Wireless power transmission / reception system and wireless power transmission / reception method

Abstract

The present invention relates to a wireless power transmission and reception system that measures an effective charging time when a voltage value measured corresponding to a power reception unit is equal to or greater than a preset voltage value, and controls transmission power such that the effective charging time is included within a preset target charging time range.

Description

Technical Field

[0001] The present invention relates to a wireless power transmission and receiving system and a wireless power transmission and receiving method, and more specifically, to a wireless power transmission and receiving system and a wireless power transmission and receiving method using a magnetic resonance method, which can effectively and stably supply wireless power in an environment where intermittent charging and transmission distance changes may occur. Background Art

[0002] Usually, if the tire pressure of a car is too high or too low, it may cause the tire to burst or the vehicle to slip, causing a major accident. In addition, if the proper air pressure cannot be maintained, fuel consumption will increase, fuel efficiency will deteriorate, tire life will be shortened, and riding comfort and braking force will be greatly reduced. The safety device installed on the vehicle to prevent such tire defects is the tire pressure monitoring system (TPMS).

[0003] The tire pressure monitoring system attaches an air pressure sensor (configured in a radio frequency identification (RFID) manner) to the tire, senses the air pressure and temperature of the tire, and transmits it to the vehicle controller so that the vehicle driver and the like can confirm it.

[0004] That is, it is designed to detect the pressure or temperature of the tire through the air pressure sensor (RFID sensor) attached to the tire, and then wirelessly transmit the information to the vehicle controller so that the driver can check the pressure status of the tire. Using this system to manage tire pressure, etc., not only improves tire durability, ride comfort, and braking force, but also improves fuel efficiency.

[0005] However, due to the constant rotation of tires during vehicle driving, it is difficult to charge the battery in a wired manner, so the life of the tire pressure monitoring system depends on the battery life.

[0006] In the past, conventional methods of extending the battery life of a vehicle's tire pressure monitoring system (TPMS) by changing the sensing signal transmission cycle or the concept of charging using induced electromotive force have been introduced. However, there are problems such as complex and large equipment configuration and difficulty in controlling power according to the tire rotation speed. Summary of the invention

[0007] Technical Problems to be Solved by the Invention

[0008] The problem to be solved by the present invention is to provide a magnetic resonance wireless power transmission and receiving system and a wireless power transmission and receiving method, which can stably and very efficiently transmit optimal power by controlling the time or length of the charging interval in order to improve the charging instability and efficiency caused by the external environment and the operation of the device in an intermittent wireless charging system set on a vehicle wheel, etc.

[0009] Furthermore, the problem to be solved by the present invention is to provide a magnetic resonance wireless power transmission and reception system capable of stably supplying necessary and sufficient power to a power receiving unit regardless of a vehicle speed through simple and effective power transmission control.

[0010] Technical Solution

[0011] To solve the above problem, the present invention provides a magnetic resonance wireless power transmission and receiving system, which has a power transmission unit (Tx) arranged on one side of the device and a power receiving unit (Rx) on the other side and realizes intermittent charging through the operation of the device, wherein the effective charging time corresponding to the voltage value measured by the power receiving unit is greater than a preset voltage value can be measured, and the transmission power is controlled so that the effective charging time is included in the preset target charging time range.

[0012] In addition, in order to solve the above-mentioned problem, the present invention provides a magnetic resonance wireless power transmission and receiving system, which has a transmission unit (Tx) arranged on one side of the device and a receiving unit (Rx) on the other side and realizes intermittent charging through the operation of the device, wherein the effective charging time as the time when the voltage value measured by the receiving unit is greater than a preset voltage value can be measured, and the transmission power is controlled so that the charging interval length calculated based on the measured effective charging time is included in the preset target charging interval length range.

[0013] Furthermore, the power transmission unit may be provided on a vehicle body side above a wheel of the vehicle, and the power reception unit may be mounted inside a tire of the vehicle.

[0014] In addition, the power transmission unit may include an AC / DC conversion circuit, a DC / RF conversion circuit, a matching circuit, a control circuit and a communication circuit, and the power receiving unit may include a matching circuit, a rectification circuit, a stabilization circuit, a DC / DC conversion circuit, a battery circuit, a control circuit, a communication circuit and an effective charging time measurement unit.

[0015] Here, the control of the transmission power may be achieved by changing the system frequency within a range of increasing or decreasing around a resonance frequency for transmitting maximum power.

[0016] Furthermore, the transmission power may be controlled by a DC input voltage of the transmission unit, or by changing a duty cycle of a PWM signal of the resonance frequency.

