WO2016138754A1

WO2016138754A1 - Primary side installed on ground, and foreign object detection method and apparatus

Info

Publication number: WO2016138754A1
Application number: PCT/CN2015/088896
Authority: WO
Inventors: 范杰; 刘俊强
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-03-04
Filing date: 2015-09-02
Publication date: 2016-09-09
Also published as: CN105990913A

Abstract

A primary side (400) installed on the ground, and a foreign object detection method and apparatus. The primary side comprises a magnetic core (410) and primary windings (420A, 420B) wound on magnetic core side columns (410A, 410B) bottoms of which extend outwards, and also comprises one or more foreign object detection coil pairs (430, 630) that are mounted on the magnetic core side columns bottoms of which extend outwards and that are mounted, in a Y-axis direction, on the primary windings wound on the magnetic core side columns. The one or more foreign object detection coil pairs are parallel to a plane where the primary side is located. Two foreign object detection coils symmetrical to an X-axis direction form a pair. Edges of the one or more foreign object detection coil pairs fully cover edges of the magnetic core side columns bottoms of which extend outwards and edges of the primary windings wound on the magnetic core side columns, wherein the Y-axis direction and the X-axis direction are parallel to the plane where the primary side is located, the Y-axis direction is a direction along which the magnetic core side columns extend, and the X-axis direction is perpendicular to the Y-axis direction. By means of the primary side and the foreign object detection method and apparatus, foreign object detection can be effectively performed, and safe wireless charging can be ensured.

Description

Primary side, foreign matter detecting method and device installed on the ground

Technical field

Embodiments of the present invention relate to, but are not limited to, the field of radio energy transmission, and in particular, to a primary side, foreign object detecting method and apparatus mounted on the ground.

Background technique

The growing number of cars places high demands on oil and natural gas-based energy, and with the depletion of petrochemical energy, oil prices will remain high in the long run. At the same time, the air pollution caused by automobile exhaust is becoming more and more serious. The development of electric vehicles (EVs) is an internationally recognized effective strategy for mitigating energy shortages and environmental pollution.

The electric vehicle is powered by the vehicle power supply and drives the wheels with the motor. Electric vehicles are widely optimistic due to their advantages such as energy saving, environmental protection and low noise. However, the development of electric vehicles still faces many technical problems. Power batteries and their charging technologies are one of the most important factors in the development of electric vehicles.

Battery charging technology is divided into wired charging (contact charging) and wireless charging. For wired charging, its operation mode is similar to that of a gas station. It requires manual operation. The disadvantages of this method are as follows: Although there are strict design specifications to ensure safety, the charging port is easy to catch fire under high voltage and high current impact. The device is aging; the charging interface components are prone to dust, rain, fog, soot, etc., monitoring and maintenance troubles; from the daily experience, the damage rate of the high-power socket is very high, and the socket of the charging station needs to be plugged and unplugged frequently, the problem will be more serious. Wireless charging, also known as Wireless Power Transmission (WPT), is a technology that transfers electrical energy in the air between a charger and a device through electromagnetic induction and the like, so that current flows to charge the battery. Such a wireless charging method is effectively applied to a hand-held communication device, an electric vehicle, and the like that require large-capacity battery charging, and since the connection point is buried in the ground, there is almost no risk of electric leakage, and the problem of poor connection in the wired charging method can be prevented. Moreover, wireless charging can be unattended, no need to do hands-on, fully automatic operation, safe and reliable; can achieve common charge, improve battery life and vehicle value after long-term use; medium power charging, small pressure on the grid, convenient Install charging devices in parking lots and garages.

In recent years, wireless charging core technology has become increasingly mature. There are three main types of wireless charging technologies: RF or microwave WPT, electromagnetic induction WPT, and electromagnetic resonance WPT. Electromagnetic induction WPT is a technology based on the principle of electromagnetic induction, using a transformer separated by the primary and secondary sides (called a loosely coupled transformer) to perform radio energy transmission under relatively close distance conditions (eg, 20 cm). At present, the more mature wireless power supply mode adopts this technology, and its wireless charging end-to-end efficiency is close to 90%, and the wireless charging power can reach 30kw or even higher.

Unless otherwise stated, the wireless charging system referred to in the following description refers to an electromagnetic induction type WPT system.

