JP7419021B2 - wireless device - Google Patents

Description

TECHNICAL FIELD The present invention relates to wireless devices.

There is a system that supplies electric power to a motor to drive it. For example, in semiconductor exposure equipment, a motor that moves the wafer minutely to form a pattern on the wafer is mounted on the stage that moves the wafer to the exposure position, and power is supplied to drive the motor. A power supply cable is connected to the stage. Since this cable moves with the movement of the stage, the tension of the cable affects the positioning accuracy of the stage. Therefore, it is being considered to wirelessly transmit power for driving the motor.

Patent Document 1 describes the configuration of a motor that wirelessly drives wheels. In order to drive a motor wirelessly, it is necessary to transmit not only electric power but also control signals for the motor drive circuit and rectifier circuit wirelessly, so wireless communication using radio waves is performed. By using this communication to send control signals to the motor drive circuit on the movable side, control of the motor drive circuit is realized.

Patent No. 6219495

In recent years, there has been a demand for highly accurate control of voltage applied to loads such as motors. For example, in a semiconductor exposure apparatus, high-speed motor control is required in order to move the stage at high speed and with high precision. The method described in Patent Document 1 speeds up motor control by sending control signals to the motor drive circuit at a cycle of several hundred μs or less, since a delay of several hundred μs to several ms occurs in wireless communication using radio waves. It's difficult to do.

An object of the present invention is to improve the accuracy of voltage application to a load based on wirelessly transmitted power.

The wireless device of the present invention includes: a power transmitting coil that wirelessly transmits power; a power receiving coil that wirelessly receives power from the power transmitting coil; and a switch circuit that applies voltage to the power transmitting coil based on a first switching signal. a rectifier circuit that rectifies the voltage output from the power receiving coil based on a second switching signal and applies the rectified voltage to a load; a first phase shift circuit that provides a phase difference , the first phase shift circuit phase shifting a reference frequency signal, and at least one of the first switching signal and the second switching signal. Output .

According to the present invention, it is possible to improve the accuracy of voltage application to a load based on wirelessly transmitted power.

It is a system configuration diagram when a wireless device is applied to a movable stage. FIG. 2 is a diagram illustrating a configuration example of a wireless device. It is a figure showing an example of composition of a rectifier circuit. It is a figure which shows the example of actual measurement of input-output voltage. FIG. 2 is a diagram illustrating a configuration example of a wireless device. FIG. 2 is a diagram illustrating a configuration example of a wireless device. FIG. 2 is a diagram illustrating a configuration example of a wireless device.

(First embodiment)
FIG. 1 is a diagram showing a configuration example of a wireless device applied to a movable stage such as a semiconductor exposure apparatus according to the first embodiment. The wireless device includes a power transmitting section 100, a power receiving section 200, a power transmitting coil 101, and a power receiving coil 201.

Power receiving unit 200 is placed on movable stage 401 and physically moves relative to power transmitting unit 100 . The power transmission unit 100 is not disposed on the movable stage 401 but on the fixed side where the movable stage power source 402 that moves the movable stage 401 is disposed, and does not move itself.

Between the power transmitting unit 100 and the power receiving unit 200, there are a power transmitting coil 101 and a power receiving coil 201 for wireless power supply and communication. Power transmitting coil 101 and power receiving coil 201 are not in contact with each other. Power receiving coil 201 is also placed on movable stage 401 and moves together with movable stage 401. By making the power transmission coil 101 long so as to cover the movement range of the movable stage 401, power can be supplied to the motor in the power receiving unit 200 without contact even if the movable stage 401 moves to an arbitrary position. .

The shape of the power transmitting coil 101 is, for example, a horizontally long elliptical coil, and the power receiving coil 201 is a shorter coil than the power transmitting coil 101. The power receiving coil 201 may be long, and the power transmitting coil 101 may be short.

