DE102016200668A1 - Transport means and circuit arrangement for operation of an electrical machine by means of two energy storage - Google Patents

Abstract

A means of locomotion and a circuit arrangement for operation of an electric machine (1) are proposed. The circuit arrangement comprises: a multi-voltage inverter with a first terminal (2) for a first voltage source, a second terminal (3) for a second voltage source, and a third terminal (4) for the electrical machine (1), and additional nonlinear device (T19, T20), wherein the additional nonlinear device (T19, T20) has a node (0) between the first port (2) and the second port (3) in an upper node (0b) and associated with the first port a lower node (0a) associated with the second port (3).

Description

State of the art

The present invention relates to a means of locomotion and an electrical arrangement for operation of an electrical machine by means of two electrical energy storage. In particular, the present invention relates to an extension of the functional scope and the structure known in the art multi-voltage inverter, hereinafter referred to as "multilevel inverter".

Hybrid battery systems can be designed differently and constructed with different power electronics topologies. Above all, the system with multilevel inverters is of great importance for hybrid applications. There are also different topologies for the multilevel inverters, in particular a multilevel inverter with a neutral connection point (neutral point clamp (NPC) multilevel inverter) being considered within the scope of the present invention. NPC multilevel inverters are basically known in the prior art and usually as discussed in detail later 1 shown constructed. In this case, two energy sources for the operation of a means of locomotion or a respective means of locomotion are provided.

The object of the invention is to bring energy from an energy source and / or from the second energy source to an electric motor, wherein the lowest possible ohmic losses are to be generated in the semiconductors.

A further object of the present invention is to charge an energy store, which is connected to the multilevel inverter, by means of a second energy store, which is connected to the multilevel inverter.

Disclosure of the invention

The above-identified object is achieved by a circuit arrangement for operation of an electric machine. The electrical machine can be configured, for example, as a synchronous machine. The electric machine can be designed, for example, as a multi-phase electric machine, in particular as a three-phase machine. Basically, the circuit arrangement comprises a multilevel inverter, as is basically known in the prior art. This has a first connection for a first voltage source (eg a battery, a fuel cell, or the like) and a second connection for a second voltage source (a battery, an accumulator or the like). A third connection is provided to electrically contact the electric machine. While the foregoing elements are known in the art, an additional non-linear device (eg, a diode and / or a switch, in particular a controllable switch) is provided which provides a node between the first terminal for the first voltage source and the first terminal second connection for the second voltage source shares. In other words, the node between the first terminal / the first voltage source and the second terminal / the second voltage source is divided and the additional non-linear component connected for subsequent electrical connection between the parts of the node. In this way, a first (upper) node and a second (lower) node are obtained which can be electrically connected to each other by the nonlinear device. Compared to a known in the art multilevel inverter, which only the operating points "only the first battery is used for the operation of the electric machine", "only the second battery is used for the operation of the electric machine" and "the two batteries connected in series in order to operate the electric machine ", knows the circuit arrangement according to the invention as described above additionally the operating point" the two sources are connected in parallel ". In the case of the parallelization of the two sources, nothing was presupposed with regard to the voltage situation of the sources, but at different voltage levels, first the source with the higher voltage position is used until the two sources have approximately the same voltage level. Only then energy is taken from both voltage sources. In this way, by means of the present invention, if necessary, a high current with the same voltage level can be removed. The voltage on the electric machine can be drastically increased by adding the two battery voltages. In addition, a charge balance of the energy storage used can be realized without additional components and control effort. In addition, 650 V IGBTs can be used (eg with a source voltage level of up to 450 V each). Finally, the cell life can be increased by the discharge, since the parallelization operates the two sources each with a half current per source rather than a full amperage and therefore significantly lower losses within the battery and within the electrical circuit. The tension on the load (Eg the electric machine) can be adjusted by predetermined switching of the switch contained in the circuit arrangement according to the invention. Depending on the design and number of strands or according to the number of phases of the electrical machine corresponding switching pattern can be used in the basic features in order to realize the advantages achieved according to the invention.

The dependent claims show preferred developments of the invention.