1 is a schematic view showing the position of wireless charging of an electric vehicle in the related art. 2 is a schematic view showing the positional relationship of the primary side, the secondary side, and the foreign matter in the related art. As shown in FIG. 1, the electric vehicle 102 is parked in a parking space 101 having a wireless charging function, and wireless charging is achieved by mounting the primary and secondary sides 103 on the parking space and on the electric vehicle, respectively. The Cartesian coordinate system OXYZ is fixed on the primary side, the origin O is taken as the center of the primary side 201, OXY is on the plane where the primary side is located, the positive direction of the X-axis is directed to the direction of the front of the electric vehicle, and the positive direction of the Z-axis is vertically upward. The secondary side 202 also has a similar Cartesian coordinate system O'X'Y'Z', and the origin O' is taken as the center of the secondary side 202. In the ideal case, O'Z' coincides with OZ, and OO' is the primary secondary side. The nominal air gap size between the two, O'X' vertical projection in the OXY plane coincides with OX, and the vertical projection of O'Y' in the OXY plane coincides with OY. Figure 2 highlights the primary side 201 and the secondary side 202 of the wireless charging system. The primary side 201 is fixedly mounted on the parking space floor, and the secondary side 202 is fixedly mounted on the electric vehicle.

3 is a schematic diagram of a loosely coupled transformer of the related art, using a planar U-shaped magnetic core, referring to the Chinese patent application CN200910032016.X "edge-expanding high-coupling coefficient non-contact transformer". The lower part is the primary side 301 of the transformer, the upper part is the secondary side 302 of the transformer, and the windings adopt a distributed planar winding structure. The U-shaped magnetic core can obtain a large distance between the magnetic columns in a certain lateral dimension, Increase the coupling coefficient. The primary magnetic core 303 and the secondary magnetic core 304 are planar U-shaped magnetic cores, and the magnetic core 303 is composed of magnetic

core side columns

303A and 303B and a magnetic core top pillar 303C. There are many kinds of materials for the core, and the right material can be selected according to the application scenario of the transformer. The loosely coupled transformer used in the electric vehicle wireless charging system is a high frequency transformer, and the magnetic core generally selects a ferrite core. The primary winding 305 and the secondary winding 306 are arranged in a distributed planar winding manner to increase the magnetic flux length of the leakage flux closure and increase the corresponding magnetic resistance. The primary winding 305 is wound around the two core-extending core legs. The two partial windings on the two core side legs are connected in series to form a primary winding 305. The secondary winding 306 is wound in a similar manner to the primary winding 305. A large air gap 307 exists between the primary side 301 and the secondary side 302 of the loosely coupled transformer, and has a size of about 20 cm as a magnetic medium. When a high frequency alternating current is applied to the primary winding 305, the primary magnetic core 303 generates an alternating magnetic field that is transmitted through the air gap 307 to the secondary core 304, where the secondary winding 306 will alternate. The magnetic field passes through, generating an induced electromotive force to achieve wireless transmission of energy. The direction of current flow in the primary winding 305 and the secondary winding 306 shown in Figure 3 is merely illustrative of the direction of current at a certain point in time.

Since the original secondary side of the wireless charging system is separated, as shown in FIG. 3, since there is an air gap 307 between the primary side 301 and the secondary side 302, especially in the wireless charging application of the electric vehicle, there is a large difference between the primary and secondary sides. The air gap may enter the foreign matter 203. Moreover, for public charging stations, it may be an open environment. There may be stones, leaves, household garbage and other debris above the wireless charging power transmitting coil, as well as metal materials such as coins, key chains, iron sheets, and metal wrapping paper. We call this anomalous object that exists between the primary and secondary sides during wireless charging as a foreign object. During the power transmission process, there is a strong alternating magnetic field between the air gaps, which induces an electromotive force in the foreign matter. If the medium is an insulator or a poor conductor with a high resistivity, the eddy current generated by the induced electromotive force is small and the power loss is small; but if the medium is a metal conductor, the same electromotive force will generate a large eddy current due to its low resistivity. As a result, a large power loss is generated, causing the temperature of the conductor to rise, and if there is a flammable item nearby, there is a fire hazard.

According to the simulation and test, the 0.5W to 1W power loss can raise the temperature of a coin by more than 80 °C. For a wireless charging system for an electric vehicle with a charging power of several kilowatts or even several tens of kilowatts, a few tenths of the power loss can warm the foreign matter to a level sufficient to ignite nearby leaves, sheets, and the like. In the wireless charging system, there are many factors that affect the charging efficiency, and it is very difficult to effectively detect one-thousandth of the abnormal power leakage.

Therefore, for high-power wireless charging systems for applications such as electric vehicles, there is still a lack of effective foreign object detection technology.

Summary of the invention

The following is an overview of the topics detailed in this document. This Summary is not intended to limit the scope of the claims.

The embodiment of the invention provides a primary side and foreign matter detecting method and device installed on the ground, which effectively performs foreign object detection and ensures safe charging.

