EP4655870A1

EP4655870A1 - Auxiliary power supply and power electronic device

Info

Publication number: EP4655870A1
Application number: EP23924696.0A
Authority: EP
Inventors: Xiong FANG; Jingfan YANG; Xin Cao; Shouxian ZHANG; Xiaofeng Jiang
Original assignee: Siemens AG; Siemens Corp
Current assignee: Siemens AG; Siemens Corp
Priority date: 2023-03-02
Filing date: 2023-03-02
Publication date: 2025-12-03
Also published as: CN120660272A; WO2024178729A1

Abstract

Embodiments of the present application provide an auxiliary power supply module and a power electronic device. The auxiliary power supply module includes: at least two power supply main modules, each of which is configured to generate different isolated power supplies, wherein input of each of the at least two power supply main modules is connected in parallel with one of at least two DC-link capacitors connected in series, different power supply main modules connect different DC-link capacitors, and the number of the power supply main modules are the same as that of the DC-link capacitors; outputs of the at least two power supply main modules are connected in parallel; and a controlling module, configured to control the at least two power supply main modules to generate required power supplies. The technical solutions of the present application can improve the power supply reliability.

Description

AUXILIARY POWER SUPPLY AND POWER ELECTRONIC DEVICE

FIELD

The present application relates to electronic technologies, and more particularly, to an auxiliary power supply and a power electronic device.

BACKGROUND

In an electronic device such as a frequency inverter, there is an auxiliary power supply unit (PSU) which is configured to generate different power supplies for some circuits, such as a driving circuit, a controlling circuit, a measuring circuit and other low-voltage circuits in the electronic device. In general, if the auxiliary PSU does not come from an external power supply, it will connect to the DC-link capacity and generate some different isolated power supplies by a step-down converter. Figure 1 is a schematic diagram illustrating a frequency inverter 1 including an auxiliary PSU. As shown in figure 1, in the frequency inverter 1, a rectifier circuit 11 is configured to convert three-phase input AC voltage IN into DC voltage, two filter capacitors Cdc1, Cdc2 are configured to filter the DC voltage outputted by the rectifier circuit 11 to obtain a smooth DC voltage, the inverter circuit 12 is configured to convert the smooth DC voltage into AC voltage for the motor M. In figure 1, the two filter capacitors Cdc1, Cdc2 connected to the DC link may be called DC-link capacitors. One input end of the auxiliary PSU connects to one end of two serially connected DC-link capacitors of the frequency inverter, and the other input end of the auxiliary PSU connects to the other end of the two serially connected DC-link capacitors. The PSU is controlled by a controller 13 to generate required power supply Vo.
In addition, those skilled in the art are committed to finding other PSU solutions.
SUMMARY
According to embodiments of the present application, an auxiliary power supply module and a power electronic device are provided to improve the power supply reliability.
The auxiliary power supply module provided by embodiments of the present application includes: at least two power supply main modules, each of which is configured to generate different isolated power supplies, wherein input of each of the at least two power supply main modules is connected in parallel with one of at least two DC-link capacitors connected in series, different power supply main modules connect different DC-link capacitors, and the number of the power supply main modules are the same as that of the DC-link capacitors; outputs of the at least two power supply main modules are connected in parallel; and a controlling module, configured to control the at least two power supply main modules to generate required power supplies.
The power electronic device provided by embodiments of the present application includes: at least two DC-link capacitors connected in series and an auxiliary power supply module mentioned above.
It can be seen from the above technical solutions in embodiments of the application, by adopting at least two power supply main modules, the input voltage for each power supply main module is one part of that of traditional PSU, and therefore the voltage stress for the switch in each power supply main module is reduced, thus the power supply reliability is improved.
In addition, since the at least two DC-link capacitors are connected in series, the outputs of the at least two power supply main modules are connected in parallel, and the switches in different power supply main modules are controlled by the same output signal of the controlling module, the at least two power supply main modules can share the output current automatically, the power supply reliability is further improved. At the same time, even the DC-link capacitors have different capacitances, the power supply main modules can balance the voltage between the DC-link capacitors and voltage-sharing resistors will be not necessary.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present application, reference should be made to the Detailed Description below, in conjunction with the following drawings in which like reference numerals refer to corresponding parts throughout the figures.
Figure 1 is a schematic diagram illustrating a frequency inverter 1 including an auxiliary PSU.
Figure 2 is a schematic diagram illustrating a flyback circuit.
Figure 3 is a flow diagram illustrating a frequency inverter including an auxiliary power supply module (PSM) according to embodiments of the present application.
Figure 4 is a schematic diagram illustrating an auxiliary PSM according to an embodiment of the present application.
Figure 5 is a schematic diagram illustrating an auxiliary PSM according to another embodiment of the present application.
Figure 6 is a schematic diagram illustrating an auxiliary PSM according to yet another embodiment of the present application.
The reference numerals are as follows:

