Mechanical systems and methods for operating mechanical systems

Abstract

A mechanical system (1) comprising an electric machine (2) and a plurality of half bridges (3) for controlling the electric machine (2), wherein the electric machine (2) has a stator winding (4) including two winding sections (4.1, 4.2), each having a winding strand (14) and a winding connection (10), the winding connection (10) of one winding section (4.1) being electrically connected to a phase connection (8) of a first group (13.1) of half bridges (3), and the winding connection (10) of the other winding section (4.2) being electrically connected to a phase connection (8) of a second group (13.1) of half bridges (3). a mechanical system (1) in which the phase connections (8) of the first group (13.1) of half bridges (3) are electrically connected to the phase connections (8) of the second group (13.2) of the half bridges (3), and each of the phase connections (8) of the first group (13.1) of half bridges (3) is electrically connectable to one of the phase connections (8) of the second group (13.2) of half bridges (3) via bridge connections (11) in order to electrically connect two winding connections (10) of different winding sections (4.1, 4.2), each bridge connection (11) being provided with a switchable switching device (12); the half-bridge (3) of the mechanical system (1) is a control half-bridge, each winding strand (14) of one of the two winding sections (4.1, 4.2) forms a strand pair (15) with one of the winding strands (14) of the other winding section (4.1, 4.2), the winding strands (14) of each strand pair (15) being 180 degrees out of phase with each other; Each bridge connection (11) is characterized in that it is switchable to conduct both current directions by a respective switching device (12).

Description

[Technical Field]

[0001] This invention starts with a mechanical system according to the attributes of the independent claims. [Background technology]

[0002] A mechanical system comprising a generator as an electromachine and a plurality of uncontrolled halfbridges of an uncontrolled full-wave rectifier circuit is already known from German Patent Application Publication No. 3227602, wherein the electromachine has a stator including a stator winding, and the halfbridge has two input nodes for connection to a DC voltage source, two switching elements connected in series between the input nodes, and one phase connection between the switching elements, and the stator winding includes two polyphase winding sections of the same number of phases, in particular two three-phase winding sections, each winding section having a number of winding strands corresponding to the number of phases and a number of winding connection sections corresponding to the number of phases, and the winding of one winding section The wire connections are electrically connected to the phase connections of the first group of half-bridges, and the winding connections of the other winding section are electrically connected to the phase connections of the second group of half-bridges. Each group of half-bridges has a number of half-bridges corresponding to the number of phases of the respective winding section. To electrically connect two winding connections of different winding sections, each phase connection of the first group of half-bridges can be electrically connected via a bridge connection to one of the phase connections of the second group of half-bridges in the formation of a half-bridge pair. Each bridge connection is provided with a thyristor as a switchable switching device for interrupting the electrical bridge connection. However, each bridge connection can only be switched to conduct in one current direction.

[0003] In the series connection operation below a specific rotational speed of the internal combustion engine, two winding portions of the stator winding are connected in series with each other, corresponding to a single winding with a large number of turns. In the parallel connection operation above a specific rotational speed of the internal combustion engine, two winding portions of the stator winding are connected in parallel with each other, corresponding to a single winding with a smaller number of turns than in the series connection operation. In both system operations, all switching devices of the bridge connection always open or close together. The uncontrolled half-bridge of the rectifier circuit includes only diodes. The phase current is determined by the phase voltage induced in the stator winding. The so-called "heterogeneous" connection is created by the bridge connection, whereby a phase shift of 60 degrees (= 180° - 120°) occurs in the phase conductors of the conductor pairs connected via each bridge connection. The two winding portions of the winding are called "opposite phases" to each other, which means that the periodic directions of the phases of the two winding portions are opposite. This can be understood from the fact that the winding conductors of the winding portion according to FIG. 3 of German Patent Application Publication No. 3227601 are arranged on the stator in opposite rotational directions.

[0004] The mechanical system includes a phase system having a plurality of phase subsystems, and each phase subsystem is formed by one of the half-bridge pairs, the bridge connection of each half-bridge pair, and two winding connections that can be connected by each half-bridge pair.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Effects of the Invention

[0006] The mechanical system according to the present invention, having the distinctive features of the independent claim, has the advantage of being able to reduce the line loss and switching loss in the semiconductor of the half-bridge on a time-averaged basis compared to the prior art, which enables an increase in the phase current of the half-bridge and / or a reduction in the thermal load. Furthermore, by connecting the winding portions in series, the impedance of the electromechanical system can be adapted according to the operating point. By reducing current ripple, the losses of the electromechanical system can be reduced. Furthermore, the torque ripple of the electromechanical system can be reduced, and the efficiency of the electromechanical system can be increased.

[0007] This is because, according to the present invention, -According to the first feature of the present invention, the half-bridge of the mechanical system is a control half-bridge for supplying phase current or phase voltage to the stator winding, -According to a second feature of the present invention, each winding strand of one of the two winding portions forms a strand pair with one of the winding strands of the other winding portion, and the winding strands of each strand pair are out of phase with each other by 180 degrees. -According to a third feature of the present invention, each bridge connection can be switched by each switching device to conduct in both current directions. This is achieved by doing so.