The non-linear device may comprise a diode, thereby simplifying the structure of the additional non-linear device, in particular in the event that the diode is the sole additional non-linear device. In order additionally to allow charging of the first voltage source by the second voltage source, the additional non-linear component may have at least one first controlled switch. In practice, two oppositely series-connected bipolar insulated gate bipolar transistors (IGBTs) are often used which comprise a freewheeling diode.

Alternatively or additionally, the diodes of each bridge branch of the multilevel inverter, a respective controllable switch may be connected in parallel. With suitably clocked control of the controllable switch, a plurality of operating states can be achieved, which will be discussed in detail in connection with the accompanying figures.

An example of a possible activation of the circuit arrangement proposed according to the invention is described by the table contained in claim 3. In this case, the rows contained in the operating states I to IV, for example, are chronologically traversed from top to bottom, so that a corresponding time sequence for the states of the contained elements can be derived. The switches T1 to T12 are assigned to individual half bridges (1st HB, 2nd HB, 3rd HB) or strands. The illustrated table thus represents switching instructions for the case where three half-bridges (eg for the operation of a three-phase electrical machine) are provided in the circuit arrangement according to the invention. The switching states of the switches T19, T20 as exemplary components of an additional non-linear component represent a significant difference from the prior art in connection with the operating state III. In the table according to claim 3, an empty cell means an open switch, D an operation as a freewheeling diode and 1 a closed (conductive) switch.

In order to be able to use the circuit arrangement according to the invention in addition to charging a first battery by a second battery (in driving operation or in stationary operation, in which latter the electric machine does not rotate), an inductance can be provided as a storage choke in at least one bridge branch of the multilevel inverter , The inductance or storage choke can be provided, for example, between the first connection for the first voltage source and the third connection for the electrical machine (for example of a respective strand of the multilevel inverter). Alternatively or additionally, the inductance or storage choke can be arranged, for example, between the second connection for the second voltage source and the third connection for the electrical machine (for example of a respective strand of the multilevel inverter). By means of the inductance, a current can also be driven against a higher voltage position by disconnecting a voltage source which initially drives a current through the inductance or disconnecting it from the inductance. In this way, for example, a first battery with a lower voltage level can be used to charge a second battery with a higher voltage level.

In order to be able to set an output voltage at the third connection for the electrical machine independently of a voltage position of the respective voltage sources by means of the inductance, the arrangement can be set up to operate clocked switches of the multilevel inverter in clocked fashion. An example of an operation of the circuit arrangement with additional inductors or storage chokes is represented by the table according to claim 6, for which the statements made in connection with the table according to claim 3 also apply. The operating state IV now relates to the case that substantially a voltage applied to the first terminal is equal to a voltage applied to the second terminal, while the operating conditions V, VI and VII new operating states for operating the electric machine in parallel with two voltage sources of different voltage ( Operating states V and VI) and the charging of an energy store connected to the second terminal by an energy store connected to the first terminal, wherein substantially a voltage applied to the first terminal is greater than a voltage applied to the second terminal (operating state VII).

In addition to the table according to claim 3 are in the table according to claim 6, the designations "FDT" for a current commutation by the freewheeling diodes of the respective switch in clocked operation, "T" for a clocked operation of the respective switch and "k" included as a parameter for the duty cycle in the clocked operation of the respective switch. As possible range limits for the clock ratio are hereby all integer divided by ten divisible percentages between 0 and 100.

The voltage on the electric machine can be adjusted by suitably activating the switches of the circuit arrangement according to the invention. In order to achieve sinusoidal currents in the electrical machine, certain switches of the circuit arrangement must be operated clocked in a suitable manner. For example, the switches to be clocked can be switched in common mode. The duty cycle of the switching pattern can be selected depending on the voltage levels of the two voltage sources at the first terminal and the second terminal. Also in the arrangement with storage chokes or during operation according to the table of claim 6, a switch of the non-linear additional device can be replaced by a diode, unless charging a first energy storage by a second energy storage should not be arbitrarily made. The mode of operation defined by the table according to claim 6 can be adapted in a corresponding manner by the person skilled in the art, depending on a modified circuit variant, without requiring an explicit instruction for this purpose. Preferably, a fourth connection can be provided as a network connection between the inductance (storage choke) and the third connection. In order to be able to charge the battery with as few components as possible from different types of energy sources (alternating current, direct current, single-phase, three-phase, etc.), the circuit arrangement according to the invention can make use of the line filter capacitors which are always present in practice at electrical mains connections. In other words, an electrical connecting line to a power grid can be connected to the fourth connection (which, like the third connection, may be single-phase or multi-phase), with three mains filter capacitors connecting the battery connected to the first connection with a three-line filter capacitor. can be charged with only a line filter capacitor, the battery at the first terminal of a two-phase source and without additional components, the battery at the first terminal of a DC voltage source, provided that the voltage level of the DC voltage source is less than or equal to the voltage level the battery is on the first port, can be charged.

