Bidirectional electrical converter arrangement employing dual active bridge converter in series with dc / ac bridge converter

Abstract

A bidirectional n-phase electrical converter device (1) has the following features: an input terminal (18) for connecting a DC voltage source; a DC / DC converter (10, 110, 210) having a first switching element (31, 134) connected to the input terminal (18); p intermediate circuits (90, 190, 290) connected on the output side to the DC / DC converter (10, 110, 210); a DC / AC converter (40, 140, 240) having a second switching element (32, 135), the DC / AC converter (40, 140, 240) being connected downstream of the p intermediate circuits (90, 190, 290); the DC / AC converter (40, 140, 240) has output terminals for connecting the electric machine (60, 160, 260) or an AC network (270); a control device (80, 280) for controlling the second switching element (32, 135) of the DC / AC converter (40, 140, 240) in such a way that a stepped n-phase output voltage (410) can be provided; and the DC / AC converter (40, 140, 240) is designed as a fundamental frequency clocked rotor controlled n-phase voltage system.

Description

Technical Field

[0001] The present invention relates to a bidirectional electrical converter device according to the features of the preamble of claim 1. Background Technology

[0002] Bidirectional electrical converters are well known in practice and are provided in a variety of embodiments. For example, a DC voltage converter with a secondary oscillation circuit capacitor is known from EP3713066A1. This DC voltage converter has a transformer, wherein a rectifier circuit and an oscillation circuit are arranged on the primary side and another rectifier circuit and an energy storage device are arranged on the secondary side.

[0003] Furthermore, a converter for potential-free power transfer is known from CH714079A2, which discloses an isolated two-stage pulse rectifier. A dual active bridge converter is provided in the first stage. The dual active bridge has full bridges on both the primary and secondary sides, and these full bridges are interconnected via transformers. The dual active bridge refers to a DC / DC converter, thereby applying DC signals to the dual active bridges on both the input and output sides. The second stage of the two-stage pulse rectifier has a three-phase bridge circuit that controls three phases.

[0004] The problem with these electrical converters, especially when operating motors, is that when using PWM control, as is typically the case in three-phase bridge circuits, not only does a large dU / dt appear on the motor's power supply lines, but also high-frequency current fluctuations occur in the sinusoidal current. High dU / dt and di / dt both lead to dense interference emissions from the drive system through the machine's control circuitry and result in high-frequency discharge currents within the machine. This, in addition to EMV (electromagnetic compatibility) radiation, can also damage the ball bearings due to micropitting. The high dU / dt of the voltage signal places increasingly stringent requirements on the machine's insulation system and reduces the overall lifespan of the machine. To mitigate these effects, active and passive filters are typically used, but this significantly increases the overall system footprint and cost. Summary of the Invention

[0005] The present invention aims to solve this problem.

[0006] This problem is solved by an electrical converter having the features of claim 1.

[0007] Advantageous designs and improvements of the invention are given in the dependent claims.

[0008] Unless otherwise stated herein, the bidirectional converter device is referred to as an electrical converter device.

[0009] Therefore, according to the present invention, an electrical converter device has an input terminal for connecting a DC voltage source and a DC / DC converter with a first switching element connected to the input terminal, wherein n is an integer greater than or equal to 1. The converter device has p intermediate circuits connected to the DC / DC converter on the output side, wherein p is an integer greater than or equal to 1. The electrical converter also has a DC / AC converter with a second switching element, wherein the DC / AC converter is connected downstream of the p intermediate circuits. The DC / AC converter has n output terminals for connecting a motor. Furthermore, a control device for controlling the second switching element is provided, such that a stepped and rotor position-dependent n-phase voltage signal can be provided, and the DC / AC converter is configured as a base-frequency timing rotor-controlled n-phase voltage system.

[0010] The electrical converter is designed to enable power flux from the input side to the output side and vice versa. In particular, this bidirectional power flux is advantageous when the electrical converter is used to operate a motor, as kinetic energy can be returned to the energy storage device connected to the input side during braking. Furthermore, the motor can supply power to the energy storage device, the power grid, or other electrical appliances via the electrical converter during generator operation.

[0011] Advantageously, the electrical converter device is configured for operating n=3-phase motors. Compared to single-phase motors, three-phase motors have a number of advantages. On the one hand, these three-phase motors generally have higher power, higher efficiency, less space requirements, and better load distribution.

[0012] In an advantageous embodiment of the invention, the control device controls the first switching element such that the output voltage of the DC / DC converter is tracked and regulated so that at least approximately sinusoidal voltage signals can be provided at n output terminals.

[0013] Advantageously, the output voltage of the DC / DC converter is tracked and regulated within a limited amplitude range, wherein the limited amplitude range is between zero and fifty percent of the intermediate circuit voltage, and wherein the limited amplitude range is preferably between zero and one-sixth of the intermediate circuit voltage.

[0014] Advantageously, the second switching element can be controlled by a control device according to the MSK method. The MSK method is described in Tobias Theopold's (formerly Rösmann) 2012 doctoral dissertation, "A mechanical commutation method for operating a permanently excited synchronous motor from a DC voltage source."

[0015] In another advantageous embodiment of the invention, the MSK control method has twelve switching states, wherein the switching states are dependent on the rotor position. An advantage of MSK control is that the second switching element switches only once per electrical rotation.

[0016] Advantageously, the regulation of the current and its torque depends on the pole wheel angle Δε, wherein for various speed-torque combinations, the corresponding pole wheel angle Δε is stored in one or more lookup tables.

[0017] As previously mentioned, the MSK method employs a switching sequence that depends on the rotor position. The rotor-controlled n-phase voltage system requires a DC voltage and a specified phase offset Δε as input variables. This DC voltage largely constitutes the intermediate circuit voltage, where the phase offset can also be referred to as the pole angle. The pole angle is the phase difference between the pole voltage and the rotor-controlled n-phase voltage system. Torque is a function of the pole angle. Torque, and therefore power, at a given speed is proportional to the independent variable of the pole angle, which is a cosine function. The pole angle is electrically located between zero and 90 degrees, where a zero-degree pole angle does not cause torque formation, and a 90-degree pole angle causes maximum torque formation. A 90-degree pole angle represents the limiting case and is called the stop point. If the pole angle exceeds 90 degrees, the motor loses synchronism and stops. The motor is operated within an unstable operating range. The electrical rotor position is determined by the mechanical rotor position and the pole evenness.

[0018] Rotor position-based adjustment methods are mostly used in permanently excited synchronous machines. Here, adjustment is also performed in the so-called dq coordinate system. In this case, the dq coordinate system is mostly oriented at the excitation flux, where, in the case of a permanently excited synchronous machine, the magnitude of the excitation flux lies in the d direction. The rotor position is determined to detect the d direction. The q direction is perpendicular to the d direction. The dq coordinate system rotates with the rotor position during operation. Besides the dq coordinate system, a stator-dependent coordinate system, also known as the αβ coordinate system, is used in the adjustment method. The α direction of the αβ coordinate system is mostly oriented along the first winding axis. The β direction is perpendicular to the α direction.