[0008] A second feature of the present invention is that when current is passed through the stator in the same direction, the winding wires of each wire pair generate magnetic flux, and their contributions to the fundamental wave are shifted in phase by 180 degrees relative to each other.

[0009] According to a third feature of the present invention, the bridge connection can be electrically disconnected by opening the switching device, or the bridge connection can be made conductive by closing the switching device.

[0010] The means enumerated in the cited claims enable advantageous improvements and enhancements to the mechanical system described in the independent claims.

[0011] According to an advantageous embodiment, each half-bridge switching element is a semiconductor switch, in particular an IGBT transistor or a MOSFET transistor, and each semiconductor switch is assigned a freewheeling diode, in particular as a separate component connected in parallel, or each semiconductor switch essentially incorporates the function of a freewheeling diode. In this way, the current of the half-bridge can be controlled by pulse width modulation in interaction with the inductance, in particular the stator inductance.

[0012] Each bridge-connected switching device may, advantageously, comprise at least one semiconductor switch, which is in particular an IGBT transistor, a MOSFET transistor, or a thyristor. According to an advantageous embodiment, the switching device may be formed by two transistors, in particular an IGBT transistor or a MOSFET transistor connected in reverse series, or by two thyristors connected in reverse parallel, in particular a triac.

[0013] Because switching devices do not need to switch as frequently as half-bridge switching elements, cost-effective semiconductor components can be used for the switching devices, and relatively high switching losses can be tolerated. Bridge-connected switching devices are preferably switched on when large phase currents flow to minimize the load on the half-bridge. Therefore, the switching devices must have high current tolerance. Since switching devices can only be periodically switched in series connection operation, the ability of the switching device to switch at high speed and efficiently is not required. Since series connection operation is only used at low to medium rotational speeds, the required switching frequency is low.

[0014] It is particularly advantageous when the winding strands of each strand pair have the same voltage-holding number of turns (with respect to the fundamental wave) and / or the same conductor cross-sectional area and / or the same inductance. In this way, power is evenly distributed to the winding portion during operation, thereby being optimally utilized and thus achieving high efficiency.

[0015] The use of two groups of half-bridges, and especially when the bridge connection including switching devices is part of the inverter, is highly advantageous. In this way, a space-saving structure can be achieved. Placing components in a cooling unit enables a cost-effective, highly integrated structure, and the small distances between components reduce wiring effort. The drive circuit can be integrated into the control unit.

[0016] The winding strands of each winding section can be advantageously connected in a star or delta configuration, and through the respective bridge connections, one pair of strands in the case of a star configuration and two pairs of strands in the case of a delta configuration can be connected to each other.

[0017] The mechanical system includes control devices for driving the switching elements of a half-bridge and for driving the switching devices of a bridge connection.

[0018] The present invention further relates to a method for operating a mechanical system according to the present invention, wherein the mechanical system comprises a phase system having a plurality of phase subsystems, each phase subsystem being formed by one of a pair of half-bridges, a bridge connection of the respective pair of half-bridges, and two winding connections connectable by the respective bridge connection, and the mechanical system is operable according to one or more system operating parameters of the electromachine, in particular rotational speed, torque and / or efficiency, and / or fault parameters of the mechanical system is operable in one of a plurality of operating states, in particular series connection operation, disconnection operation, emergency operation, or active short-circuit operation. The selection of the operating state can be performed, for example, by a lookup table. Series connection operation is particularly suitable for low and medium rotational speeds, and disconnection operation is suitable for high rotational speeds.

[0019] In series connection operation, depending on at least one subsystem operation parameter, it is intended that one of the phase subsystems operates as a passive subsystem, or the remaining phase subsystems operate as active subsystems.

[0020] In passive subsystem operation, both half-bridges of each phase subsystem are deactivated in the formation of the passive phase subsystem. Furthermore, in passive subsystem operation, the bridge connection of the passive phase subsystem is conducted by the corresponding switching position to allow bidirectional current flow from one of the two winding connections to the other of the two winding connections via the bridge connection of the passive phase subsystem.

[0021] In active subsystem operation, both half-bridges of each phase subsystem are driven under the formation of the active phase subsystem to provide two control phase currents that are 180 degrees out of phase with each other, and are identical in size and shape but have different signs. Furthermore, in active subsystem operation, the bridge connection of the active phase subsystem is electrically disconnected by the corresponding switching position of the respective switching device.

[0022] It is particularly advantageous when the half-bridges of each active-phase subsystem are driven in opposite phase with respect to pulse width modulation. Since the half-bridges provide opposite-phase phase currents in the active state, the switch-on duration (duty cycle) set by the half-bridges is also in opposite phase. Therefore, with opposite-phase pulse width modulation of the half-bridge pair (a 180° phase difference with respect to the PWM frequency between the centers of the switch-on periods), a nearly opposite-phase voltage profile can be achieved at the winding connection. As a result, the phase currents (displacement currents) flowing through the coupling capacitors in the winding section, especially for the rotor, are also in opposite phase and cancel each other out. The rotor voltage caused by capacitive coupling can be reduced, thus avoiding leakage currents that could damage the ball bearings. In some cases, necessary rotor grounding measures or insulated ceramic bearings can be omitted.

