KR20120029334A - Filter for a three-phase alternating voltage and a three-phase alternating current, method for filtering a three-phase alternating voltage and a three-phase alternating current, and compressor system comprising the same - Google Patents

Abstract

PURPOSE: A filter for a 3 phase AC current and 3 phase voltage, a filtering method of the filter3 phase AC current and 3 phase voltage, and a compressor system including the same are provided to accomplish high symmetric of a circuit by arranging one capacitor between two phases. CONSTITUTION: A filter(200) is for 3 phase AC current and 3 phase voltage. The filter comprises a conductor assembly, 3 inductors(Lf), and a capacitor assembly. The conductor assembly is composed of 3 electrical conductors. The 3 inductors have a same inductance value. Each one of the inductors is serially connected to one conductor. The capacitor assembly is composed of 3 capacitors(Cfd). The 3 capacitors have same capacitance. Each one of the capacitors is connected to an interval between two conductors.

Description

Filter for three-phase alternating voltage and three-phase alternating current, filtering method for three-phase alternating voltage and three-phase alternating current, and a compressor system having the same FOR FILTERING A THREE-PHASE ALTERNATING VOLTAGE AND A THREE-PHASE ALTERNATING CURRENT, AND COMPRESSOR SYSTEM COMPRISING THE SAME}

The present invention relates to a filter for three-phase alternating voltage and three-phase alternating current, a filtering method for filtering three-phase alternating voltage and three-phase alternating current, and a compressor system, according to the independent claims.

DE 19928481 B4 describes a method for simplifying field-oriented control of a synchronous machine.

The three phase alternating voltage and three phase alternating current for controlling the inductor can be filtered by the filter assembly.

Against this background, the present invention provides a filter for three-phase alternating current and three-phase alternating current, and a compressor system using the filter, as well as a corresponding filter for finally filtering three-phase alternating voltage and three-phase alternating current. Each filtering method is presented according to the independent claims. Preferred embodiments are shown in the respective dependent claims and in the detailed description below.

The present invention is based on the recognition that further losses of the stator and rotor occur in the inductor by the clock-controlled mode of operation of the pulse controlled inverter PWR, and further measures are required to prevent this loss. One measure is to use a passive LC filter between the pulse controlled inverter and the inductor. In this case, the inductor can be implemented as a synchronous or asynchronous device, as a switched reluctance machine, or as a homopolar machine. In particular, the induction machine may be an electric motor of an electric turbo compressor (ETC). According to the invention an LC filter with capacitors is implemented in a delta circuit.

Preferably, under conditions of equal filter effect, the value of the filter capacitance per filter capacitor is reduced by a triangular circuit to one third of that value in the alternative star circuit. The current in the filter capacitor is as low as the factor √3 compared to the molded circuit. The current load substantially determines the heating state of the capacitor and thus its lifetime. Thus, higher filter effects can be achieved when the overall size of the capacitors is the same. In this case, it should be noted that the voltage load of the capacitors preferably increases by a factor √3. However, even if the voltage load rises, the total size of the capacitors does not need to be enlarged to the same overall size as the three times the value of the filter capacity. The triangular circuit thus offers the advantage that the overall size is considerably smaller, so that the mounting volume required by the filter is as small as possible. Furthermore, by applying a triangular circuit to the LC filter for powering the turbo compressor, the distortion current can be prevented.

Unlike a molded circuit, in a triangular circuit, the capacitance of the capacitor does not always need to represent the calculated nominal value for the filter. In addition, the capacitors are not supplied with a relatively high current and therefore are not supplied with a high ripple current. Since the star point is omitted, there is no forming point implemented in a floating manner that can be clearly distinguished from the forming point of the device at the potential. The distortion current is thereby prevented.

The present invention provides a filter for three-phase AC voltage and three-phase AC current, the filter,

A conductor assembly consisting of three electrical conductors for three phase alternating voltage and three phase alternating current,

Three inductors, each of which is connected in series with each one of the conductors,

Each one of the capacitors comprises a capacitor assembly consisting of three capacitors connected between each two of the conductors.