[0019] The control of the electrical converter device is specifically performed through a digital control unit. The control of the electrical converter device is significantly affected by the switching behavior of the switching elements. The control of the first and second switching elements depends on current, voltage, rotor position, and time. The control of the first and second switching elements is coordinated by the control unit. A three-phase bridge circuit arranged on the input side of the DC / DC converter measures the voltage at the input terminals. The measured voltage is transmitted to the control unit. Furthermore, voltage measurements are performed on one or more intermediate circuits. The intermediate circuit voltage measured through the intermediate circuit capacitors is also transmitted to the control unit. The current of the motor's electrical phase is measured by current measurement and transmitted to the control unit. The rotor position is detected by rotor bearing detection and transmitted to the control unit.

[0020] The control device preferably controls the second switching element of the DC / AC converter according to the MSK method. The output voltage generated by the DC / AC converter is actively controlled by a high-performance DC / DC converter as an adjustment element. Therefore, the amplitude of the stator current can be adjusted by controlling the stator voltage, and thus the torque can also be controlled / regulated.

[0021] Torque and phase current are interdependent. A larger phase current results in a larger torque, and vice versa. If a permanently excited synchronous machine is used as envisioned in this embodiment, an angle is set between the pole wheel voltage and the rotor's controlled n-phase voltage system according to the operating conditions. This angle is called the pole wheel angle and is independent of the load. The pole wheel voltage is defined as a voltage representing the voltage induced in the stator windings by the excited rotor. Both speed and torque behavior can be actively influenced over a wide operating range using appropriate lookup tables.

[0022] Motor control can also be performed using a so-called block timing method. A rectangular current is applied to the motor windings through a certain current regulation, where, in the case of a three-phase motor, current is always guided in only two branches. Phase control depends on the rotor position. As the rotor passes through an electrical angle, a commutation to the next phase occurs electrically every sixty degrees. The magnitude of the output voltage, and therefore the magnitude of the output current, is specified in this drive method by the magnitude of the intermediate circuit voltage. An undesirable common-mode voltage is set in this control method, which must be derived.

[0023] The block timing method has a relatively simple adjustment structure. In this case, it refers, for example, to cascaded regulation with internal and external adjustment circuits. The internal current regulation circuit is subdivided into an external speed regulation circuit. The current regulator outputs a target voltage value, which is set by the power switch of the inverter circuit. The phase current value and rotor position are determined and, if necessary, transmitted as actual values ​​to the corresponding adjustment circuits using differentiation or integration. The adjustment structures of both adjustment circuits employ negative feedback. The actual value is subtracted from the target value, and then the corresponding adjustment variable is set.

[0024] Another control method used to control motors is pulse width modulation (PWM). In this method, the semiconductor is hard-switched on and off multiple times within one electrical cycle, resulting in an average output signal that approximates a sinusoidal sine wave. The advantage of PWM is that the output current can be directly adjusted, enabling high-performance electrical converter devices.

[0025] Advantageously, a combination of MSK and PWM methods can be used to control electrical converter devices. In this case, the PWM method is used during startup or at low speeds, while the MSK method is used as the speed increases. With one pole pair and a maximum speed of 3000 rpm, this combination of control methods means, for example, that the PWM method is used at approximately 10% of the maximum speed, or approximately 300 rpm, while the MSK method is used for speeds above this.

[0026] According to an advantageous improvement of the invention, the motor has a mechanical commutation device. The mechanical commutation device can be implemented using brushes or slip rings. The mechanical commutation device is characterized by its robust, durable, and cost-effective structure. This control does not require complex electronics, thus improving reliability.

[0027] In another design embodiment of the invention, the p intermediate circuits are designed as capacitive intermediate circuits. Here, capacitive intermediate circuits have lower interference sensitivity than inductive intermediate circuits. This reduces electromagnetic interference. Furthermore, capacitive intermediate circuits have a fast response time, allowing them to respond quickly to load changes. Capacitive intermediate circuits are used in applications requiring rapid adjustment. Typically, capacitive intermediate circuits have lower losses, require less structural space, and are less expensive than inductive intermediate circuits. One or more intermediate circuit capacitors are charged when the electrical converter device is put into operation.

[0028] Advantageously, the capacitive intermediate circuit is implemented using one or more capacitors. It is recommended to connect capacitors with different ESRs in parallel. For example, it is recommended to connect a capacitor with a high ESR in parallel with a capacitor with a low ESR. In most cases, electrolytic capacitors, ceramic capacitors, and film capacitors are connected in parallel with each other in electro-converter devices. Generally, electrolytic capacitors have a larger ESR than film capacitors or ceramic capacitors. Unlike electrolytic capacitors, which have a liquid as a dielectric, ceramic capacitors have a ceramic dielectric, or film capacitors have a layered metal film. The liquid in an electrolytic capacitor has a higher resistance and therefore a larger ESR. Electrolytic capacitors are mostly used as energy buffers, while ceramic and film capacitors are used to filter out high-frequency components of the current.

[0029] Furthermore, the intermediate circuit can be constructed from an arrangement of capacitive and inductive impedances. The impedances are connected in a CLC arrangement, where the CLC arrangement forms a first capacitor connected in parallel to the rectifier. An inductor connects the first capacitor and a second capacitor, also connected in parallel to the rectifier, to each other. This special arrangement of impedances should be referred to here and below as a decoupling filter. A decoupling filter has better common-mode rejection than a single intermediate circuit capacitor. In the case of a simple intermediate circuit capacitor, the neutral conductor jumps back and forth between different potentials, thus increasing common-mode interference. Another possibility for making the intermediate circuit less sensitive to common-mode interference is to connect two intermediate circuit capacitors in series. The neutral conductor is connected between the two series-connected intermediate circuit capacitors. The intermediate circuit voltage is clamped to a certain voltage value.

[0030] In a particularly preferred embodiment of the present invention, the switching frequency of the first switching element is in the range of about 500 kHz to about 1 MHz.

[0031] According to another advantageous improvement of the invention, the DC / DC resonant converter has a three-phase high-frequency transformer. The advantage of a high-frequency transformer is that, for the same power, the required structural space is significantly smaller than that required with a low-frequency transformer. Furthermore, high-frequency transformers generally have higher efficiency. High-frequency transformers also have lower leakage magnetic fields. This is particularly advantageous in sensitive applications. The high-frequency transformer is preferably configured as a planar transformer. Planar transformers generally have a smaller structural space than conventional transformers because the windings are arranged flat on a plane. Furthermore, planar transformers have lower leakage inductance. This improves efficiency and reduces electromagnetic interference. Cooling of the high-frequency transformer is more easily achieved due to the planar structure, i.e., the planar transformer is mounted on one or more cooling bodies.

[0032] Advantageously, the high-frequency transformer is configured as a delta-star transformer, wherein the primary side of the high-frequency transformer is connected in a delta configuration and the secondary side of the high-frequency transformer is connected in a star configuration.

[0033] In another design embodiment of the invention, the DC / DC resonant converter is configured as a CLLC topology, wherein the CLLC topology has two capacitors and two inductors of a high-frequency transformer. The impedance of the CLLC topology is designed such that zero-voltage switching (ZVS) or zero-current switching (ZCS) can be achieved over the widest possible frequency range and over the widest possible voltage range on both the input and output sides, thereby reducing switching losses. In the case of ZVS, the semiconductor is switched when the voltage crosses zero, so ideally no power loss occurs. In the case of ZCS, the semiconductor is switched when the current crosses zero. Here, even under idealized observation, no power loss occurs.

