WO2024113100A1

WO2024113100A1 - Power converter and electronic device charger

Info

Publication number: WO2024113100A1
Application number: PCT/CN2022/134709
Authority: WO
Inventors: Xiaocun YANG; Yanbo Zou
Original assignee: Innoscience (suzhou) Semiconductor Co., Ltd.
Filing date: 2022-11-28
Publication date: 2024-06-06

Abstract

A power converter (200) includes: an input port (211) configured to be electrically coupled to an AC power supply (210); an output port (299) configured to be electrically coupled to a load (295,296); and a transformer (235) configured to transform a DC voltage to an output voltage. The transformer (235) includes a primary winding (240) and a secondary winding (250) magnetically coupled with the primary winding (240). The transformer (235) further comprises a noise-cancellation module (285) arranged between the primary winding (240) and the secondary winding (250) and configured to eliminate the common mode noise current generated during an operation of power conversion. The noise-cancellation module (285) comprises: a noise-cancellation winding (280) having a first end (281) electrically connected to a first terminal (241) of the primary winding (240); and a noise-cancellation foil (290) electrically connected to a second end (282) of the noise-cancellation winding (280).

Description

POWER CONVERTER AND ELECTRONIC DEVICE CHARGER

Field of the Invention:

The present invention generally relates to a power converter and an electronic device charger including the same, and more specifically, the present invention relates to a common mode noise cancellation in the power converter.

Background of the Invention:

Power converters are inevitable devices that are used to power many household and industrial machines by providing a direct current (DC) power source that has been rectified from an alternating current (AC) power source provided by an AC source. Typically, the power converters include a transformer and tend to generate common mode noise.

Several architectures have been proposed to eliminate the common mode noise in a transformer of a power converter. As shown in FIG. 1, by adopting multi-strand winding as a noise-cancellation winding 180 in a transformer 135 having a primary winding 140 and a secondary winding 150, noise elimination can be achieved if a condition: Vp*Cps = Vs*Css is fulfilled, where Vp is the induced voltage between the primary winding 140 and the secondary winding 150, Vs the induced voltage between the noise-cancellation winding 180 and the secondary winding 150, Cps is the parasitic capacitance between the primary winding 140 and the secondary winding 150, and Css is the coupling capacitance between the noise-cancellation winding 180 and the secondary winding 150. However, as the wire diameter of a primary winding and a secondary winding is much thicker than a wire diameter of the noise-cancellation winding in general, the noise elimination effect may not uniform from product to product in the mass production due to the following scenarios.

To be specific, in first scenario as shown in FIG. 2A, when the winding strength of the noise-cancellation winding 180 is too small, a formation of the noise-cancellation winding is flat. Eventually, the noise-cancellation winding is arranged evenly but the distance between the noise-cancellation winding and the primary winding 140 is large. In second scenario as shown in FIG. 2B, when the winding strength of the noise-cancellation winding 180 is moderate, the formation of the noise-cancellation winding 180 is uneven and the distance between the noise-cancellation winding and the primary winding 140 is reduced. In third scenario as shown in FIG. 2C, when the winding strength of the noise-cancellation winding 180 is large, the formation of the noise-cancellation winding is not flat, but some turns of the noise-cancellation winding may be embedded in the gaps between the primary winding 140. Eventually the distance between the noise-cancellation winding 180 and the primary winding 140 is small. Based on the above, coupling capacitance between the noise-cancellation winding and the primary winding may vary, thus make it difficult to fulfill the common mode noise cancellation condition with the same transformer design.

Along with requirement of a common mode noise cancellation in the power converter, it could be desirable to develop the power converter with effective noise cancellation for certain applications in the field and uniform EMI shielding performance from product to product in the mass production.

Summary of the Invention:

According to one aspect of the present invention, a power converter design is provided to address the above issues. The power converter of the invention includes, an input port configured to electrically coupled to an AC power supply; an output port configured to electrically coupled to a load; and a transformer configured to transform a DC voltage to an output voltage, the transformer including a primary winding and a secondary winding magnetically coupled with the primary winding. The transformer further comprises a noise-cancellation module arranged between the primary winding and the secondary winding and configured to eliminate the common mode noise current generated during an operation of power conversion. The noise-cancellation module comprises: a noise-cancellation winding having a first end electrically connected to a first terminal of the primary winding; and a noise-cancellation foil electrically connected to a second end of the noise-cancellation winding. The noise-cancellation winding has a number of turns of coil and the noise-cancellation foil has an area such that a product of an induced voltage at the second end of the noise-cancellation winding and a coupling capacitance between the secondary winding and the noise-cancellation foil is equal to a product of an induced voltage at a second terminal of the primary winding and a parasitic capacitance between the primary winding and the secondary winding.

