and antiparallel diodes electrically connected in series and arranged to conduct in the same direction is shown in Figure 4C. Alternatively, as described above, the first, second, third, and fourth controllable switches S1, S2, ..., S4 may be implemented using a single pre-packaged module having two pairs of controllable semiconductors defining two legs whose leg terminals are not electrically connected to each other (e.g., the DC terminals are not connected to each other). The third, fourth, fifth, and sixth pre-packaged modules M3, M4, ..., M6 may be chopper modules, each chopper module comprising a controllable semiconductor switch (e.g., an IGBT and an antiparallel diode) electrically connected in anti-series with a diode. An example of a chopper module having an IGBT and an antiparallel diode electrically connected in anti-series with a diode is shown in Figures 4D and 4E. The IGBT and diode are arranged to conduct in opposite directions. The third and fifth pre-packaged modules M3 and M5 may be implemented using the chopper module shown in Figure 4D, and the fourth and sixth pre-packaged modules M4 and M6 may be implemented using the chopper module shown in Figure 4E.

[0111] The third, fourth, fifth, and sixth pre-packaged modules M3, M4, ..., M6 may also be half-bridge modules, as shown in Figure 4C, but one of the pair of IGBTs can be disabled, thereby making its switching redundant without affecting its respective antiparallel diode. This is shown in Figure 4F, where one of the IGBTs is ghosted to indicate redundancy. The gate and emitter terminals of the ghosted IGBT can be seen to be shorted. This makes it possible to implement the switching module 10 using six (or fewer) identical pre-packaged half-bridge modules, where, for the third, fourth, fifth, and sixth pre-packaged modules M3, M4, ..., M6, only one of the IGBTs can be switched on and off. The other IGBT is disabled, but current can still flow through its respective antiparallel diode.

[0112] As shown in Figures 2 and 3A-3C, implementing H-bridge and active-clamp circuits using MOSFETs minimizes conduction losses. Using IGBTs, as shown in Figures 4A-4F, may be less expensive, but switching modules have higher conduction losses. Both configurations using MOSFETs or IGBTs require a total of six (or fewer) pre-packaged modules M1, M2, ..., M6.

[0113] The following description refers to a switching module 10 that uses IGBTs, but it should be understood that other types of controllable semiconductor switches, such as MOSFETs shown in Figures 2 and 3A-3B, may also be used.

[0114] The coil commutation process of the switching module 10, which is implemented using IGBTs, will be explained with reference to Figures 5A to 5F.

[0115] In the first phase shown in Figure 5A, I coil =+I dc And Icoil is the coil current, and I dc is a DC current supplied by a DC current source, for example, the DC current source 56 described later. The first and fourth controllable semiconductor switches S1, S4 are switched on. All other controllable semiconductor switches are switched off. Current flows through the coil 14 in the direction indicated by the arrow in FIG. 5A, that is, from the first DC bridge terminal DC1 through the first diode D1, the first controllable semiconductor switch S1, the coil 14, the fourth controllable semiconductor switch S4, and the fourth diode D4 to the second DC bridge terminal DC2.

[0116] In the second phase shown in FIG. 5B, the first and fourth controllable semiconductor switches S1, S4 remain on. The second, third, sixth, and seventh controllable semiconductor switches S2, S3, S6, and S7 are switched on. This imposes a negative voltage across the coil 14. V coil =-V clamp , and V coil is the coil voltage, and V clamp is the DC voltage across capacitor C of the active clamp circuit 16 (i.e., the capacitor voltage). The coil current starts to decrease and capacitor C discharges. When the coil current reaches a threshold value (e.g., I coil =+I dc / 2), the process transitions to the third phase shown in FIG. 5C.

[0117] In the third phase, the first controllable semiconductor switch S1 is switched off. The second, third, fourth, sixth, and seventh controllable semiconductor switches S2, S3, S4, S6, and S7 remain on. This maintains the negative voltage across the coil 14. The coil current continues to decrease and approaches zero. Capacitor C is charged. When the coil current reaches zero, the process transitions to the fourth phase shown in FIG. 5D.

[0118] In the fourth phase, the second, third, fourth, sixth, and seventh controllable semiconductor switches S2, S3, S4, S6, and S7 remain on. This maintains a negative voltage across coil 14. The coil current, which is currently negative, continues to become more negative. Capacitor C discharges. The coil current reaches a threshold (e.g., I coil =-I dc When it reaches (2), the process moves to the fifth phase shown in Figure 5E.