The filter is suitable for the low-harmonic power supply of inductors. For example, the filter can be used as an output filter for a pulse controlled inverter for low loss power supply of an electric turbo compressor. The three phase AC voltage or the three phase AC voltages may include three AC voltages having a phase shift of 120 ° and having the same frequency. Three-phase alternating current or three-phase alternating currents may include three alternating currents exhibiting a phase shift of 120 ° and having the same frequency. The three phase alternating current may be referred to as three phase current and the three phase alternating voltage may be referred to as three phase voltage. The size of the electrical conductor is set to carry three-phase voltage and three-phase current. Inductors and capacitors can be realized as discrete components. The inductor may be implemented as a choke or coil and inserted into the conductor at a suitable location. In addition, the inductor may be formed by the conductor itself so that the conductor includes the inductor. Capacitors and inductors can each cause a phase shift between current and voltage. Through suitable values for the capacitance of the capacitors and the inductors, the filter characteristics of the filter can be adjusted. The filter may be designed to pass one or more active components of three-phase alternating voltage and three-phase alternating current without variation and to filter one or more interference components of three-phase alternating voltage and three-phase alternating current.

The three capacitors can be connected to each other in a triangular circuit. Triangular circuits can reduce the current load, thereby increasing the life of triangle mounted components. In the case of the triangular circuit of capacitors, the circulating current generated in some cases between the capacitors can be prevented by the triangular circuit being configured as symmetrically as possible.

The filter may be a low pass filter. Thus, three-phase alternating voltage can pass undisturbed at frequencies below the low pass filter's limit frequency, while frequencies above the low pass filter's limit are attenuated, eliminating high frequencies that overlap the three-phase alternating voltage. Can be.

The conductor assembly may include first terminals for picking up the three-phase alternating current and three-phase alternating current from the pulse controlled inverter and second terminals for outputting the filtered three-phase alternating voltage and the filtered three-phase alternating current to the inductor. And the capacitor assembly is connected with the second terminals of the conductor assembly. The filtered three-phase AC voltage and the filtered three-phase AC current may be generated through filtering of the three-phase AC voltage and the three-phase AC current using a filter. This can eliminate signal interference in three-phase alternating voltage and three-phase alternating current, resulting from the pulse controlled inverter, so that additional losses of stator and rotor in the inductor can be reduced.

According to an embodiment of the invention, the first terminal of the first inductor of the inductors is connected with the first terminal of the first conductor of the conductors and the second terminal of the first inductor is connected with the second terminal of the first conductor A first terminal of the second inductor of the inductors is connected with a first terminal of the second conductor of the conductors, a second terminal of the second inductor is connected with a second terminal of the second conductor, and a third inductor of the inductors The first terminal of is connected with the first terminal of the third of the conductors, the second terminal of the third inductor is connected with the second terminal of the third conductor, and the first terminal of the first capacitor of the capacitors is first Connected with a second terminal of the conductor and a second terminal of the first capacitor connected with a second terminal of the second conductor, wherein a first terminal of the second capacitor of the capacitor is connected with a second terminal of the second conductor and The second terminal of the capacitor is connected with the second terminal of the third conductor, and the first terminal of the third capacitor of the capacitor The second terminal of the third conductor may be connected and the second terminal of the third capacitor may be connected to the second terminal of the first conductor. By placing the inductors in front of the capacitors, a more improved transient response of the filter can be ensured.

Each of the three inductors may include inductance values of the same magnitude. Correspondingly, the three capacitors may each contain capacitance values of the same magnitude. By doing so, a symmetrical structure is possible.

In addition, the present invention provides a compressor system, the compressor system,

A turbocompressor for compressing a gas including an induction machine as a drive device;

A pulse controlled inverter for supplying three-phase alternating voltage and three-phase alternating current for an inductor;

A filter according to the invention for three-phase alternating voltage and three-phase alternating current.