[0017] Furthermore, the effective charging time measurement unit may be configured to measure a time when the voltage value measured by the power receiving unit is equal to or greater than any one of the output voltage value Vr of the stabilization circuit, the output voltage value Vo of the DC-DC conversion circuit, and the output voltage value Vb of the battery circuit.

[0018] In addition, in order to solve the above-mentioned problem, the present invention provides a wireless power transmission and reception method, which utilizes a magnetic resonance wireless power transmission and reception system having a power transmission unit (Tx) arranged on one side of a device and a power receiving unit (Rx) on the other side and realizing intermittent charging through the operation of the device, and the wireless power transmission and reception method includes: step (a), the power receiving unit measures the voltage value of the power receiving unit for the wireless power transmitted by the power transmission unit; step (b), the power receiving unit measures the effective charging time when the voltage value of the power receiving unit corresponding to the measurement is greater than the charging effective voltage value; and step (c), the power transmission unit controls the transmission power so that the measured charging time received from the power receiving unit is included in a preset target charging time range.

[0019] In addition, in order to solve the above-mentioned problem, the present invention provides a wireless power transmission and reception method, which utilizes a magnetic resonance wireless power transmission and reception system having a power transmission unit (Tx) arranged on one side of a device and a power receiving unit (Rx) on the other side and realizing intermittent charging through the operation of the device, and the wireless power transmission and reception method includes: step (a): the power receiving unit measures the voltage value of the power receiving unit for the wireless power transmitted by the power transmission unit; step (b): calculating the charging interval length corresponding to the rotation length of the tire during the charging interval according to the measured voltage value of the power receiving unit; and step (c): the power transmission unit controls the transmission power so that the calculated charging interval length received from the power receiving unit is included in a preset target charging interval length range.

[0020] Here, the voltage value of the power receiving unit may be any one of an output voltage value Vo of the power receiving unit, a stable voltage value Vr of the power receiving unit, and a voltage value Vb of a battery being charged.

[0021] In addition, the step (b) may include: step (b1), the power receiving unit measures the effective charging time when the voltage value corresponding to the measured power receiving unit is greater than the charging effective voltage value; and step (b2), calculating the length of the charging interval based on the effective charging time measured by the power receiving unit and the vehicle speed within the effective charging time.

[0022] In addition, in the step (c), the control of the transmission power may be achieved by changing the system frequency within a range that increases or decreases around a resonance frequency for transmitting maximum power.

[0023] Furthermore, in the step (c), the transmission power may be controlled by a DC input voltage of the transmission unit, or by changing a duty cycle of a PWM signal of the resonance frequency.

[0024] Beneficial Effects

[0025] According to the magnetic resonance wireless power transmission receiving system and wireless power transmission receiving method using charging interval control of the present invention, a magnetic resonance wireless power transmission receiving system is provided, which can stably and very efficiently transmit optimal power by controlling the time or length of the charging interval in order to improve the charging instability and efficiency caused by the external environment and the operation of the device in an intermittent wireless charging system set on a vehicle wheel, etc.

[0026] In addition, according to the magnetic resonance wireless power transmission and receiving system and wireless power transmission and receiving method using charging interval control of the present invention, a magnetic resonance wireless power transmission and receiving system is provided, which can stably supply necessary and sufficient power to the power receiving unit regardless of the vehicle speed through stable and effective power transmission control.

[0027] In addition, according to the magnetic resonance wireless power transmission receiving system and wireless power transmission receiving method using charging interval control of the present invention, a magnetic resonance wireless power transmission receiving system is provided, which can be applied to various devices or systems such as intermittent charging or environments with changing transmission distances, and can transmit power stably and efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The configuration of the magnetic resonance wireless power transmission and reception system using the charging interval control according to the embodiment of the present invention and the fluctuation of the voltage measured by the power receiving unit are shown.

[0029] Figure 2 A detailed block diagram configuration of a magnetic resonance wireless power transmission receiving system using charging interval control according to an embodiment of the present invention is shown.

[0030] Figure 3 A flow chart of a magnetic resonance wireless power transmission receiving method using charging time control of a charging interval according to an embodiment of the present invention is shown.

[0031] Figure 4 A flow chart of a magnetic resonance wireless power transmission receiving method using charging interval length control according to an embodiment of the present invention is shown.

[0032] Figure 5 A graph showing changes in output voltage of a power receiving unit of a wireless power transmission and reception system while a vehicle is traveling is shown.

[0033] Figure 6 A graph showing a power receiving unit voltage in a magnetic resonance wireless power transmission and reception method using a charging interval control when the reception power is insufficient is shown.

[0034] Figure 7 A graph showing a power receiving unit voltage in a magnetic resonance wireless power transmission and reception method using a charging interval control when the reception power is excessive is shown according to an embodiment of the present invention.