The noise-cancellation module design provided by the present invention can provide effective noise cancellation and uniform EMI shielding performance from product to product in mass production. Firstly, the use of noise-cancellation foil can solve the problem of being embedded in gaps between wound wires of the inner windings (e.g., primary and/or secondary windings) . Secondly, the noise-cancellation winding requires fewer number of turns as it only need to serve function of providing the induced voltage (at the connection node between its terminal and the noise-cancellation foil) for noise-cancellation while the noise-cancellation foil serves the function of providing the coupling capacitance (between itself and the secondary winding) for noise-cancellation. Thicker wires can also be used for making the noise-cancellation winding to avoid being embedded in gaps between wound wires of the inner windings. Therefore, the consistency and effectiveness of common mode noise cancellation in transformer from product to product can be achieved and maintained.

Brief Description of the Drawings:

Aspects of the present disclosure may be readily understood from the following detailed description with reference to the accompanying figures. The illustrations may not necessarily be drawn to scale. That is, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion. There may be distinctions between the artistic renditions in the present disclosure and the actual apparatus due to manufacturing processes and tolerances. Common reference numerals may be used throughout the drawings and the detailed description to indicate the same or similar components.

FIG. 1 is a cross-section view of a conventional transformer in a power converter.

FIGS. 2A –2C illustrate scenarios of formation of noise-cancellation winding in a transformer for different winding strengths of the noise-cancellation winding.

FIG. 3A illustrates a circuit diagram of a power converter according to an exemplary embodiment of the precent invention; FIG. 3B is closeup view of a transformer in the power converter of FIG. 3A; and FIG. 3C is cross-section view of an exemplary configuration of a transformer in the power converter of FIG. 3A.

FIG. 4A illustrates a circuit diagram of a power converter according to an exemplary embodiment of the precent invention; FIG. 4B is closeup view of a transformer in the power converter of FIG. 4A; and FIG. 4C is cross-section view of an exemplary configuration of a transformer in the power converter of FIG. 4A;

FIG. 5 illustrates a block diagram of an electronic device charger according to an exemplary embodiment of the precent invention.

Detailed Description:

In the following description, preferred examples of the present disclosure will be set forth as embodiments which are to be regarded as illustrative rather than restrictive. Specific details may be omitted so as not to obscure the present disclosure; however, the present invention is written to enable one skilled in the art to practice the teachings herein without undue experimentation.

It is to be understood that other embodiment may be utilized and structural changes may be made without departing from the scope of the present invention. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including, ” “comprising, ” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected, ” “coupled, ” and “mounted, ” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings.

FIG. 3A illustrates a circuit diagram of a power converter according to an exemplary embodiment of the present invention. Referring to FIG. 3A, the power converter 200 includes an AC power supply 210, a line impedance stabilization network (LISN) 220, a rectifier 230, a transformer 235, a switching element 260, a synchronous rectifying element 270, an output capacitor 295.

The power converter 200 is an AC-DC converter.

In one embodiment, the power 200 is a nitride-based AC-DC converter.

The input port 211 is electrically coupled to an AC power supply 210.

The line impedance stabilization network (LISN) 220 is electrically coupled to the input port 211 and configured to stabilize an input impedance of the power converter 200. The LISN 220 is electrically coupled to the input port 211 and configured to stabilize an input impedance of the power converter 200.

In one embodiment, the LISN 220 is an auxiliary circuit for testing conducted electromagnetic interference. The voltage drop in the LISN 220 is a common mode voltage.

The LISN 220 includes a plurality of inductors and a plurality of impedance networks. The plurality of inductors includes a first inductor 221 and a second inductor 222.

The rectifier 230 is electrically coupled to the LISN 220 and configured to convert an input AC voltage from the AC power supply 210 to a DC voltage. The rectifier 230 includes a first diode 231, a second diode 232, a third diode 233, a fourth diode 234.

Each of the first diode 231, the second diode 232, the third diode 233, and the fourth diode 234 includes an anode and a cathode. The anode of the first diode 231 is coupled to the cathode of the second diode 232. The anode of the second diode 232 is coupled to the anode of the third diode 233. The cathode of the third diode 233 is coupled to the anode of the fourth diode 234. The cathode of the fourth diode 234 is coupled to the cathode of the first diode 231.

