阅读说明：本技术 他励同步电机的转子的去磁 (Demagnetization of rotor of separately excited synchronous machine ) 是由 M·席德迈尔 S·布鲁塞克 于 2020-09-09 设计创作，主要内容包括：本发明涉及一种用于他励同步电机的转子的去磁的电路装置以及用于运行这样的电路装置的方法,该电路装置包括至少一个与他励同步电机的转子绕组(W-R)的各个极相连接的开关电路,所述开关电路具有二极管(D-3)、后置于所述二极管(D-3)的电容器(C-S)和第一开关(S-9)。(The invention relates to a circuit arrangement for demagnetization of a rotor of a separately excited synchronous machine, comprising at least one rotor winding (W) that is connected to the separately excited synchronous machine, and to a method for operating such a circuit arrangement R ) Having a diode (D) 3 ) Is arranged behind the diode (D) 3 ) Capacitor (C) S ) And a first switch (S) 9 )。)

1. A circuit arrangement for demagnetizing the rotor of a separately excited synchronous machine (FSM) comprises at least one rotor winding (W) which is connected to the separately excited synchronous machine_R) Having a diode (D)₃) Is arranged behind the diode (D)₃) Capacitor (C)_S) And a first switch (S)₉)。

2. A circuit arrangement as claimed in claim 1, characterized in that the capacitor (C) is connected to_S) A first resistor (R) is connected in parallel_E)。

3. A circuit arrangement as claimed in claim 1 or 2, characterized in that the capacitor (C)_S) Via the second switch (S)₁₀) And the rotor winding (W)_R) The positive electrode of (1) is connected; the capacitor (C)_S) Via a third switch (S)₁₁) And the rotor winding (W)_R) Is connected to the negative electrode of (1).

4. Circuit arrangement according to claim 1, characterized in that the capacitor (C)_S) Via the fourth switch (S)₁₂) Is connected to the positive electrode of the intermediate circuit capacitor (C) of the separately excited synchronous machine; the capacitor (C)_S) Via a second resistor (R) and a fifth switch (S)₁₃) Is connected to the negative electrode of the intermediate circuit capacitor (C) of the separately excited synchronous machine.

5. Circuit arrangement according to claim 1, characterized in that the capacitor (C)_S) Via a second resistor (R) and a fourth switch (S)₁₂) Is connected to the positive electrode of the intermediate circuit capacitor (C) of the separately excited synchronous machine; the capacitor (C)_S) Via a fifth switch (S)₁₃) Is connected to the negative electrode of the intermediate circuit capacitor (C) of the separately excited synchronous machine.

6. A circuit arrangement as claimed in claim 1, characterized in that the capacitor (C) is connected to_S) An energy storage inductor (L) is connected in parallel_S)。

7. Circuit arrangement according to claim 6, characterized in that the energy-storing inductance (L)_S) Via a sixth switch (S)₁₄) And a seventh switch (S)₁₅) And the capacitor (C)_S) And via an eighth switch (S)₁₆) And a ninth switch (S)₁₇) Is connected to the electrodes of the intermediate circuit capacitor (C) of the separately excited synchronous machine.

8. Method for demagnetizing the rotor of a separately excited synchronous machine, in which method at least one circuit arrangement according to one of the preceding claims is connected to at least one rotor winding (W) of a separately excited synchronous machine_R) Is conductively connected and is to be stored in the rotor winding (W)_R) To a capacitor (C) of the circuit arrangement_S) In (1).

9. Method according to claim 8, characterized in that the capacitor (C) to be stored in the circuit arrangement is immediately followed_S) Is at least partially transferred into an intermediate circuit capacitor (C) of the separately excited synchronous machine.

10. Method according to claim 8, characterized in that the capacitor (C) to be stored in the circuit arrangement is immediately followed_S) At least partially transferring the electric energy to an energy storage inductor (L)_S) In (1).

Technical Field

The invention relates to a circuit arrangement for demagnetizing/demagnetizing a rotor of a separately excited synchronous machine and to a method for operating a circuit arrangement.