[0119] In the fifth phase, the fourth controllable semiconductor switch S4 is switched off. The second, third, sixth, and seventh controllable semiconductor switches S2, S3, S6, and S7 remain on. This maintains a negative voltage across coil 14. The coil current continues to become more negative, -I dc It approaches. Capacitor C charges. The coil current is -I dc When this is reached, the process transitions to the sixth phase shown in Figure 5F. The sixth and seventh switches S6, S7 may remain on until the end of the fifth phase, but they may be switched off during the fifth phase because their antiparallel diodes D6a, D7a carry current. The advantage of switching the sixth and seventh switches S6, S7 off during the fifth phase is that the coil current is -I dc When it reaches this point, the fifth phase automatically ends, and if the switch remains on, the coil current is -I dc If it exceeds this limit, there is a risk that the coil current may overshoot.

[0120] In the sixth phase, I coil =-I dc (That is, the coil current is +I dc kara-I dc (The current is being commutated to the other side), and the second and third semiconductor switches S2 and S3 remain ON.

[0121] The net charge to or from capacitor C during the coil commutation process is determined by the duration of each of the second to fifth phases. These total durations remain the same for a given clamp voltage, DC current, and coil inductance. However, the timing of the transitions between the second and third phases, and between the fourth and fifth phases, determines the change in net capacitor charge, and therefore capacitor voltage. For example, if the third and fifth phases are equal in length due to shorter second and fourth phases, a net charge will exist on capacitor C, and the capacitor voltage at the end of the coil commutation process will be greater than at the beginning. Phase durations can be adjusted, for example, by adjusting the coil current threshold that triggers the end of each phase.

[0122] Although not shown in the diagram, the coil current is reduced to -I using the corresponding coil commutation process. dc From +I dc It can be commutated to. In particular, in the first phase, I coil =-I dc The second and third controllable semiconductor switches S2 and S3 are switched on. All other controllable semiconductor switches are switched off. Current flows from the first DC bridge terminal DC1 through the third diode D3, the third controllable semiconductor switch S3, the coil 14, the second controllable semiconductor switch S2, and the second diode D2 to the second DC bridge terminal DC2, through the coil 14.

[0123] In the second phase, the second and third controllable semiconductor switches S2 and S3 remain on. The first, fourth, fifth, and eighth controllable semiconductor switches S1, S4, S5, and S8 are switched on. This applies a positive voltage across coil 14. coil =+V clamp The coil current starts as a small negative value, and the capacitor C discharges. When the coil current reaches a threshold (for example, I coil =-I dc When it reaches (2), the process moves to the third phase.

[0124] In the third phase, the third controllable semiconductor switch S3 is switched off. The first, second, fourth, fifth, and eighth controllable semiconductor switches S1, S2, S4, S5, and S8 remain on. This maintains a positive voltage across coil 14. The coil current continues to decrease in negative value, approaching zero. Capacitor C charges. When the coil current reaches zero, the process transitions to the fourth phase.

[0125] In the fourth phase, the first, second, fourth, fifth, and eighth controllable semiconductor switches S1, S2, S4, S5, and S8 remain on. This maintains a positive voltage across coil 14. The coil current, which is now positive, continues to increase. Capacitor C discharges. When the coil current reaches a threshold (e.g., I coil =+I dc When it reaches (2), the process moves to the fifth phase.

[0126] In the fifth phase, the second controllable semiconductor switch S2 is switched off. The first, fourth, fifth, and eighth controllable semiconductor switches S1, S4, S5, and S8 remain on. This maintains a positive voltage across coil 14. The coil current continues to increase, +I dc It approaches. Capacitor C charges. The coil current is +I dc When this is reached, the process moves to the sixth phase. The fifth and eighth switches S5, S8 may remain on until the end of the fifth phase, but they may be switched off during the fifth phase because their antiparallel diodes D5a, D8a carry current. The advantage of switching the fifth and eighth switches S5, S8 off during the fifth phase is that the coil current is +I dc When it reaches this point, the fifth phase automatically ends, and if the switch remains on, the coil current is +I dc If it exceeds this limit, there is a risk that the coil current may overshoot.

[0127] In the sixth phase, Icoil =+I dc (That is, the coil current is -I dc From +I dc (The current is being commutated to the first and fourth semiconductor switches S1 and S4 remain ON.)