A turbocompressor may mean a turbo machine that, if mechanical energy is provided in the form of a rotation, is capable of raising the gas compressible by the rotating component, ie the rotor, to a pressure level above the ambient pressure level. Turbo compressor may also mean a thermal turbo appliance and in particular a turbo compressor. The turbo machine may thus comprise a compressor and / or a turbine. Within the compressor the turbo machine can compress gases. The mechanical energy required for compression can be supplied from the induction machine. In the turbine the turbomachine can decompress the gas. The energy can then be provided in the form of mechanical energy that can be delivered to a compressor or converted into electrical energy by an inductor.

The inductor can be an electric motor including three inductors that can be disposed at an angle of 120 °. An inductor can convert electrical energy into mechanical energy and vice versa. The pulse controlled inverter may be an electrical device capable of converting an input voltage into an alternating voltage having a predetermined frequency and amplitude. The alternating voltage may be a three phase alternating voltage. The inductor can be operated with three phase alternating voltage. Compressor systems can be used in conjunction with fuel cells. In this case, the gas compressed by the turbo compressor may be supplied to the fuel cell.

In addition, the present invention provides a filtering method for filtering a three-phase AC voltage, the method,

A three-phase alternating voltage and a three-phase alternating current in a conductor assembly consisting of three electrical conductors under the condition that each inductor is connected in series with each one of the conductors and each capacitor is connected between two respective ones of the conductors. Applying a three-phase alternating current.

The invention is illustrated in more detail by way of example on the basis of the accompanying drawings.
1 is a circuit diagram showing a filter assembly for a three-phase electric motor.
2 is a circuit diagram illustrating an embodiment of a filter assembly according to an embodiment of the present invention.
3 is a flowchart illustrating a procedure of a method according to an embodiment of the present invention.

In the following description of the preferred embodiment of the present invention, the same or similar reference numerals are used for members that are shown in different figures but act similarly, and repeated descriptions of the members are omitted.

1 shows an embodiment of a filter assembly. The filter 100 is arranged in a three phase line between the pulse control inverter 110 and the three phase motor 120. The pulse control inverter 110 outputs a three-phase AC voltage and a three-phase AC current filtered by the filter assembly 100 and drives the three-phase electric motor 120. Filter assembly 100 includes three inductors L _F as well as three capacitors C _F. Capacitors C _F are disposed in the molded circuit. According to the present embodiment, the LC filter 100 between the pulse control inverter 110 and the motor 120 includes the capacitors after the inductors L _F are connected in series with the pulse control inverter 110 in each phase. C _F ) is formed so that it can be connected to the forming circuit in front of the device 120.

Pulse control inverter 110 is present respectively as a DC voltage and DC current, and a capacitor (C _DC) via smoothed (smoothed) input voltage (U _DC) and the input current (I _DC) for each of the three ac voltage (u _p1 is , u _p2 , u _p3 ) and three alternating currents i _p1 , i _p2 , i _p3 . The alternating currents i _p1 , i _p2 , i _{p3 pass} through the inductors L _F and then the current components i _{c _ stern1} , i _{c _ stern2} , i _{c _ stern3 through the} capacitors C _F. ) And the current components i _m1 , i _m2 , i _m3 supplied to the three-phase electric motor 120. The alternating voltages u _p1 , u _p2 , u _p3 are applied between the output contacts of the pulse control inverter 110 and the forming point of the capacitors C _F connected to each other in the forming circuit. The resultant voltages u _m1 , u _m2 , u _m3 are applied between the input terminals 1, 2, 3 of the three-phase motor 120 and the forming point to torque M at the three-phase motor 120. ) And rotation speed n are generated. Voltages u _m12 , u _m23 and u _m31 are applied between the input terminals 1, 2 and 3.