An embodiment of the present invention provides a primary side mounted on a ground, comprising: a magnetic core and a primary winding wound around the magnetic core side pillars extending outwardly at the two bottoms, further comprising: at the bottom of the two bottoms And an outer pair of magnetic core side pillars and a pair of pairs of foreign object detecting coils mounted along the Y-axis direction above the primary winding wound thereon, the pair of pairs of foreign matter detecting coils and the primary side The planes are parallel, and the two foreign object detecting coils symmetrical in the X-axis direction are a pair; the edge of the pair of pairs or pairs of foreign object detecting coils expands the two core-extending core legs and the winding thereof The edge of the primary winding is completely covered, wherein the Y-axis direction and the X-axis direction are parallel to a plane where the primary side is located, and the Y-axis direction is an extending direction of the core side pillar, The X-axis direction is perpendicular to the Y-axis direction.

An embodiment of the present invention further provides a foreign object detecting method based on the primary side, comprising the steps of: detecting an induced voltage of two foreign object detecting coils in each pair of foreign object detecting coil pairs when there is no secondary side; calculating each pair of foreign objects Detecting the difference in induced voltage of the two foreign object detecting coils in the pair of coils; when there is a difference between the induced voltages of the two foreign object detecting coils in the pair of foreign object detecting coils is greater than the preset foreign matter detecting threshold, it is determined that foreign matter exists on the primary side .

Optionally, the foreign object detecting method further includes: when the difference in induced voltages of the two foreign object detecting coils in all the foreign object detecting coil pairs is not greater than a preset foreign object detecting threshold, determining that no foreign matter exists on the primary side.

Optionally, the foreign matter detecting method further includes: when there is no foreign object on the primary side, and there is no secondary side, detecting an induced voltage of the two foreign object detecting coils in each pair of foreign object detecting coil pairs, and setting the current The induced voltage difference between the two foreign object detecting coils in each pair of foreign matter detecting coil pairs is a foreign matter detecting threshold corresponding to each pair of foreign matter detecting coils.

Optionally, wherein the induced voltage difference degree of the two foreign object detecting coils in each pair of foreign object detecting coil pairs is η=|(V ₊ -V ₋ )|, wherein V ₊ and V ₋ are each pair of foreign objects respectively The induced voltage of the two foreign object detecting coils in the pair of coils is detected.

Optionally, the foreign matter detecting method further includes: detecting an induced voltage of two foreign object detecting coils in each pair of foreign object detecting coil pairs when no foreign matter exists on the primary side, and no secondary side exists, and calculating the two foreign objects Detecting an average value V ₀ of induced voltages of the coils, calculating an induced voltage difference degree of each of the foreign matter detecting coil pairs in each pair of foreign object detecting coil pairs according to the average value, and setting two pairs of each pair of foreign object detecting coils at this time The induced voltage difference degree of the foreign matter detecting coil is a foreign matter detecting threshold corresponding to each pair of foreign matter detecting coils.

Optionally, wherein the induced voltage difference degree of the two foreign object detecting coils in each pair of foreign object detecting coil pairs is η=|(V ₊ -V ₋ )/V ₀ |, wherein V ₊ and V ₋ are respectively The induced voltage of the two foreign matter detecting coils in each pair of foreign matter detecting coil pairs, and V ₀ is an average value of the induced voltages of the two foreign matter detecting coils.

The embodiment of the present invention further provides a foreign object detecting device based on the primary side, comprising: an induced voltage detecting module, configured to detect an induced voltage of two foreign object detecting coils in each pair of foreign object detecting coil pairs when there is no secondary side The induced voltage difference degree calculation module is configured to calculate an induced voltage difference degree of the two foreign object detecting coils of each pair of foreign object detecting coil pairs; and the determining module is configured to have two foreign body detecting coils in the pair of foreign body detecting coil pairs When the induced voltage difference is greater than the preset foreign object detection threshold, it is determined that foreign matter exists on the primary side.

Optionally, the determining module is further configured to: when the difference in induced voltages of the two foreign object detecting coils in all the foreign object detecting coil pairs is not greater than a preset foreign object detecting threshold, it is determined that the primary side does not exist. foreign matter.

Optionally, the foreign object detecting device further includes a threshold setting module configured to set two foreign object detecting coils in each pair of foreign object detecting coil pairs at the time when there is no foreign matter on the primary side and there is no secondary side The induced voltage difference is the foreign matter detection threshold corresponding to each pair of foreign object detecting coils.