[0128] If the switching module 10 is implemented using MOSFETs, the MOSFETs may need to be switched off just before current stops flowing through their respective antiparallel diodes and switched on just after current begins flowing through their respective antiparallel diodes. In other words, a dead time must typically be added to the coil commutation process to avoid short-circuiting the capacitor C of the active clamp circuit 16. For example, in the third phase shown in Figure 5C, which is implemented using MOSFETs instead of IGBTs, the ninth controllable semiconductor switch S9 must be switched off just before the first controllable semiconductor switch S1 is switched off. When the first controllable semiconductor switch S1 is switched off, the body diode of the eleventh controllable semiconductor switch S11 is switched on. Thus, the eleventh controllable semiconductor switch S11 is switched on immediately after the first controllable semiconductor switch S1 is switched off.

[0129] The switching module 10 may be associated with one or more electronic circuits, such as a control circuit or a gate driver circuit for driving a controllable semiconductor switch. The electronic circuits may communicate with a main controller, for example, by an optical fiber link or other galvanically isolated communication channel. The electronic circuits typically require a power supply. In one configuration, power for the electronic circuits may be provided by a capacitor C in the switching module 10, instead of being supplied by a separate power supply. Thus, referring to Figure 6, the switching module 10 may include a power supply circuit 18 (e.g., a low-voltage power supply circuit) electrically connected in parallel with the capacitor C between the first and second DC clamp terminals DC3, DC4. The power supply circuit 18 is electrically connectable to one or more local electronic circuits 20, 22. The power supply circuit may be a power converter, such as a step-down power converter, for deriving a suitable output voltage from the capacitor voltage. A suitable power converter may be a DC / DC power converter, such as a forward converter or a flyback converter. Capacitor C can be charged by a DC current source through the first and second DC bridge terminals DC1 and DC2, or by a current induced in coil 14 electrically connected to the first and second AC bridge terminals AC1 and AC2. In the latter case, the induced current flows through one or more semiconductor devices of the H-bridge circuit 12 and the active clamp circuit 16. For example, once capacitor C is charged by performing a pre-charge process, power can be supplied to one or more electronic circuits 20, 22 associated with the switching module 10 using the power supply circuit 18.

[0130] Referring to Figure 7, the switching module 10 may further include a battery 24 (or a battery bank with multiple electrically connected batteries) electrically connected in parallel with the capacitor C between the first and second DC clamp terminals DC3, DC4. By integrating additional energy storage beyond what is required for energy recovery, a distributed energy storage network can be provided for a power electronic switching assembly with multiple electrically connected switching modules. The battery voltage and state of charge (SoC) of the battery 24 can be controlled by an active clamp circuit 16. The active clamp circuit 16 may be designed to match the battery voltage range over an acceptable variation in the SoC of the battery 24. In some situations, the battery 24 may also be used to absorb excess power induced in coils 14 electrically connected to the first and second AC bridge terminals AC1, AC2 during overspeed conditions of a DC electromachine, for example, which includes multiple switching modules, each of which is electrically connected to the stator coil of the DC electromachine. An example of a DC electromachine is described below with reference to Figure 9.

[0131] Referring to Figure 8, the switching module 10 may further include a dynamic braking system 26 electrically connected in parallel with the capacitor C between the first and second DC clamp terminals DC3 and DC4. The dynamic braking system 26 may be of any suitable type. For example, as shown in Figure 8, the dynamic braking system 26 includes a braking resistor 28 and a controllable semiconductor switch 30 electrically connected in series between the first and second DC clamp terminals DC3 and DC4. The dynamic braking system 26 also includes a diode 32 electrically connected in parallel with the braking resistor 28. The dynamic braking system 26 can be used, for example, to provide short-term power dissipation during overspeed conditions of a DC electromachine.

[0132] Referring to Figure 9, the DC electric machine 50 is, Multiple stator coils 541, 542, ..., 54 nA statator 52 having n is an integer of 2 or more, A rotor (not shown) and DC current source 56, Power electronic switching assembly 58 and Includes.

[0133] The power electronic switching assembly 58 has n switching modules 101, 102, ..., 10 as described above. n It will be understood that the power electronic switching assembly 58 may also be implemented using the switching modules shown in Figures 2, 3A, and 3B, in which the controllable semiconductor switch is a MOSFET, or the switching modules shown in Figures 4A and 4B, in which the controllable semiconductor switch is an IGBT. Switching modules implemented using other types of controllable semiconductor switches can also be used.