[0023] The method according to the present invention achieves that, in response to the provision of a control phase current in the active phase subsystem, an indirect control phase current is automatically generated in the series connection of the two winding sections, and this indirect control phase current flows in one of two directions, depending on its sign, through the bridge connection of the passive phase subsystem. In this way, appropriate phase currents can be supplied to each winding connection of each inactive phase subsystem.

[0024] Furthermore, in series connection operation, it is advantageous when all phase subsystems are sequentially changed to passive subsystem operation in a continuous sequence according to the subsystem operation parameters.

[0025] In this way, the reduction in the heat load on the half-bridge spreads evenly over time.

[0026] It is highly advantageous when the subsystem operating parameter is the magnitude of the phase current in the phase subsystem, respectively, in passive subsystem operation, when the phase current exceeds a threshold in magnitude, particularly around the peak value of the phase current, the phase subsystem operates in a positive and negative current half-wave during the time interval from one-twelfth of the electrical period of the phase current to one-twelfth of the electrical period before the peak value to one-twelfth of the electrical period after the peak value.

[0027] In this way, the phase current is transferred from the bridge connection of one winding section to the other winding section during the time interval of the maximum phase current, so this phase current does not need to be controlled by the halfbridge of the passive phase subsystem. Since the power loss in the halfbridge is proportional to the current-time-area ratio through which the current flows, the load on the halfbridge is minimized by setting the passive subsystem operation to work at the intervals described above.

[0028] Furthermore, in isolation operation, it is advantageous that the two winding sections are controlled separately by all bridge connections being disconnected by a switching device and all half-bridges of the first and second groups being driven, in order to provide control phase current to all winding connections of the two winding sections.

[0029] In this way, the need for field weakening current is reduced during separation operation, and the supply voltage can be optimally utilized to generate higher power at higher rotational speeds.

[0030] Furthermore, in emergency operation, it is advantageous that only one of the two winding sections is energized by driving only the first or second group half-bridge to provide control phase current to only one of the two winding sections. In emergency operation, all bridge connections are disconnected by the switching device.

[0031] In this way, even if there is an insulation defect in one of the two winding sections, for example, the other winding section can still conduct electricity, enabling limp-home operation.

[0032] In active short-circuit operation, it is also advantageous when all half-bridges in all phase subsystems are deactivated and all bridge connections conduct, in order to generate an active short circuit of the electromechanical system by bridge connection.

[0033] In fault operation, all half-bridges are deactivated, so the two winding sections are not electrically connected to the voltage supply. As a result, the winding sections are in an active short-circuit state with no potential (especially when the system is battery-powered), which ensures that one of the two winding sections remains safe even if an insulation fault occurs.

[0034] In series connection and disconnection operations, the phase current at the winding connection of the first winding section forms a first three-phase current, and the phase current at the winding connection of the second winding section forms a second three-phase current. It is also advantageous that the two three-phase currents in the two winding sections are 180° out of phase with respect to each other.

[0035] The two winding strands of each strand pair are 180 degrees out of phase with each other due to their corresponding configuration, and the phase currents of each active-phase subsystem are also 180 degrees out of phase with each other, and are identical in size and shape but have different signs, thereby generating magnetic flux that is addedly superimposed to generate torque in the stator. The first and second three-phase currents function almost like three-phase currents in the machine, and their amplitudes correspond to the sum of the amplitudes of the two three-phase currents.

[0036] The method according to the present invention reduces the power loss in the half-bridge due to the inactive phase of the half-bridge on a time-averaged basis, thereby lowering the temperature of the half-bridge with the same cooling. Therefore, it is possible to increase the phase current of the mechanical system at the same maximum semiconductor temperature. Because it is possible to increase the phase current in the mechanical system, it is also possible to reduce the number of voltage-holding turns of the electromachine at the same maximum torque, which reduces the need for field-weakening current at higher rotational speeds. That is, in the isolation operation, at higher rotational speeds, it is possible to move to an operating point where a smaller proportion of the phase current is required for field-weakening current, thereby allowing a larger proportion of the phase current to contribute to torque generation. Therefore, it is possible to significantly increase the power and efficiency of the electromachine at high rotational speeds.

[0037] In the case of a current-controlled half-bridge in an active phase subsystem, based on the electrically conductive bridge connection in the passive phase subsystem, the winding portion appears as a load with greater inductance, greater ohm resistance, and greater pole-ring voltage, thereby setting a larger duty cycle. This reduces current ripple or current distortion and torque ripple. Furthermore, electromechanical iron losses are also reduced. [Brief explanation of the drawing]

[0038] Exemplary embodiments of the present invention are shown in a simplified form in the drawings and will be described in more detail in the following description.