Optionally, wherein the induced voltage difference degree of the two foreign object detecting coils in each pair of foreign object detecting coil pairs is η=|(V ₊ -V ₋ )|, wherein V ₊ and V ₋ are each pair of foreign objects respectively Detecting the induced voltage of the two foreign object detecting coils in the pair of coils; or

The induced voltage difference degree of the two foreign object detecting coils in each pair of foreign object detecting coil pairs is η=|(V ₊ -V ₋ )/V ₀ |, wherein V ₊ and V ₋ are respectively pairs of foreign body detecting coils The induced voltage of the two foreign matter detecting coils, V ₀ is an average value of the induced voltages of the two foreign matter detecting coils.

Compared with the related art, the method and device for detecting a primary side and a foreign object mounted on the ground provided by the embodiment of the present invention install a foreign object detecting coil pair on the primary side, and detect the induced voltage of the foreign object detecting coil pair when the secondary side does not exist. To effectively detect foreign objects and ensure wireless safe charging.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF abstract

1 is a schematic diagram of a position of wireless charging of an electric vehicle in the related art;

2 is a schematic diagram showing the positional relationship of a primary side, a secondary side, and a foreign object in the related art;

3 is a schematic view of a loosely coupled transformer using a planar U-shaped magnetic core in the related art;

4 is a top plan view of a primary side according to a first embodiment of the present invention;

Figure 5 is a cross-sectional view taken along line A-A of Figure 4;

6 is a top plan view of a primary side according to a second embodiment of the present invention;

7 is a flowchart of a method for detecting a foreign object on a primary side according to a third embodiment of the present invention;

8 is a flowchart of a method for detecting a foreign object on a primary side according to a fourth embodiment of the present invention;

9 is a flow chart of a method for detecting a foreign object on a primary side according to a fifth embodiment of the present invention;

Fig. 10 is a schematic view showing a foreign matter detecting device of a primary side according to a sixth embodiment of the present invention.

Embodiments of the invention

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments of the present invention may be arbitrarily combined with each other.

Embodiments of the present invention are applied to an electromagnetic induction type WPT system.

Embodiment 1

Embodiments of the present invention provide a primary side mounted on a ground, including: a magnetic core, a primary winding wound around a magnetic core side pillar extending outward from the two bottoms, and expanding outward at the two bottoms And a pair of pairs of foreign object detecting coils mounted on the magnetic core side column and the primary winding wound thereon along the Y-axis direction, the pair of the pair of foreign matter detecting coils and the plane of the primary side Parallel, two foreign object detecting coils symmetrical in the X-axis direction are a pair; the edge of the pair of pairs or pairs of foreign object detecting coils expands the two core-extending core legs and the winding thereon The edge of the primary winding is completely covered, wherein the Y-axis direction and the X-axis direction are parallel to a plane where the primary side is located, and the Y-axis direction is an extending direction of the core side pillar, the X-axis The direction is perpendicular to the Y-axis direction.

In the first embodiment of the present invention, the primary side of a pair of foreign object detecting coil pairs is taken as an example, and FIG. 4 is a schematic top view of the primary side provided by the first embodiment of the present invention. Figure 5 is a cross-sectional view taken along line A-A of Figure 4; Please refer to Figure 4 and Figure 5 together.

As shown in FIG. 4, the loose coupling transformer primary side 400 includes a primary core 410, a primary winding wound around the two core-outwardly extending core legs, and foreign

object detecting coils

430A and 430B. Among them, the magnetic core 410 is composed of magnetic

core side columns

410A and 410B and a magnetic core top column 410C. The foreign

matter detecting coils

430A and 430B constitute a pair of foreign matter detecting coil pairs 430. The primary winding is composed of two parts of 420A and 420B in series, and the two parts of 420A and 420B are wound around the core side of the primary core 410 which is outwardly extended. The foreign matter detecting coil pair 430 is placed on the

side legs

410A and 410B of the primary side magnetic core 410 and the

primary side windings

420A and 420B wound on the

side legs

410A and 410B.

The foreign

matter detecting coils

430A and 430B belonging to the foreign matter detecting coil pair have the same structural dimensions, and the material thereof may be the same as or different from the material of the primary winding. The edges of the detecting

coils

430A and 430B completely cover the edges of the

primary windings

420A and 420B. With the X-axis as a line of symmetry, the detecting coil 430A covers the upper half of the

primary windings

420A and 420B, and the detecting coil 430B covers the lower half of the

primary windings

420A and 420B. Here, for convenience of illustration, a gap is left between the two foreign object detecting coils, and actually the two foreign matter detecting coils are next to each other. Here, for example, the induced voltage on the foreign matter detecting coil 430A is V ₊ , and the induced voltage on the foreign matter detecting coil 430B is V ₋ .