[0034] In another design of the invention, the impedance arrangement of the CLLC topology begins with a capacitor, followed by two inductors and another capacitor connected downstream. Typically, DC / DC CLLC converters are characterized by high efficiency, up to 99%.

[0035] Advantageously, the control device is configured to control the first and second switching elements based on current, voltage, rotor position, and time.

[0036] According to an advantageous improvement of the invention, the DC / DC converter in a three-phase system has a three-phase bridge circuit on the input side. The three-phase bridge circuit, also known as the B6C bridge, is characterized by its simple structure and has proven itself to be a reliable inverter circuit in practice. In a single-phase system, the DC / DC converter has a full bridge on both the input and output sides. In addition to two-stage inverter topologies, three-stage inverter topologies, such as neutral-point clamped inverters or flying capacitor inverters, as well as multi-stage inverter topologies, can also be used.

[0037] In another preferred embodiment of the invention, the three-phase bridge circuit of the DC / DC converter has three half-bridges on both the input and output sides of the DC / DC converter, wherein each half-bridge has two switching elements.

[0038] According to an advantageous improvement of the invention, the first switching element is configured as a silicon carbide (SiC) or gallium nitride (GaN) power switch, for example, a MOSFET. Semiconductors made of silicon carbide are characterized by their high voltage strength. Furthermore, higher switching frequencies than conventional silicon semiconductors are possible. Typically, silicon carbide semiconductors have lower losses, higher temperature tolerance, and lower RDSon than conventional silicon semiconductors. Gallium nitride semiconductors are primarily used in high-switching-frequency applications. The switching losses of GaN semiconductors are significantly lower than those of conventional silicon semiconductors.

[0039] In another advantageous embodiment of the invention, the second switching element is configured as an IGBT or a MOSFET. For lower switching frequencies, conventional silicon-based MOSFETs or IGBTs are recommended because they offer significant cost advantages over SiC or GaN semiconductors.

[0040] Advantageously, the DC / DC converter and the DC / AC converter are arranged in a common conductive housing. The housing is preferably made of metal. The metal housing improves the electromagnetic compatibility of the entire system. The metal housing can shield against electromagnetic interference from or acting on the components located therein. The metal housing also provides protection against external influences such as moisture and dirt. Furthermore, the metal housing is more robust and resistant to external influences than a plastic housing.

[0041] According to the present invention, a method for operating an electrical converter device is described, wherein the electrical converter device controls at least one DC / DC converter via a first switching element and at least one DC / AC converter via a second switching element by means of a control device, wherein the second switching element of the DC / AC converter is controlled such that at least one output voltage of the DC / AC converter is configured as a pulse, wherein the at least one output voltage of the DC / DC converter is tracked and regulated between the pulses of the output voltage of the DC / AC converter such that a quasi-sinusoidal phase current is formed at the output of the electrical converter device.

[0042] In another advantageous method for operating an electrical converter device, the second switching element of the DC / AC converter is controlled according to the MSK method, wherein the MSK method generates a twelve-pulse output voltage at the output of the electrical converter device.

[0043] In another advantageous method for operating an electrical converter device, the DC / DC converter is a regulating element of the rotor-controlled n-phase voltage system, so that the amplitude of the phase current is regulated by the DC / DC converter.

[0044] In another advantageous method for operating an electrical converter device, torque regulation is performed by a phase shift between the pole wheel voltage and the rotor controlled n-phase voltage system.

[0045] Advantageously, the electrical converter device is used to operate the motor.

[0046] Advantageously, the electrical converter device is used to supply power to the AC power grid.

[0047] Three embodiments of the present invention are described below with reference to the accompanying drawings. In the first embodiment, a three-phase motor is controlled by a DC / AC converter, which is powered through p=3 intermediate circuits. In the second embodiment, a three-phase motor is controlled by a DC / AC converter, which is powered through p=1 intermediate circuit. In the third embodiment of the present invention, the motor is operated in generator operation and supplies power to the three-phase power grid. Attached Figure Description

[0048] Figure 1 The circuit diagram of the electrical converter device is shown, which includes a three-phase DC / DC converter, three intermediate circuits, a three-phase DC / AC converter, a control device, and a motor.

[0049] Figure 2 A circuit diagram of the equivalent circuit technology of an electrical converter device is shown, which includes a single-phase DC / DC converter, an intermediate circuit, a three-phase DC / AC converter, a control device, and a motor.

[0050] Figure 3 A circuit diagram of the equivalent circuit technology of an electrical converter device is shown, which includes a single-phase DC / DC converter, an intermediate circuit, a three-phase DC / AC converter, and a control device.

[0051] Figure 4 A block diagram of the control unit for the electrical converter device is shown, which has three sub-areas: drive regulation, motor regulation, and power electronics.

[0052] Figure 5 The switch table controlled by MSK is shown;

[0053] Figure 6 An example is shown of the output voltage signal of the phase, which has 12 switching states. Furthermore, a time curve of the tracked regulated output voltage of the DC / DC converter's phase is also shown.

[0054] Figure 7 The time curve of the phase current in the motor is shown. Detailed Implementation

[0055] In the following figures, the same reference numerals denote the same parts having the same meaning.

[0056] Reference Figure 1 The first embodiment of the present invention will be described in more detail below.

[0057] The electrical converter device 1 of the first embodiment includes a three-phase DC / DC converter 10, three intermediate circuits 90, a three-phase DC / AC converter 40, a control device 80, and a motor 60.

[0058] The DC / DC converter 10 has a DC voltage input side 11 and a DC voltage output side 12. The DC voltage input side 11 of the DC / DC converter 10 is powered at the input terminal 22 by an energy storage device, an AC power grid, or a DC power grid (none of which are shown). The DC / DC converter 10 is configured as a three-phase high-efficiency DC / DC resonant converter 17. The DC / DC converter 10 has a DC / AC converter 14 on the input side, wherein the DC / AC converter 14 is preferably configured as a three-phase bridge circuit 15. On the output side, the DC / DC converter 10 has an AC / DC converter 13 that converts AC signals into DC signals. A three-phase high-performance high-frequency transformer 20 is configured between the three-phase bridge circuit 20 arranged on the input side and the AC / DC converter 13, and a capacitor 21 and an inductor 22 are connected upstream or downstream of the three-phase high-performance high-frequency transformer 20 on both the input and output sides. Furthermore, a fuse 100 is connected upstream of the DC / DC converter 10, which triggers and disconnects the electrical converter 1 in the event of a fault. Alternatively, the safe disconnection of the electrical converter 1 can be achieved by corresponding control of switching elements 30, wherein the electrical converter has a first switching element 31 and a second switching element 32. The DC / DC converter 10 has the first switching element 31, and the DC / AC converter 40 has the second switching element 32.

[0059] The DC / DC converter 10 has three half-bridges 36 arranged on the input side of the three-phase bridge circuit 15. Each of the three half-bridges 36 has two first switching elements 31. The two first switching elements 31 of a half-bridge 36 are connected in series with each other. The first switching element 31 of a half-bridge 36 connected to the positive terminal 2 is called the upper switching element 33, and the first switching element 31 connected to the negative terminal 3 is called the lower switching element 34.

[0060] The first switching element 31 is preferably configured as a MOSFET. The semiconductor material of the first switching element 31 is preferably made of silicon carbide or gallium nitride. The MOSFET is topologically configured to consist of a switch 37 and a body diode 35 arranged in anti-parallel with the switch 37. If the characteristics of the body diode 35 are insufficient for possible applications, it is recommended to arrange another diode in anti-parallel with the switch 37 so that the required characteristics of the switching element 30 are satisfied.