[0134] Each switching module 101, 102, ..., 10 n The first and second AC bridge terminals AC1 and AC2 are connected to the respective stator coils 541, 542, ..., 54 n The first DC bridge terminal DC1 of the first switching module 101 is electrically connected to the first DC terminal 60 of the DC current source 56, and the nth switching module 10 n The second DC bridge terminal DC2 of the first switching module is electrically connected to the second DC terminal 62 of the DC current source 56, and the first and second DC bridge terminals DC1 and DC2 of the remaining switching modules are electrically connected in series. For example, the second DC bridge terminal DC2 of the first switching module 101 is electrically connected to the first DC bridge terminal DC1 of the second switching module 102, the second DC bridge terminal DC2 of the second switching module 102 is electrically connected to the first DC bridge terminal of the third switching module, and so on for the (n-1) switching module 10 (n-1) The second DC bridge terminal DC2 is connected to the nth switching module 10n This continues until it is electrically connected to the first DC bridge terminal DC1. In other words, switching modules 101, 102, ..., 10 n These may be electrically connected in a series chain link structure between the first and second DC terminals 60 and 62 of the DC current source 56, as shown in Figure 9.

[0135] Figure 9 also shows the first set of switching modules 101, 102, ..., 10 n The diagram shows a second set of switching modules connected in parallel to the first set of switching modules in a series chain link structure between the first and second DC terminals of the DC current source 56. In practice, three or more sets of switching modules connected in a series chain link structure may be electrically connected in parallel between the first and second DC terminals of the DC current source 56.

[0136] Stator coils 541, 542, ..., 54 n These may be housed in slots formed in the stator 52. Stator coils 541, 542, ..., 54 n The rotor may be of any suitable type (e.g., single-layer, double-layer, etc.) and may be arranged around the stator to have any suitable winding topology. The rotor (not shown) rotates relative to the stationary stator 52 and is separated from the stator 52 by an air gap. As described above, the rotor (not shown) can have any suitable structure.

[0137] The DC current source 56 shown in Figure 9 is a power converter, for example, the first and nth switching modules 101, 10 of the power electronic switching assembly 58. nThis is an AC / DC power converter having first and second DC terminals 60, 62 electrically connected to and three AC terminals 64 electrically connected to an AC circuit or power grid (e.g., a three-phase power grid). Although not shown, the DC current source may also be another DC electromachine, such as a generator that provides a DC output voltage. The DC electromachine 50 can operate as a motor or a generator. In particular, power is supplied from the DC current source 56 to switching modules 101, 102, ..., 10 n It can supply power to drive the rotor (not shown), or the rotor can be rotationally driven (for example, by a prime mover), and power can be supplied to the stator coils 541, 542, ..., 54 n Generated by switching modules 101, 102, ..., 10 n This can be used to supply DC current to the DC current source 56. Other DC current sources can also be used.

[0138] Each switching module 101, 102, ..., 10 n This is the coil commutation process (i.e., when the DC electromachine 50 is operating, the stator coils 541, 542, ..., 54 n The system may further include controllers (not shown) adapted to commutate each switching module according to the repeated reversal of the current flowing through them. Alternatively, one or more controllers may be associated with two or more switching modules, each controller adapted to commutate the switching modules according to its respective coil commutation process. Each switching module 101, 102, ..., 10 n Stator coils 541, 542, ..., 54 n The coils may be commutated, and each coil commutation process may be interleaved. Stator coils 541, 542, ..., 54 of DC electromachine 50 nThese may be arranged around the stator 52 to provide multiple phase-shifted coil voltages, typically having multiple phases. For example, a DC electromachine 50 having p phases may include a first group of at least p stator coils, whose EMFs are phase-shifted from each other by 360 / p°, where p is an integer greater than or equal to 2, where one cycle of the stator fundamental frequency occupies 360°, and each EMF crosses zero twice per cycle. The DC electromachine 50 may have any convenient number of stator coils (i.e., n may be any suitable number), and therefore may have more phases with smaller phase shifts between EMFs. The number of coil commutation events per cycle of the stator fundamental frequency is equal to twice the number of phases, and therefore consecutive coil commutations are interleaved. Several overlapping coil commutation events may be progressing in any given time.

[0139] The timing parameters for each coil commutation event are determined by the respective switching modules 101, 102, ..., 10 n The active clamp circuit 16 can be modified or adjusted to provide closed-loop control of the voltage across capacitor C.

[0140] Referring to Figures 10 and 11, the power converter 70 is Multiple first coils 741, 742, ..., 74 n and several second coils 761, 762, ..., 76 n A transformer assembly 72 having, DC current source 78 and Power electronic switching assembly 80 and Includes.