[0039] [Figure 1]This is an equivalent circuit diagram of a mechanical system according to the present invention, comprising an electromachine according to a first exemplary embodiment, operating in series connection mode according to the present invention, and in state at time Y as shown in Figures 2A to 2C. [Figure 1A] This figure shows one of the half-bridges shown in Figure 1. [Figure 2] Figure 2A shows the phase current profiles of the phase subsystem 21V in series connection operation according to Figure 1, both in active and passive subsystem operation. Figure 2B shows the phase current profiles of the phase subsystem 21U in series connection operation according to Figure 1, both in active and passive subsystem operation. Figure 2C shows the phase current profiles of the phase subsystem 21W in series connection operation according to Figure 1, both in active and passive subsystem operation. [Figure 3] Figure 1 is an equivalent circuit diagram of the mechanical system according to the present invention, which operates using the separation operation according to the present invention. [Figure 4] This figure shows the phase current profiles at the phase connections of each half-bridge in each phase subsystem of a mechanical system operating with the isolated operation shown in Figure 3. [Figure 5] Figure 1 is an equivalent circuit diagram of the mechanical system according to the present invention, which operates in emergency mode according to the present invention. [Figure 6] Figure 1 is an equivalent circuit diagram of the mechanical system according to the present invention, which operates using the active short-circuit operation according to the present invention. [Figure 7] This is an equivalent circuit diagram of a mechanical system according to the present invention, comprising an electromachine according to a second exemplary embodiment, and operating in series connection operation according to the present invention. [Modes for carrying out the invention]

[0040] Figure 1 shows an equivalent circuit diagram of a mechanical system according to the present invention, comprising an electromachine according to a first exemplary embodiment, and operating in series connection operation according to the present invention.

[0041] The mechanical system 1 according to the present invention comprises an electromachine 2 and a plurality of half-bridges 3 arranged in an electrical circuit to control the electromachine 2. The electromachine 2 has a stator including stator windings 4. According to Figure 1A, each half-bridge 3 of the mechanical system 1 according to the present invention has two input nodes 5 for connecting to a DC voltage source 6, such as a vehicle battery, two switching elements 7 connected in series between the input nodes 5, and one phase connection 8 between the two switching elements 7.

[0042] The stator winding 4 includes two polyphase, particularly three-phase, winding sections 4.1 and 4.2 of the same number of phases, each winding section 4.1 and 4.2 having a number of winding strands 14 corresponding to the number of phases and a number of winding connection sections 10 corresponding to the number of phases. Each winding strand 14 may have parallel sub-strands.

[0043] The winding connection 10 of one winding portion 4.1 of the stator winding 4 is electrically connected to the phase connection 8 of the first group 13.1 of the half-bridge 3, and the winding connection 10 of the other winding portion 4.2 is electrically connected to the phase connection 8 of the second group 13.2 of the half-bridge 3. The first group 13.1 of the half-bridge 3 includes a number of half-bridges 3 corresponding to the number of phases of the winding portion 4.1. Similarly, the second group 13.2 of the half-bridge 3 includes a number of half-bridges 3 corresponding to the number of phases of the winding portion 4.2. Each winding connection 10 of each winding portion 4.1, 4.2 is electrically connected to another half-bridge 3 of the respective groups 13.1, 13.2 of the half-bridge 3.

[0044] Each of the phase connections 8 of the first group 13.1 of the half-bridge 3 is electrically connectable via bridge connections 11 to one of the phase connections 8 of the second group 13.2 of the half-bridge 3 in the formation of a half-bridge pair 23, in order to electrically (directly) connect two winding connections 10 of different winding portions 4.1 and 4.2 of the stator winding 4. Each bridge connection 11 is provided with a switchable switching device 12 for disconnecting the respective electrical bridge connection 11.

[0045] According to the present invention, the phase current I u , I v , I w Alternatively, the half-bridge 3 of the mechanical system 1 is intended to be a control half-bridge in order to supply phase voltages to the stator windings 4.

[0046] Furthermore, according to the present invention, each winding strand 14 of one of the two winding portions 4.1 and 4.2 forms a strand pair 15 with one of the winding strands 14 of the other winding portion 4.1 and 4.2, and the winding strands 14 of each strand pair 15 are intended to be 180 degrees out of phase with each other.

[0047] Furthermore, according to the present invention, each bridge connection 11 is intended to be switchable by each switching device 12 to conduct in both current directions. That is, each bridge connection 11 can be switched to a state in which it conducts in both current directions. In other words, each bridge connection 11 conducts or is electrically disconnected depending on the switching position of the switching device 12.

[0048] Each switching element 7 in the half-bridge 3 is an electronic semiconductor switch, specifically an IGBT transistor or MOSFET transistor. Each semiconductor switch 7 can be assigned a freewheeling diode 9 as a separate component connected in parallel. Alternatively, each semiconductor switch 7 can essentially incorporate the function of a freewheeling diode.

[0049] Two groups 13.1 and 13.2 of the half-bridge 3 are part of the inverter 16. According to an exemplary embodiment, the bridge connection 11 (including the switching device 12) is also part of the inverter 16, for example.

[0050] Each pair of wires 15, specifically the winding wires 14, is designed to generate magnetic flux in the machine when energized, with their fundamental wave components having a 180-degree phase difference from one another.

