Electric drive system
The invention relates to an electric drive system with an n-phase electric machine, n>1, having at least two multiphase winding strands; a first inverter, the output connections of which are connected to the phase connections of a first of the multiphase winding strands of the electric machine; a second inverter, which is connected in parallel to the first inverter and the output connections of which are connected to the phase connections of a second of the multiphase winding strands of the electric machine; and a DC voltage source, which has a plurality of battery modules connected in series and a first output connection of which is connected to a first input connection of the first inverter and second output connection of which is connected to a first input connection of the second inverter. A second input connection of the first inverter and a second input connection of the second inverter are connected to each other such that the first inverter and the second inverter are arranged in a series circuit, and the second input connection of the first inverter and the second input connection of the second inverter are connected to a center tap of the DC voltage source between two sub-groups of the battery modules connected in series.
1. An electric drive system ( 30 ), comprising:
an n-phase electric machine ( 6 ), n>1, having at least two multiphase winding strands ( 6 a , 6 b );
a first inverter ( 3 a ), output connections of which are connected to the phase connections of a first of the multiphase winding strands ( 6 a , 6 b ) of the electric machine ( 6 );
a second inverter ( 3 b ), the output connections of which are connected to the phase connections of a second of the multiphase winding strands ( 6 a , 6 b ) of the electric machine ( 6 );
a DC voltage source ( 1 ), which has a plurality of battery modules ( 5 ) connected in series and a first output connection of which is connected to a first input connection of the first inverter ( 3 a ) and a second output connection of which is connected to the first input connection of the second inverter ( 3 b ); and
a first DC voltage intermediate circuit ( 2 a ) connected to the first input connection of the first inverter ( 3 a ) and to a second input connection of the first inverter ( 3 a ),
wherein the second input connection of the first inverter ( 3 a ) and a second input connection of the second inverter ( 3 b ) are connected to each other such that the first inverter ( 3 a ) and the second inverter ( 3 b ) are arranged in a series circuit, and
wherein the second input connection of the first inverter ( 3 a ) and the second input connection of the second inverter ( 3 b ) are connected to a center tap (M) of the DC voltage source ( 1 ) between two sub-groups of the battery modules ( 5 ) connected in series.
2. The electric drive system ( 30 ) according to claim 1 , wherein the first and the second inverter ( 3 a , 3 b ) each comprise a three-phase, self-piloted inverter, which includes three symmetrical half bridges each including two power semiconductor switches (H 1 , H 2 ; H 3 , H 4 ; H 5 , H 6 ) in a series circuit.
3. The electric drive system ( 30 ) according to claim 2 , wherein the power semiconductor switches (H 1 , H 2 ; H 3 , H 4 ; H 5 , H 6 ) are MOSFET switches or IGBT switches.
4. The electric drive system ( 30 ) according to claim 2 , further comprising:
a control device configured to actuate the power semiconductor switches (H 1 , H 2 ; H 3 , H 4 ; H 5 , H 6 ) of the first inverter ( 3 a ) and the second inverter ( 3 b ),
wherein the control device is disposed on a central control circuit board for the first inverter ( 3 a ) and the second inverter ( 3 b ).
5. An electric drive system ( 30 ) comprising:
an n-phase electric machine ( 6 ), n>1, having at least two multiphase winding strands ( 6 a , 6 b );
a first inverter ( 3 a ), output connections of which are connected to the phase connections of a first of the multiphase winding strands ( 6 a , 6 b ) of the electric machine ( 6 );
a second inverter ( 3 b ), the output connections of which are connected to the phase connections of a second of the multiphase winding strands ( 6 a , 6 b ) of the electric machine ( 6 );
a DC voltage source ( 1 ), which has a plurality of battery modules ( 5 ) connected in series and a first output connection of which is connected to a first input connection of the first inverter ( 3 a ) and a second output connection of which is connected to the first input connection of the second inverter ( 3 b );
at least one third inverter ( 3 c ) connected in parallel to the first inverter ( 3 a ), input connections of which are each coupled to input connections of the first inverter ( 3 a ); and
at least one fourth inverter ( 3 d ) which is connected in parallel to the second inverter ( 3 b ) and the input connections of which are each coupled to input connections of the second inverter ( 3 b ),
wherein a second input connection of the first inverter ( 3 a ) and a second input connection of the second inverter ( 3 b ) are connected to each other such that the first inverter ( 3 a ) and the second inverter ( 3 b ) are arranged in a series circuit, and
wherein the second input connection of the first inverter ( 3 a ) and the second input connection of the second inverter ( 3 b ) are connected to a center tap (M) of the DC voltage source ( 1 ) between two sub-groups of the battery modules ( 5 ) connected in series.