[0141] The power electronic switching assembly 80 has n switching modules 101, 102, ..., 10 as described above. nIt will be understood that the power electronic switching assembly 80 may also be implemented using the switching modules shown in Figures 2, 3A, and 3B, in which the controllable semiconductor switch is a MOSFET, or the switching modules shown in Figures 4A and 4B, in which the controllable semiconductor switch is an IGBT. Switching modules implemented using other types of controllable semiconductor switches can also be used. Figure 11 shows a switching module implemented using a MOSFET as an example.

[0142] Each switching module 101, 102, ..., 10 n The first and second AC bridge terminals AC1 and AC2 are connected to the first coils 741, 742, and 74 of the transformer assembly 72, respectively. n It is electrically connected to the first AC terminal AC1 of the switching module 101 and the first coils 741 of each of the optional series capacitors SC. The first DC bridge terminal DC1 of the first switching module 101 is electrically connected to the first DC terminal 82 of the DC current source and to the nth switching module 10 n The second DC bridge terminal DC2 of the first switching module 101 is electrically connectable to the second DC terminal 84 of the DC current source 78, and the first and second DC bridge terminals DC1 and DC2 of the remaining switching modules are electrically connected in series. For example, the second DC bridge terminal DC2 of the first switching module 101 is electrically connected to the first DC bridge terminal DC1 of the second switching module 102, the second DC bridge terminal DC2 of the second switching module 102 is electrically connected to the first DC bridge terminal DC1 of the third switching module, and so on, until the second DC bridge terminal DC2 of the (n-1) switching module is connected to the nth switching module 10 n This continues until it is electrically connected to the first DC bridge terminal DC1. In other words, switching modules 101, 102, ..., 10 nThese may be electrically connected in a series chain link structure between the first and second DC terminals 82 and 84 of the DC current source 78, as shown in Figure 10.

[0143] Each switching module 101, 102, ..., 10 n The output current waveform is for each of the first coils 741, 742, ..., 74 n It can function as a DC / AC power converter. For example, to generate a positive voltage in each of the first coils, the first, fourth, fifth, and eighth controllable semiconductor switches S1, S4, S5, and S8 of the switching module can be switched on, and the remaining controllable semiconductor switches can be switched off. To generate a negative voltage in each of the first coils, the second, third, sixth, and seventh controllable semiconductor switches S2, S3, S6, and S7 of the switching module can be switched on, and the remaining controllable semiconductor switches can be switched off. The output current waveform may have any suitable frequency, for example, about 1 to 10 kHz or higher. This makes it possible to minimize the size of the transformer assembly 72 and achieve high power density.

[0144] More specifically, the first, fourth, fifth, and eighth controllable semiconductor switches S1, S4, S5, and S8 can be switched on to generate a positive voltage across each of the first coils. In this state, one of the second and third controllable semiconductor switches S2, S3 may be switched on to short-circuit the DC current source (State A). If neither of the second and third controllable semiconductor switches S2, S3 is switched on (State B), the voltage across the DC current source is equal to the clamp voltage.

[0145] The second, third, sixth, and seventh controllable semiconductor switches S2, S3, S6, and S7 can be switched on to generate a negative voltage across each of the first coils. In this state, either the first or fourth controllable semiconductor switch S1 or S4 may be switched on to short-circuit the DC current source (State C). If neither the first nor fourth controllable switches S1 or S4 are switched on (State D), the voltage across the DC current source is equal to the clamp voltage.

[0146] Therefore, the voltage in the DC current source is a square wave with an amplitude equal to the clamp voltage. The average voltage is set by the duty cycles of states A and B, and states C and D. The applied switching pattern, including the 9th, 10th, 11th, and 12th controllable semiconductor switches S9, S10, ..., S12, can be optimally selected to minimize the number of switching events and regulate the power from the DC current source to the circuit by controlling the average DC input voltage.

[0147] Each of the second coils 761, 762, ..., 76 n These are the respective AC / DC power converters 861, 862, ..., 86 n It is electrically connected to. Any suitable AC / DC power converter can be used. For example, as shown in Figure 10, each AC / DC power converter 861, 862, ..., 86 n These are the second coils 761, 762, ..., 76 n It has two AC terminals electrically connected to the DC circuit 88 and two DC terminals electrically connected to the DC circuit 88. The DC circuit 88 includes a capacitor 90. AC / DC power converters 861, 862, ..., 86 n Other configurations may be used, and they may be electrically connected in different ways; for example, AC / DC power converters may be electrically connected in series, parallel, or series-parallel.

[0148] If an AC output voltage is required, this can be derived from the DC circuit 88 using any suitable DC / AC power converter 92. For example, as shown in Figure 10, the DC / AC power converter 92 has two DC terminals 94, 96 electrically connected to the DC circuit 88 and three AC terminals 98 that provide the desired AC output voltage at the desired frequency (e.g., 60 Hz).