According to a second aspect of the present invention, there is proposed a means of transportation (eg, a car, a van, a truck, an air and / or water vehicle) having a circuit arrangement according to the first aspect of the invention. The circuit arrangement can be used to supply an electric traction machine or another electric machine of the means of locomotion. The features, combinations of features and the advantages arising therefrom therefore correspond so clearly to those of the first-mentioned aspect of the invention that reference is made to the above statements to avoid repetition.

Brief description of the drawings

Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings. In the drawings:

1 a circuit diagram of an embodiment of a multilevel inverter with neutral connection point (NPC-MLI) with two batteries as DC voltage sources and a three-phase electric machine;

2 a circuit diagram of a first modification according to the invention of the NPC-MLI after 1 ;

3 a circuit diagram of a second inventive modification of the NPC-MLI according to 1 ;

4 a circuit diagram of a third inventive modification of an NPC-MLI according to 1 ;

5 a circuit diagram of a fourth inventive modification of an NPC-MLI after 1 ;

6 a circuit diagram of a fifth inventive modification of an NPC-MLI according to 1 ; and

7 a schematic diagram illustrating components of an embodiment of a means of transport according to the invention.

Embodiments of the invention

1 shows an NPC MLI which is connected to a first port 2 a battery B1 as a DC voltage source with an internal resistance R _i1 and at a second electrical connection 3 a second battery B2 as a DC electric power source having an internal resistance R _i2 . On the output side is the NPC-MLI with a three-phase electrical machine 1 coupled, which has three inductances L1, L2, L3 and each connected in series with these ohmic resistors R1, R2, R3 for representing the ohmic losses. One at the first connection 2 connected first strand SI has a first switch T1, a second switch T2, a third switch T3 and a fourth switch T4. All switches in the illustrated circuit are implemented as insulated gate bipolar transistors ("IGBTs").

Between a second terminal of the first switch T1 and a first terminal of the second switch T2, a first diode D1 is connected, which on the other hand to the neutral connection point 0 connected. The flow direction of the diode D1 is oriented in the direction of the first switch T1. Between the second electrical connection 3 and the second switch T2, a third switch T3 and a fourth switch T4 are provided, wherein a second diode D2 connected between a second terminal of the third switch T3 and a first terminal of the fourth switch T4 and on the other hand to the neutral terminal point 0 electrically connected. The flow direction of the second diode D2 is in the direction of the neutral connection point 0 oriented. Between the second terminal of the second switch T2 and the first terminal of the third switch T3 is a phase of the electric machine 1 connected. The structure of the two remaining strands SII, SIII, which with respect to the electrical connections 2 . 3 of the NPC-MLI are connected in parallel to the first strand SI, corresponds in each case to the structure of the above-described strand SI, so reference is made to the above statements to avoid repetition.

2 shows a first modification of the invention NPC-MLI, as in connection with 1 has been presented in detail. Part of the modification is that the neutral connection point 0 (NPC) by a first IGBT T19 and a second IGBT T20 as components of a nonlinear device in an upper node 0b and a lower node 0a has been divided. In other words, the strands SI, SII, SIII connected in parallel to the respective batteries B1, B2 became at the common connection point 0 initially separated and then again electrically connected to each other via the IGBTs T19, T20. In addition, the diodes D1 to D6 have been replaced by respective IGBTs T13 to T18, which are identical in orientation to their respective inherent diodes to the respective third connection point 4 associated IGBTs T2, T3, T6, T7, T10, T11. A clocked operation according to the states mentioned in the table according to claim 6 allows a parallel operation of the batteries B1, B2 for the power supply of the electrical machine 1 ,

3 and 4 show a preferred modification of in 2 illustrated circuit arrangement in which a respective inductance L between a neutral point of the respective three switches T1, T2, T13; T5, T6, T15; T9, T10, T17 in 3 or T3, T4, T14; T7, T8, T16; T11, T12, T18 in 4 and the respective third connection point 4 for the electric machine 1 is arranged. By a clocked drive according to the table in claim 6, the inductors L can be used to allow a parallel operation at different voltage levels of the batteries B1, B2 and / or a charging operation of a battery by the other battery.