[0051] For example, the winding strands 14 of each pair of strands 15 can be offset from each other by the angle of the stator poles. Alternatively, the winding strands 14 of each pair of strands 15 can be identical strands, but with the winding start and end reversed. Approximately the same voltage is induced in the winding strands 14 of each pair of strands 15.

[0052] Each switching device 12 of the bridge connection 11 includes, for example, at least one semiconductor switching element, in particular an IGBT transistor, a MOSFET transistor, or a thyristor.

[0053] The winding strands 14 of each strand pair 15 may have the same voltage-holding number of turns and / or the same conductor cross-sectional area and / or the same inductance.

[0054] The winding strands 14 of each winding section 4.1 and 4.2 are connected in a star configuration according to the first exemplary embodiment shown in Figures 1-6, and in a delta configuration according to the second exemplary embodiment shown in Figure 7. Two specific winding connection sections 10, consisting of different winding sections 4.1 and 4.2, can be electrically connected via their respective bridge connections 11, and the two specific winding connection sections 10 form a connection pair of winding connection sections 10. The connection pair of winding connection sections 10 allows one strand pair 15 to be connected to each other in the case of a star configuration, and two strand pairs 15 to be connected in the case of a delta configuration.

[0055] The mechanical system 1 further includes a control device 17 for driving the switching elements 7 of the half-bridge 3 and for driving the switching devices 12 of the bridge connection 11.

[0056] The mechanical system 1 comprises multiple phase subsystems 21, for example 21 u ,twenty one v ,twenty one w The system includes a phase system 20 having the following: The number of phase subsystems 21 corresponds to the number of phases in one of the winding portions 4.1 and 4.2 of the stator winding 4.

[0057] Each phase subsystem 21 is formed by one of the half-bridge pairs 23, a bridge connection 11 between the respective half-bridge pairs 23, and two winding connection parts 10 of two winding sections 4.1 and 4.2 that can be (directly) connected by the respective bridge connection 11.

[0058] The mechanical system 1 can operate in one of several operating states, particularly in series operation, disconnection operation, emergency operation, or active short-circuit operation, depending on one or more system operating parameters, in particular the rotational speed, torque, and / or efficiency of the electromachine 2, and / or the fault parameters of the mechanical system 1.

[0059] According to Figure 1, the mechanical system 1 is in series connection operation, and the state of the mechanical system 1 in Figure 1 is shown exemplarily for time Y in Figures 2A to 2C.

[0060] In series connection operation, depending on at least one subsystem operation parameter, one of the phase subsystems 21 is in passive subsystem operation ("passive"), or the remaining phase subsystems are in active subsystem operation ("active").

[0061] In passive subsystem operation, the two half-bridges 3 of each phase subsystem 21 are deactivated or switched to inactive in the formation of the passive phase subsystem 21, and the bridge connection 11 of the passive phase subsystem 21 conducts by the corresponding switching position of the switching device 12 to allow current to flow in both directions from one of the two winding connections 10 to the other of the two winding connections 10 through the bridge connection 11 of the passive phase subsystem 21.

[0062] In active subsystem operation, two control phase currents I are 180 degrees out of phase with each other, and are identical in size and shape, but have different signs. u , I v , Iw To provide, two half - bridges 3 of each phase subsystem 21 are driven under the formation of the active phase subsystem 21. The bridge connection 11 of the active phase subsystem 21 is electrically interrupted or is to be interrupted by the corresponding switching position using each switching device 12.

[0063] FIG. 2A shows the profiles of the phase currents in the active and passive subsystem operations of the series - connection operation with respect to the electrical phase angle for the phase subsystem 21V according to FIG. 1.

[0064] In particular, FIG. 2Aa shows the profile of the phase current I v at the winding connection 10 of the phase subsystem 21V, FIG. 2Ab shows the profile of the phase current I v at the phase connection 8 of the two half - bridges 3 of the phase subsystem 21V, FIG. 2Ac shows the profile of the phase current I br at the bridge connection 11 of the phase subsystem 21V, FIG. 2Ad shows the change between the active subsystem operation "active" and the passive subsystem operation "passive" of the phase subsystem 21V with respect to the electrical phase angle.

[0065] FIG. 2B shows the profiles of the phase currents in the active and passive subsystem operations of the series - connection operation with respect to the electrical phase angle for the phase subsystem 21U according to FIG. 1.

[0066] In particular, FIG. 2Ba shows the profile of the phase current I u at the winding connection 10 of the phase subsystem 21U, FIG. 2Bb shows the profile of the phase current I u at the phase connection 8 of the two half - bridges 3 of the phase subsystem 21U, FIG. 2Bc shows the profile of the phase current I brThe profile is shown, Figure 2Bd shows the change between the active subsystem operation ("active") and the passive subsystem operation ("passive") of the phase subsystem 21U with respect to the electrical phase angle.

[0067] Figure 2C shows the phase current profiles for the phase subsystem 21W according to Figure 1, in both active and passive subsystem operation with respect to the electrical phase angle in series connection.