Since the two

portions

420A and 420B of the primary winding are formed in series in the forward direction, the alternating induced magnetic fields formed by the two portions are equal in magnitude and opposite in direction. Therefore, when there is no foreign matter between the primary side and the secondary side, the induced potential on the foreign

matter detecting coils

430A and 430B is zero or a small value close to zero; when foreign matter exists between the primary side and the secondary side At this time, the induced potential on the foreign

matter detecting coil

430A or 430B is changed. By detecting changes in the induced potential on the foreign

matter detecting coils

430A and 430B, it is possible to detect the presence or absence of foreign matter between the primary and secondary sides.

Embodiment 2

In the second embodiment of the present invention, the primary side of the pair of foreign object detecting coil pairs is taken as an example, and FIG. 6 is a schematic plan view of the primary side provided by the second embodiment of the present invention. 6 shows a case of two pairs of foreign object detecting coil pairs. For convenience of description, the X-axis is a symmetrical line, the foreign

matter detecting coils

630B and 630C are foreign matter detecting coil pairs 1, and the foreign

matter detecting coils

630A and 630D are foreign body detecting coil pairs. 2. The purpose of grouping the foreign object detecting coils in this way is that the two foreign body detecting coils of each group are similar in the two parts of the primary winding which are respectively covered, and the induced potentials are similar, which can improve the accuracy of foreign matter detection. Further, for example, the induced voltage on the foreign matter detecting coil 630B is V ₁₊ , the induced voltage on the foreign matter detecting coil 630C is V ₁₋ ; the induced voltage on the foreign matter detecting coil 630A is V ₂₊ , and the sensing on the foreign matter detecting coil 630D The voltage is V _2- .

Embodiment 3

As shown in FIG. 7, the embodiment of the present invention provides a foreign object detecting method based on the primary side as described above, including the following steps:

S101: detecting an induced voltage of two foreign object detecting coils in each pair of foreign object detecting coil pairs when there is no secondary side;

S102: Calculate an induced voltage difference degree of two foreign object detecting coils in each pair of foreign object detecting coil pairs;

S103: comparing the induced voltage difference between the two foreign object detecting coils of each pair of foreign object detecting coils with a preset foreign matter detecting threshold, wherein the difference in induced voltage between the two foreign object detecting coils of the pair of foreign object detecting coil pairs is greater than The preset foreign object detection threshold, step S104 is performed, if not greater than step S105;

S104: When there is a difference between the induced voltages of the two foreign object detecting coils in the pair of foreign object detecting coils being greater than a preset foreign matter detecting threshold, it is determined that the foreign matter exists on the primary side.

The foreign matter detecting coil is independently detected by foreign matter, and as long as a pair of foreign matter detecting coils detects foreign matter, the result of the determination is that foreign matter is present.

S105: When the difference of induced voltages of the two foreign object detecting coils in all the foreign object detecting coil pairs is not greater than a preset foreign matter detecting threshold, it is determined that no foreign matter exists on the primary side.

Wherein, before step S101, the step of initializing the setting may also be included:

When there is no foreign matter on the primary side and there is no secondary side, the induced voltage of the two foreign object detecting coils in each pair of foreign object detecting coil pairs is detected, and two foreign object detecting coils in each pair of foreign object detecting coil pairs are set at this time. The induced voltage difference is the foreign matter detection threshold corresponding to each pair of foreign object detecting coils. When it is determined whether or not foreign matter is present on the primary side, the difference in induced voltage between the two foreign object detecting coils of the pair of foreign matter detecting coils is compared with the foreign matter detecting threshold corresponding to the foreign matter detecting coil.

An optional method is to record the induced voltages of the two foreign object detecting coils in each pair of foreign object detecting coils as V ₊ and V ₋ , respectively, and the two foreign object detecting coils in each pair of foreign object detecting coil pairs The induced voltage difference is η=|(V ₊ -V _- )|.

When there is no foreign matter on the primary side and the secondary side does not exist, as shown in FIG. 4, the induced voltage on the foreign matter detecting coil 430A is V ₀₊ , and the induced voltage on the foreign matter detecting coil 430B is V _0- , the foreign matter detecting foreign matter detection threshold coil pair _{_{η 0 = | (V 0+ -V}} 0-) |, the value [eta] ₀ is controlled by a foreign matter detection sensitivity: η _0, the higher the sensitivity of detection, erroneous detection (false alarm) probability The larger the η ₀ is, the lower the detection sensitivity is, and the greater the probability of miss detection.