[0061] A MOSFET has a drain pin, a source pin, and a gate pin. When an external voltage is applied to the gate pin of the MOSFET, the voltage between the gate and source changes, and the resistance between the drain and source decreases. Switching element 30 turns on. If the external voltage previously applied to the gate pin is removed, no voltage is applied between the gate and source, and the resistance between the drain and source increases. Switching element 30 turns off. Due to the high switching frequency, it is recommended to use a first switching element 31 with a small RDSon to keep switching losses as low as possible. Here, RDSon represents the minimum on-resistance of the MOSFET.

[0062] The first switching element 31 of the three-phase bridge circuit 15 arranged on the input side of the DC / DC converter 10 converts the DC signal at the input terminal 19 of the DC / DC converter 10 into a high-frequency AC signal. The high-frequency AC signal is transmitted through the high-frequency transformer 20. The high-frequency transformer 20 has a conversion ratio of 1, but it can also have a conversion ratio other than 1, such as 7 / 4.

[0063] The high-frequency transformer 20 has a primary side 24 and a secondary side 25. The high-frequency transformer 20 has a plated isolation section 27 between the primary side 24 and the secondary side 25, depending on the topology. Therefore, the DC voltage input side 11 is plated isolated from the motor 60, resulting in different reference voltages for the two subsystems and reduced interference signals.

[0064] The high-frequency transformer 20 is preferably operated in a frequency range between 500 kHz and 1 MHz. The high-frequency transformer 20 can also be operated in a smaller or larger frequency range. The higher the frequency at which the high-frequency transformer 20 is operated, the smaller its structural space becomes for the same power transmission. The high-frequency transformer 20 is configured as a three-phase transformer 26. The three-phase transformer 26 is smaller, cheaper, and lighter than three interconnected single-phase transformers because it makes more efficient use of copper and iron cores. Particularly preferably, the high-frequency transformer 20 is configured as a three-phase planar transformer 28. The planar transformer 28 is implemented either as a single component or integrated onto a single printed circuit board.

[0065] The high-frequency transformer 20 is preferably configured as a delta-star transformer. Here, the primary side 24 of the high-frequency transformer 20 is connected in a delta configuration, while the secondary side 25 of the high-frequency transformer 20 is connected in a star configuration.

[0066] The DC / DC converter 10 is preferably configured as a DC / DC resonant converter 17. The DC / DC resonant converter 17 has a CLLC topology. The CLLC topology in... Figure 1 In the illustrated embodiment, a capacitor 21 is connected to the primary side 24 of the high-frequency transformer 20, followed by an inductor 22. The secondary side 25 of the high-frequency transformer 20 has another inductor 22 and a series-connected capacitor 21, starting from the topology-conditional electroplated isolation section. Here, the two inductors 22 in the CLLC topology can be the leakage inductance 23 of the high-frequency transformer 20, or, in addition to the topology-conditional leakage inductance 23 of the high-frequency transformer 20, there is an additional inductor 22 connected in series with the leakage inductance 23 of the high-frequency transformer 20.

[0067] In a CLLC topology, inductor 22 and capacitor 23 form a series resonance. If the resonant frequency of the series resonance is greater than the switching frequency of the first switching element, the first switching element 31 can be switched on and off almost without loss. Preferably, the first switching element 31 is switched on and off without loss. For this purpose, the first switching element 31 is controlled such that it simultaneously uses a zero-voltage switching method or a zero-current switching method, or both.

[0068] In zero-current switching, switching element 30 is turned on or off when the current crosses zero. In zero-voltage switching, switching element 30 is turned on or off when the voltage crosses zero. If both zero-voltage and zero-current switching are used in a single switching process, then switching element 30 is turned on or off at both the current and voltage crossings. The power loss during the switching process arises from the product of the current and voltage applied during the switching process. If either the current or voltage, or both the current and voltage, are zero at the switching time, then the power loss during the switching process is also zero.

[0069] An AC / DC converter 13 is connected downstream of the secondary side 25 of the high-frequency transformer 20. The AC / DC converter 13 is preferably configured as a three-phase bridge circuit 16. Each output phase 29 of the high-frequency transformer 20 is connected to a half-bridge 36 of the output-side three-phase bridge circuit 16 of the DC / DC converter 10. The output phase 29 of the high-frequency transformer 20 is connected between the upper switching element 33 and the lower switching element 34 of the first switching element 31 of the half-bridge 36. An intermediate circuit capacitor 91 is connected downstream of each half-bridge 36. The first switching element 31 of the output-side three-phase bridge circuit 16 of the DC / DC converter 10 is controlled such that the currents cancel each other out. The intermediate circuit capacitor 91 maintains the intermediate circuit voltage at a predetermined voltage value. In the first embodiment, the electrical converter device 1 has three intermediate circuit capacitors 91 and therefore three intermediate circuits 90.

[0070] When the operating voltage is very high, it is recommended to connect multiple intermediate circuit capacitors 91 in series to achieve the required voltage level. Due to the series connection of the intermediate circuit capacitors 91, the total capacitance of the series-connected intermediate circuit capacitors 91 is reduced by a factor of 1 / z, where z is the number of intermediate circuit capacitors 91 connected in series. The intermediate circuit 90 preferably has electrolytic capacitors and ceramic capacitors and / or film capacitors, wherein the electrolytic capacitors are arranged in parallel with the ceramic capacitors and / or film capacitors. Here, the electrolytic capacitors act as energy buffers, while the ceramic capacitors and / or film capacitors compensate for high-frequency current fluctuations and thus maintain the intermediate circuit voltage at an approximately constant value. The intermediate circuit capacitors 91 are connected to each other on the negative side.

[0071] A half-bridge 36 is connected downstream of each intermediate circuit capacitor 91. Each half-bridge 36 connected downstream of the intermediate circuit capacitor has a second switching element 32. The three half-bridges 36 connected downstream of the intermediate circuit capacitor 91 are components of the DC / AC converter 40. Each half-bridge 36 connected downstream of the intermediate circuit capacitor 91 is connected to phase 62 of the motor 60.

[0072] The second switching element 32 is preferably configured as an IGBT or a MOSFET. The switching of the second switching element 32 is much slower than that of the first switching element 31. The half-bridge 36 connected downstream of the intermediate circuit capacitor 91 controls the various phases 62 of the motor 60. If an IGBT is used as the switching element 30, unlike a MOSFET, the diode must be installed in anti-parallel with the switch 37 because the topology-conditional body diode 35 of the MOSFET is absent in the IGBT.

[0073] The motor 60 is particularly preferably designed as a permanently excited synchronous machine 63. The permanently excited synchronous machine 63 has permanent magnets in its rotor. Thus, the rotor is always magnetized and does not need to be magnetized via the stator, as is the case in asynchronous machines or reluctance machines. In particular, magnetization of the rotor over a large air gap leads to considerable losses. Therefore, the permanently excited synchronous machine 63 is characterized by higher efficiency and higher power density compared to asynchronous machines and reluctance machines.