6. The electric drive system ( 30 ) according to claim 5 , wherein the first inverter, the second inverter, the third inverter and the fourth inverter ( 3 a , 3 b ) each comprise a three-phase, self-piloted inverter, which includes three symmetrical half bridges each including two power semiconductor switches (H 1 , H 2 ; H 3 , H 4 ; H 5 , H 6 ) in a series circuit.
7. The electric drive system ( 30 ) according to claim 6 , wherein the power semiconductor switches (H 1 , H 2 ; H 3 , H 4 ; H 5 , H 6 ) are MOSFET switches or IGBT switches.
8. The electric drive system ( 30 ) according to claim 7 , further comprising:
a control device configured to actuate the power semiconductor switches (H 1 , H 2 ; H 3 , H 4 ; H 5 , H 6 ) of the first inverter ( 3 a ), the second inverter ( 3 b ), the third inverter ( 3 c ) and the fourth inverter ( 3 d ),
wherein the control device is disposed on a central control circuit board for the first inverter ( 3 a ), the second inverter ( 3 b ), the third inverter ( 3 c ) and the fourth inverter ( 3 d ).
9. The electric drive system ( 30 ) according to claim 8 , wherein the third invertor ( 3 c ) includes output connections connected to the phase connections of a third multiphase winding strand ( 6 c ) of the electric machine ( 6 ), wherein the fourth invertor ( 3 d ) includes output connections connected to the phase connections of a fourth multiphase winding strand ( 6 d ) of the electric machine ( 6 ), and wherein the n-phase electric machine ( 6 ) is a twelve-phase machine.
10. The electric drive system ( 30 ) according to claim 1 , further comprising a second DC voltage intermediate circuit ( 2 b ) connected to the first input connection of the second inverter ( 3 b ) and to the second input connection of the second inverter ( 3 b ).
11. An electric drive system ( 30 ) comprising:
an n-phase electric machine ( 6 ), n>1, having at least four multiphase winding strands ( 6 a , 6 b , 6 c , 6 d );
a first inverter ( 3 a ), output connections of which are connected to the phase connections of a first of the multiphase winding strands ( 6 a ) of the electric machine ( 6 );
a second inverter ( 3 b ), output connections of which are connected to the phase connections of a second of the multiphase winding strands ( 6 b ) of the electric machine ( 6 );
a third inverter ( 3 c ), output connections of which are connected to the phase connections of a third of the multiphase winding strands ( 6 c ) of the electric machine ( 6 );
a fourth inverter ( 3 d ), output connections of which are connected to the phase connections of a fourth of the multiphase winding strands ( 6 d ) of the electric machine ( 6 ); and
a DC voltage source ( 1 ), which has a plurality of battery modules ( 5 ) connected in series and a first output connection of which is connected to a first input connection of the first inverter ( 3 a ) and a first input connection of the third inverter ( 3 c ), and a second output connection of which is connected to the first input connection of the second inverter ( 3 b ) and a first input connection of the fourth inverter ( 3 d )
wherein the second input connection of the first inverter ( 3 a ) and the second input connection of the third inverter ( 3 c ) are connected to a first center tap (M) of the DC voltage source ( 1 ) between two sub-groups of the battery modules ( 5 ) connected in series.
12. The electric drive system ( 30 ) according to claim 11 , wherein the second input connection of the second inverter ( 3 b ) and the second input connection of the fourth inverter ( 3 d ) are connected to a second center tap (M) of the DC voltage source ( 1 ) having a different voltage than the first center tap.