[0149] Switching modules 101, 102, ..., 10 of a power electronic switching assembly (for example, power electronic switching assembly 58 shown in Figure 9, or power electronic switching assembly 80 shown in Figure 10) n The H-bridge or active clamp circuit may be bypassed in the event of a failure. Referring to Figure 12, a bypass switch Q1 (e.g., a mechanical switch or a controllable semiconductor switch) can be electrically connected between the first and second DC bridge terminals DC1, DC2 of each switching module 10. The bypass switch Q1 is normally switched off (or normally open to prevent current from flowing through the bypass circuit between the first and second DC bridge terminals), but can be selectively switched on (or closed) to bypass the H-bridge circuit 12. This allows the power electronic switching assembly to continue operating, possibly at a slightly reduced rating, if one or more switching modules fail and need to be bypassed. Instead of applying a direct short circuit across the first and second DC bridge terminals DC1, DC2, the bypass switch Q1 may also be electrically connected in series with an energy absorption device (not shown), such as a varistor or capacitor. This may be beneficial in certain applications where a direct short circuit is undesirable. [Explanation of Symbols]

[0150] 1 Switching module 2 H-bridge circuit 4 coils 6 Active clamp rotations 10 Alternative switching modules 14 coils 18 Power supply circuit 20 Local Electronic Circuits 22 Local Electronic Circuits 24 batteries 26 Dynamic braking system 28 Braking resistor 30 controllable semiconductor switches 32 diodes 50 DC Electrical Machinery 56 DC current source 58 Power Electronic Switching Assembly 60 First DC terminal 62 Second DC terminal 64 AC terminal 70 Power Converters 72 Transformer Assembly 78 DC current source 80 Power Electronic Switching Assembly 82 First DC terminal 84 Second DC terminal 88 DC circuit 90 Capacitors 92 DC / AC Power Converters 94 DC terminal 96 DC terminal 98 AC terminal 100 Switching Modules 102 H-bridge circuit 104 coils 106 Active clamp circuit 101 First Switching Module 102 Second switching module 10 (n-1) The (n-1)th switching module 10 n The nth switching module 541 Stator Coil 542 Stator Coil 54 (n-1) Stator coil 54 n Stator coil 741 First coil 742 First coil 74 n First coil 761 Second coil 762 Second coil 76 n Second coil 861 AC / DC Power Converter 862 AC / DC Power Converter 86 n AC / DC Power Converter C Capacitor / Energy Storage Device D1 First diode / first semiconductor device D2 Second diode / second semiconductor device D3 Third diode / third semiconductor device D4 Fourth diode / fourth semiconductor device D1a Antiparallel diode D2a antiparallel diode D3a Antiparallel diode D4a antiparallel diode D5a antiparallel diode D6a antiparallel diode D7a Antiparallel diode D8a antiparallel diode M1 First pre-packaged module M2 Second pre-packaged module M3 Third pre-packaged module M4 4th pre-packaged module M5 5th pre-packaged module M6 6th pre-packaged module Q1 Bypass switch S1 First controllable semiconductor switch S2 Second controllable semiconductor switch S3 Third controllable semiconductor switch S4 4th controllable semiconductor switch S5 Fifth controllable semiconductor switch S6 Sixth controllable semiconductor switch S7 7th controllable semiconductor switch S8 8th controllable semiconductor switch S9 Ninth controllable semiconductor switch / First semiconductor device S10 10th controllable semiconductor switch / 2nd semiconductor device S11 11th controllable semiconductor switch / 3rd semiconductor device S12 12th controllable semiconductor switch / 4th semiconductor device AC1 First AC bridge terminal AC2 Second AC bridge terminal AC3 First AC clamp terminal AC4 Second AC clamp terminal DC1 First DC bridge terminal DC2 Second DC Bridge Terminal DC3 First DC clamp terminal DC4 Second DC clamp terminal

