CN104659922B - Method of Electricity Calculation - Google Patents

Abstract

The invention relates to a method for calculating electric power, which is suitable for a wireless electric power system and comprises the following steps: firstly, carrying out multipoint sampling on input or output current of a voltage stabilizing unit, and carrying out square root calculation on the result to obtain a current square root value; then, carrying out multi-point sampling on the input or output voltage of the voltage stabilizing unit, and carrying out square root calculation on the result to obtain a voltage square root value; then, multiplying the square root of the voltage by the square root of the current and by a cosine of an included angle to obtain a power value of the voltage stabilizing unit; then, dividing the power value of the voltage stabilizing unit by the efficiency value of the power receiving end to obtain a receiving power value; finally, the received power value is transmitted to a power transmitting end of the wireless power system.

Description

Method of Electricity Calculation

【Technical field】

The present invention relates to a power calculation method, in particular to a power calculation method applicable to a wireless power system for performing foreign object detection (FOD).

【Background technique】

Wireless power (wireless power), or wireless energy transmission (wireless energy transmission), is a technology that uses near-field induction, such as inductive coupling, to transmit energy from power supply equipment to power electronic devices. For example, in the application of wireless charging (wireless charging), the electronic device receives energy through wireless power, charges the battery included in it, and can be used for the operation of the electronic device itself at the same time. Since energy is transmitted between the electronic device and the power supply device through inductive coupling, and the two are not connected by wires, both the electronic device and the power supply device can have no exposed conductive contacts. Due to the design of no conductive contacts, wireless power technology can avoid the risk of electric shock, and the power transmission components are not exposed, so they will not be corroded by moisture and oxygen in the air. In addition, due to the existence of no contact point, there will be no loss of mechanical wear or possible danger caused by sparks (spark) during connection and separation.

The technological development of wireless power has brought great contributions in medical applications as well as the use of consumer electronics. Wireless power technology makes medical implants safer, and users can charge medical devices implanted in the human body without damaging body tissues, without the need for wires to pass through the skin and other autologous tissues, eliminating the need for risk of infection. In addition, wireless charging also brings considerable convenience to the use of consumer electronic devices, because the device does not need to be connected with a wire when charging, as long as it is placed near the charger; moreover, technically, one charger can charge multiple devices. The electrical device feeds in electricity, so when there are multiple electrical devices, multiple chargers can be omitted, multiple power sockets are not occupied, and there is no trouble of multiple wires being entangled with each other.

FIG. 1 is a schematic diagram of a conventional wireless power system 100 . In the wireless power system 100 , the power supply 110 , the power supply coupling capacitor 120 and the primary coil 130 form a wireless power transmitting end, and the secondary coil 150 , the resonant capacitor 160 and the resonant capacitor 165 form a wireless power receiving end. The wireless power transmitting end generates the wireless power 140 in the form of alternating current, and uses near-field induction, such as (but not limited to) the inductive coupling of the primary coil 130 and the secondary coil 150, so that the wireless power receiving end can receive wireless power. Electric power 140, and generate a power in the form of alternating current to input the rectifier 170. In addition, the resonant circuit formed by the secondary coil 150 , the resonant capacitor 160 and the resonant capacitor 165 can produce a bandpass effect, so that the wireless power receiving end can be selective to the AC frequency of the wire power 140 . The rectifier 170 is used to convert the received AC power into a DC voltage and output the DC voltage. The wireless power system 100 may further include a voltage stabilizing unit 180, which receives the DC voltage output by the rectifier 170 and generates a stable output voltage for use by the subsequent load 190, or the voltage stabilizing unit 180 generates a stable output voltage Or output current to charge a battery, which is the application of wireless charging.

However, when there are other metal foreign objects (not shown in the figure) in the wireless power path between the wireless power transmitting end and the wireless power receiving end, the metal foreign objects tend to absorb the energy of the wireless power 140, causing the wireless power system 100 to In case of loss in power transmission, the metal foreign matter may even affect the magnetic field distribution of the wireless power 140 , causing abnormal changes in temperature, such as an abnormal increase in local temperature, which may cause danger. Therefore, the purpose of foreign object detection in the wireless power system is to determine whether there is a foreign object that causes power transmission loss on the wireless power path, so that the system can eliminate this abnormal situation and return to normal use. The current foreign object detection method in the wireless power system is to use the difference between the power transmitted by the wireless power transmitter and the power received by the wireless power receiver. When the difference between the two is judged to be too large, that is It is judged that there may be a foreign object on the wireless power path, and this abnormal situation must be further ruled out in order to ensure the normal and safe use of the wireless power system.