DETAILED DESCRIPTION

In the specific implementation, the PSU is generally achieved by a flyback circuit. Figure 2 is a schematic diagram illustrating a flyback circuit. As shown in figure 2, the flyback circuit includes a voltage clamping circuit 21, a transformer T, at least one rectifier filter circuit 22, a switch S1, a feedback circuit 23, a controller 13 and a driving circuit 24.
The voltage clamping circuit 21 is configured to clamp the voltage of the switch S1. In figure 1, the voltage clamping circuit 21 includes a resistor R1, a capacitor C1 and a diode D1. The resistor R1 and the capacitor C1are connected in parallel to form an RC parallel circuit. The cathode of the diode D1 is connected with one end of the RC parallel circuit to form the voltage clamping circuit 21. The other end of the RC parallel circuit is the first end of the voltage clamping circuit 21 and is one input end of the PSU, the anode of the diode D1 is the second end of the voltage clamping circuit 21.
The switch S1 is configured to convert the DC voltage into a PWM switch signal according to a driving signal. The drain of the switch S1 is connected with the second end of the voltage clamping circuit 21, the grid of the switch S1 is connected with one end of the driving circuit 24, the source and the substrate of the switch S1 is the other input end of the PSU.
The transformer T is configured to convert the PWM switch signal from high voltage signal to different low voltage signals. There are multiple secondary coils in the transformer T, and different secondary coils corresponds to different low voltage signals, but only one secondary coil namely the secondary coil Ns1 in figure 2 is taken as the main control coil. The primary coil Np of the transformer T is connected in parallel with the voltage clamping circuit 21, the secondary coil Ns1 of the transformer T is connected in parallel with the rectifier filter circuit 22, and each of other secondary coils for example the secondary coil Nsn of the transformer T is also connected in parallel with a rectifier filter circuit 22.
Each rectifier filter circuit 22 is configured to rectify and filter a low-voltage signal to obtain a required output voltage. The number of rectifier filter circuit 22 is the same as that of secondary coils of the transformer T, and one rectifier filter circuit 22 corresponds to one secondary coil. Each rectifier filter circuit 22 includes a rectifier diode D21/…/D2n and a filter capacitor C21/…/C2n. The rectifier diode D21/…/D2n and the filter capacitor C21/…/C2n are connected in series to form the rectifier filter circuit 22, and two output ends of the filter capacitor C21/…/C2n are one output Vo1/…/Von of PSU for providing corresponding power supply for the load L1/Ln. Different rectifier filter circuits 22 may include different rectifier diodes D21, …, D2n and different filter capacitors C21, …, C2n.
The feedback circuit 23 is configured to feed back the output voltage corresponding to the main control coil to the controller 13.
The controller 13 is configured to generate a control signal for adjusting the duty cycle according to the output voltage.
The driving circuit 24 is configured to generate a driving signal for the switch S1 according to the control signal.
When the flyback circuit shown in figure 2 are adopted by the PSU shown in figure 1, since the frequency inverter has wide-range input voltage for different global power line system, the DC-link will have a wide-range voltage, namely the flyback circuit will have a wide-range input voltage, in order to meet the wide input voltage range requirement, at least a rated 1500V MOSFET is most configured in the flyback circuit as the main switch. 1500V is nearly the maximum rated value that a normal MOSTFET can have, and compared to lower voltage MOSFET, 1500V MOSFET has much higher on-resistor which can cause higher power loss. Moreover, if 690V power line system is considered, even1500V MOSFET is not enough for flyback converter.
Therefore, a multiple-PSU solution is considered to be adopted in embodiments of this application.
Reference will now be made in detail to examples, which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present application. Also, the figures are illustrations of an example, in which assemblies shown in the figures are not necessarily essential for implementing the present application. In other instances, well-known assemblies, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the examples.