[0035] Figure 8 A diagram illustrating a transmission power control algorithm of a magnetic resonance wireless power transmission and reception method using charging interval control according to an embodiment of the present invention is shown.

[0036] Fig. 9 A resonant frequency PWM signal of a duty ratio is illustrated by a transmission power control device of a magnetic resonance wireless power transmission and reception method using a charging interval control according to an embodiment of the present invention. DETAILED DESCRIPTION

[0037] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may also be implemented in other forms. On the contrary, the embodiments introduced herein are provided to make the disclosed contents thorough and complete and to fully convey the inventive ideas to those of ordinary skill in the art. The same reference numerals throughout the specification represent the same constituent elements.

[0038] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0039] Figure 1 The figure shows the configuration of the magnetic resonance wireless power transmission and receiving system using the charging interval control according to the embodiment of the present invention and the fluctuation of the voltage measured by the power receiving unit 200. Figure 2 A detailed block diagram configuration of a magnetic resonance wireless power transmission receiving system using charging interval control according to an embodiment of the present invention is shown.

[0040] like Figure 1As shown, in a magnetic resonance wireless power transmission and receiving system using charging interval control according to an embodiment of the present invention, there is a power transmission unit 100 (Tx) arranged on one side of the device and a power receiving unit 200 (Rx) on the other side, and in a magnetic resonance wireless power transmission and receiving system in which intermittent charging is achieved through the operation of the device, the effective charging time corresponding to the voltage value measured by the power receiving unit 200 is greater than a preset voltage value, and the transmission power can be controlled so that the effective charging time is included in a preset target charging time range.

[0041] In addition, according to another embodiment of the present invention, a magnetic resonance wireless power transmission and receiving system using charging interval control has a power transmission unit 100 (Tx) provided on one side of the device and a power receiving unit 200 (Rx) on the other side, and in which intermittent charging is achieved through the operation of the device, an effective charging time is measured as the time when the voltage value measured by the power receiving unit 200 is greater than a preset voltage value, and the transmission power can be controlled so that the charging interval length calculated based on the measured effective charging time is included in the preset target charging interval length range.

[0042] That is, the magnetic resonance wireless power transmission and reception system according to the embodiment of the present invention is composed of a power transmission unit 100 and a power reception unit 200 which are spaced apart from each other and arranged on one side and the other side of the device, and while one side of the device is operating, the power transmission unit 100 and the power reception unit 200 are intermittently close to each other so that charging can be performed, and a wireless power transmission and reception system is provided, which controls the transmission power of the power transmission unit 100 to measure or calculate the effective charging time or the charging interval length so that the range of the charging time or the charging interval length is included in the target charging interval range preset with the optimal charging interval.

[0043] As described above, the present invention provides a magnetic resonance wireless power transmission and receiving system, which can stably and very efficiently transmit optimal power by controlling the time or length of the charging interval in order to improve the charging instability and efficiency caused by the external environment and the operation of the device in an intermittent wireless charging system installed on a vehicle wheel, etc.

[0044] like Figure 1 As shown, when a vehicle is applied as an embodiment of a device equipped with the system of the present invention, the magnetic resonance wireless power transmission and reception system using charging interval control may include a power transmission unit 100 arranged on the vehicle body side above the vehicle wheel and a power receiving unit 200 installed inside the vehicle tire.

[0045] The magnetic resonance wireless power transmission and receiving system according to the embodiment of the present invention can be applied to any device or product that realizes intermittent charging while operating one side of the power transmission unit 100 and the power reception unit 200, and changes the charging distance according to the device change and the external environment, in addition to the above-mentioned vehicle. Hereinafter, a detailed description will be given focusing on the wireless power transmission and receiving system installed on the wheel of a vehicle.

[0046] like Figure 1 As shown in part (a) of FIG. 1 , when the vehicle is running, the tire rotates while the wireless power receiving unit 200 mounted on the inner surface of the tire receives the wireless power from the power transmitting unit 100 during the “charging interval”, and as shown in FIG. Figure 1 As shown in part (b) of FIG. 1 , after passing through the charging section, it can be divided into a usage section in which the electric power charged in the battery is used.

[0047] That is, as the tire continues to rotate, Figure 1 As shown in the graph of part (b) of FIG. 1 , the charging section and the battery use section in which the charging voltage appears intermittently are repeated.

[0048] Here, the "charging interval" does not refer to the physical length of the coil of the power transmission unit 100, but refers to the interval in which the output voltage of the power reception unit 200 is kept constant, and both include the concept of time or length. The length of the charging interval increases or decreases in proportion to the physical length of the coil of the power transmission unit 100, and increases as the power transmission of the power transmission unit 100 increases, but the maximum interval may be limited by the physical size of the coil.