FIG. 2 is a schematic diagram of a conventional power calculation method in a wireless power system, which is illustrated in conjunction with the wireless power system 100 in FIG. 1 . The voltage regulator in the wireless power system 100 is a linear voltage regulator, and under normal operating conditions, the input current and the output current of the linear voltage regulator are almost equal. In the wireless power system 100, the detection voltage and detection current shown in FIG. 2 are obtained by detecting the instantaneous input voltage and the instantaneous output current of the linear voltage regulator; After multiplication, a received power value can be obtained; then the received power value is transmitted to the power transmitter for utilization, such as foreign object detection and the like. This prior art has at least the following disadvantages, resulting in inaccuracy in application: first, the received power value calculated in Fig. 2 is an instantaneous power value, and the sequence formed over time has a more severe Therefore, a larger bandwidth is required to transmit data back to the power transmitter; second, the calculated received power value does not take into account the power loss caused by the front end of the wireless power receiver and the rectifier, so it is different from the actual wireless power Compared with the power received by the receiving end, there may be a not small amount of error.

【Content of invention】

In view of the above problems, the present invention provides a power calculation method, especially a power calculation method applicable to a wireless power system for foreign object detection.

The present invention proposes a power calculation method, which is suitable for a power receiving end of a wireless power system, and is used for detecting foreign objects in the wireless power system. The power calculation method includes the following steps:

Firstly, multi-point sampling is performed on the input current or output current of a voltage stabilizing unit included in the power receiving end, and the root mean square calculation is performed on the result of the multi-point sampling of the current to obtain a current root mean square value. Next, multi-point sampling is performed on the input voltage or output voltage of the voltage stabilizing unit, and the root-mean-square calculation is performed on the multi-point sampling results of the voltage to obtain a voltage root-mean-square value. Then, the root mean square value of the voltage is multiplied by the root mean square value of the current, and multiplied by the cosine value of an included angle to obtain a voltage stabilizing unit power value, wherein the included angle is related to the sampled input voltage or output of the stabilizing unit voltage, and the signal phase difference between the sampled input current or output current of the voltage stabilizing unit. Furthermore, the power value of the voltage stabilizing unit is divided by a power receiving end efficiency value to obtain a receiving power value, wherein the power receiving end efficiency value is a function of the root mean square value of the current. Finally, the received power value is sent to a power transmitter of the wireless power system for foreign object detection.

The present invention further proposes a power calculation method, which is suitable for a power receiving end of a wireless power system, and is used for detecting foreign objects in the wireless power system. The power calculation method includes the following steps:

First, current sampling is performed on the input current or output current of a voltage stabilizing unit included in the power receiving end, and at the same time voltage sampling is performed on the input voltage or output voltage of the voltage stabilizing unit to obtain a current sampling value and a voltage sampled value. Next, multiply the current sampled value and the voltage sampled value, and divide by a power receiving end efficiency value to obtain an instant received power value, wherein the power receiving end efficiency value is a function of the current sampled value. Then, the current sampling and the voltage sampling are repeated several times, and after corresponding several instantaneous received power values are obtained, the average value of the several instantaneous received power values is calculated to obtain a received power value. Finally, the received power value is sent to a power transmitter of the wireless power system for foreign object detection.

The effect of the present invention is that the power calculation method disclosed in the present invention can obtain more accurate power calculation results in the applicable wireless power system, so as to facilitate the wireless power system to perform such as foreign object detection or power efficiency optimization Wait for work.

Regarding the features, implementation and effects of the present invention, the preferred embodiments are described in detail below in conjunction with the drawings.

【Description of drawings】

FIG. 1 is a schematic diagram of a conventional wireless power system.

FIG. 2 is a schematic diagram of a conventional power calculation method in a wireless power system.

FIG. 3 is a schematic diagram of a power calculation method according to a first embodiment of the present invention.

FIG. 4 is a schematic diagram of a power calculation method disclosed in a second embodiment of the present invention.

FIG. 5 is a flow chart of steps summarized corresponding to the first embodiment disclosed in the present invention.

FIG. 6 is a schematic diagram of a power calculation method according to a third embodiment of the present invention.

FIG. 7 is a schematic diagram of a method for calculating power according to a fourth embodiment of the present invention.

FIG. 8 is a flow chart of steps summarized corresponding to the third embodiment disclosed in the present invention.