Figure 3 is a schematic diagram illustrating a frequency inverter including an auxiliary power supply module (PSM) according to embodiments of the present application. As shown in figure 3, the frequency inverter includes at least two DC-link capacitors and an auxiliary PSM, and the auxiliary PSM includes at least two power supply main modules 31 and a controlling module 32. In figure 3, it is taken as an example that there are two DC-link capacitors and two power supply main modules 31.
Each of the at least two power supply main modules 31 is configured to generate different isolated power supplies, wherein input of each of the at least two power supply main modules 31 is connected in parallel with one of at least two DC-link capacitors connected in series, different power supply main modules 31 connect different DC-link capacitors, and the number of the power supply main modules 31 are the same as that of the DC-link capacitors; outputs of the at least two power supply main modules 31 are connected in parallel.
The controlling module 32, configured to control the at least two power supply main modules 31 to generate required power supplies.
In the specific implementation, the power supply main module 31 and the controlling module 32 may be achieved in many ways.
For example, figure 4 is a schematic diagram illustrating an auxiliary PSM according to an embodiment of the present application. As shown in figure 4, in the embodiment, each of the at least two power supply main modules may include: a voltage clamping circuit 21, a first switch S1, a transformer T and at least one rectifier filter circuit 22. The structure of each of the clamping circuit 21, the first switch S1, the transformer T and the at least one rectifier filter circuit 22 in figure 4 may be similar to that in figure 2.
The voltage clamping circuit 21 is configured to clamp the voltage of the first switch S1, one end of the voltage clamping circuit 21 is one input end of corresponding power supply main module 31.
The first switch S1is configured to convert a DC voltage into a PWM switch signal according to a driving signal outputted by the controlling module 32, the drain of the first switch S1is connected with the other end of the voltage clamping circuit 21, the source of the first switch S1is the other input end of corresponding power supply main module 31, the grid of the first switch S1is connected with the output end of the controlling module 32.
The transformer T is configured to convert the PWM switch signal from high voltage signal to different low voltage signals.
Each rectifier filter circuit 22 is configured to rectify and filter a low-voltage signal to obtain a required output voltage. Two output ends of the rectifier filter circuit 22 are one output of corresponding power supply main module 31.
In the embodiment, the output corresponding to a main control coil of the transformer T in every power supply main module 31 is connected in parallel with each other. As shown in the dotted line in figure 4, the output corresponding to a same non-main control coil of the transformer T in every power supply main module 31 may be connected in parallel with each other, or be not connected with each other.
The controlling module 32 may include a feedback circuit 23, a controller 13 and a driving circuit 24.
The feedback circuit 23 is configured to feed back an output voltage of the output corresponding to the main control coil to the controller 13.
The controller 13 is configured to generate a control signal for adjusting the duty cycle according to the output voltage.
The driving circuit 24 is configured to generate a driving signal for the switch S1 according to the control signal.
Figure 5 is a schematic diagram illustrating an auxiliary PSM according to another embodiment of the present application. As shown in figure 5, compare to the auxiliary PSM in figure 4, in the embodiment, each of the at least two power supply main modules may further include: a second switch S2. The drain of the second switch S2 is connected with the other end of the voltage clamping circuit 21, and the source and the substrate of the second switch S2 is connected with the drain of the first switch S1.
Figure 6 is a schematic diagram illustrating an auxiliary PSM according to yet another embodiment of the present application. As shown in figure 6, compare to the auxiliary PSM in figure 5, in the embodiment, the voltage clamping circuit 21 only includes a diode, namely the voltage clamping circuit 21 is achieved by a voltage clamping diode. In addition, the connection relationship of the first switch S1 and the second switch S2 are different from that in figure 5. That is, in figure 6, each of the at least two power supply main modules may include: a first voltage clamping diode D3, a second voltage clamping diode D4, a transformer T, a first switch S1, a second switch S2 and at least one rectifier filter circuits 22.