[0049] In addition, see the detailed configuration of the wireless power transmission receiving system according to the embodiment of the present invention, such as Figure 2 As shown, according to an embodiment of the present invention, a magnetic resonance wireless power transmission and receiving system using charging interval control can be configured to include: a power transmission unit 100, including an AC / DC conversion circuit 110, a DC / RF conversion circuit 120, a matching circuit 130, a control circuit 150 and a communication circuit 160; and a power receiving unit 200, including a matching circuit 210, a rectifier circuit 220, a stabilization circuit 230, a DC / DC conversion circuit 240, a battery charging circuit 300, a control circuit 260, a communication circuit 250 and an effective charging time measurement unit 270.

[0050] Here, the DC / RF conversion circuit 120 converts a DC input current into a radio frequency (RF), and the control circuit 150 may control a resonance frequency when the DC / RF conversion circuit 120 converts direct current into RF power.

[0051] In addition, the matching circuit 130 is a circuit for magnetic resonance coupling, and the communication circuit 160 may be a power transmission coil connected to the matching circuit 130 and a circuit that transmits and receives a voltage or current signal.

[0052] The matching circuit 220 of the power receiving unit 200 may include the above-mentioned power transmission coil, a power reception coil for coupling within a certain power transmission distance, and a resonance circuit for causing a magnetic resonance effect.

[0053] In addition, the rectifying circuit 220 may be a circuit that rectify the high-frequency received power signal at the rear end of the resonance circuit, and the stabilizing circuit 240 may be a circuit that stabilizes the output voltage rectified at the rear end of the rectifying circuit 220 .

[0054] In addition, the DC / DC conversion circuit 240 may be a circuit that outputs a predetermined voltage from a voltage stabilized at the rear end of the stabilization circuit 240 , and the battery charging circuit 300 may be a circuit that charges the battery end using the power output from the DC / DC conversion circuit 240 .

[0055] In addition, the effective charging time measurement unit 270 can be configured to measure the effective charging time, which refers to the effective charging time when the voltage value of any one of the stabilized voltage Vr measured at the output end of the stabilization circuit 230, the output voltage Vo measured at the output end of the DC / DC conversion circuit 240, and the battery voltage Vr measured at the output end of the battery charging circuit corresponds to a preset voltage value or above.

[0056] In addition, the control circuit 250 can be a circuit that receives the current signal from the rectifier circuit 220, the voltage and / or current signal received from the output end of the DC / DC conversion circuit 240, and the effective charging time signal received from the above-mentioned effective charging time measurement unit 270 and generates a feedback control signal, and the communication circuit 250 can be a circuit that transmits the feedback control signal generated by the control circuit 250 to the communication circuit 160 of the transmission unit 100.

[0057] By viewing the control algorithm for optimal power transmission through the configuration of the wireless power transmission receiving system according to the embodiment of the present invention, when the tire rotates, the voltage fluctuation of the power receiving unit 200 repeats the charging interval and the battery use interval, such as Figure 2 As shown in (b), the battery voltage of the power receiving unit 200 presents a repetitive waveform. During the charging interval, wireless power is received, so the charging voltage is maintained. When leaving the charging interval, the wireless power originally received disappears, so only the remaining battery voltage is displayed.

[0058] In addition, the feedback voltage value used for control may be a voltage value that can be measured at the power receiving unit 200, and a voltage signal that clearly shows the voltage difference between the charging section and the battery consumption section may be used as a feedback signal for control including the time and length of the effective charging section.

[0059] That is, any one of the voltage stabilization circuit output voltage Vr or the DC / DC conversion circuit output voltage Vo or the battery charging voltage Vb may be used as the feedback signal voltage.

[0060] For example, assuming that the power receiving unit 200 uses a 3.7 V lithium-ion battery, the battery charging voltage may be 4.2 V, the DC-DC output voltage may be 5 V, and the stabilization circuit voltage may be approximately 7 V. Alternatively, the DC-DC conversion circuit output may be used to directly generate 4.2 V as the battery charging voltage so that it can be used immediately for charging the battery.

[0061] As described above, the wireless power transmission and receiving system according to the embodiment of the present invention measures the voltage value of the power receiving unit 200, thereby measuring the charging time of the corresponding effective charging interval or calculating the length of the charging interval, and transmits it to the power transmitting unit 100 as a feedback signal, so as to control the transmission power.

[0062] Figure 3 A flowchart of a magnetic resonance wireless power transmission receiving method using charging time control of a charging interval according to an embodiment of the present invention is shown. Figure 4 A flow chart of a magnetic resonance wireless power transmission receiving method using charging interval length control according to an embodiment of the present invention is shown.