2 shows an output filter for a pulse controlled inverter for low loss power supply of an electric turbo compressor according to an embodiment of the invention. The filter 200 is arranged in a three phase line between the pulse control inverter 110 and the inductor or electrical device 120. The pulse control inverter 110 converts an input DC voltage U _DC and an input DC current I _DC smoothed through the input capacitor C _DC to convert the AC voltages u _p1 , u _p2 , u into three output parts. _p3 ) and alternating currents i _p1 , i _p2 , i _p3 .

The filter 200 is disposed in a conductor assembly consisting of three conductors, which connect the inputs 1, 2, 3 of the inductor 120 and the outputs of the pulse control inverter 110. Filter 200 is implemented as an LC output filter and includes three inductors L _F and three capacitors C _F. The inductors L _F are connected between the corresponding outputs of the pulse controlled inverter 110 and the inductor 120 and a current i _p1 , i _p2 , i _p3 flows through the inductors. The currents i _p1 , i _p2 , i _p3 after the inductors L _F are not only the current components i _{c _ dreieck1} , i _{c _ dreieck2} , i _{c _ dreieck3} supplied to the capacitors C _F The current components i _m1 , i _m2 and i _m3 supplied to the three-phase electric motor 120 are divided. Since the capacitors C _F are arranged in a triangular circuit, the first of the capacitors C _F is connected between the first input unit 1 and the second input unit 2 of the inductor 120, and the capacitors ( The second capacitor of C _F ) is connected between the second input unit 2 and the third input unit 3 of the inductor 120, and the third one of the capacitors C _F is the first input unit of the inductor 120. It is connected between (1) and the third input unit (3). The one capacitor (C _F), the first capacitor current (i _{c _ str)} and voltage (u _m12) that drop across the first capacitor (C _F) flowing through the (C _F) is shown for. To each of the capacitors, a voltage u _m12 , u _m23 , u _m31 between each of the two phases to which each capacitor is connected is applied. Therefore, the voltage u _m1 is applied to the first input unit 1 of the inductor, the voltage u _m2 is applied to the second input unit 2, and the voltage u _m3 is applied to the third input unit 3. The voltage u _m12 is between the first input unit 1 and the second input unit 2, the voltage u _m23 is between the second input unit 2 and the third input unit 3, and the third input unit 3. ) And the first input unit 1 drop the voltage u _m31 . The voltages u _m1 , u _m2 , u _m3 and currents i _m1 , i _m2 , i _m3 applied to the inputs 1, 2, 3 of the inductor are inductor 120 in operation of the inductor 120. It causes an electric field to rotate through the three inductors in the field, and this electric field moves the rotor of the inductor 120 to generate torque M and rotation speed n in the rotor.

This method is based on the following calculation principle. In this case the filter of the shaping circuit is the basis, which comprises the filter capacitance C _F , the current in the filter capacitor i _{c _ stern} and the voltage u _m1 at the filter capacitor. Based on this, the following calculation for the required capacitance can be derived.

Current in triangular circuit:

Differential equation of capacitor in triangular circuit:

Differential equation of capacitor in molded circuit:

Comparison of capacitance in molded and triangular circuits:

From the above equation, it is suggested that only one third of the capacitance of the filter capacitor mounted in the molded circuit of the same action is required in the triangular capacitor when the frequencies are the same. On the basis of this, the advantage of reducing the overall size of the electric turbocharger (TCE) of the fuel cell when applied to the automotive field is proposed. In addition, since the higher filter effect is achieved when the total size of the filter capacitors in the triangular circuit is the same, the losses incurred in the electrical equipment of the turbocompressor can also be reduced.

3 shows an embodiment of a filtering method for filtering a three-phase AC voltage according to an embodiment of the present invention. In step 310 a three-phase alternating voltage and a three-phase alternating current are supplied. Three-phase alternating voltage and three-phase alternating current are applied to a filter for three-phase alternating voltage and three-phase alternating current in step 310, the filter comprising a conductor assembly consisting of three electrical conductors, each one inductor Are connected in series with each one of the conductors, and each one capacitor is connected between each two of the conductors. Subsequently, the filtered three phase alternating voltage and the filtered three phase alternating current may be output to, for example, an inductor.