During a positive half cycle of the AC source 210, the first diode 231 and the third diode 233 is turned on and during a negative half cycle of the AC source 210, the second diode 232 and the fourth diode 243 is turned on. By this way, the power converter 200 is configured to rectify an AC input voltage to a DC output voltage in the positive half cycle and the negative half cycle of the AC source 210.

The transformer 235 is configured to transform the rectified DC voltage to an output voltage.

FIG. 3B shows a closeup view of the transformer 235 in FIG. 3A. FIG. 3C shows a cross-section view of an exemplary configuration of the transformer 235. The transformer 235 includes a primary winding 240 and a secondary winding 250. The secondary winding 250 is magnetically coupled with the primary winding 240. The primary winding 240 is being electrically coupled to the rectifier 230. The secondary winding 250 is being electrically coupled to a load 296 through the output port 299.

The primary winding 240 includes a terminal 241 and a terminal 242. the terminal 241 of the primary winding 240 is coupled to a terminal of the rectifier 230 at a connection node B and the terminal 242 of the primary winding 240 is coupled to the switching element 260 at a connection node SW.

The secondary winding 250 includes a terminal 251 and a terminal 252. The terminal 251 of the secondary winding 250 is coupled to a terminal Vo+ of the output port 299 and the terminal 252 of the secondary winding 250 is coupled to the synchronous rectifying element 270.

The transformer 235 further includes one or more noise-cancellation modules 285 configured to eliminate a common mode noise current generated during an operation of power conversion. The noise-cancellation modules 285 are arranged between the primary winding 240 and the secondary winding 250. Each noise-cancellation module 285 includes a noise-cancellation winding 280 and a noise-cancellation foil 290.

The noise-cancellation winding 280 includes an end 281 and an end 282. The end 281 of the noise-cancellation winding 280 is electrically coupled to the terminal 241 of the primary winding 240 at the connection node B and the end 282 of the noise-cancellation winding 280 is electrically connected to the noise-cancellation foil 290 at a connection node S’ .

In some embodiments, the primary winding 240 may include a first primary sub-winding 240a and a second primary sub-winding 240b. The primary winding 240, the secondary winding 250, and the noise-cancellation winding 280 are wounded concentrically about a longitudinal axis Z.In other words, the primary winding 240, the secondary winding 250, and the noise-cancellation winding 280 are wounded concentrically in a z-axis.

A voltage Vs′ induced at the connection node S’ (that is, at the second end of the noise-cancellation winding 280) is dependent and proportional the number of turns of coil in the noise-cancellation winding 280.

A capacitance Css’ between the secondary winding 250 and the noise-cancellation foil 290 is dependent and proportional to the area of the noise-cancellation foil 290.

The noise-cancellation winding 280 may be selected to have Nc turns of coil and the noise-cancellation foil 290 may be selected to have an area A such that a product of the induced voltage at the second end of the noise-cancellation winding 280 and a coupling capacitance between the secondary winding 250 and the noise-cancellation foil 290 is equal to a product of an induced voltage Vsw at the connection node SW (that is, at the terminal 242 of the primary winding) and a parasitic capacitance Cps between the primary winding 240 and the secondary winding 250. That is, a noise-cancellation condition may be given by:

Vsw*Cps=Vs′ *Css′-→ (1)

The switching element 260 is electrically connected to the primary winding 240 and configured to block and conduct a primary current flowing through the primary winding 240.

In some embodiments, the switching element 260 is a n-type MOSFET transistor.

The switching element 260 includes a source terminal, a drain terminal and a gate terminal. The drain terminal of the switching element 260 is electrically coupled to the terminal 242 of the primary winding 240. The source terminal is coupled to a second terminal of the rectifier 230. The gate terminal is coupled to a control pin of a controller (not shown) to receive a control signal from the controller. In other words, the controller is configured to perform a switching operation of the switching element 260.

In some embodiments, the switching element 260 may be a p-type transistor, thus the type of the switching element 260 is not limited in this disclosure.

In some embodiments, the switching element 260 may be SiC MOSFET.

In some embodiments, the switching element 260 may be a GaN device, such as a AlGaN/GaN enhanced-mode high electron mobility field effect transistor, or bipolar junction transistor (BJT) or insulated-gate bipolar transistor (IGBT) or thyristor or a diode, thus the type of the switching element 260 is not limited in this disclosure.

The power converter 200 includes a diode 255. The diode 255 includes an anode and a cathode. The anode of diode 255 is coupled to the terminal 242 of the primary winding 240.