Description of main component symbols:

100 Wireless Power System 150 Secondary Coil

110 Power supply 160, 165 Resonance capacitor

120 Power supply coupling capacitor 170 Rectifier

130 primary coil 180 voltage stabilizing unit

140 wireless power 190 load

【detailed description】

FIG. 3 is a schematic diagram of a power calculation method disclosed in a first embodiment of the present invention, which is applicable to a power receiving end of a wireless power system, such as the wireless power system 100 shown in FIG. 1 . The power calculation method disclosed in the present invention can be used for foreign object detection or efficiency optimization of the wireless power system 100 . The method for calculating the electric power is first to carry out multi-point sampling on the input current or output current of the voltage stabilizer and the input voltage or output voltage of the voltage stabilizer respectively. It is worth noting that the decision to sample the input current (voltage) or the output current (voltage) depends on various considerations in the application, such as the electrical specifications that the sampling circuit can withstand, the input current (voltage) Or which one of the output current (voltage) signal is more stable, or whether the physical configuration of the circuit components can be minimized, etc. In this embodiment, multi-point sampling is performed on the input voltage and output current of the voltage regulator respectively. This aspect is used to illustrate the spirit of the present invention, but not to limit the scope of the present invention. As for the sampling technology of voltage and current signals, it is well known to those skilled in the art. After knowing the spirit and related descriptions disclosed by the present invention, they can learn from the known technology according to the differences in their applications. A suitable circuit pattern is selected for application, so no further details are given here.

After performing multi-point sampling to obtain the detection voltage and the detection current sequence, respectively, the root-mean-square (RMS) value is calculated for the detection voltage sequence and the detection current sequence, respectively. Get the root mean square value of the voltage and the root mean square value of the current. It is worth noting that since the calculation of the RMS value does not involve the initial phase of the sampled current signal or voltage signal, in this embodiment, when the voltage and current are respectively multi-point sampled, the sampling actions of the two can be Asynchronous (asynchronous), that is, the action of sampling at different time points.

Then, the root mean square value of the voltage is multiplied by the root mean square value of the current, and multiplied by the cosine (cosine) value of an included angle to obtain the power value of the voltage stabilizing unit, wherein the included angle is related to the sampled voltage stabilizing unit The signal phase difference between the input voltage or output voltage and the sampled input current or output current of the voltage stabilizing unit is due to the fact that when the sampled voltage and current are in a period of one multi-point sampling When using a signal, the calculation of power will be related to the phase difference of the signal between the voltage and current. However, when the sampled voltage or current is in the form of a direct current, the included angle is equivalent to 0 degree, that is, its cosine value is 1.

Furthermore, the power value of the voltage stabilizing unit obtained in the previous paragraph is divided by a power receiving end efficiency value to obtain a received power value. The power receiving end efficiency value is the power efficiency parameter between a certain stage in the wireless power system 100 and the voltage regulator 180 (that is, the conversion efficiency between input power and output power), which can be adjusted according to the application requirements. Adjustment. For example, the power receiving end efficiency may be a power efficiency parameter between the secondary coil 150 and the voltage regulator 180 , and the received power value thus obtained is the wireless power value received at the secondary coil 150 . And when the rectifier 170 and the voltage regulator 180 are integrated circuits formed by semiconductor manufacturing process, and the power calculation method disclosed in the present invention is integrated in the integrated circuit, due to the secondary coil 150 of the external component Etc. Different components may be used according to different applications. At this time, the definition of the efficiency of the power receiving end can also be the power efficiency parameter between the input of the rectifier 170 and the voltage stabilizer 180, and the received power value obtained from this is the rectifier 170 is the input of the wireless power value received by the premises. In addition, when the wireless power receiving end can know the normal power efficiency parameters of the wireless power path, the efficiency of the power receiving end may also be the power efficiency parameter between the primary coil 130 and the voltage regulator 180, so that the wireless power transmission can be reversed. The amount of wireless power transmitted by the terminal at the primary coil 130. Furthermore, when the sampled voltage and current are not simultaneously the input voltage and the input current of the voltage regulator, the power receiving end efficiency must further include the power efficiency parameter of the voltage regulator itself.