The 5 and 6 show a modification of the circuit arrangements according to the 3 respectively. 4 by inserting an additional fourth port 5 as mains connection between the inductance and the third connection. About the fourth connection 5 An external power supply connection can be coupled to the circuit arrangement according to the invention. The mains filter capacitors, which are always present in commercial power supply connections, form, in conjunction with the respective choke coil L, a respective resonant circuit by means of which the circuit arrangement according to the invention can be set up, a battery with particularly few components by a multiplicity of different types of energy sources (eg AC voltage, DC voltage, phase, three-phase or multi-phase) can charge.

7 shows a schematic view of an embodiment of a means of transport according to the invention 10 in which an electric machine 1 is used as a traction machine. The three phases of the electric machine 1 are with a circuit arrangement according to the invention 6 electrically connected, the first and second terminals with a respective battery B1, B2 and the fourth connection as a power connection with a power plug 7 electrically connected. In this way, the illustrated means of transport 10 assume the same features, operating conditions and advantages, which have been described in detail in connection with the circuit arrangement according to the invention.

Claims (10)

Circuit arrangement for operation of an electrical machine ( 1 ) comprising - a multi-voltage inverter, hereinafter called "multilevel inverter", having - a first terminal ( 2 ) for a first voltage source, - a second connection ( 3 ) for a second voltage source and - a third connection ( 4 ) for the electric machine ( 1 ), and - an additional non-linear component (T19, T20), wherein the additional non-linear component (T19, T20) is a node ( 0 ) between the first port ( 2 ) and the second connection ( 3 ) in an upper node associated with the first port ( 0b ) and a second port ( 3 ) associated lower node ( 0a ) separates. Circuit arrangement according to claim 1, wherein - The non-linear component (T19, T20) comprises a diode, and / or - The diodes (D1-D6) of each bridge branch of the multilevel inverter, a respective controllable switch (T13-T18) is connected in parallel. Circuit arrangement according to Claim 1 or 2, the non-linear component (T19, T20) comprising a controllable switch, in particular an IGBT, preferably two IGBTs, the switch being arranged in an extremely preferred manner to assume switching states in accordance with the table reproduced below.

in which - "I" for a first operating state, in which the arrangement only with one at the first port ( 2 ) is operated for a second operating state, in which the arrangement is connected only to one at the second connection (FIG. 3 ) connected second power source (B2) is operated, - "III" for a third operating condition, in which the arrangement with one at the first connection ( 2 ) connected in series with one at the second port (B1) 3 ) is operated - "IV" for a fourth operating state, in which the arrangement with a at the first port ( 2 ) connected in series with one at the second port (B1) 3 ) is operated second power source (B2), - "1. HB "for a first half-bridge of the multilevel inverter, -" 2. HB "for a second half bridge, if present, of the multilevel inverter, -" 3. HB "for a third half-bridge, if present, of the multilevel inverter, -" U_R1 "for a first voltage at the third connection ( 4 ) for a first strand of the electrical machine ( 1 ), - "U_R2" for a second voltage at the third terminal ( 4 ) for a second strand, if any, of the electric machine ( 1 ), - "U_R3" for a third voltage at the third terminal ( 4 ) for a third strand, if any, of the electric machine ( 1 ), - "S_B1" for a switching state of a first IGBT, if present, in the controllable switch, - "S_B2" for a switching state of a second IGBT, if present, in the controllable switch, - "1" for a conducting state, - "D "For operation of a diode as freewheeling diode, -" T1 "to" T12 "for the switches of the half bridges - if present - of the multilevel inverter and -" u "for a maximum voltage at the third connection ( 4 ) stands. Circuit arrangement according to one of the preceding claims, wherein - in at least one bridge branch of the multilevel inverter, an inductance (L) is provided, which in particular - between the first terminal ( 2 ) for the first voltage source (B1) and the third terminal ( 4 ) for the electric machine ( 1 ) and / or - between the second port ( 3 ) for the second voltage source (B2) and the third terminal ( 4 ) for the electric machine ( 1 ) is arranged. Circuit arrangement according to claim 4, wherein the arrangement is arranged to operate predefined switches of the multilevel inverter clocked. Circuit arrangement according to claim 4 or 5, wherein the arrangement is set up to perform the clocked operation of the predefined switches in accordance with the following table,