[0074] The permanently excited synchronous machine 63 can have magnets embedded in the rotor (IPM) or surface-mounted magnets. Different structural forms of the permanently excited synchronous machine result in different permeability values ​​along the d-direction and the q-direction, thus creating different inductances Ld and Lq in the d-direction and q-direction, respectively. For the permanently excited synchronous machine 63, Ld is not equal to Lq, where Ld is less than Lq, and for a rotationally symmetric rotor with surface magnets, Ld = Lq applies. The typical torque consists of reluctance torque and synchronous torque. The reluctance torque is generated by the interaction of different inductances along the d-direction and q-direction with the phase current, while the synchronous torque is generated by the interaction of the permanently excited magnet with the phase current. The three phase currents are converted into a dq coordinate system to simplify adjustment processing.

[0075] In the permanently excited synchronous machine where Ld=Lq is applicable, no reluctance torque is generated, making it recommended to use only the iq current during basic speed operation, where the id current is adjusted to zero. Applying a negative id current within the field decay range attenuates the field, reducing the induced voltage in the winding lines, thus enabling higher speeds at the same voltage. The disadvantage is lower torque output.

[0076] In a permanent excitation synchronous machine where Ld is less than Lq, MMPA optimization is used, for example, in the basic speed range, while MMPV optimization is used, for example, in the field decay range.

[0077] In another embodiment of the invention, the electrical mechanism is an externally excited synchronous machine. The externally excited synchronous machine has an excitation winding in the rotor. The externally excited synchronous machine can be easily adjusted via the excitation winding because the magnetization of the rotor can be easily controlled by the supplied current in the excitation winding.

[0078] The regulation of an externally excited synchronous machine is similar to that of a permanently excited synchronous machine, except that current regulation is based on the principal flux, not the excitation flux. The location of the principal flux is calculated using a current-voltage model.

[0079] In another embodiment of the invention, the electrical mechanism is called a reluctance machine. In the case of reluctance machines, a distinction is typically made between synchronous reluctance machines and switched reluctance machines. For both topologies, reluctance machines are characterized by an extremely robust structure and low manufacturing cost. Furthermore, reluctance machines mostly operate at very high speeds, resulting in significantly higher power densities compared to asynchronous machines.

[0080] The three electrical phases 62 of the motor 60 are connected to each other in a star circuit 61. However, phases 62 can also be connected in a delta circuit. In the star circuit 61, the switching element 30 of the electrical converter device 1 must be controlled such that the current in the neutral conductor is compensated.

[0081] The electrical converter device 1 measures current and voltage values ​​within a relevant range. Current and voltage measurements 81 are performed on the DC voltage input side 11 and transmitted to the control device 80. Furthermore, voltage measurements 82 are performed on three intermediate circuits 90 and also transmitted to the same control device 80. Current measurement 83 is performed at phase 62 of the motor 60. The current determined by current measurement 83 and the rotor position determined by rotor position detection 84 are transmitted to the control device 80.

[0082] Figure 2 The diagram shows an electrical converter device 1, a single-phase DC / DC converter 110, an intermediate circuit 190, a three-phase DC / AC converter 140, a control device 180, and a motor 160.

[0083] The DC / DC converter 110 is connected to an energy source on its input side. The energy source can be a battery, an AC / DC power supply, or a DC / DC power supply. A fuse 200 is connected between the energy source and the DC / DC converter 110, which safely disconnects the electrical converter 110 from the energy source in the event of a failure.

[0084] The DC / DC converter 110 is configured as a single phase. The DC / DC converter 110 has an input-side full-bridge 111 and an output-side full-bridge 112, both having a first switching element 134. A transformer 120 is configured between the two full-bridges 111-112. Preferably, the transformer 120 is configured as a high-frequency transformer 121. Each full-bridge 111-112 has four switching elements 130. The switching elements 130 are arranged in half-bridges 136. Each half-bridge 136 consists of two switching elements 130 connected in series. Each switching element 130 has a switch 132 and a diode 133 arranged in anti-parallel to the switch 132. Each full-bridge 111-112 has two half-bridges 131 connected in parallel. The first switching element 134 of the input-side full-bridge 111 converts a DC signal into a high-frequency AC signal, while the output-side full-bridge 112 converts the high-frequency AC signal into a DC signal. The advantage of high-frequency AC signals is that the high-frequency transformer 121 has higher efficiency and smaller structural space than the case of low-frequency AC signals at the same power.

[0085] The first switching element 134 is preferably configured as a MOSFET and uses gallium nitride or silicon carbide as the semiconductor material. The switching frequency of the first switching element 134 of the two full-bridge 111-112 of the DC / DC converter 110 is preferably between 500 kHz and 1 MHz. However, the switching frequency of the first switching element 134 can also be in a smaller or larger frequency range.

[0086] A high-frequency transformer 121 is connected between the two full-bridge converters 111-112 of the DC / DC converter 110. The high-frequency transformer 121 has impedances on both the input and output sides. The impedances on the input and output sides refer to a capacitor 122 and an inductor 123, respectively, wherein the inductor 123 may be the leakage inductance 124 of the high-frequency transformer 121. Therefore, the DC / DC converter 110 is preferably configured as a DC / DC resonant converter 113 in a CLLC topology.

[0087] The high-frequency transformer 121 is connected to the power supply line 125 between the two first switching elements 134 of one half-bridge 131 of the full bridge 111-112. The discharge line 126 of the high-frequency transformer is connected between the two first switching elements 134 of the other half-bridge 131 of the full bridge 111-112.

[0088] On the output side, the DC / DC converter 110 is connected to a capacitive intermediate circuit 190. The capacitive intermediate circuit 190 is implemented using intermediate circuit capacitors 191. Here, the intermediate circuit capacitors 191 can be implemented by multiple intermediate circuit capacitors 191 arranged in series or parallel with each other. Preferably, electrolytic capacitors, film capacitors, and ceramic capacitors are used. The intermediate circuit 190 acts as an energy buffer and filters out high-frequency current components.

[0089] A DC / AC converter 140 is connected downstream of the intermediate circuit capacitor 191, wherein the DC / AC converter 140 is configured as a three-phase bridge circuit 141. Here, the three-phase bridge circuit 141 has three half-bridges 131, each of which has two second switching elements 135. The second switching elements 135 are configured as IGBTs or MOSFETs. The switching frequency of the second switching elements 135 is significantly lower than the switching frequency of the first switching element 134 and is approximately in the three-digit frequency range. However, the switching frequency can also be in a larger or smaller frequency range.

[0090] A three-phase bridge circuit 141 controls each phase 161 of the motor 160. As a control method, the MSK method, block timing, PWM method, or a combination thereof can be used.

[0091] The control of the first switching element 134 and the second switching element 135 is taken over by the control device 180. For this purpose, voltage, current, and rotor position are detected and supplied to the control device 180. The control device 180 controls the second switching element 135 of the three-phase bridge circuit 141 to generate a twelve-pulse voltage signal. Furthermore, the control device 180 controls the first switching element 134 of the DC / DC converter 110 such that the output voltage of the DC / DC converter 110 is tracked and regulated so that the output voltage of the DC / DC converter 110 and the output voltage of the three-phase bridge circuit 141 induce a quasi-sinusoidal current curve in phase 162 of the motor 160.