The synchronous rectifying element 270 includes an anode and a cathode. The cathode of the synchronous rectifying element 270 is electrically coupled to the terminal 252 of the secondary winding 250. The anode of the synchronous rectifying element 270 is coupled to a second terminal Vo-of the output port 299. The synchronous rectifying element 270 is configured to rectifying a secondary current flowing through the secondary winding 250.

In some embodiments, the synchronous rectifying element 270 is a diode having an anode electrically coupled to a second terminal of the load and a cathode electrically coupled to the terminal 252 of the secondary winding 250. In some embodiments, the diode is constructed with a transistor, such as a AlGaN/GaN transistor, having a source and a gate shorted together to act as the anode and a drain acting as the cathode.

The output port 299 includes a load capacitor 295 and a load resistor 296. The load capacitor 295 includes a first terminal and a second terminal. Similarly, the load resistor 296 includes a first terminal and a second terminal. The first terminal of the load capacitor 295 and the first terminal of the load resistor 296 are coupled to the first terminal Vo+ of the output port 299. The second terminal of the load capacitor 295 and the second terminal of the load resistor 296 are coupled to the second terminal Vo-of the output port 299.

Based on the above configuration, a common mode noise cancellation in the power converter 200 is achieved.

FIG. 4A illustrates a circuit diagram of a power converter 300 according to another exemplary embodiment of the present invention. The power converter 300 is similar to the power convert 200 of FIG. 3A except for that an end 381 of a noise-cancellation winding 380 of a noise-cancellation module 385 in a transformer 335 of the power converter 300 is electrically coupled to a ground. FIG. 4B shows a closeup view of the transformer 335. FIG. 4C shows a cross-section view of an exemplary configuration of the transformer 335. For conciseness, identical elements in FIGS. 2A-2C and 3A-3C are given the same reference numerals and will not be further described in details.

Similarly, the noise-cancellation winding 380 may be selected to have Nc turns of coil and the noise-cancellation foil 390 may be selected to have an area A such that a product of the induced voltage Vs’ at the end 382 of the noise-cancellation winding 380 and a coupling capacitance Css’ between the secondary winding 250 and the noise-cancellation foil 390 is equal to a product of an induced voltage Vsw at a terminal 242 of the primary winding 240 and a parasitic capacitance Cps between the primary winding 240 and the secondary winding 250. Based on the above configuration, a common mode noise cancellation in the power converter 300 is achieved.

FIG. 5 illustrates a block diagram of an electronic device charger according to an exemplary embodiment of the present invention. The electronic device charger 400 includes a power converter 410. The electronic device charger 400 is configured to supply an AC voltage from an AC source to a device connected to the electronic device charger 400. The power converter 410 is configured to convert the AC voltage to a DC voltage to the device connected to the electronic device charger 400.

In one embodiment, with reference to FIG. 3A, the power converter 410 is similar to power converter 200, thus the detailed description of the power converter 410 is omitted herein.

In some embodiments, with reference to FIG. 4A, the power converter 410 is similar to a power converter 300, thus the detailed description of the power converter 410 is omitted herein.

Based on the above, in the embodiments of the invention, common mode noise cancellation is achieved in the power converter 410 of the electronic device charger 400.

The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated. While the methods disclosed herein have been described with reference to particular operations performed in a particular order, it will be understood that these operations may be combined, sub-divided, or re-ordered to form an equivalent method without departing from the teachings of the present disclosure. Accordingly, unless specifically indicated herein, the order and grouping of the operations are not limitations. While the apparatuses disclosed herein have been described with reference to particular structures, shapes, materials, composition of matter and relationships…etc., these descriptions and illustrations are not limiting. Modifications may be made to adapt a particular situation to the objective, spirit and scope of the present disclosure. All such modifications are intended to be within the scope of the claims appended hereto.