FIG. 2 is a block diagram showing a configuration example of the wireless device 300 according to the first embodiment. Wireless device 300 includes power transmitting section 100 , power receiving section 200 , power transmitting coil 101 , and power receiving coil 201 . Power transmitting coil 101 and power receiving coil 201 are not physically connected, and power is sent from power transmitting coil 101 to power receiving coil 201 without contact. Power transmitting unit 100 and power receiving unit 200 are also not physically connected.

Power transmission unit 100 includes a phase shift circuit 102, a controller 103, a power supply 104, a reference frequency source 105, and a switch circuit 106. Power receiving unit 200 includes a reference frequency source 202 , a power receiving circuit 204 , a gate drive circuit 205 , a rectifier circuit 206 , and a motor 400 .

Power source 104 is a power source that drives motor 400. The switch circuit 106 drives a switching element using a switching control signal obtained by phase-shifting the reference frequency signal generated by the reference frequency source 105 by the phase shift circuit 102, performs high-frequency switching of the power supplied from the power supply 104, and is capable of wireless power transmission. converts it into high-frequency power. At this time, the switching frequency is higher than the period of the command signal of the controller 103, that is, the motor control frequency.

The controller 103 issues a command for the next position based on current position information of the motor 400 obtained from an optical sensor or the like. Specifically, the controller 103 outputs an output voltage amplitude value of the power source 104 that determines the thrust of the motor 400 and motor applied voltage sign information that determines the direction in which the motor moves. The output voltage amplitude value is determined by sending a command signal from the controller 103 to the power supply 104, and the power supply 104 changes the output voltage amplitude value to the commanded value. Motor applied voltage sign information is output from controller 103 to phase shift circuit 102 . Reference frequency source 105 outputs a reference frequency signal to phase shift circuit 102 . The phase shift circuit 102 outputs a signal obtained by shifting the phase of the reference frequency signal output from the reference frequency source 105 to the switch circuit 106 as a first switching signal based on the motor applied voltage sign information output from the controller 103.

The switch circuit 106 supplies (applies) a power transmission voltage (current) containing information necessary for motor control to the power transmission coil 101 based on the first switching signal (voltage F3). The power transmission coil 101 wirelessly transmits power. The power receiving coil 201, which is electromagnetically coupled to the power transmitting coil 101 in a non-contact manner, is excited by the electromagnetic field of the power transmitting coil 101 and generates high-frequency power. The power receiving coil 201 receives power from the power transmitting coil 101 wirelessly.

Power receiving circuit 204 is provided between power receiving coil 201 and rectifier circuit 206. The power receiving circuit 204 is formed of a resonant circuit including an inductor and a capacitor, and its resonant frequency is approximately equal to the switching operating frequency of the switch circuit 106. The output of power receiving circuit 204 is connected to rectifier circuit 206 .

The rectifier circuit 206 rectifies the output voltage of the power receiving circuit 204 based on the second switching signal (voltage F6) of the gate drive circuit 205, and applies the rectified voltage to the motor 400. Here, the second switching signal is a signal whose frequency is synchronized with the reference frequency source 202. The reference frequency source 202 is synchronized in frequency with the reference frequency source 105 and outputs a reference frequency signal to the gate drive circuit 205. The gate drive circuit 205 drives the rectifier circuit 206 with a second switching signal based on the reference frequency signal from the reference frequency source 202. Note that if the reference frequency source 105 and the reference frequency source 202 are synchronized in frequency, the output voltage (power) of the rectifier circuit 206 can be controlled by the amount of phase shift of the phase shift circuit 102. Motor 400 is a load and is rotated by the output voltage of rectifier circuit 206.

The reference frequency source 202 can be replaced by a means for non-contactly transmitting the reference frequency signal of the reference frequency source 105 by electromagnetic coupling communication or optical coupling communication. For example, a laser or a light-emitting diode with sharp directivity is placed on the fixed reference frequency source 105 and emitted along the moving direction of the stage, and a light-receiving device such as a photodiode is placed so that the light-receiving surface is located on the optical path. The element may be placed in the reference frequency source 202 on the movable side. The electromagnetic field coupling in this embodiment includes both electric field coupling and magnetic field coupling. That is, contactless transmission of signals may be performed by electric field coupling, magnetic field coupling, or both electric field coupling and magnetic field coupling.