[0092] Figure 3 A third embodiment of the electrical converter device 1 is shown, which includes a single-phase DC / DC converter 210, two intermediate circuits 290, a three-phase DC / AC converter 240, and a control device 280. The three-phase DC / AC converter 240 is configured as a three-phase bridge circuit 241, wherein the three-phase bridge circuit 241 is connected to a three-phase AC power grid 270. However, the AC power grid 270 may also be configured as a single phase, so the DC / AC converter 240 is preferably configured as a full bridge. An intermediate circuit 250 is configured between the three-phase bridge circuit 221 connected to the motor and the DC / DC converter 210. Another intermediate circuit 290 is configured between the three-phase bridge circuit 241 connected to the AC power grid 270 and the DC / DC converter 210.

[0093] The electrical converter device 1 in this embodiment is the same as the electrical converter device 1 from the second embodiment, but it may also correspond to the electrical converter device 1 from the first embodiment.

[0094] In a preferred embodiment, unlike the embodiments shown above, motor 260 is additionally connected to the DC voltage input side 211 of DC / DC converter 210 via DC / AC converter 220. Preferably, an intermediate circuit capacitor 251 connected to motor 260 is connected between DC / DC converter 210 and DC / AC converter 220. Preferably, a three-phase motor 260 is used, such that DC / AC converter 220 is preferably configured as a three-phase bridge circuit 220. The switching elements 230 of the three-phase bridge circuit 220 have a maximum switching frequency of several hundred hertz. The switching elements 230 are preferably configured as IGBTs or MOSFETs and consist of a switch 231 and a diode 232 arranged in anti-parallel to the switch 231. A single-phase motor 260 may also be used, which is connected to intermediate circuit 250 via full bridge 222.

[0095] exist Figure 4 The diagram illustrates control of the electrical converter device 1 via control devices 80 and 280. This control is similar for the three application examples listed earlier.

[0096] The control unit 80; 280 can be further divided into three sub-regions. These sub-regions are drive regulation 310, motor regulation 330, and power electronics 350 and measurement data detection 390. Power electronics 350 controls the motor. Measurement data detection 390 measures voltage, current, and rotor position and provides the values ​​to the control unit.

[0097] Drive adjustment 310 refers to cascaded adjustment with three adjustment circuits. The distinction is made between the external adjustment circuit 316 of position adjustment 315, the intermediate adjustment circuit 321 of speed adjustment 320, and the internal adjustment circuit 326 of current adjustment 325.

[0098] The target position value ε_ref and the actual position value ε_ist are transmitted to the external regulating circuit 316 that performs the position adjustment 315. The actual position value ε_ist can be determined by means of rotor position detection (84). The actual position value ε_ist and the target position value ε_ref are subtracted from each other. Since no interfering variables act on this regulating circuit based on experience, it is recommended that the position regulator 315 be implemented as a P regulator. The output variable of the position regulator 315 is the target speed value n_ref of the speed regulator 320.

[0099] The speed regulator 320 maps to the intermediate regulator circuit 321. The target speed value n_ref of the position regulator 315 is transmitted to the speed regulator 320. The actual speed n_ist is determined based on the change in the motor position angle and is also transmitted to the speed regulator 320. The intermediate regulator circuit 321, like all three regulator circuits, has negative feedback. This means that the actual value is subtracted from the target value. It is recommended that the speed regulator 320 be implemented as a PI regulator. An I component is needed to compensate for load torque disturbance variables. The output variable of the speed regulator 320 is the torque target value M_ref of the current regulator 325.

[0100] The current regulator 325 constitutes the internal regulation circuit 326. On the input side, the target torque M_ref and the actual current are transmitted. It is recommended that the actual current be converted to the dq coordinate system before being transmitted to the internal regulation circuit 326. In this case, the current is determined for each or at least two phases of the motor, for example, using a Rogowski spule. Subsequently, the three phase currents 62;161 are converted to the dq coordinate system using a Park-Transformation. In this case, it is recommended that the id current and iq current be regulated independently of each other. To this end, the two regulation sections of the d and q components are decoupled by pre-control of coupling terms. The current regulator 325 has voltages U_(sd_ref) and U_(sq_ref) as output variables.

[0101] The output voltages U_(sd_ref) and U_(sq_ref) of the current regulator 325 are transferred to the Cartesian polar coordinate converter 340. The Cartesian polar coordinate converter 340 converts the voltages U_(sd_ref) and U_(sq_ref) existing in the Cartesian coordinate system into polar coordinates. In the polar coordinate system, a voltage space vector with amplitude and angle is given. The Cartesian polar coordinate converter 340 has the pole wheel angle Δε and the voltage amplitude U_(abs_ref) as output variables. Here, the pole wheel angle Δε is the phase shift between the pole wheel voltage and the rotor-controlled multiphase voltage system.

[0102] The current intermediate circuit voltage U_(dc_act), pole angle Δε, and current rotor position ε are transmitted to the MSK modulator 360, which provides a DC / AC output voltage 420. As its name suggests, the MSK modulator 360 controls the corresponding switching elements 30; 130; 230 according to the MSK method. The power required at the operating point depends on the speed and torque. At a given speed, the current, and therefore the torque, is regulated by the pole angle Δε. Different pole angle Δε is set for different speed-torque combinations. Here, the corresponding pole angle Δε can be stored in one or more lookup tables. By correspondingly changing the pole angle Δε, both speed and torque behavior can be actively influenced over a wide operating range. By pre-calculating the pole angle Δε, real-time calculation requirements can be significantly reduced.

[0103] The voltage U_(abs_ref) is transmitted to the DC / DC regulator 370, and also to the current voltage of the DC / DC converters 10; 110; 210 at the motor terminals and the output voltage 420 of the DC / AC converter. The MSK modulator 360 sets these voltages via the second switching elements 32; 135 of the DC / AC converters 10; 110; 210. The DC / DC regulator 370 transmits the target voltage value U_(dcdc_act) of the DC / DC converter to the CLLC modulator 380. Then, the first switching elements 31, 134 are switched such that the voltage at the output of the DC / DC converters 10; 110; 210 is tracked and regulated such that a quasi-sinusoidal current curve is set in the phase of the motor 60; 160; 260 or the AC grid 270 by superposition with the output voltage 410 of the DC / AC converters 40; 140; 240. The tracking regulation voltage representing the intermediate circuit voltage at the output 420 of the DC / DC converters 10, 110, and 210 is tracked and regulated within a limited amplitude range. This limited amplitude range is between zero and fifty percent of the intermediate circuit voltage, preferably between zero and one-sixth of the intermediate circuit voltage.

[0104] The regulator of the DC / DC converter 370 also has a cascaded structure. An external voltage regulation circuit is superimposed on the internal current regulation circuit. Both the current regulator and the voltage regulator are preferably implemented as PI regulators. The DC / DC converters 10, 110, and 210 serve as regulating elements in the rotor-controlled multiphase voltage system. The regulation of the DC / DC converters 10, 110, and 210 regulates and limits the current in the electrical converter device 1 and therefore also in the motors 60, 160, and 260.