Background

In the field of electromotion, electric machines are generally applied for electric traction, typically asynchronous machines (ASMs), permanent magnet excited synchronous machines (PSMs) or separately excited synchronous machines (FSMs).

The separately excited synchronous machine has the feature that its rotor is neither a short-circuit cage as in the case of ASM nor an element equipped with permanent magnets as in the case of PSM, but is instead briefly described as a rotating coil. The current flowing through the coil can be regulated by corresponding electronics. The current determines the regulation of the electric machine or the regulation of the vehicle traction.

The regulation of the FSM is typically performed by a pulse inverter (PWR), which is typically configured with an intermediate circuit capacitor. The stator winding of the FSM is also driven by six switches and its ac voltage or ac current is regulated. Typically, the PWR is connected to and powered by a high voltage battery.

A typical circuit is shown in figure 1. The intermediate circuit capacitor C and the switching element S are shown here₁To S₆Which drives the stator windings of the FSM. Stator winding W_RIs connected in parallel with the intermediate circuit capacitor C. The circuit additionally comprises a switching element S₇And S₈And a diode D₁And D₂By means of which the current through the rotor of the FSM can be regulated.

If the rotor should be demagnetized (e.g. in case of a crash or other critical driving situation), the following possibilities exist:

1. on/off switch S₇And S₈. The current then flows through the diode D₁An intermediate circuit capacitor C and a diode D₂. Thereby continuing to charge the capacitor C. In this case, an overload of the capacitor C is encountered. In the worst case, this overload can lead to a failure of the component or of other components due to an overvoltage;

2. open switch S₇Switch S₈And remain closed. The current flows through the switch S₈And a diode D₂. Thereby eliminating the magnetization of the rotor, which however occurs very slowly. This may last for a long time depending on the resistance of the rotor and the voltage drop over the semiconductors. Furthermore, the energy in the resistors and semiconductors is dissipated. That is, converting electrical energy into thermal energy, which then becomes unavailable to the vehicle and its traction;

3. open switch S₈Switch S₇And remain closed. The current now flows through the diode D₁And switch S₇. Also here as in possible embodiment 2The long demagnetization time and the loss of usable electrical energy are likewise disadvantageous.

Disclosure of Invention

Against this background, the object underlying the invention is to provide a switching circuit and a method for demagnetizing a rotor of a separately excited synchronous machine, which enable reliable and rapid demagnetization of the rotor and avoid the conversion of electrical energy into heat as far as possible.

DE 3241086 a1 discloses a device for reducing the losses of electrical energy stored in a load-shedding network. The energy stored in the motor windings is output to capacitors in the load shedding network during switching of the inverter and is transferred to another location in the circuit.

Document DE 102009024362 a1 relates to an energy supply circuit for a ground vehicle. The energy transport in the supply circuit of the asynchronous machine of the industrial truck generates a magnetic field in the coil, and in the event of a magnetic field being eliminated, a current is generated which is stored in a capacitor of the supply circuit.

Document DE 102005050551 a1 discloses an energy supply unit for a motor vehicle and a method for operating an energy supply unit. The energy generated when the magnetic field of the coil of the motor vehicle is removed is temporarily stored in a capacitor and used to supply the load of the vehicle.

This object is achieved according to the invention by a device having the features of claim 1 and a method having the features of claim 8. The design and the development of the invention result from the dependent claims and the description.

According to the invention, the energy stored in the magnetic field of the rotor is converted into electrostatic energy by means of a snubber circuit/absorber circuit with a capacitor. The capacitor can absorb the energy stored in the rotor of the FSM in case of a fault.

The invention relates to a circuit arrangement for demagnetizing the rotor of a separately excited synchronous machine (FSM), comprising at least one switching circuit connected to a plurality of poles of the rotor winding of the FSM, said switching circuit having a diode, a capacitor connected downstream of the diode, and a first switch.