[0068] especially, Figure 2Ca shows the phase current I at the winding connection 10 of the phase subsystem 21W. w The profile is shown, Figure 2Cb shows the phase current I at the phase connection point 8 of the two half-bridges 3 of the phase subsystem 21W. w The profile is shown, Figure 2Cc shows the phase current I in the bridge connection 11 of the phase subsystem 21W. br The profile is shown, Figure 2Cd shows the change between the active subsystem operation ("active") and the passive subsystem operation ("passive") of the phase subsystem 21W with respect to the electrical phase angle.

[0069] From Figures 2Aa to 2Cd, it can be seen that in series connection operation, depending on the operating parameter of at least one subsystem, one of the phase subsystems 21 will operate in passive subsystem mode, or the remaining phase subsystems will operate in active subsystem mode.

[0070] Phase current I in the phase connection section 8 of the half bridge 3 u , I v , I w The profile, as shown in Figures 2Ab, 2Bb, and 2Cb, shows a rapid change to a value of 0 at the time interval dt.

[0071] In series connection and disconnection operations, the phase current I in the winding connection portion 10 of the first winding portion 4.1 u , I v , I w The first three-phase current is formed at any point in time or in any state. Furthermore, the phase current at the winding connection 10 of the second winding section 4.2 forms a second three-phase current at any point in time, and the two three-phase currents in the two winding sections 4.1 and 4.2 are out of phase by 180° from each other. The phase current I of each of the two three-phase currents u , I v , I w These are each 120 degrees out of phase with respect to one another, and are, for example, a waveform or a sine wave.

[0072] Control phase current I in the active phase subsystem 21 as shown in Figures 2Ab, 2Bb, and 2Cb. u , I v , I w In response to the provision, the bridge connection 11 of the passive phase subsystem 21 conducts according to the corresponding switching position of the switching device 12, thereby causing the phase current I br When the current flows in one of two directions via the bridge connection 11 of the passive phase subsystem 21 according to its sign, the remaining (not directly controlled by the half-bridge 3) phase currents in the series connection of the two winding sections 4.1 and 4.2 indirectly controlled phase current I u , I v , I w It occurs automatically.

[0073] At time point Y in Figures 2A to 2C of the mechanical system 1, for example, the phase subsystem 21 v ,twenty one w This is in active subsystem operation, phase subsystem 21 u This is in passive subsystem operation. That is, active phase subsystem 21 v ,twenty one w Then, half-bridge 3 operates actively, and as a result, phase current I is supplied to the phase connection part 8 of half-bridge 3. v , I w This is provided. Passive phase subsystem 21 uTherefore, half-bridge 3 is inactive, and as a result, the phase current I is in the phase connection part 8 of half-bridge 3. u It is not provided. Two active phase subsystems 21 v ,twenty one w Control phase current I v , I w In response to the provision, the bridge connection 11 of the passive phase subsystem 21 conducts according to the corresponding switching position of the switching device 12, so that the series connection of the two winding sections 4.1 and 4.2 each provides an indirect control phase current I u This occurs automatically, thereby causing the phase current I br However, the passive phase subsystem 21 u The current flows through the bridge connection 11 in one of two directions, thereby in the phase subsystem 21 u It is provided to the winding connection portion 10 of the phase subsystem 21U. Therefore, the phase current I in the winding connection portion 10 of the phase subsystem 21U u In passive subsystem operation, despite the temporary deactivation of halfbridge 3, it maintains a waveform profile, such as a sinusoidal waveform.

[0074] The automatic generation of phase currents in each passive phase subsystem 21 occurs because Kirchhoff's first rule (the sum of all phase currents equals zero) is applied to each winding section 4.1 and 4.2, respectively. Thus, one of the phase currents in winding sections 4.1 and 4.2 is determined by the remaining phase currents, and there is no need to actively control one of the phase currents.

[0075] In series connection operation, all phase subsystems 21 are sequentially changed to passive subsystem operation in a continuous sequence according to the subsystem operation parameters.

[0076] The subsystem operating parameters include, for example, the phase current I in the phase subsystem 21. u , I v , I w The magnitude can be such that the phase current I u , Iv , I w In terms of magnitude, the phase current I before the peak value S exceeds the threshold X. u , I v , I w Phase current I from 1 / 12th of the electrical period u , I v , I w The phase subsystem 21, which is in a time interval dt up to 1 / 12th of the electrical period after the peak value S, operates in passive subsystem mode.

[0077] Each phase current I u , I v , I w For each electrical cycle, the bridge connection 11 of the associated phase subsystem 21 conducts for two time intervals dt, thereby enabling two switch-on processes and two switch-off processes in each switching device 12, which can be achieved through appropriate control.

[0078] Figure 3 shows an equivalent circuit diagram of the mechanical system according to the present invention shown in Figure 1, operating with the isolation operation according to the present invention.

[0079] In isolation operation, the two winding sections 4.1 and 4.2 are either disconnected by the switching device 12 when all bridge connections 11 of the mechanical system are disconnected, or when all half-bridges 3 of the first and second groups 13.1 and 13.2 are active, i.e., all winding connections 10 of the two winding sections 4.1 and 4.2 are connected to a control phase current I u , I v , I w They are controlled separately by being driven to provide.