[0105] In the third embodiment, almost the same regulation topology as in the first and second embodiments is used. Regulation of the DC / AC converters 40; 140; 240, directly connected to the AC grid 270, ensures that as much active power as the motors 60; 160; 260 feeds into the AC grid 270 on the input side; otherwise, the intermediate circuit voltage at the intermediate circuit capacitors 91; 191 would change, which is undesirable. The second switching element 32; 135 is switched by the control device 80; 280 such that the intermediate circuit voltage remains almost constant at a predetermined target value. The current flowing from the DC / AC converters 40; 140; 240 into the intermediate circuit capacitors 91; 191 is referred to herein and hereinafter as DC. DC is proportional to the active current on the grid side under constant grid voltage and constant intermediate circuit voltage. It is recommended to regulate the active current to the grid side using phase voltage as the regulation element, rather than DC. Reactive current is generated from the active current. In the equivalent circuit diagram of the regulation technique, the active current corresponds to the current id, and the reactive current corresponds to the current iq. During quiescent operation, the reactive current is regulated to zero, thereby setting a power factor of 1.

[0106] Figure 5 A switch table 401 for the MSK control method is shown. Each switch changes its state only once per electrical rotation. Switch table 401 has eleven columns. The first column indicates the name of the corresponding switch state. In this case, a distinction is also made between F-states and I-states. Switch states with the prefix F correspond to the switch state of the base frequency timing during direct self-regulation, and switch states with the prefix I correspond to a switch state in the branch that does not conduct current. The combination of switch states with the prefix F and switch states with the prefix I contains all the switch states of the MSK method. The second column indicates at which electrical rotor angle the switch state changes. In the switch sequence shown in this exemplary annotation, the switch sequence begins at F1 and ends at I6. The switch state changes electrically once every 30 degrees. Columns three through five indicate the state of the branch voltage. Columns six through twelfth indicate the switch state of the second switching element. 1 indicates the switch is closed, and zero indicates the switch is open.

[0107] exist Figure 6The diagram shows the output voltage 410 of the DC / AC converter 40;140;240 for electrical phases 62;161 of motors 60;160;260. Output voltage 410 has a twelve-pulse switching pattern. Therefore, the twelve-pulse capability is due to the fact that three additional possible voltage states can be set. These voltage states are positive, negative, and zero. Positive indicates that a positive voltage is applied to the phase, negative indicates that a negative voltage is applied to the phase, and zero indicates that no voltage is applied across phases 62;161 and therefore no current flows through the corresponding phases 62;161. It has been shown that when switching with zero phase, the length of the voltage pointer is shortened, making it only a quasi-twelve-pulse three-phase voltage system. The zero state in the branch is preferably set directly. What happens within the switching sequence is that the anti-parallel diodes 35;133;232 of the second switching element 32;135 clamp the series voltage to either the positive or negative terminal. The inductive behavior of the phase branch causes the current to continue to be driven initially, even when the circuit is on or off, and the corresponding diodes conduct. If the current decreases, the diode turns off and reaches the actual voltage state. Switching at zero current crossing can at least partially prevent or shorten this undesirable clamping of the branch voltage.

[0108] In addition, Figure 6 In the same figure, the tracking regulation voltage 420 at the output of the DC / DC converters 10, 110, and 210 for electrical phases 62 and 161 of motors 60, 160, and 260 is shown. A quasi-sine curve for the phase current 430 of motors 60, 160, and 260 is generated by superimposing the output voltage 410 of the DC / AC converters 40, 140, and 240 with the tracking regulation voltage 420 at the output of the DC / DC converters 10, 110, and 210.

[0109] The dynamic tracking regulation voltage 420 of the high-performance DC / DC converters 10, 110, and 210 is within a limited range. The limited range of the tracking regulation voltage 420 is preferably from zero to fifty percent, and in particular, the tracking regulation voltage 420 should have a range from zero to one-sixth of the intermediate circuit voltage.

[0110] exist Figure 7 The diagram shows a quasi-sinusoidal curve of the phase current 430 in the motor. The quasi-sinusoidal curve of the phase current 430 in the motor is set by superimposing the output voltage 410 of the DC / AC converter and the tracking regulation voltage 420 of the DC / DC converter. The approximate sinusoidal curve of the phase voltage generates the approximate sinusoidal curve of the phase current 430 in the motor.

[0111] List of reference numerals

[0112] 1 Electrical converter device

[0113] 2 positive electrode

[0114] 3 negative electrodes

[0115] 10 DC / DC converter

[0116] 11 DC voltage input side

[0117] 12 DC voltage output side

[0118] 13 AC / DC converter

[0119] 14 DC / AC converter

[0120] 15. Three-phase bridge circuit (primary)

[0121] 16. Three-phase bridge circuit (secondary)