To demagnetize the rotor, the switch is closed. The current of the rotor flows into the capacitor via the diode. The capacitor is charged. The larger the capacitor is charged, the faster the magnetic energy of the rotor is removed. If the magnetic energy of the rotor becomes zero, the passing current also becomes zero. The diode inhibits the passing current from the capacitor back into the rotor.

In one embodiment, a first resistor is connected in parallel with the capacitor, by means of which the energy of the capacitor can be dissipated.

In a further embodiment, the positive electrode of the capacitor is connected to the positive electrode of the rotor winding via a second switch; and the negative electrode of the capacitor is connected to the negative electrode of the rotor winding via a third switch.

Once the driving operation of the vehicle is again to be performed, the energy of the capacitor can be converted into magnetic energy in the rotor again, by: the first switch is opened and the second and third switches are closed. If the capacitor discharges to 0V, the second and third switches are opened again.

In a further embodiment, the positive electrode of the capacitor is connected to the positive electrode of the intermediate circuit capacitor of the FSM via a fourth switch; and the negative electrode of the capacitor is connected to the negative electrode of the intermediate circuit capacitor via a second resistor and a fifth switch. Alternatively, the second resistor may also be arranged in series with the fourth switch, i.e. in the circuit branch connected to the positive electrode of the capacitor.

The capacitor is connected in parallel with the intermediate circuit capacitor by the closing of the fourth and fifth switches. If the magnetic energy of the rotor is stored in a capacitor, at least a part of the stored energy may flow into the intermediate circuit capacitor. A second resistor placed in series with the capacitor is used to limit the recharge current. This embodiment can only achieve: the voltage of the capacitor is equal to the voltage of the intermediate circuit capacitor. Complete transfer of electrostatic energy from the capacitor into the intermediate circuit capacitor is thus not possible.

In a further embodiment, an energy storage inductance is connected in parallel with the capacitor. The poles of the storage inductance are connected to the poles of the capacitor via a sixth switch and a seventh switch and to the poles of the intermediate circuit capacitor of the FSM via an eighth switch and a ninth switch.

If the capacitor is charged, the storage inductor can be charged by closing the sixth and seventh switches. Then, the sixth and seventh switches are opened, and the eighth and ninth switches are closed. The current stored in the storage inductance then flows through the intermediate circuit capacitor and charges the latter. This process can be repeated so long until the charge of the capacitor is removed and transferred into the intermediate circuit capacitor.

The switch may be configured as a mechanical, electromechanical or electronic switch, or as a combination of a semiconductor switch and an electromechanical switch. Examples of suitable electronic switches are power semiconductor switches, such as IGBTs, MOSFETs or thyristors. Examples of suitable electromechanical switches are contactors and relays.

In one embodiment, the diode is designed as a conventional semiconductor diode. In a further embodiment, the diode is designed as a schottky diode.

The invention also relates to a method for demagnetizing a rotor of a separately excited synchronous machine (FSM) using the circuit arrangement according to the invention, i.e. to a method for operating the circuit arrangement according to the invention.

In one embodiment of the method, at least one circuit arrangement according to the invention is electrically conductively connected to a plurality of poles of at least one rotor winding of the FSM and electromagnetic energy stored in the rotor winding is transferred to a capacitor of the circuit arrangement.

In one embodiment of the method, the electrical energy stored in the capacitor is returned to the rotor winding if the driving mode of the vehicle is to be performed again.

In a further embodiment of the method, the electrical energy stored in the capacitors of the circuit arrangement is then at least partially transferred into the intermediate circuit capacitors of the FSM. For this purpose, a capacitor is connected in parallel with the intermediate circuit capacitor.

In a further embodiment of the method, the electrical energy stored in the capacitor of the circuit arrangement is then at least partially transferred into the storage inductance. For this purpose, a capacitor is connected in parallel with the storage inductor.

In another embodiment, the electromagnetic energy is then transferred from the energy storage inductor to the intermediate circuit capacitor of the FSM. For this purpose, the intermediate circuit capacitor is connected in parallel with the energy storage inductor.