in which - "I" for a first operating state, in which the arrangement only with one at the first port ( 2 ) is operated for a second operating state, in which the arrangement is connected only to one at the second connection (FIG. 3 operated second power source (B2), - "III" for a third operating state, in which the arrangement with a at the first port ( 2 ) connected in series with one at the second port (B1) 3 ) is operated - "IV" for a fourth operating state, in which the arrangement with a at the first port ( 2 ) connected in parallel to one at the second terminal (B1) 3 ) is operated, wherein substantially one at the first terminal ( 2 ) voltage equal to one at the second terminal ( 3 ) voltage is, - "V" for a fifth operating state, in which the arrangement with one at the first port ( 2 ) connected in parallel to one at the second terminal (B1) 3 ) is operated, wherein substantially one at the first terminal ( 2 ) voltage is less than one at the second terminal ( 3 ) voltage is, - "VI" for a sixth operating state, in which the arrangement with one at the first terminal ( 2 ) connected in parallel to one at the second terminal (B1) 3 ) is operated, wherein substantially one at the first terminal ( 2 ) voltage greater than one at the second terminal ( 3 ) voltage is, - "VII" for a seventh operating state, in which the arrangement for transmitting electrical energy from the first terminal ( 2 ) to the second port ( 3 ), essentially one at the first port ( 2 ) voltage greater than one at the second terminal ( 3 ) is applied voltage, - "VIII" for an eighth operating condition in which the arrangement for transmitting electrical energy from the first terminal ( 2 ) to the second port ( 3 ), essentially one at the first port ( 2 ) voltage is less than one at the second terminal ( 3 ) voltage is, - "IX" for a ninth operating state, in which the arrangement for transmitting electrical energy from the second terminal ( 3 ) to the first connection ( 2 ), essentially one at the first port ( 2 ) voltage is less than one at the second terminal ( 3 ) voltage is, - "X" for a tenth operating state, in which the arrangement for transmitting electrical energy from the second terminal ( 3 ) to the first connection ( 2 ), essentially one at the first port ( 2 ) voltage greater than one at the second terminal ( 3 ) voltage is, - "1. HB "for a first half-bridge of the multilevel inverter, -" 2. HB "for a second half bridge, if present, of the multilevel inverter, -" 3. HB "for a third half-bridge, if present, of the multilevel inverter, -" U_R1 "for a first voltage at the third connection ( 4 ) for a first strand of the electrical machine ( 1 ), - "U_R2" for a second voltage at the third terminal ( 4 ) for a second strand, if any, of the electric machine ( 1 ), - "U_R3" for a third voltage at the third terminal ( 4 ) for a third strand, if any, of the electric machine ( 1 ), - "S_B1" for a switching state of a first IGBT in the controllable switch, - "S_B2" for a switching state of a second IGBT, if present, in the controllable switch, - "1" for a conducting state, - "D" for operation a diode as freewheeling diode, - "T1" to "T12" for the switches of the half bridges - if available - the multilevel inverter, - "u" for a maximum voltage at the third connection ( 4 ), - "FDT" for a current commutation over freewheeling diodes when the clocked switch is turned off, - "+" a positive DC voltage in a respective string, - "-" a negative DC voltage in a respective string - "T" for a clocked Operation of the respective switch and - "k" stands for a duty cycle for the clocked operation of the switch. Circuit arrangement according to claim 4, 5 or 6, wherein a fourth connection ( 5 ) as a grid connection between the inductance (L) and the third terminal ( 4 ) is provided. Circuit arrangement according to one of the preceding claims, wherein - the electric machine ( 1 ) is a synchronous machine and / or a traction machine for a means of transportation. Circuit arrangement according to one of the preceding claims, wherein - the third connection ( 4 ) is designed three-phase and the electric machine ( 1 ) is a three-phase machine. Means comprising a circuit arrangement according to one of the preceding claims.

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