Claims

A power converter, comprising:

an input port configured to electrically coupled to an AC power supply;

an output port configured to electrically coupled to a load; and

a transformer configured to transform a rectified DC voltage to an output voltage, the transformer including a primary winding and a secondary winding magnetically coupled with the primary winding;

wherein the transformer further includes a noise-cancellation winding; and a noise-cancellation foil electrically connected to a first end of the noise-cancellation winding;

wherein the noise-cancellation winding has a number of turns of coil and the noise-cancellation foil has an area such that a product of an induced voltage at the first end of the noise-cancellation winding and a coupling capacitance between the secondary winding and the noise-cancellation foil is equal to a product of an induced voltage at a first terminal of the primary winding and a parasitic capacitance between the primary winding and the secondary winding.
The power converter according to claim 1, further comprising a line impedance stabilization network (LISN) electrically coupled to the input port and configured to stabilize an input impedance of the power converter.
The power converter according to claim 2, further comprising a rectifier electrically coupled to the LISN and configured to convert an input AC voltage from the AC power supply to the DC voltage.
The power converter according to claim 3, further comprising:

a switching element electrically connected to the primary winding and configured to block and conduct a primary current flowing through the primary winding; and

a synchronous rectifying element electrically coupled to the secondary winding and configured to rectifying a secondary current flowing through the second secondary winding.
The power converter according to claim 4, wherein

the first terminal of the primary winding is further coupled to the switching element and a second terminal of the primary winding is coupled to a first terminal of the rectifier; and

a first terminal of the secondary winding is coupled to a first terminal of the output port and a second terminal of the secondary winding is coupled to the synchronous rectifying element.
The power converter according to claim 5, wherein a second end of the noise-cancellation winding is electrically coupled to the second terminal of the primary winding.
The power converter according to claim 6, wherein the primary winding, secondary winding and the noise-cancellation winding are wounded concentrically about a longitudinal axis.
The power converter according to claim 5, wherein a second end of the noise-cancellation winding is electrically coupled to a ground.
The power converter according to claim 8, wherein the primary winding, secondary winding and the noise-cancellation winding are wounded concentrically about a longitudinal axis.
The power converter according to any one of claims 4 to 9, wherein the switching element is a transistor having a source coupled to a second terminal of the rectifier, a drain electrically coupled to the second terminal of the primary winding and a gate electrically coupled to a control pin of a controller to receive a control signal from the controller.
The power converter according to claim 10, wherein the transistor is a AlGaN/GaN enhanced-mode high electron mobility field effect transistor.
The power converter according to any one of claims 4 to 9, wherein

the synchronous rectifying element is a diode having an anode electrically coupled to a second terminal of the load and a cathode electrically coupled to the second terminal of the secondary winding.
The power converter according to claim 14, wherein the diode is constructed with a AlGaN/GaN transistor having a source and a gate shorted together to act as the anode and a drain acting as the cathode.
An electronic device charger including the power converter according to claim 1.
The power converter according to claim 14, further comprising a line impedance stabilization network (LISN) electrically coupled to the input port and configured to stabilize an input impedance of the power converter.
The electronic device charger according to claim 15, further comprising a rectifier electrically coupled to the LISN and configured to convert an input AC voltage from the AC power supply to the DC voltage.
The electronic device charger according to claim 16, further comprising:

a switching element electrically connected to the primary winding and configured to block and conduct a primary current flowing through the primary winding; and

a synchronous rectifying element electrically coupled to the secondary winding and configured to rectifying a secondary current flowing through the second secondary winding.
The electronic device charger according to claim 17, wherein

the first terminal of the primary winding is further coupled to the switching element and a second terminal of the primary winding is coupled to a first terminal of the rectifier; and

a first terminal of the secondary winding is coupled to a first terminal of the output port and a second terminal of the secondary winding is coupled to the synchronous rectifying element.
The electronic device charger according to claim 18, wherein a second end of the noise-cancellation winding is electrically coupled to the second terminal of the primary winding.
The electronic device charger according to claim 19, wherein the primary winding, secondary winding and the noise-cancellation winding are wounded concentrically about a longitudinal axis.
The electronic device charger according to claim 18, wherein a second end of the noise-cancellation winding is electrically coupled to a ground.
The electronic device charger according to claim 21, wherein the primary winding, secondary winding and the noise-cancellation winding are wounded concentrically about a longitudinal axis.
The electronic device charger according to any one of claims 17 to 22, wherein the switching element is a transistor having a source coupled to a second terminal of the rectifier, a drain electrically coupled to the second terminal of the primary winding and a gate electrically coupled to a control pin of a controller to receive a control signal from the controller.
The electronic device charger according to claim 23, wherein the transistor is a AlGaN/GaN enhanced-mode high electron mobility field effect transistor.
The electronic device charger according to any one of claims 17 to 22, wherein

the synchronous rectifying element is a diode having an anode electrically coupled to a second terminal of the load and a cathode electrically coupled to the second terminal of the secondary winding.
The electronic device charger according to claim 25, wherein the diode is constructed with a AlGaN/GaN transistor having a source and a gate shorted together to act as the anode and a drain acting as the cathode.