[0063] like Figure 3 As shown, according to an embodiment of the present invention, a magnetic resonance wireless power transmission and receiving method using charging time control in a charging interval, in a wireless power transmission and receiving method using the above-mentioned magnetic resonance wireless power transmission and receiving system, may include: step (a), the power receiving unit 200 measures the voltage value of the power receiving unit 200 for the wireless power transmitted by the power transmitting unit 100 (step S110); step (b), the power receiving unit 200 measures the effective charging time corresponding to the measured voltage value of the power receiving unit 200 being greater than the charging effective voltage value (step S120); and step (c), the power transmitting unit 100 controls the transmission power in a manner included in the measured charging time received from the power receiving unit 200 and a preset target charging time range (step S130).

[0064] In addition, if Figure 4As shown, according to the magnetic resonance wireless power transmission and receiving method using charging interval length control according to an embodiment of the present invention, in the wireless power transmission and receiving method using the above-mentioned magnetic resonance wireless power transmission and receiving system, it can include: step (a), the power receiving unit 200 measures the voltage value of the power receiving unit 200 for the wireless power transmitted by the power transmitting unit 100 (step S210); step (b), calculating the charging interval length corresponding to the rotation length of the tire during the charging interval according to the measured voltage value of the power receiving unit 200; and step (c), the power transmitting unit 100 controls the transmission power so that the calculated charging interval length received from the power receiving unit 200 is included in a preset target charging interval length range (step S240).

[0065] Here, Figure 4 The step (b) shown may include: step S220, the power receiving unit 200 measures the effective charging time when the voltage value corresponding to the measured power receiving unit 200 is greater than the charging effective voltage value; and step S230: calculating the length of the charging interval through the effective charging time measured by the power receiving unit 200 and the vehicle speed within the effective charging time.

[0066] The voltage value of the power receiving unit 200 may be any one of the output voltage value (Vo) of the power receiving unit 200 , the stable voltage value Vr of the power receiving unit 200 , and the voltage value Vb of the battery being charged.

[0067] In addition, the control of the transmitted power can be achieved by changing the system frequency within a preset range that increases or decreases around the resonant frequency used to transmit maximum power, or by controlling the DC input voltage of the transmission unit 100, or by changing the duty cycle of the PWM signal of the resonant frequency.

[0068] Hereinafter, the magnetic resonance wireless power transmission method using charging interval control according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, focusing on the voltage change of the power receiving unit 200 .

[0069] Figure 5 1 is a diagram showing changes in the output voltage of the power receiving unit 200 of the wireless power transmission and reception system while the vehicle is running.

[0070] like Figure 5 As shown, in the wireless power transmission method according to the embodiment of the present invention, the signal voltage of the power receiving section 200 to be used for feedback is a voltage value measured in the power receiving section 200 entering the charging section.

[0071] However, in the embodiment of the present invention, the voltage value of the power receiving unit 200 used as the feedback signal should not be just the voltage value, but it should be possible to use these signals to measure the length of one tire rotation and the corresponding charging interval.

[0072] Therefore, in the embodiment of the present invention, the voltage value of the power receiving unit 200 that can be used as the feedback signal voltage is as follows: Figure 1 As described in the description, any one of the stabilized voltage value Vr as the measured voltage at the output end of the stabilization circuit 230, the output voltage value Vo as the measured voltage at the output end of the DC-DC conversion circuit 240, and the battery voltage value Vb as the measured voltage at the output end of the battery charging circuit 300 can be used.

[0073] Here, the length of one rotation of the tire can be calculated using the tire outer diameter and can be regarded as a constant value as long as the tire does not change.

[0074] Figure 6 A graph showing the voltage of the power receiving unit 200 when the received power is insufficient in the magnetic resonance wireless power transmission and reception method using the charging interval control according to the embodiment of the present invention is shown.

[0075] Figure 6 The embodiment shown is a case where the target charging interval length is set to 320 mm, which is 1 / 10 of the length of one rotation of the tire, when the length of one rotation of the tire is 3200 mm (i.e., assuming that the outer diameter of the tire is constant and is approximately 1020 mm). These settings can be preset by considering the size and type of the tire, the specifications of the system, etc.

[0076] Figure 6 Part (a) of FIG. 1 is a graph showing a change in voltage of the power receiving unit 200 during a charging interval when the received power of the power receiving unit 200 is less than a target value. Figure 6 Part (b) is a graph showing a change in the voltage of the power receiving unit 200 when the power transmitting unit 100 controls the transmission power to increase by a feedback signal from the power receiving unit 200 so that the charging section of the power receiving unit 200 reaches a target value.