Furthermore, by using synchronous rectification using active switching elements, the rectifier circuit 206 can rectify even a small voltage of several millivolts, which cannot be rectified by a diode, and can apply a minute voltage to the motor 400, thereby increasing the motor 400. Accurate control is possible.

Note that the power transmitting coil 101 and the power receiving coil 201 may be formed by wiring on a printed circuit board. A magnetic sheet may be attached to the printed circuit board to reduce loss during magnetic field coupling. Further, the power transmitting coil 101 and the power receiving coil 201 may be a wire-wound transformer using a magnetic material such as ferrite and a winding wire such as a Litz wire.

Next, the operating principle of wireless device 300 will be explained from a mathematical perspective. Voltages F1 to F7 in FIG. 2 are expressed as functions of voltage waveforms at each part. The voltage F1 is the output voltage of the power supply 104, and is the absolute value of the voltage required to drive the motor, and can be expressed by [Equation 1].

Voltage F4 is the output voltage of reference frequency source 105, and is expressed by [Equation 2]. Note that a rectangular wave may be used for the voltage F4.

Voltage F3 is a control signal of switch circuit 106 whose phase is shifted by phase difference φ by phase shift circuit 102 according to a command from controller 103, and is expressed by [Equation 3].

The switch circuit 106 can be considered as a multiplier that multiplies voltages F1 and F3 on the time axis, and its output voltage F2 is given by [Equation 4].

This voltage F2 propagates from the power transmitting coil 101 to the power receiving coil 201 via electromagnetic coupling, is subjected to power factor adjustment by the power receiving circuit 204, and then input to the rectifier circuit 206. For convenience, it is assumed here that the power transmitting coil 101 and the power receiving coil 201 are ideally coupled at a voltage ratio of 1:1. The input voltage F5 of the rectifier circuit 206 is given by [Equation 5].

Here, θ is the sum of phase differences due to propagation delay from the power transmitting coil 101 to just before the rectifier circuit 206 and resonance shift of the power receiving circuit 204. Voltage F6 is a drive signal for the rectifier circuit 206, and can be expressed by [Equation 6]. Although voltage F6 does not necessarily need to be synchronized with the phase of voltage F4, here, for simplicity, the phase difference is set to 0. The phase shift circuit 102 provides a phase difference φ between the voltage F3 and the voltage F6. Voltage F3 and voltage F6 have the same period.

Since the rectifier circuit 206 can be considered as a multiplier like the switch circuit 106, its output voltage F7 is given by [Equation 7].

Here, regarding [Equation 7], the first item means a harmonic component generated by multiplication. Since a smoothing capacitor exhibiting a sufficiently low impedance with respect to the power transmission frequency is mounted on the output of the rectifier circuit 206, harmonic components are attenuated to a negligible extent. As a result, the drive voltage of motor 400 is represented by the second item. Therefore, the drive voltage F7 of the motor 400 is given by [Equation 8].

[Equation 8] shows that the motor control voltage F7 can be controlled sinusoidally by the phase shift amount φ of the phase shift circuit 102. Note that the maximum value in [Equation 8] can be read as 1/2 of the power supply 104, but this is the result when the switch circuit 106 is driven with a sine wave, and when it is driven with an ideal square wave with a duty ratio of 50%. Assuming that, the maximum value of [Equation 8] will be the same as that of the power supply 104. Therefore, the motor drive voltage F7' in that case can be rewritten as [Equation 9].

As described above, the operation of the wireless device 300 could be expressed mathematically, albeit simply. A specific example of controlling forward/reverse rotation of the motor 400 will be shown below. When the phase shift amount φ is alternately switched between 0 and π, the voltage F7' is given by [Equation 10].