[0080] Figure 4 shows the phase current profiles of all phase subsystems of a mechanical system operating with the isolated operation shown in Figure 3, with respect to the electrical phase angle.

[0081] Figure 5 shows an equivalent circuit diagram of the mechanical system according to the present invention shown in Figure 1, operating in emergency mode according to the present invention.

[0082] In emergency operation, a control phase current I is supplied to the winding connection 10 of one of the two winding sections 4.1 and 4.2. u , I v , I w To provide this, only one of the two winding sections 4.1, 4.2 is energized by driving only the half-bridge 3 of the first or second group 13.1, 13.2. In this case, all bridge connections 11 are disconnected by the corresponding switching position using the switching device 12. In emergency operation, the phase subsystem 21 is in a "semi-active" state, in which case one of the half-bridges 23, half-bridge 3, controls the control phase current I u , I v , I w To provide this, one half-bridge 3 is actively driven, while the other half-bridge 3 is passive.

[0083] Figure 6 shows an equivalent circuit diagram of the mechanical system according to the present invention shown in Figure 1, which operates using the active short-circuit operation according to the present invention.

[0084] In active short-circuit operation, all half-bridges 3 of all phase subsystems 21 are either passive or deactivated. Furthermore, all bridge connections 11 of the mechanical system 1 are conducted by their corresponding switching positions using switching devices 12 to generate an active short circuit of the electromachine 2 by the bridge connections 11.

Claims

1. A mechanical system (1) comprising an electric machine (2) and a plurality of half-bridges (3) for controlling the electric machine (2), The aforementioned electrical machine (2) has a stator including a stator winding (4), The half-bridge (3) has two input nodes (5) for connecting to a DC voltage source (6), two switching elements (7) connected in series between the input nodes (5), and one phase connection section (8) between each of the switching elements (7). The stator winding (4) includes two multiphase winding sections (4.1, 4.2) of the same number of phases, and each winding section (4.1, 4.2) has a number of winding strands (14) corresponding to the number of phases and a number of winding connection sections (10) corresponding to the number of phases, the winding connection section (10) of one winding section (4.1) is electrically connected to the phase connection section (8) of the first group (13.1) of the halfbridge (3), the winding connection section (10) of the other winding section (4.2) is electrically connected to the phase connection section (8) of the second group (13.2) of the halfbridge (3), and each group (13.1, 13.2) of the halfbridge (3) is the respective The winding section (4.1, 4.2) has a number of half-bridges (3) corresponding to the number of phases, and in order to electrically connect two winding connection sections (10) of different winding sections (4.1, 4.2), the phase connection sections (8) of the first group (13.1) of the half-bridges (3) can each be electrically connected via a bridge connection (11) to one of the phase connection sections (8) of the second group (13.2) of the half-bridges (3) in the formation of a half-bridge pair (23), and each of the bridge connections (11) is provided with a switchable switching device (12) for disconnecting the electrical bridge connection (11). In mechanical system (1), - Phase current (I ｕ , I ｖ , I ｗ ) or in order to supply a phase voltage, the half-bridge (3) of the mechanical system (1) is a control half-bridge, - Each of the aforementioned bridge connections (11) can be switched to conduct in both current directions by each of the aforementioned switching devices (12). A mechanical system (1) characterized by the following: - Each winding strand (14) of one of the two winding sections (4.1, 4.2) forms a strand pair (15) with one of the winding strands (14) of the other winding section (4.1, 4.2), and the winding strands (14) of each strand pair (15) are 180 degrees out of phase with each other so that the strand pairs (15) of the two winding sections (4.1, 4.2) that are not supplied with power from their respective half-bridge pairs (23) can be connected in series. Mechanical system (1).

2. The mechanical system (1) according to claim 1, characterized in that the stator winding (4) includes two three-phase winding portions.

3. The mechanical system (1) according to claim 1, characterized in that the switching element (7) of each of the half-bridges (3) is a semiconductor switch.

4. The mechanical system (1) according to claim 3, characterized in that the semiconductor switch is an IGBT transistor or a MOSFET transistor.

5. The semiconductor switch is A freewheel diode (9) is assigned as a separate component connected in parallel to the semiconductor switch, or Essentially includes the function of a freewheeling diode. The mechanical system (1) according to claim 3, characterized in that

6. The mechanical system (1) according to claim 1, characterized in that the two groups (13.1, 13.2) of the half-bridge (3) and the bridge connection (11) are part of the inverter (16).

7. The mechanical system (1) according to claim 1, characterized in that the switching device (12) of each of the bridge connections (11) includes at least one semiconductor switch.

8. The mechanical system (1) according to claim 7, characterized in that the semiconductor switch is an IGBT transistor, a MOSFET transistor, or a thyristor.

9. The mechanical system (1) according to claim 7, characterized in that the switching device (12) is formed by the inverse series connection of two transistors or by the inverse parallel connection of two thyristors.