The first voltage clamping diode D3 is configured to clamp the voltage of the second switch S2, an anode of the first voltage clamping diode D3 is connected with a source of the first switch S1 and is one input end of corresponding power supply main module, and a cathode of the first voltage clamping diode D3 is connected with one end of a primary coil Np of the transformer T.
The first switch S1 is configured to convert a DC voltage into a PWM switch signal according to a driving signal outputted by the controlling module 32, a drain of the first switch S1 is connected with the other end of the primary coil Np of the transformer T, and a grid of the first switch S1 is connected with an output of the controlling module 32.
The second voltage clamping diode D4 is configured to clamp the voltage of the first switch S1, an anode of the second voltage clamping diode D4 is connected with the drain of the first switch S1, and a cathode of the second voltage clamping diode D4 is connected with a drain of the second switch S2 and is the other input end of corresponding power supply main module.
The second switch S2 is configured to convert the DC voltage into a PWM switch signal according to a driving signal outputted by the controlling module 32, a source of the second switch S2 is connected with the cathode of the first voltage clamping diode D3, and a grid of the second switch S2 is connected with the output of the controlling module 32.
The functions and the structures of the transformer T and the at least one rectifier filter circuit may be the same as that in figure 4, and no further descriptions will be given here.
The technical solutions of auxiliary power supply module mentioned in the embodiments of the present invention is also applicable to other power electronic devices, such as a driver, including an auxiliary power supply in addition to the frequency converter mentioned in the above embodiments.
It can be seen from the above technical solutions in embodiments of the application, by adopting at least two power supply main modules, the input voltage for each power supply main module is one part of that of traditional PSU, and therefore the voltage stress for the switch in each power supply main module is reduced, thus the power supply reliability is improved.
In addition, since the at least two DC-link capacitors are connected in series, the outputs of the at least two power supply main modules are connected in parallel, and the switches in different power supply main modules are controlled by the same output signal of the controlling module, the at least two power supply main modules can share the output current automatically. Namely, two power supply main modules are taken as an example, if an output current of one of the tow power supply main modules is larger than that of the other power supply main module, that means the one power supply main module transfers more power from the DC-link capacitor, therefore the voltage of the DC-link capacitor will be lower than another, and then the lower voltage will result in lower output voltage of the one power supply main module, which will reduce the sharing current. Finally, the output current of the one power supply main module will be the same as that of the other power supply main module due to the negative feedback as described. Therefore, the power supply reliability is further improved. At the same time, even the DC-link capacitors have different capacitances, the power supply main modules can balance the voltage between the DC-link capacitors and voltage-sharing resistors will be not necessary.
It should be understood that, as configured herein, unless the context clearly supports exceptions, the singular forms "a" ( "a" , "an" , "the" ) are intended to include the plural forms. It should also be understood that, "and /or" configured herein is intended to include any and all possible combinations of one or more of the associated listed items.
The number of the embodiments of the present application are only configured for description, and do not represent the merits of the implementations.
The foregoing description, for purpose of explanation, has been described with reference to specific examples. However, the illustrative discussions above are not intended to be exhaustive or to limit the present application to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The examples were chosen and described in order to best explain the principles of the present application and its practical applications, to thereby enable others skilled in the art to best utilize the present application and various examples with various modifications as are suited to the particular use contemplated.