In one embodiment of the method, the capacitor is connected in parallel with the storage inductor for such a long time that the capacitor is completely discharged. The poles of the storage inductor are then separated from the poles of the capacitor and connected to the poles of the intermediate circuit capacitor for such a long time that the current through the storage inductor becomes zero.

In a further embodiment of the method, the capacitor is alternately connected to the storage inductance and the storage inductance is connected to the intermediate circuit capacitor, wherein only a portion of the electrical energy stored in the capacitor is transferred in each case; and these steps are repeated so frequently until the capacitor is fully discharged. In one embodiment, these steps are repeated at a high frequency.

The advantages of the circuit arrangement according to the invention and of the method according to the invention include: it protects the components of the FSM from overpressure and improves the energy efficiency of the overall system, since the magnetic energy of the rotor can be stored and re-applied.

Further advantages and design aspects of the invention result from the description and the drawings.

It goes without saying that the features mentioned above and those yet to be elucidated below can be used not only in the respectively indicated combination, but also in other combinations or alone without departing from the scope of the invention.

Drawings

The invention is illustrated schematically in the drawing by means of embodiments and is further elucidated with reference to the drawing. Wherein:

fig. 1 shows a circuit diagram of a FSM according to the prior art;

fig. 2 shows a circuit diagram of an FSM with a first embodiment of the circuit arrangement according to the invention;

FIG. 3 shows a circuit diagram of a FSM with a second embodiment of the circuit arrangement according to the invention;

FIG. 4 shows a circuit diagram of a FSM with a third embodiment of the circuit arrangement according to the invention;

fig. 5 shows a circuit diagram of an FSM with a fourth embodiment of the circuit arrangement according to the invention.

List of reference numerals:

S_iswitch element (i ═ 1-17)

D_iDiode (i 1-3)

C intermediate circuit capacitor

C_SBuffer capacitor

W_RRotor winding

R_EDischarge resistor

R resistance for limiting current

L_SEnergy storage inductor

Detailed Description

Fig. 1 schematically shows a circuit diagram of a FSM according to the prior art. Here, a capacitor C with an intermediate circuit and a switching element S are depicted₁To S₆Of the circuit, the switching element S₁To S₆Driving the stator windings of the FSM. Rotor winding W_RIs connected in parallel with the intermediate circuit capacitor C. The circuit additionally comprises a switching element S₇And S₈And a diode D₁And D₂By means of which the current through the rotor of the FSM can be regulated.

In order to demagnetize the rotor (for example in the case of a crash or other critical driving situation), the following possibilities exist:

1. switch S₇And S₈Is opened. The current then flows through the diode D₁An intermediate circuit capacitor C and a diode D₂. Thereby continuing to charge the capacitor C. In this case, an overload of the capacitor C is encountered. In the worst case, this overload can lead to a failure of the component or of other components due to an overvoltage;

2. switch S₇Is turned on, switch S₈And remain closed. The current flows through the switch S₈And a diode D₂. Thereby eliminating the magnetization of the rotor, which however occurs very slowly. Dependent on the resistance of the rotor and the voltage across the semiconductorThis may last for a long time. Furthermore, the energy in the resistors and semiconductors is dissipated. That is, converting electrical energy into thermal energy, which then becomes unavailable to the vehicle and its traction;

3. switch S₈Is turned on, switch S₇And remain closed. The current now flows through the diode D₁And switch S₇. Here, too, as in the case of the possible variant 2, the disadvantages are long demagnetization times and the loss of available electrical energy.

Fig. 2 shows a circuit diagram of an FSM with a first embodiment of the circuit arrangement according to the invention. In the rotor winding W_RIs connected to a switching circuit having a diode D₃Buffer capacitor C arranged in the diode_SAnd a first switch S₉. Capacitor C_SA discharge resistor R is connected in parallel_EThe capacitor C can be eliminated by the discharge resistor_SThe energy of (a).