Claims

1. First and second AC bridge terminals (AC1, AC2) that can be electrically connected to each coil (4;14), First and second DC bridge terminals (DC1, DC2) that can be electrically connected to a DC current source (56; 78) or the DC bridge terminal of another switching module, A first switch assembly electrically connected between the first AC bridge terminal (AC1) and the first DC bridge terminal (DC1), wherein the first switch assembly comprises a first controllable semiconductor switch (S1) and a first semiconductor device (S9; D1) electrically connected in series, A second switch assembly electrically connected between the first AC bridge terminal (AC1) and the second DC bridge terminal (DC2), the second switch assembly comprising a second controllable semiconductor switch (S2) and a second semiconductor device (S10; D2) electrically connected in series, A third switch assembly electrically connected between the second AC bridge terminal (AC2) and the first DC bridge terminal (DC1), wherein the third switch assembly comprises a third controllable semiconductor switch (S3) and a third semiconductor device (S11; D3) electrically connected in series, A fourth switch assembly electrically connected between the second AC bridge terminal (AC2) and the second DC bridge terminal (DC2), wherein the fourth switch assembly comprises a fourth controllable semiconductor switch (S4) and a fourth semiconductor device (S12; D4) electrically connected in series. An H-bridge circuit (2;12) equipped with, First and second DC clamp terminals (DC3, DC4), A first DC clamp terminal (DC3) and a fifth controllable semiconductor switch (S5) electrically connected between the junction between the first controllable semiconductor switch (S1) and the first semiconductor device (S9; D1), A second DC clamp terminal (DC4) and a sixth controllable semiconductor switch (S6) electrically connected between the junction between the second controllable semiconductor switch (S2) and the second semiconductor device (S10; D2), A seventh controllable semiconductor switch (S7) is electrically connected between the first DC clamp terminal (DC3) and the junction between the third controllable semiconductor switch (S3) and the third semiconductor device (S11; D3), The second DC clamp terminal (DC4) and the eighth controllable semiconductor switch (S8) are electrically connected between the junction between the fourth controllable semiconductor switch (S4) and the fourth semiconductor device (S12; D4), An energy storage device (C) electrically connected between the first and second DC clamp terminals (DC3, DC4) and An active clamp circuit (6;16) equipped with A switching module (1;10) is provided.

2. The switching module (1) according to claim 1, wherein the first semiconductor device (S9; D1) is a ninth controllable semiconductor switch (S9), the second semiconductor device (S10; D2) is a tenth controllable semiconductor switch (S10), the third semiconductor device (S11; D3) is an eleventh controllable semiconductor switch (S11), and the fourth semiconductor device (S12; D4) is a twelfth controllable semiconductor switch (S12).

3. The first and second controllable semiconductor switches (S1, S2) are of the same type and are implemented as a pre-packaged module (M1) arranged so that the first and second controllable semiconductor switches (S1, S2) conduct in the same direction. The third and fourth controllable semiconductor switches (S3, S4) are of the same type and are implemented as a pre-packaged module (M2) arranged so that the third and fourth controllable semiconductor switches (S3, S4) conduct in the same direction. The fifth and ninth controllable semiconductor switches (S5, S9) are of the same type and are implemented as a pre-packaged module (M3) arranged such that the fifth and ninth controllable semiconductor switches (S5, S9) conduct in the same direction. The sixth and tenth controllable semiconductor switches (S6, S10) are of the same type and are implemented as a pre-packaged module (M4) in which the sixth and tenth controllable semiconductor switches (S6, S10) are arranged to conduct in the same direction. The seventh and eleventh controllable semiconductor switches (S7, S11) are of the same type and are implemented as a pre-packaged module (M5) in which the seventh and eleventh controllable semiconductor switches (S7, S11) are arranged to conduct in the same direction. The switching module (1) according to claim 2, wherein the eighth and twelfth controllable semiconductor switches (S8, S12) are of the same type and are mounted as a pre-packaged module (M6) in which the eighth and twelfth controllable semiconductor switches (S8, S12) are arranged to conduct in the same direction.

4. The switching module (1) according to claim 1, wherein all of the controllable semiconductor switches (S1, S2, ..., S12) of the H-bridge circuit (2) and the active clamp circuit (6) are MOSFETs.

5. The first and ninth controllable semiconductor switches (S1, S9) are electrically connected in reverse series in a common drain configuration. The second and tenth controllable semiconductor switches (S2, S10) are electrically connected in reverse series in a common source configuration. The third and eleventh controllable semiconductor switches (S3, S11) are electrically connected in reverse series in a common drain configuration. The switching module (1) according to claim 4, wherein the fourth and twelfth controllable semiconductor switches (S4, S12) are electrically connected in reverse series in a common source configuration.

6. The switching module (10) according to claim 1, wherein the first semiconductor device (S9; D1) is a first diode (D1), the second semiconductor device (S10; D2) is a second diode (D2), the third semiconductor device (S11; D3) is a third diode (D3), and the fourth semiconductor device (S12; D4) is a fourth diode (D4).