10. The mechanical system (1) according to claim 9, characterized in that the inverse series connection of the two transistors is formed by an inverse series connection of IGBT transistors or MOSFET transistors.

11. The mechanical system (1) according to claim 9, characterized in that the antiparallel connection of the two thyristors is a triac.

12. The mechanical system (1) according to claim 1, characterized in that the winding wires (14) of each wire pair (15) have the same voltage holding turn count and / or the same conductor cross-sectional area and / or the same inductance.

13. The mechanical system (1) according to claim 1, characterized in that the winding strands (14) of each of the winding portions (4.1, 4.2) are connected in a star connection or a delta connection, and that in the case of a star connection, one pair of strands (15) can be connected to each other via the respective bridge connection (11), and in the case of a delta connection, two pairs of strands (15) can be connected to each other.

14. The mechanical system (1) according to claim 1, characterized in that a control device (17) is provided for driving the switching element (7) of the half-bridge (3) and for driving the switching device (12) of the bridge connection (11).

15. A method for operating the mechanical system (1) described in claim 1, The mechanical system (1) comprises a phase system (20) having a plurality of phase subsystems (21), each of which phase subsystems (21) is formed by one of the half-bridge pairs (23), the bridge connection (11) of each of the half-bridge pairs (23), and two winding connection portions (10) that can be connected by each of the bridge connections (11). The mechanical system (1) is capable of operating in one of a plurality of operating states, including series connection operation, disconnection operation, emergency operation, or active short-circuit operation, depending on one or more system operating parameters, including the rotational speed, torque and efficiency of the electromachine and at least one of the fault parameters of the mechanical system (1). In the method, In the series connection operation described above, depending on at least one subsystem operation parameter, one of the phase subsystems (21) operates in passive subsystem mode, or the remaining phase subsystems (21) operate in active subsystem mode. - In the passive subsystem operation, both half-bridges (3) of each phase subsystem (21) are deactivated under the formation of the passive phase subsystem (21), and the bridge connection (11) of the passive phase subsystem (21) is conductive to allow current to flow in both directions from one of the two winding connections (10) to the other of the two winding connections (10) via the bridge connection (11) of the passive phase subsystem (21). - In the active subsystem operation (active), in order to provide two control phase currents (Iu, Iv, Iw) with different signs and a 180-degree phase difference between them, both half-bridges (3) of each phase subsystem (21) are driven under the formation of the active phase subsystem (21), and the bridge connection (11) of the active phase subsystem (21) is electrically disconnected by the respective switching devices (12). method.

16. The control phase current (I) in the active phase subsystem (21) ｕ , I ｖ , I ｗ The method according to claim 15, characterized in that, in response to the provision of ), an indirect control phase current is automatically generated in the series connection of the two winding portions (4.1, 4.2), and the indirect control phase current flows in one of the two directions via the bridge connection (11) of the passive phase subsystem (21) according to its sign.

17. The method according to claim 15, characterized in that, in the series connection operation, all phase subsystems (21) are sequentially changed to the passive subsystem operation in a continuous sequence according to the subsystem operation parameters.

18. The subsystem operation parameters are the magnitudes of the phase currents (I ｕ , I ｖ , I ｗ ) in the phase subsystem (21). In each case, in the passive operation of the passive subsystem, the phase currents (I ｕ , I ｖ , I ｗ ) exceed a threshold value (X) with respect to magnitude, particularly in a time interval (dt) of one twelfth of the electrical period of the phase current around the peak value (S) of the phase currents (I ｕ , I ｖ , I ｗ ). The phase subsystem (21) operates. The method according to claim 15, characterized in that.

19. In the separation operation, a control phase current (I) is applied to all winding connections (10) of the two winding sections (4.1, 4.2). ｕ , I ｖ , I ｗ The method according to claim 15, characterized in that the two winding portions (4.1, 4.2) are controlled separately by all bridge connections (11) being interrupted by the switching device (12) and all half-bridges (3) of the first and second groups (3.1, 3.2) being driven, in order to provide the following:

20. In the emergency operation described above, the control phase current (I) is supplied only to one of the two winding sections (4.1, 4.2), specifically to the winding connection section (10). ｕ , I ｖ , I ｗ The method according to claim 15, characterized in that, in order to provide, only the half-bridge (3) of the first group (3.1) or the second group (3.2) is driven so that only one of the two winding portions (4.1, 4.2) is energized, and in the emergency operation, all bridge connections (11) are disconnected by the switching device (12).

21. The method according to claim 15, characterized in that, in the active short-circuit operation, all half-bridges (3) of all phase subsystems (21) are deactivated and all bridge connections (11) are made conductive in order to generate an active short circuit of the electromechanism (2) by the bridge connection (11).

22. In the series connection operation and the separation operation, the phase current (I ｕ , I ｖ , I ｗ ) forms the first three-phase current, and the phase current (I) in the winding connection portion (10) of the second winding portion (4.2) ｕ , I ｖ , I ｗ The method according to claim 15, characterized in that the above forms a second three-phase current, and the two three-phase currents in the two winding portions (4.1, 4.2) are out of phase by 180° from each other.

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