For demagnetization of the rotor, the switch S is opened₇And S₈Closing switch S₉. The current of the rotor then passes through the diode D₃Flows to the capacitor C_SIn (1). The capacitor is charged. Capacitor C_SThe further the charging, the faster the magnetic energy of the rotor is removed. If the magnetic energy of the rotor becomes zero, the passing current also becomes zero. Diode D₃Now the prevention: capacitor C_SEnergy is transmitted back to the rotor because of the diode D₃Current backflow is inhibited. Discharge resistor R_EFor the cancelable buffer capacitor C_SThe energy of (a).

FIG. 3 shows a circuit diagram of a FSM with a second embodiment of the circuit arrangement according to the invention, without a discharge resistor R_E. Instead, a capacitor C_SVia the second switch S₁₀And rotor winding W_RIs connected to the positive pole of the capacitor C_SVia a third switch S₁₁And rotor winding W_RIs connected to the negative electrode of (1).

If now with the aid of switch S₉And a diode D₃Demagnetizing and energizing the rotorContainer C_SCharging, then for the capacitor C_SMay replace the discharge resistor R depicted in fig. 2_EOr combined with a resistance R_EUsing a switch S₁₀And switch S₁₁. When the vehicle is to be driven again, the switch S is used₁₀And switch S₁₁Can also be used to turn on the capacitor C_SIs converted into magnetic energy in the rotor. If the capacitor C is connected_SDischarge to 0V, then switch S is opened again₁₀And switch S₁₁。

FIG. 4 shows a circuit diagram of a FSM with a third embodiment of the circuit arrangement according to the invention, capacitor C_SVia a switch S₁₂Is connected to the positive electrode of an intermediate circuit capacitor C, and the capacitor C_SVia a resistor R and a switch S₁₃Is connected to the negative electrode of the intermediate circuit capacitor C.

If the magnetic energy of the rotor is stored in the capacitor C_SThen, through switch S₁₂And S₁₃Make the capacitor C_SIn parallel with the intermediate circuit capacitor C. This then takes care of causing storage in the buffer capacitor C_SMay flow at least partially into the intermediate circuit capacitor C. And switch S₁₃The series resistor R is responsible here for limiting the recharge current.

It should be mentioned here that this embodiment only allows: capacitor C_SIs equal to the voltage of the intermediate circuit capacitor C. Whereby it is impossible to realize electrostatic energy consisting of C_SComplete transmission to C. To achieve this, the embodiment shown in fig. 5 is suitable.

FIG. 5 shows a circuit diagram of a FSM with a fourth embodiment of the circuit arrangement according to the invention, capacitor C_SThe energy storage inductor L is connected in parallel_S. Energy storage inductor L_SVia a switch S₁₄And S₁₅And a capacitor C_SIs connected via a switch S₁₆And S₁₇Connected to the electrodes of the intermediate circuit capacitor C.

If the capacitor C_SBy means ofAt switch S₉And a diode D₃Charged as described above and the rotor is field-free, then switch S is opened₉By closing two switches S₁₄And S₁₅Can provide energy storage inductance L_SAnd (6) charging. Then the switch S is opened₁₅And closing the switch S₁₆And S₁₇. In the energy storage inductance L_SThe stored current then flows through the intermediate circuit capacitor C and charges it. This process can be repeated so long until the capacitor C_SIs eliminated and transferred into the capacitor C.

In one variant of the method, the switch S is closed for such a long time₁₄And S₁₅Up to capacitor C_SAnd (4) completely discharging. Subsequently opening the switch S₁₅And so long as switch S is closed₁₆And S₁₇Until it passes through the inductor L_SBecomes zero. Then switch S is opened again₁₆And S₁₇And the process ends. In this way the number of switching processes is minimized and the losses in the switches are as low as possible. Naturally, it is necessary to use a choke L_SThe maximum energy stored in (c) is high here.

In an alternative variant of the method, the switch S is switched a plurality of times at a higher frequency₁₅、S₁₆And S₁₇And the process is performed multiple times. From this inductance L_SCan be determined to be significantly smaller.