[0077] like Figure 6 As shown in part (a), the charging section length is measured or calculated to be 290 mm by voltage measurement of the power receiving unit 200, and since the charging section length is less than the target value of 320 mm, it can be seen that control can be performed in the direction of increasing the transmitted power.

[0078] like Figure 6 As shown in part (b), it is confirmed that the feedback signal of the power reception unit 200 is smaller than the target charging section length, and the power transmission unit 100 controls the transmission power to increase, thereby changing and maintaining the charging section at 320 mm.

[0079] Here, the length or time of the target charging interval may be set to a single value, but is preferably set to a certain range to achieve system stability.

[0080] Figure 7 A graph showing the voltage of the power receiving unit 200 when the received power is too large in the magnetic resonance wireless power transmission and reception method using the charging interval control according to the embodiment of the present invention is shown.

[0081] and Figure 6 The same as the embodiment, Figure 7 The embodiment shown in shows a case where the target charging interval length is set to 320 mm, which is 1 / 10 of the length of one tire rotation, when the length of one tire rotation is 3200 mm (ie, assuming that the tire outer diameter is constant and is approximately 1020 mm).

[0082] Figure 7 Part (a) of FIG. 1 is a graph showing a change in voltage of the power receiving unit 200 when the charging section is formed such that the received power of the power receiving unit 200 is greater than the target value. Figure 7 Part (b) of FIG. 1 is a graph showing a change in the voltage of the power receiving unit 200 when the power transmitting unit 100 controls the power transmission to be reduced so that the charging section of the power receiving unit 200 reaches a target value based on a feedback signal from the power receiving unit 200 .

[0083] like Figure 7 As shown in part (a), the charging section length is measured or calculated to be 335 mm by voltage measurement of the power receiving unit 200, and since the charging section length is greater than the target value 320 mm, it can be seen that control can be performed in the direction of reducing the transmitted power.

[0084] like Figure 7 As shown in part (b), it is confirmed that the feedback signal of the power reception unit 200 is greater than the target charging section length, and the power transmission unit 100 changes and maintains the charging section at 320 mm by controlling the transmission power to decrease.

[0085] Here, the length of one rotation of the tire of the vehicle may be calculated using the tire outer diameter and may be a constant value as shown in the following Mathematical Formula 1. The length of one rotation of the tire may be calculated in advance using the mounted vehicle tire information.

[0086] Mathematical formula 1

[0087] The length of a tire rotation = π × tire outer diameter

[0088] If the time interval of the "rising edge signal" generated in the feedback voltage signal is measured each time the power receiving unit 200 enters the charging interval, it becomes the "time for the tire to rotate once", and the vehicle speed can be calculated by dividing the "length of the tire to rotate once" by this time, as shown in the following mathematical formula 2. Here, the "rising edge signal" refers to the signal at the time point when the voltage signal of the power receiving unit 200 changes from a low state to a high state.

[0089] Mathematical formula 2

[0090]

[0091] The length of the charging section can be calculated by the following mathematical formula 3, which is obtained by multiplying the time value by the "vehicle speed" calculated by mathematical formula 2 after measuring the time when the feedback signal voltage measured by the power receiving unit 200 is stimulated and maintained above the reference value when the power receiving unit 200 enters the charging section.

[0092] Mathematical formula 3

[0093] Charging interval length = charging time × vehicle speed

[0094] The charging section length at each time is finally calculated by Math 3, and the transmission power of the power transmission unit 100 can be controlled so that the value is maintained or included in a preset target charging section length or range.

[0095] In addition, the magnetic resonance wireless power transmission and receiving method using charging interval control according to the embodiment of the present invention can use not only the "charging interval length" but also the "charging time" as a feedback control signal.

[0096] In this case, the charging time target value can be calculated by calculating the length of one tire rotation and the charging interval ratio and multiplying it by the "time for one tire rotation". For example, when the length of one tire rotation is 3200mm and the charging interval target value is 320mm, the ratio is 10%, that is, 0.1, and the charging time control target value at the vehicle speed can be calculated by multiplying the time for one tire rotation measured according to the vehicle speed change by 0.1.

[0097] Figure 8 : is a diagram illustrating a transmission power control algorithm of a magnetic resonance wireless power transmission and reception method using charging interval control according to an embodiment of the present invention. Figure 8 Part (a) is a diagram showing frequency control area settings for controlling transmission power, Figure 8 Part (b) is a graph showing an example of fluctuation of the charging interval according to the control frequency and the transmission distance.

[0098] like Figure 8As shown, in the example of the magnetic resonance wireless power transmission and reception method using the charging interval control according to the embodiment of the present invention, the control device of the transmitted power is limited to the frequency control for explanation.