[0122] 17 DC / DC Resonant Converter

[0123] 18 input terminals

[0124] 20 high-frequency transformers

[0125] 21 capacitors

[0126] 22 Inductors

[0127] 23 Leakage Inductance

[0128] 24 Primary Side

[0129] 25 secondary sides

[0130] 26 Three-phase transformer

[0131] 27 Electroplating Insulation Section

[0132] 28 planar transformers

[0133] 29 phases

[0134] 30 Switching Components

[0135] 31 First Switching Element

[0136] 32 Second Switching Element

[0137] 33 upper switching element

[0138] 34-way switching element

[0139] 35-body diode

[0140] 36 half bridge

[0141] 37 switches

[0142] 40 DC / AC converter

[0143] 60 motor

[0144] 61 star circuit

[0145] 62 electrical phases

[0146] 63 Permanent Excitation Synchronous Machine

[0147] 81 DC Current and Voltage Measurement

[0148] 82 Intermediate Circuit Voltage Measurement

[0149] 83 Motor Current Measurement

[0150] 84 Rotor Position Detection

[0151] 90 intermediate circuit

[0152] 91 intermediate circuit capacitor

[0153] 100 safety device

[0154] 110 DC / DC converter

[0155] 111 full-bridge input side

[0156] 112 Full Bridge Output Side

[0157] 113 DC / DC Resonant Converter

[0158] 120 transformer

[0159] 121 High-Frequency Transformer

[0160] 122 capacitor

[0161] 123 Inductor

[0162] 124 leakage inductance

[0163] 125 power supply line

[0164] 126 discharge circuit

[0165] 130 switching element

[0166] 131 Half Bridge

[0167] 132 switch

[0168] 133 diode

[0169] 134 First Switching Element

[0170] 135 Second Switching Element

[0171] 140 DC / AC converter

[0172] 141 Three-phase bridge circuit

[0173] 160 motor

[0174] 161 motor phases

[0175] 190 intermediate circuit

[0176] 191 intermediate circuit capacitor

[0177] 200 safety devices

[0178] 210 DC / DC converter

[0179] 211 DC voltage input side

[0180] 220 DC / AC converter

[0181] 221 Three-phase bridge circuit

[0182] 222 Full Bridge

[0183] 230 switching element

[0184] 231 switch

[0185] 232 diode

[0186] 240 DC / AC converter

[0187] 241 Three-phase bridge circuit

[0188] 250 motor intermediate circuit

[0189] 251 AC / DC intermediate circuit capacitor

[0190] 260 motor

[0191] 270 AC power grid

[0192] 280 control device

[0193] 290 power grid intermediate circuit

[0194] 310 drive adjustment

[0195] 315 Position Adjustment

[0196] 316 External Adjustment Circuit

[0197] 320 RPM Adjustment

[0198] 321 intermediate adjustment circuit

[0199] 325 Current Adjustment

[0200] 326 Internal Adjustment Circuit

[0201] 330 Motor Controller

[0202] 340 Cartesian polar coordinate converter

[0203] 350 power electronic devices

[0204] 360MSK modulator

[0205] 370 DC / DC converter regulation

[0206] 380CLLC modulator

[0207] 390 Measurement Data Detection

[0208] 401 switch meter

[0209] 410 DC / AC output voltage

[0210] 420 Tracking Regulated Voltage

[0211] 430-phase current

Claims

1. A bidirectional n-phase electrical converter device (1), which has the following characteristics: Input terminal (18) for connecting to a DC voltage source; A DC / DC converter (10; 110; 210) having a first switching element (31; 134) connected to the input terminal (18); p intermediate circuits (90; 190; 290) are connected to the DC / DC converter (10; 110; 210) on the output side. A DC / AC converter (40; 140; 240) with a second switching element (32; 135), wherein, The DC / AC converter (40; 140; 240) is connected downstream of the p intermediate circuits (90; 190; 290); The DC / AC converter (40; 140; 240) has output terminals for connecting a motor (60; 160; 260) or an AC power grid (270); Control devices (80; 280) are used to control the second switching element (32; 135) of the DC / AC converter (40; 140; 240) so that a stepped n-phase output voltage (410) can be provided; and The DC / AC converters (40; 140; 240) are configured as a base frequency timing rotor controlled n-phase voltage system.

2. The electrical converter device (1) according to claim 1, characterized in that, The electrical converter device (1) is configured as n=3 phases.

3. The electrical converter device (1) according to claim 1, characterized in that, The control device (80; 280) controls the first switching element (31; 134) such that the output voltage of the DC / DC converter (10; 110; 210) is tracked and regulated so that at least an approximately sinusoidal voltage signal can be provided at n output terminals.

4. The electrical converter device (1) according to claim 3, characterized in that, The output voltage (420) of the DC / DC converter (10; 110; 210) is tracked and regulated within a limited amplitude range, wherein the limited amplitude range is within 0 to 50 percent of the intermediate circuit voltage, and wherein the limited amplitude range is preferably within 0 to 1 / 6 of the intermediate circuit voltage.

5. The electrical converter device (1) according to any one of claims 1 to 4, characterized in that, The control of the second switching element (32; 135) of the DC / AC converter (40; 140; 240) is performed according to the MSK method.

6. The electrical converter device (1) according to claim 5, characterized in that, The MSK control method has twelve switching states, wherein the switching states are dependent on the rotor position.

7. The electrical converter device (1) according to any one of the preceding claims, characterized in that, The regulation of current and its torque depends on the pole angle Δε, where for various speed-torque combinations, the corresponding pole angle Δε is stored in one or more lookup tables.

8. The electrical converter device (1) according to any one of the preceding claims, characterized in that, The motors (60; 160; 260) have mechanical commutation devices.

9. The electrical converter device (1) according to any one of the preceding claims, characterized in that, The p intermediate circuits (90; 190; 290) are designed as capacitive intermediate circuits (90; 190; 290).

10. The electrical converter device (1) according to claim 9, characterized in that, The capacitive intermediate circuit (90; 190; 290) is implemented by intermediate circuit capacitors (91; 191).

11. The electrical converter device (1) according to any one of the preceding claims, characterized in that, The switching frequency of the first switching element (31; 134) is in the range of about 500 kHz to about 1 MHz.

12. The electrical converter device (1) according to any one of the preceding claims, characterized in that, The DC / DC converters (10; 110; 210) have three-phase high-frequency transformers (20; 120).

13. The electrical converter device (1) according to claim 12, characterized in that, The high-frequency transformers (20; 120) are configured as delta-star transformers, wherein the primary side of the high-frequency transformers (20; 120) is connected in a delta configuration, and the secondary side of the high-frequency transformers (20; 120) is connected in a star configuration.

14. The electrical converter device (1) according to any one of the preceding claims, characterized in that, The DC / DC converters (10; 110; 210) are configured as DC / DC resonant converters (17; 113).

15. The electrical converter device (1) according to claim 14, characterized in that, The DC / DC converters (10; 110; 210) are configured as CLLC topologies, wherein a CLLC topology has two capacitors (21; 122) and two inductors (22; 123) of the high-frequency transformer (20; 120).

16. The electrical converter device (1) according to any one of claims 14 to 15, characterized in that, The impedance arrangement of the CLLC topology first has a capacitor (21; 122), followed by two inductors (22; 123) and another capacitor (21; 122) connected downstream.

17. The electrical converter device (1) according to claim 15 or 16, characterized in that, The inductance (22; 123) of the CLLC topology is the leakage inductance (123; 124) of the high-frequency transformer (20; 120).

18. The electrical converter device (1) according to any one of the preceding claims, characterized in that, The control device (80; 280) is configured such that the first switching element (31; 134) and the second switching element (32; 135) are controlled in relation to current, voltage, rotor position and time.

19. The electrical converter device (1) according to any one of the preceding claims, characterized in that, The DC / DC converters (10; 110; 210) have three-phase bridge circuits (15; 141) on the input and output sides.

20. The electrical converter device (1) according to claim 19, characterized in that, The three-phase bridge circuit (15; 141) has n half-bridges (36; 131), wherein each half-bridge (36; 131) has two switching elements (32; 135).

21. The electrical converter device (1) according to any one of the preceding claims, characterized in that, The first switching element (31; 134) is configured as a silicon carbide (SiC) or gallium nitride (GaN) MOSFET.

22. The electrical converter device (1) according to any one of the preceding claims, characterized in that, The second switching element (32; 135) is configured as an IGBT or a MOSFET.

23. The electrical converter device (1) according to any one of the preceding claims, characterized in that, The DC / DC converters (10; 110; 210) and the DC / AC converters (40; 140; 240) are arranged in a metal housing.

24. A method for operating an electrical converter device (1), wherein, The electrical converter device (1) controls at least one DC / DC converter (10; 110; 210) via a first switching element (31; 134) and at least one DC / AC converter (40; 140; 240) via a second switching element (32; 135) of the DC / AC converter (40; 140; 240), wherein the second switching element (32; 135) of the DC / AC converter (40; 140; 240) is controlled such that the at least one output voltage (410) of the DC / AC converter (40; 140; 240) is pulsed, wherein the at least one output voltage (420) of the DC / DC converter (10; 110; 210) is tracked and regulated between the pulses of the output voltage (410) of the DC / AC converter (40; 140; 240) such that a quasi-sinusoidal phase current (430) is formed at the output of the electrical converter device (1).

25. The method for operating an electrical converter device (1) according to claim 25, characterized in that, The second switching element (32; 135) of the DC / AC converter (40; 140; 240) is controlled according to the MSK method, wherein the MSK method generates a twelve-pulse output voltage (410) at the output of the electrical converter device (1).

26. The method for operating the electrical converter device (1) according to any one of claims 25 to 26, characterized in that, The DC / DC converter (10; 110; 210) is the regulating element of the rotor-controlled n-phase voltage system, so that the amplitude of the phase current (430) is regulated by the DC / DC converter (10; 110; 210).

27. The method for operating the electrical converter device (1) according to any one of claims 25 to 27, characterized in that, Torque regulation is achieved through a phase shift between the pole wheel voltage and the rotor controlled n-phase voltage system.

28. The electrical converter device (1) according to any one of the preceding claims, characterized in that, The electrical converter device (1) is used to operate the motor (60; 160; 260) or to supply power to the n-phase AC power grid (270).

Images