To further illustrate, the power efficiency parameter is usually not a fixed value, but a function of current. For example, as shown in FIG. 3 , the efficiency value of the power receiving end of this embodiment is a function of the root mean square value of the current. Therefore, after the current is sampled at multiple points and its root mean square value is calculated, its corresponding power receiving end efficiency value can be obtained for further processing to obtain a received power value. Assume that the detection voltages for multi-point sampling at N points are V1, V2, ..., VN, and the detection currents for multi-point sampling at N points are I1, I2, ..., IN, and the power received corresponding to the root mean square value of the current The terminal efficiency value is E, and the aforementioned included angle is □, then the following equation (1) can be obtained to obtain the received power value P:

$\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; =</span>\frac{\frac{\sqrt{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; \&times;</span>\sqrt{\frac{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; N</span>}}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}}{\mathrm{<span\; class="notranslate">\; E.</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Finally, the obtained received power value is transmitted to the power transmitting end of the wireless power system 100 for judgment of foreign object detection or efficiency optimization and the like. As for the transmission method, the wireless transmission method is the main method, and its specific implementation methods are familiar to those skilled in the art, and will not be repeated here.

FIG. 4 is a schematic diagram of a power calculation method disclosed in a second embodiment of the present invention. The difference between the second embodiment disclosed in Figure 4 and the first embodiment disclosed in Figure 3 is that the functions of voltage drift compensation and current drift compensation are added in the second embodiment, and other parts can be directly referred to Relevant description of the first embodiment.

As shown in Figure 4, after multi-point sampling of current and voltage to obtain the sequence of detection current and detection voltage, since the sampling circuit may have an offset (offset), the multi-point sampling of current and voltage can be After adding the current drift compensation value and the voltage drift compensation value to the sampled value, the root mean square calculation is performed to obtain more accurate current root mean square value and current root mean square value. It is found from practice that the current drift compensation value and the voltage drift compensation value can be summed up as a function of the detection current to obtain the best compensation effect. Therefore, in practice, as shown in the figure, different degrees of compensation can be performed according to the magnitude of the detection current according to the function. Certainly, the current drift compensation value and the voltage drift compensation value may also be a fixed value, or a function value of other parameters. Those skilled in the art can make optimized designs according to different applications and according to the spirit disclosed in the present invention.

To further illustrate, assume that the voltage drift compensation values corresponding to the detection voltages V1, V2, ..., VN are respectively Vos1, Vos2, ..., VosN, and the current drift compensation values corresponding to the detection currents I1, I2, ..., IN are respectively Ios1, Ios2, ..., IosN, the efficiency value of the power receiving end corresponding to the root mean square value of the current is E, and the aforementioned included angle is □, then the following formula (2) can be obtained to obtain the received power value P:

$\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; =</span>\frac{\sqrt{\frac{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; os</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; os</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; OSN</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; N</span>}}}<span\; class="notranslate">\; \&times;</span>\sqrt{\frac{{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; os</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; os</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; OSN</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; N</span>}}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}}{\mathrm{<span\; class="notranslate">\; E.</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

FIG. 5 is a flow chart of steps summarized corresponding to the first embodiment of the present invention disclosed in FIG. 3, including the following steps:

As shown in step 510, multi-point sampling is performed on the input current or output current of a voltage stabilizing unit included in the power receiving end, and the root mean square calculation is performed on the result of the multi-point sampling of the current to obtain the current root mean square value.

As shown in step 530, multi-point sampling is performed on the input voltage or output voltage of the voltage stabilizing unit, and root mean square calculation is performed on the multi-point sampling results of the voltage to obtain the voltage root mean square value.

As shown in step 550, the root mean square value of the voltage is multiplied by the root mean square value of the current, and then multiplied by the cosine value of an included angle to obtain a voltage stabilizing unit power value, wherein the included angle is related to the sampled input voltage of the stabilizing unit or the output voltage, and the signal phase difference between the sampled input current or output current of the voltage stabilizing unit.

As shown in step 570, the power value of the voltage stabilizing unit is divided by a power receiving end efficiency value to obtain a receiving power value, wherein the power receiving end efficiency value is a function of the root mean square value of the current.

As shown in step 590, the received power value is transmitted to a power transmitter of the wireless power system for foreign object detection.

In addition, in step 510, it may further include adding a current drift compensation value to the multi-point sampling values of the current, and then performing RMS calculation to obtain the RMS value of the current. Wherein, the current drift compensation value may be a function of the sampled input current or output current of the voltage stabilizing unit.

Furthermore, in step 530, it may further include adding a voltage drift compensation value to the multi-point sampled values of the voltage, and then performing root mean square calculation to obtain the voltage root mean square value. Wherein, the voltage drift compensation value may be a function of the sampled input current or output current of the voltage stabilizing unit.