[0099] First, if Figure 8 As shown in part (a) of FIG. 1 , the frequency control region is set. This means that the power transmission unit 100 is designed and manufactured so as to have Figure 8 The power transmission characteristics according to the frequency setting shown in part (a) of FIG. Figure 8 Part (a) means that the power transmission unit 100 is manufactured or set so that when the frequency is set close to the resonance frequency, the transmission power increases, and when the frequency is increased, the transmission power decreases.

[0100] Regarding the resonant frequency, preferably, when designing the transmission distance specification, the frequency that can transmit power well at the longest transmission distance is set as the resonant frequency of the system. This is because the frequency that can transmit the maximum power among the system operation control frequencies can become the resonant frequency.

[0101] The frequency control region can be set to one side of the left or right region based on the resonance frequency. That is, it can be set to control within a range that increases with the resonance frequency as the center or to control within a range that decreases. All examples described below are embodiments in which the right side of the resonance frequency is set as the frequency control region.

[0102] Figure 8 An example of charging interval length characteristics according to frequency and transmission distance is shown.

[0103] For example, if the control target charging interval length is set to 320 mm and control is started at a transmission distance of 240 mm, control starts from the initial resonant frequency, and if the maximum power is transmitted at this time, the measured charging holding length will be greater than 320 m.

[0104] Therefore, the frequency is gradually reduced in such a way that the charging interval length becomes 320 mm. Figure 8 As shown, the frequency is maintained and controlled at about 196.4 to 196.5 kHz. This is the case ①.

[0105] In case ①, if the vehicle load increases or the length of power transmission unit 100 and power reception unit 200 decreases by 20 mm due to some other reasons, resulting in a transmission distance of 220 mm, the charging section length increases from 320 mm to 335 mm, resulting in case ②.

[0106] In this case, in order to restore the charging section length to 320 mm, the transmitted power needs to be reduced. To this end, the frequency is controlled to increase and the frequency is increased to 196.9 kHz, thus shifting to situation ③.

[0107] As the opposite case, when the charge holding length decreases for whatever reason, the control frequency is lowered so as to increase the transmitted electric power, and the charge holding length is controlled to be maintained at the target value.

[0108] By controlling in this manner, necessary and sufficient electric power can be stably supplied to power receiving unit 200 regardless of the vehicle speed.

[0109] In addition, as a transmission power control decoration of the magnetic resonance wireless power transmission and reception method using charging interval control according to an embodiment of the present invention, in addition to frequency control, "DC input" can also be used.

[0110] like Figure 1 As shown, when a circuit capable of increasing or decreasing the input voltage is added at the "DC input" position in the transmission unit 100 circuit, when the "DC input" voltage is increased, the transmission power increases, and when the "DC input" voltage is reduced, the transmission power decreases, so it can be used as a control device for the transmission power.

[0111] Fig. 9 A resonant frequency PWM signal of a duty ratio is illustrated by a transmission power control device of a magnetic resonance wireless power transmission and reception method using a charging interval control according to an embodiment of the present invention.

[0112] like Fig. 9 As shown, as another means of controlling the transmission power of the magnetic resonance wireless power transmission and reception method using the charging interval control according to the embodiment of the present invention, a "duty cycle" can be used. Fig. 9 As shown, the resonant frequency is implemented as a square wave pulse width modulation (PWM) signal, where "duty cycle" is defined as the following mathematical formula 4, and PWM control refers to a method of controlling the average voltage by changing the duty cycle (Duty) within a certain period.

[0113] Mathematical formula 4

[0114]

[0115] As shown in Mathematical Formula 4, when the duty cycle increases, the time of turning on the power is extended, resulting in an increase in the transmitted power. When the duty cycle decreases, the time of turning on the power is shortened, resulting in a decrease in the transmitted power. By utilizing this characteristic, it can be used as a transmission power control device for the magnetic resonance wireless power transmission and receiving method using charging interval control according to an embodiment of the present invention.

[0116] Although the preferred embodiments of the present invention are described in this specification, it is understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the scope of the concept and field of the present invention as described in the following claims. Therefore, if the modified embodiments substantially include the constituent elements of the claims of the present invention, they should be deemed to be included in the technical scope of the present invention.

Claims

1. A wireless power transmission and reception system, the wireless power transmission and reception system having a power transmission unit (Tx) provided on one side of a device and a power reception unit (Rx) provided on the other side and realizing intermittent charging through the operation of the device, characterized in that: An effective charging time corresponding to when the voltage value measured by the power receiving unit is equal to or greater than a preset voltage value is measured, and the transmitted power is controlled so that the effective charging time is included in a preset target charging time range.