Placing one capacitor each between two of the phases achieves a high symmetry of the circuit and a defined voltage on each of the capacitors. As a result of the higher voltages occurring, the current flowing in the same load is reduced, which means a reduction in the thermal load of the capacitors. Since current flow is an important variable for the durability of electronic components, life is increased by decreasing current strength. In addition, the higher voltage and lower capacitor current compared to the molded circuit make the capacitors more efficient, so that capacitors with small capacitance can be mounted to achieve the same filtering performance as in the molded circuit. Capacitors with small capacitance occupy less mounting space, which improves the possibility of placing capacitors in tight spaces.

The described embodiments shown in the drawings are selected by way of example only. Different embodiments may be combined with each other completely or with respect to individual features. In addition, one embodiment may be supplemented by the features of a further embodiment. In addition, the method steps according to the invention may be executed repeatedly or in a different order than the described order.

Claims (9)

Filter 200 for three-phase alternating voltage and three-phase alternating current,
The filter,
A conductor assembly consisting of three electrical conductors for three phase alternating voltage and three phase alternating current,
Three inductors L _F , each one of the inductors connected in series with a respective one of the conductors,
A capacitor assembly consisting of three capacitors (C _FD ), each one of which is connected between two of each of the conductors
Filter 200 included. The filter (200) of claim 1, wherein the three capacitors (C _FD ) are connected to each other in a triangular circuit. The filter (200) of claim 1 or 2, wherein the filter (200) is a low pass filter. 3. The conductor assembly according to claim 1 or 2, wherein the conductor assembly comprises first terminals for picking up the three-phase alternating current and the three-phase alternating current from the pulse control inverter 110 and the filtered three-phase alternating current and the three-phase alternating current. A second terminal (1, 2, 3) for output to an inductor (120), the capacitor assembly being connected with the second terminals of the conductor assembly. The method of claim 1 or 2, wherein the second terminal of the inductors (L _F) of the first first terminal conductors of the first claim and being a first inductor (L _F) connected to the first terminal of the conductor of the inductor Is connected to the second terminal 1 of the first conductor, and the first terminal of the second inductor of the inductors L _F is connected to the first terminal of the second conductor of the conductors and the second inductor L _F The second terminal of is connected to the second terminal 2 of the second conductor, and the first terminal of the third inductor of the inductors L _F is connected to the first terminal of the third conductor of the conductors and the third inductor The second terminal of L _{F is} connected to the second terminal 3 of the third conductor, and the first terminal of the first capacitor of the capacitors C _FD is connected to the second terminal 1 of the first conductor. The second terminal of the first capacitor C _{FD is} connected to the second terminal 2 of the second conductor, and the first terminal of the second capacitor of the capacitors C _FD is the second terminal of the second conductor ( 2) and the second terminal of the second capacitor C _FD is The second, being connected to the second terminal (3) of the body, the first terminal of the third capacitor of the capacitors (C _FD) is connected to the second terminal (3) of the third conductor the third capacitor (C _FD) The terminal is connected to the second terminal (1) of the first conductor (200). The filter (200) of claim 1 or 2, wherein the three inductors (L _F ) each comprise an inductance value of the same magnitude. The filter (200) of claim 1 or 2, wherein the three capacitors (C _FD ) each comprise the same capacitance. Compressor system,
The compressor system,
A turbo compressor for compressing gas, including an inductor 120 as a drive device;
A pulse control inverter 110 for supplying a three-phase alternating voltage for an inductor,
The filter 200 for three-phase AC voltage according to claim 1 or
Including compressor system. A filtering method 300 for filtering three-phase alternating voltage and three-phase alternating current,
The method comprises:
A conductor consisting of three electrical conductors under the condition that each one inductor L _F is connected in series with each one of the conductors and each one capacitor C _FD is connected between each of the two conductors Applying a three-phase alternating voltage and three-phase alternating current to the assembly (310)
Including filtering method 300.

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