FIG. 6 is a schematic diagram of a power calculation method disclosed in a third embodiment of the present invention, which is also applicable to the power receiving end of the wireless power system 100 shown in FIG. 1 . The power calculation method disclosed in the present invention can be used for foreign object detection or efficiency optimization of the wireless power system 100 . The method for power calculation is firstly to simultaneously sample the input current or output current of the voltage stabilizer and the input voltage or output voltage of the voltage stabilizer to obtain a current sampling value and a voltage sampling value respectively. It is worth noting that the decision to sample the input current (voltage) or the output current (voltage), the sampling method in this embodiment, and the sampling technology of voltage and current signals can refer to the first Relevant descriptions in the embodiments are not repeated here.

Then, the current sampling value and the voltage sampling value are multiplied, and divided by a power receiving end efficiency value to obtain an instant receiving power value. For the relevant description of the efficiency value of the power receiving end, reference may be made to the relevant description in the first embodiment shown in FIG. 3 , so details are not repeated here.

To further illustrate, the power efficiency parameter is usually not a fixed value, but a function of current. For example, as shown in FIG. 3 , the efficiency value of the power receiving end in this embodiment is a function of the current sampling value. Therefore, after the current is sampled, its corresponding power receiving end efficiency value can be obtained for further processing to obtain a received power value. Assuming that the detection voltages for N-point multi-point sampling are V1, V2, ..., VN, and the detection currents for N-point multi-point sampling are I1, I2, ..., IN, the corresponding power receiving end efficiency The values are E1, E2, ..., EN, then the following equation (3) can be obtained to obtain the received power value P:

$\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; =</span>\frac{\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}}}{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Finally, the obtained received power value is transmitted to the power transmitting end of the wireless power system 100 for judgment of foreign object detection or efficiency optimization and the like. As for the transmission method, the wireless transmission method is the main method, and its specific implementation methods are familiar to those skilled in the art, and will not be repeated here.

FIG. 7 is a schematic diagram of a method for calculating power according to a fourth embodiment of the present invention. The difference between the fourth embodiment disclosed in FIG. 7 and the third embodiment disclosed in FIG. 6 is that the functions of voltage drift compensation and current drift compensation are added in the fourth embodiment, and other parts can be directly referred to in Section 1. Relevant descriptions of the three embodiments.

As shown in Figure 7, after sampling the current and voltage, since the sampling circuit may have drift, the current and voltage sampling values can be added to the current drift compensation value and the voltage drift compensation value respectively to obtain a more accurate Accurate current sampling value and voltage sampling value. It is found from practice that the current drift compensation value and the voltage drift compensation value can be summed up as a function of the detection current to obtain the best compensation effect. Therefore, as shown in the figure, different degrees of compensation can be performed according to the magnitude of the detection current according to the function. Certainly, the current drift compensation value and the voltage drift compensation value may also be a fixed value, or a function value of other parameters. Those skilled in the art can make optimized designs according to different applications and according to the spirit disclosed in the present invention.

To further illustrate, assume that the voltage drift compensation values corresponding to the detection voltages V1, V2, ..., VN are respectively Vos1, Vos2, ..., VosN, and the current drift compensation values corresponding to the detection currents I1, I2, ..., IN are respectively Ios1, Ios2, ..., IosN, and corresponding to the efficiency values E1, E2, ..., EN of the power receiving end, the following formula (4) can be obtained to obtain the received power value P:

$\mathrm{<span\; class="notranslate">\; P</span>}<span\; class="notranslate">\; =</span>\frac{\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; os</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; os</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; os</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; os</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; OSN</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; OSN</span>}}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; N</span>}}}}{\mathrm{<span\; class="notranslate">\; N</span>}}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Finally, the obtained received power value is transmitted to the power transmitting end of the wireless power system 100 for judgment of foreign object detection or efficiency optimization and the like. As for the transmission method, the wireless transmission method is the main method, and its specific implementation methods are familiar to those skilled in the art, and will not be repeated here.

FIG. 8 is a flow chart of steps corresponding to the third embodiment of the present invention disclosed in FIG. 6, including the following steps:

As shown in step 810, current sampling is performed on the input current or output current of a voltage stabilizing unit included in the power receiving end, and at the same time, voltage sampling is performed on the input voltage or output voltage of the voltage stabilizing unit to obtain current sampling values respectively and voltage samples.

As shown in step 830, the current sampled value and the voltage sampled value are multiplied and divided by a power receiving end efficiency value to obtain an instant received power value, wherein the power receiving end efficiency value is a value of the current sampled value function.