2. A wireless power transmission and reception system, the wireless power transmission and reception system having a power transmission unit (Tx) provided on one side of a device and a power reception unit (Rx) provided on the other side and realizing intermittent charging through the operation of the device, characterized in that: An effective charging time is measured as a time when a voltage value measured by the power receiving unit is equal to or greater than a preset voltage value, and the transmitted power is controlled so that a charging section length calculated based on the measured effective charging time is within a preset target charging section length range.

3. The wireless power transmission and receiving system according to claim 1 or 2, characterized in that: The power transmission unit is provided on the vehicle body side above the vehicle wheel. The power receiving unit is mounted inside a tire of the vehicle.

4. The wireless power transmission and receiving system according to claim 1, characterized in that: The power transmission unit includes an AC / DC conversion circuit, a DC / RF conversion circuit, a matching circuit, a control circuit and a communication circuit. The power receiving unit includes a matching circuit, a rectifying circuit, a stabilizing circuit, a DC / DC conversion circuit, a battery circuit, a control circuit, a communication circuit, and an effective charging time measuring unit.

5. The wireless power transmission and receiving system according to claim 1 or 2, characterized in that: The control of the transmission power is achieved by changing the system frequency within a range of increasing or decreasing around the resonant frequency for transmitting the maximum power.

6. The wireless power transmission and receiving system according to claim 1 or 2, characterized in that: The transmission power is controlled by a DC input voltage of the transmission unit.

7. The wireless power transmission and receiving system according to claim 1 or 12, characterized in that: The control of the transmission power is achieved by changing the duty ratio of the pulse width modulation signal of the resonance frequency.

8. The wireless power transmission and receiving system according to claim 3, characterized in that: The effective charging time measuring unit is configured as follows: The time during which the voltage is equal to or greater than any one of the output voltage value (Vr) of the stabilization circuit, the output voltage value (Vo) of the DC-DC conversion circuit, and the output voltage value (Vb) of the battery circuit is measured.

9. A magnetic resonance wireless power transmission and reception method using charging interval control, which uses a magnetic resonance wireless power transmission and reception system having a power transmission unit (Tx) provided on one side of a device and a power reception unit (Rx) provided on the other side and realizing intermittent charging through the operation of the device, characterized in that: include: Step (a), the power receiving unit measures a voltage value of the power receiving unit with respect to the wireless power transmitted by the power transmitting unit; Step (b), the power receiving unit measures the effective charging time corresponding to when the voltage value of the power receiving unit measured is greater than the effective charging voltage value; as well as In step (c), the power transmission unit controls the transmission power so as to be within a range between the measured charging time received from the power reception unit and a preset target charging time.

10. A magnetic resonance wireless power transmission and reception method using charging interval control, which uses a magnetic resonance wireless power transmission and reception system having a power transmission unit (Tx) provided on one side of a device and a power reception unit (Rx) provided on the other side and realizing intermittent charging through the operation of the device, characterized in that: include: Step (a), the power receiving unit measures a voltage value of the power receiving unit with respect to the wireless power transmitted by the power transmitting unit; (b) calculating a charging section length corresponding to a rotation length of the tire during the charging section based on the measured voltage value of the power receiving unit; as well as In step (c), the power transmission unit controls the transmission power so that the calculated charging section length received from the power reception unit is within a preset target charging section length range.

11. The magnetic resonance wireless power transmission and receiving method using charging interval control according to claim 9 or 10, characterized in that: The voltage value of the power receiving unit is any one of an output voltage value (Vo) of the power receiving unit, a stable voltage value (Vr) of the power receiving unit, and a voltage value (Vb) of a battery being charged.

12. The magnetic resonance wireless power transmission and receiving method using charging interval control according to claim 10, characterized in that: The step (b) comprises: Step (b1), the power receiving unit measures an effective charging time corresponding to when the voltage value of the power receiving unit measured is greater than a charging effective voltage value; and Step (b2) of calculating a charging section length using the effective charging time measured by the power receiving unit and the vehicle speed during the effective charging time.

13. The magnetic resonance wireless power transmission and receiving method using charging interval control according to claim 9 or 10, characterized in that: In the step (c), the control of the transmission power is achieved by changing the system frequency within a range of increasing or decreasing around a resonance frequency for transmitting maximum power.

14. The magnetic resonance wireless power transmission and receiving method using charging interval control according to claim 9 or 10, characterized in that: In the step (c), the transmission power is controlled by a DC input voltage of the transmission unit.

15. The magnetic resonance wireless power transmission and receiving method using charging interval control according to claim 9 or 10, characterized in that: In the step (c), the control of the transmission power is achieved by changing the duty cycle of the pulse width modulation signal of the resonance frequency.

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