In addition, as another optional manner, the method further includes:

When there is no foreign matter on the primary side and there is no secondary side, the induced voltages of the two foreign object detecting coils in each pair of foreign object detecting coil pairs are detected, and the average value of the induced voltages of the two foreign body detecting coils is calculated as V ₀ = (V ₀₊ +V _0- )/2, calculating an induced voltage difference degree of two foreign object detecting coils in each pair of foreign object detecting coil pairs according to the average value, and setting two pairs of each pair of foreign object detecting coils at this time The induced voltage difference degree of the foreign matter detecting coil is a foreign matter detecting threshold corresponding to each pair of foreign matter detecting coils;

The induced voltages of the two foreign object detecting coils in each pair of foreign object detecting coil pairs are respectively denoted as V ₊ and V ₋ , and the induced voltage difference degree of the two foreign body detecting coils in each pair of foreign object detecting coil pairs is η=|(V ₊ -V _- )/V ₀ |. The foreign matter detection threshold of the foreign object detecting coil pair is η ₀ =|(V ₀₊ -V _0- )/V ₀ |.

Embodiment 4

FIG. 8 is a flowchart of a method for detecting foreign matter on the primary side according to the first embodiment of the present invention. As shown in FIG. 8, the foreign object detecting method based on the primary side in which only a pair of foreign object detecting coil pairs are mounted as shown in FIG. 4 includes the following steps:

S201: Initializing the setting, when there is no foreign matter on the primary side, and the secondary side does not exist, the induced voltage on the foreign matter detecting coil 430A is V ₀₊ , and the induced voltage on the foreign matter detecting coil 430B is V _0- , and V ₀ is The foreign

matter detecting coils

430A and 430B induce an average value of the voltage, V ₀ = (V ₀₊ + V _0- )/2; the foreign matter detecting threshold of the foreign matter detecting coil pair is η ₀ =|(V ₀₊ -V _0- ) /V ₀ |;

S202: When there is no secondary side, the induced voltages on the foreign matter detecting coil 430A and the foreign matter detecting coil 430B are measured in real time, and are recorded as V ₊ and V ₋ ;

S203: calculating a degree of difference η=|(V ₊ -V ₋ )/V ₀ | of the induced voltage on the foreign matter detecting coil 430A and the foreign matter detecting coil 430B;

S204: If η>η ₀ , it is determined that there is a foreign object between the primary side and the secondary side, that is, there is a foreign matter on the primary side, and the process proceeds to S205; if η≤η ₀ , it is determined that there is no foreign matter, the charging process is continued, or permission is allowed. Start charging, go to S202;

Alternatively, if η≥η _0, it is determined that foreign matter is present between the primary and secondary side, i.e. the edge of the original foreign matter is present, go to S205; if η <η _0, it is determined that there is no foreign matter, the charging process continues, or to allow Start charging, go to S202;

S205: It is determined that there is a foreign object on the primary side, and it is necessary to stop the charging process or prohibit the charging from being started.

Embodiment 5

FIG. 9 is a flow chart of a method for detecting a foreign object on a primary side according to a second embodiment of the present invention. As shown in FIG. 9, the foreign matter detecting method based on the primary side of the pair of foreign object detecting coil pairs as shown in FIG. 6 includes the following steps:

S301: Initial setting, the number of foreign object detecting coil pairs is N. As shown in FIG. 6, N=2, the foreign matter detecting coil pair 1 includes foreign

matter detecting coils

630B and 630C, and the foreign matter detecting coil pair 2 includes foreign

matter detecting coils

630A and 630D. For any pair of foreign object detecting coil pair #i, when there is no foreign matter on the primary side, and the secondary side does not exist, the induced voltages of the two foreign object detecting coils in the foreign object detecting coil pair #i are V _i0+ and V _i0- , _respectively . It is noted that V _{i0 is} its average value, and V _i0 = (V _{i0 +} +V _i0- )/2. The foreign matter detecting sensitivity parameter of the foreign matter detecting coil pair #i is, for example, η _i0 =|(V _i0+ -V _i0- )/V _i0 |. Among them, the foreign object detection sensitivity of the pair of different foreign object detecting coils can be controlled by the value of η _i0 .