As shown in step 850, the current sampling and the voltage sampling are repeated several times, and after calculating several instantaneous received power values, an average value of the several instantaneous received power values is calculated to obtain a received power value.

As shown in step 870, the received power value is transmitted to a power transmitter of the wireless power system for foreign object detection.

In addition, in step 810, it may further include adding a current drift compensation value to the current sampling result to obtain the current sampling value. Wherein, the current drift compensation value may be a function of the sampled input current or output current of the voltage stabilizing unit.

Furthermore, in step 810, it may further include adding a voltage drift compensation value to the voltage sampling result to obtain the voltage sampling value. Wherein, the voltage drift compensation value may be a function of the sampled input current or output current of the voltage stabilizing unit.

Although the embodiments of the present invention are disclosed as above, they are not intended to limit the present invention. Anyone skilled in the relevant art can use the shapes, structures, and features described in the application scope of the present invention without departing from the spirit and scope of the present invention. and quantity can be slightly changed, so the scope of patent protection of the present invention must be defined by the scope of patent application attached to this specification.

Claims (10)

1. A method of power calculation, suitable for a power receiving end of a wireless power system, for detecting foreign objects in the wireless power system, characterized in that the method of power calculation comprises the following steps: performing multi-point sampling on the input current or output current of a voltage stabilizing unit included in the power receiving end, and performing root-mean-square calculation on the result of the multi-point sampling of the current, so as to obtain a current root-mean-square value; performing multi-point sampling on the input voltage or output voltage of the voltage stabilizing unit, and performing root-mean-square calculation on the multi-point sampling results of the voltage to obtain a voltage root-mean-square value; multiplying the root mean square value of the voltage by the root mean square value of the current, and multiplying the cosine value of an included angle to obtain a power value of a voltage stabilizing unit, wherein the included angle is related to the sampled input voltage of the stabilizing unit or the output voltage, and the signal phase difference between the sampled input current or output current of the voltage stabilizing unit; dividing the voltage stabilizing unit power value by a power receiving end efficiency value to obtain a receiving power value, wherein the power receiving end efficiency value is a function of the root mean square value of the current; and The received power value is sent to a power transmitter of the wireless power system for foreign object detection. 2. The method for calculating electric power as described in item 1 of the claim, wherein the step of obtaining the root mean square value of the current further includes adding a current drift compensation value to the multi-point sampling value of the current , and then calculate the root mean square to obtain the root mean square value of the current. 3. The method for power calculation according to claim item 2, wherein the current drift compensation value is a function of the input current or output current of the voltage stabilizing unit being sampled. 4. The method for calculating electric power as described in item 1 of the claim, wherein the step of obtaining the root-mean-square value of the voltage further includes adding a voltage drift compensation value to the multi-point sampling value of the voltage respectively , and then calculate the root mean square to obtain the root mean square value of the voltage. 5. The method for power calculation according to claim item 4, wherein the voltage drift compensation value is a function of the input current or output current of the voltage stabilizing unit being sampled. 6. A power calculation method, suitable for a power receiving end of a wireless power system, for detecting foreign objects in the wireless power system, characterized in that the power calculation method comprises the following steps: performing current sampling on the input current or output current of a voltage stabilizing unit included in the power receiving end, and simultaneously performing voltage sampling on the input voltage or output voltage of the voltage stabilizing unit to obtain a current sampling value and a voltage sample value; multiplying the current sampling value and the voltage sampling value, and dividing by a power receiving end efficiency value to obtain an instant receiving power value, wherein the power receiving end efficiency value is a value of the current sampling value function; Repeating the current sampling and voltage sampling several times, and after obtaining the corresponding several instantaneous received power values, calculating the average value of the several instantaneous received power values to obtain a received power value; and The received power value is sent to a power transmitter of the wireless power system for foreign object detection. 7. The method for calculating electric power as described in item 6 of the claim, wherein the step of performing current sampling further includes adding a current drift compensation value to the current sampling result to obtain the current sampling value. 8. The method for power calculation according to claim item 7, wherein the current drift compensation value is a function of the sampled input current or output current of the voltage stabilizing unit. 9. The method for calculating electric power as described in item 6 of the claim, wherein the step of performing voltage sampling further includes adding a voltage drift compensation value to the voltage sampling result to obtain the voltage sampling value. 10. The method for power calculation according to claim item 9, wherein the voltage drift compensation value is a function of the input current or output current of the voltage stabilizing unit being sampled.