Claims

An auxiliary power supply module, characterized in that, comprising:

at least two power supply main modules (31) , each of which is configured to generate different isolated power supplies, wherein input of each of the at least two power supply main modules (31) is connected in parallel with one of at least two DC-link capacitors connected in series, different power supply main modules (31) connect different DC-link capacitors, and the number of the power supply main modules (31) are the same as that of the DC-link capacitors; outputs of the at least two power supply main modules (31) are connected in parallel; and

a controlling module (32) , configured to control the at least two power supply main modules (31) to generate required power supplies.
The auxiliary power supply module according to claim 1, characterized in that, wherein each of the at least two power supply main modules (31) comprises: a voltage clamping circuit (21) , a first switch (S1) , a transformer (T) and at least one rectifier filter circuit (22) , wherein

the voltage clamping circuit (21) is configured to clamp the voltage of the first switch (S1) ; one end of the voltage clamping circuit (21) is one input end of corresponding power supply main module;

the first switch (S1) is configured to convert a DC voltage into a PWM switch signal according to a driving signal outputted by the controlling module (32) , a drain of the first switch (S1) is connected with the other end of the voltage clamping circuit (21) , a source of the first switch (S1) is the other input end of corresponding power supply main module, and a grid of the first switch (S1) is connected with an output of the controlling module (32) ;

the transformer (T) is configured to convert the PWM switch signal from high voltage signal to different low voltage signals;

each rectifier filter circuit (22) is configured to rectify and filter a low-voltage signal to obtain a required output voltage; two output ends of the rectifier filter circuit (22) are one output of corresponding power supply main module, and the output corresponding to a main control coil of the transformer (T) in every power supply main module is connected in parallel with each other.
The auxiliary power supply module according to claim 2, characterized in that, wherein each of the at least two power supply main modules further comprises: a second switch (S2) , whose drain is connected with the other end of the voltage clamping circuit (21) , and source is connected with the drain of the first switch (S1) .
The auxiliary power supply module according to claim 2, characterized in that, wherein each of the at least two power supply main modules comprises: a first voltage clamping diode (D3) , a second voltage clamping diode (D4) , a transformer (T) , a first switch (S1) , a second switch (S2) and at least one rectifier filter circuits (22) , wherein

the first voltage clamping diode (D3) is configured to clamp the voltage of the second switch (S2) ; an anode of the first voltage clamping diode (D3) is connected with a source of the first switch (S1) and is one input end of corresponding power supply main module, and a cathode of the first voltage clamping diode (D3) is connected with one end of a primary coil (Np) of the transformer (T) ;

the first switch (S1) is configured to convert a DC voltage into a PWM switch signal according to a driving signal outputted by the controlling module (32) , a drain of the first switch (S1) is connected with the other end of the primary coil (Np) of the transformer (T) , and a grid of the first switch (S1) is connected with an output of the controlling module (32) ;

the second voltage clamping diode (D4) is configured to clamp the voltage of the first switch (S1) ; an anode of the second voltage clamping diode (D4) is connected with the drain of the first switch (S1) , and a cathode of the second voltage clamping diode (D4) is connected with a drain of the second switch (S2) and is the other input end of corresponding power supply main module;

the second switch (S2) is configured to convert the DC voltage into a PWM switch signal according to a driving signal outputted by the controlling module (32) , a source of the second switch (S2) is connected with the cathode of the first voltage clamping diode (D3) , and a grid of the second switch (S2) is connected with the output of the controlling module (32) ;

the transformer (T) is configured to convert the PWM switch signal from high voltage signal to different low voltage signals;

each rectifier filter circuit (22) is configured to rectify and filter a low-voltage signal to obtain a required output voltage; two output ends of the rectifier filter circuit (22) are one output of corresponding power supply main module, and the output corresponding to a main control coil of the transformer (T) in every power supply main module is connected in parallel with each other.
The auxiliary power supply module according to any one of claims 2 to 4, characterized in that, the controlling module (32) comprises: a feedback circuit (23) , a controller (13) and a driving circuit (24) , wherein

the feedback circuit (23) is configured to feed back an output voltage of the output corresponding to the main control coil to the controller (13) ;

the controller (13) is configured to generate a control signal for adjusting the duty cycle according to the output voltage;

the driving circuit (24) is configured to generate a driving signal for each switch according to the control signal.
A power electronic device, comprising at least two DC-link capacitors connected in series, characterized in that, further comprising an auxiliary power supply module according to any one of claims 1 to 5.
The electronic device according to claim 4, characterized in that, the power electronic device is a frequency converter or a driver.