S302: For the foreign object detecting coil pair #i, when there is no secondary side, the induced voltages on the two foreign object detecting coils are measured in real time, and are denoted as V _i+ and V _i- ;

S303: Calculating a degree of difference η _i =|(V _i+ -V _i- )/V _i0 | of the induced voltages on the two foreign object detecting coils for the foreign matter detecting coil pair #i;

S304: If η _i > η _i0 , it is determined that there is a foreign object between the primary side and the secondary side, that is, there is a foreign object on the primary side, and the process proceeds to S305; if η _i _≤ η _i0 , the processing of the next foreign object detecting coil pair is continued. Go to S302;

Alternatively, if η _i ≥ η _i0 , it is determined that there is a foreign object between the primary side and the secondary side, that is, there is a foreign matter on the primary side, and the process proceeds to S305; if η _i < η _i0 , the processing of the next foreign object detecting coil pair is continued, Go to S302;

The foreign matter detecting coil is independently detected by foreign matter, and as long as a pair of foreign matter detecting coils detects foreign matter, the result of the determination is that foreign matter is present. When all the foreign matter detecting coil pairs are judged to be free from foreign matter, the charging process can be continued, or charging can be started.

S305: It is determined that there is a foreign matter on the primary side, and the foreign matter position is within a range corresponding to the coverage area of the two foreign object detecting coils included in the foreign matter detecting coil pair #i, and it is necessary to stop the charging process or prohibit the charging from being started.

According to the above description, those skilled in the art can easily extend two pairs of foreign object detecting coil pairs to more pairs of foreign body detecting coils, each pair of foreign body detecting coils being symmetric with respect to the X axis, which will not be described herein. The more the foreign matter detecting coil pair is set, the higher the foreign matter detection accuracy is, and the smaller the foreign matter can be detected.

Embodiment 6

As shown in FIG. 10, an embodiment of the present invention further provides a foreign object detecting device based on the primary side as described above, including an induced voltage detecting module 1001, an induced voltage difference degree calculating module 1002, and a decision module 1003, wherein:

The induced voltage detecting module 1001 is configured to detect an induced voltage of two foreign object detecting coils in each pair of foreign object detecting coil pairs when there is no secondary side;

The induced voltage difference degree calculation module 1002 is configured to calculate an induced voltage difference degree of two foreign object detecting coils in each pair of foreign object detecting coil pairs;

The decision module 1003 is configured to determine that a foreign object exists on the primary side when there is a difference in induced voltage difference between the two foreign object detecting coils in the pair of foreign object detecting coil pairs is greater than a preset foreign matter detecting threshold.

In an optional embodiment, the determining module 1003 is further configured to determine that no foreign matter exists on the primary side when the induced voltage difference between the two foreign object detecting coils of all the foreign object detecting coil pairs is not greater than a preset foreign object detecting threshold. .

In an optional embodiment, the foreign object detecting device based on the primary side as described above further includes a threshold setting module configured to set each pair at this time when there is no foreign matter on the primary side and there is no secondary side The induced voltage difference degree of the two foreign matter detecting coils in the pair of foreign matter detecting coils is a foreign matter detecting threshold corresponding to each pair of foreign matter detecting coils.

among them:

The induced voltage difference degree of the two foreign object detecting coils in each pair of foreign object detecting coil pairs is η=|(V ₊ -V ₋ )|, wherein V ₊ and V ₋ are respectively two pairs of pairs of foreign matter detecting coils The induced voltage of the foreign matter detecting coil; or

The operation procedure of the foreign matter detecting device based on the primary side as described above in the alternative embodiment is the same as that described above, and thus will not be described again.

The primary side and foreign matter detecting method and apparatus provided in this embodiment are not only applicable to electric vehicle charging detection of foreign objects, but also applicable to foreign matter detection of other high power wireless charging systems.

It can be seen from the above-mentioned embodiments that, in relation to the related art, the primary side and foreign matter detecting method and apparatus installed on the ground provided in the above embodiments are provided with a foreign object detecting coil pair on the primary side, and the foreign matter is detected by the secondary side when the secondary side does not exist. Detecting the induced voltage of the coil pair to effectively detect foreign matter and ensure wireless safe charging.

One of ordinary skill in the art will appreciate that all or a portion of the steps described above can be accomplished by a program that instructs the associated hardware, such as a read-only memory, a magnetic or optical disk, and the like. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the foregoing embodiment may be implemented in the form of hardware or in the form of a software function module. Embodiments of the invention are not limited to any specific form of combination of hardware and software.