7. The first and second controllable semiconductor switches (S1, S2) are of the same type and are implemented as a pre-packaged module (M1) arranged so that the first and second controllable semiconductor switches (S1, S2) conduct in the same direction. The third and fourth controllable semiconductor switches (S3, S4) are of the same type and are implemented as a pre-packaged module (M2) arranged so that the third and fourth controllable semiconductor switches (S3, S4) conduct in the same direction. The fifth controllable semiconductor switch (S5) and the first diode (D1) are implemented as a pre-packaged module (M3) in which the fifth controllable semiconductor switch (S5) and the first diode (D1) are electrically connected in reverse series and arranged to conduct in opposite directions. The sixth controllable semiconductor switch (S6) and the second diode (D2) are implemented as a pre-packaged module (M4) in which the sixth controllable semiconductor switch (S6) and the second diode (D2) are electrically connected in reverse series and arranged to conduct in opposite directions. The seventh controllable semiconductor switch (S7) and the third diode (D3) are implemented as a pre-packaged module (M5) in which the seventh controllable semiconductor switch (S7) and the third diode (D3) are electrically connected in reverse series and arranged to conduct in opposite directions. The switching module (10) according to claim 6, wherein the eighth controllable semiconductor switch (S8) and the fourth diode (D4) are mounted as a pre-packaged module (M6) in which the eighth controllable semiconductor switch (S8) and the fourth diode (D4) are electrically connected in reverse series and arranged to conduct in opposite directions.

8. The switching module (10) according to claim 6, wherein all of the controllable semiconductor switches (S1, S2, ..., S8) of the H-bridge circuit (12) and the active clamp circuit (16) are IGBTs.

9. The switching module (1) according to claim 1, wherein the energy storage device (C) is a capacitor (C).

10. The switching module (10) according to claim 1, further comprising a power supply circuit (18) electrically connected in parallel with the energy storage device (C) between the first and second DC clamp terminals (DC3, DC4), wherein the power supply circuit (18) is electrically connectable to one or more electronic circuits (20, 22) associated with the switching module (10).

11. The switching module (10) according to claim 1, further comprising a battery (24) electrically connected in parallel with the energy storage device (C) between the first and second DC clamp terminals (DC3, DC4).

12. A switching module (10) according to any one of claims 1 to 11, further comprising a dynamic braking system (26) electrically connected in parallel with the energy storage device (C) between the first and second DC clamp terminals (DC3, DC4).

13. Multiple stator coils (54 １ , 54 ２ , . . , 54 ｎ A stator (52) having ) Rotor and, DC current source (56), n switching modules (10 according to any one of claims 1 to 12 １ , 10 ２ , ..., 10 ｎ ), which is a power electronic switching assembly (58), wherein n is an integer of 2 or more, and each switching module (10 １ , 10 ２ , ..., 10 ｎ ), said first and second AC bridge terminals (AC1, AC2) are electrically connected to at least one respective stator coil (54 １ , 54 ２ , ..., 54 ｎ ), said first DC bridge terminal (DC1) of a first switching module (10 １ ) is electrically connected to said DC current source (56), and said second DC bridge terminal (DC2) of an n-th switching module (10 ｎ ) is electrically connected to said DC current source (56), and said first and second DC bridge terminals (DC1, DC2) of the remaining switching modules constitute the power electronic switching assembly (58) electrically connected in series A DC electrical machine (50) equipped with a DC power supply.

14. The DC current source (56) is a power converter (70), for example, an AC / DC converter (86 １ , 86 ２ , . . , 86 ｎ The DC electric machine (50) according to claim 13, which is either another DC electric machine.

15. Multiple first coils (74 １ , 74 ２ , . . , 74 ｎ A transformer assembly (72) having ) DC current source (78), n switching modules (10) according to any one of claims 1 to 9 １ , 10 ２ , . . , 10 ｎ A power electronic switching assembly (80) comprising ), where n is an integer of 2 or more, and each switching module (10 １ , 10 ２ , . . , 10 ｎ The first and second AC bridge terminals (AC1, AC2) of the ) are connected to the respective first coils (74 １ , 74 ２ , . . , 74 ｎ ) is electrically connected to the first switching module (10 １ The first DC bridge terminal (DC1) of the ) is electrically connected to the DC current source (78), and the nth switching module (10 ｎ The second DC bridge terminal (DC2) of the switching module is electrically connected to the DC current source (78), and the first and second DC bridge terminals (DC1, DC2) of the remaining switching module are electrically connected in series to a power electronic switching assembly (80) A power converter (70) is provided.

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