Industrial applicability

Claims

A primary side mounted on the ground includes: a magnetic core and a primary winding wound around the core side pillars extending outwardly at the two bottoms, and further comprising:

One or more pairs of foreign matter detecting coil pairs installed along the Y-axis direction above the two core-outwardly extending core side pillars and the primary winding wound thereon, the one or more pairs of foreign objects The detection coil pair is parallel to the plane in which the primary side is located, and the two foreign object detecting coils symmetrical in the X-axis direction are a pair; the edges of the pair or the pair of foreign object detecting coil pairs expand the two bottoms outwardly. The core post and the edge of the primary winding wound thereon are completely covered, wherein the Y-axis direction and the X-axis direction are parallel to the plane of the primary side, and the Y-axis direction is the core side The direction in which the column extends, the X-axis direction being perpendicular to the Y-axis direction.
A foreign matter detecting method based on the primary side according to claim 1, comprising the steps of:

When there is no secondary side, detecting an induced voltage of two foreign object detecting coils in each pair of foreign object detecting coil pairs;

Calculating a difference in induced voltage of two foreign object detecting coils in each pair of foreign object detecting coil pairs;

When there is a difference in the induced voltage difference between the two foreign object detecting coils in the pair of foreign matter detecting coil pairs, the foreign matter is determined to exist on the primary side.
The foreign matter detecting method according to claim 2, further comprising:

When the difference in induced voltage between the two foreign object detecting coils of all the foreign matter detecting coil pairs is not greater than the preset foreign matter detecting threshold, it is determined that there is no foreign matter on the primary side.
The foreign matter detecting method according to claim 2, further comprising:

When there is no foreign matter on the primary side and there is no secondary side, the induced voltage of the two foreign object detecting coils in each pair of foreign object detecting coil pairs is detected, and two foreign object detecting coils in each pair of foreign object detecting coil pairs are set at this time. The induced voltage difference is the foreign matter detection threshold corresponding to each pair of foreign object detecting coils.
The foreign matter detecting method according to claim 2 or 4, wherein: the induced voltage difference degree of the two foreign matter detecting coils in each pair of foreign object detecting coil pairs is η=|(V + -V - )|, wherein, V + and V - are the induced voltages of the two foreign object detecting coils in each pair of foreign matter detecting coil pairs, respectively.
The foreign matter detecting method according to claim 2, further comprising:

When there is no foreign matter on the primary side and there is no secondary side, detecting the induced voltage of the two foreign object detecting coils in each pair of foreign object detecting coil pairs, and calculating an average value V 0 of the induced voltages of the two foreign body detecting coils, according to The average value calculates an induced voltage difference degree of two foreign object detecting coils in each pair of foreign object detecting coil pairs, and sets an induced voltage difference degree of each of the two foreign body detecting coil pairs in each pair of foreign object detecting coil pairs as each pair of foreign objects The foreign matter detection threshold corresponding to the detection coil is detected.
The foreign matter detecting method according to claim 2 or 6, wherein: the induced voltage difference degree of the two foreign object detecting coils in each pair of foreign matter detecting coil pairs is η=|(V + -V - )/V 0 |, Wherein, V + and V − are induced voltages of two foreign object detecting coils in each pair of foreign object detecting coil pairs, and V 0 is an average value of induced voltages of the two foreign body detecting coils.
A foreign matter detecting device based on the primary side according to claim 1, comprising:

The induced voltage detecting module is configured to detect an induced voltage of two foreign object detecting coils in each pair of foreign object detecting coil pairs when there is no secondary side;

An induced voltage difference calculation module configured to calculate an induced voltage difference degree of two foreign object detecting coils in each pair of foreign object detecting coil pairs;

The decision module is configured to determine that there is a foreign object on the primary side when there is a difference in the induced voltage difference between the two foreign object detecting coils in the pair of foreign object detecting coil pairs being greater than a preset foreign matter detecting threshold.
The foreign matter detecting device according to claim 8, wherein the decision module is further configured to: when the difference in induced voltage between the two foreign object detecting coils of all the foreign matter detecting coil pairs is not greater than a preset foreign matter detecting threshold, Then it is determined that there is no foreign matter on the primary side.
The foreign matter detecting device according to claim 8, further comprising a threshold setting module configured to set a pair of the foreign object detecting coils at the time when there is no foreign matter on the primary side and there is no secondary side The induced voltage difference between the two foreign object detecting coils is a foreign matter detecting threshold corresponding to each pair of foreign matter detecting coils.
The foreign matter detecting device according to claim 8 or 10, wherein:

The induced voltage difference degree of the two foreign object detecting coils in each pair of foreign object detecting coil pairs is η=|(V + -V − )|, wherein V + and V − are respectively two pairs of pairs of foreign matter detecting coils The induced voltage of the foreign matter detecting coil; or

The induced voltage difference degree of the two foreign object detecting coils in each pair of foreign object detecting coil pairs is η=|(V + -V - )/V 0 |, wherein V + and V − are respectively pairs of foreign body detecting coils The induced voltage of the two foreign matter detecting coils, V 0 is an average value of the induced voltages of the two foreign matter detecting coils.