From [Equation 10], it can be seen that in order to perform forward/reverse rotation control, it is sufficient to switch the phase shift amount φ between 0 and π, regardless of the value of the input voltage of the power supply 104 or the propagation delay θ. For example, if the motor drive voltage F7' is 1V when the amount of phase shift is 0, when the amount of phase shift changes to π, the motor drive voltage F7' changes to -1V.

In other words, as long as the reference frequency source 105 and the reference frequency source 202 are synchronized in frequency, the thrust, forward rotation, and reverse rotation of the motor 400 can be controlled without contactless transmission of control signals. becomes. In order to drive the motor 400 with high precision, it is desirable that the change in the motor drive voltage F7' with respect to the output voltage of the power supply 104 be proportional to the voltage value at a constant rate. If there is a condition where this proportional relationship collapses due to some factor, it is possible to improve the proportional relationship by finely adjusting the amount of phase shift in the phase shift circuit 102.

Further, in [Equation 10], if θ is 0, the absolute value of the motor drive voltage F7' becomes equal to the output voltage A of the power supply 104, which is the most ideal. In order to satisfy this condition, it is preferable to measure the correspondence between the output voltage of the rectifier circuit 206 and the output voltage of the power supply 104 in advance, and adjust the initial phase of the phase shift circuit 102 so that the correspondence becomes the most suitable state.

FIG. 3 is a diagram showing a configuration example of the rectifier circuit 206. A typical synchronous rectifier circuit is realized using four switching elements, but with this configuration, it is not possible to output a rectified output that changes both positive and negative. This is because a switch element has a body diode or an equivalent parasitic element, and if a reverse bias is applied between the drain and source of a transistor, the drain and source become conductive regardless of the gate drive state. It's for a reason. Therefore, the rectifier circuit 206 includes a plurality of bidirectional switches each including two switching elements per gate drive circuit. With this configuration, the switching element does not become conductive unless the gate drive circuit performs on control, and it becomes possible to output a rectified output that changes both positive and negative. Note that the driving power source between the source and the gate can be realized by constructing an insulated power source or the like and supplying it from a floating power source capable of supplying a voltage of about 5 to 10 V with each source potential as a reference.

Next, the operation of the rectifier circuit 206 will be explained. Basically, the functional requirements can be achieved if the gate drive circuit 205 controls each bidirectional switch at the same frequency as the reference frequency source 105, regardless of whether the output voltage of the rectifier circuit 206 is large or small, positive or negative. Specifically, at the same frequency as the reference frequency source 105, the upper left and lower right of the four bidirectional switches of the rectifier circuit 206 are turned on during a certain half cycle, the lower left and upper right are turned off, and the next half cycle is switched on. During this time, you can switch to the opposite operation described above. As described above, if the phase shift amount φ of the phase shift circuit 102 changes while this operation is repeated, the rectified output voltage F7' corresponding to the phase shift amount φ is obtained.

Note that in this gate drive sequence, for example, if the upper right and lower right bidirectional switches are turned on at the same time, a through current flows, causing a large loss. In some cases, this loss may damage the bidirectional switch, which is undesirable. Therefore, it is necessary to take measures to avoid the through current by inserting a so-called dead time into the gate drive signal at the switching timing of the bidirectional switch. The drive signals for the plurality of bidirectional switches are provided with a dead time to prevent through current. Insertion of dead time has no effect on frequency synchronization, so it does not interfere with rectification operation. Note that although the rectifier circuit 206 has been described as a full bridge type, it may be of a center tap type. In that case, the power receiving coil 201 needs to be of a center tap type, which complicates the wiring, but the number of switching elements in the rectifier circuit 206 can be reduced to four.

Being able to realize the rectifier circuit 206 that can output positive and negative voltages with such a simple circuit configuration is very advantageous in terms of miniaturization of the wireless device 300. In addition, the only condition required to satisfy the functional requirements of the rectifier circuit 206 is that it be driven by a control signal frequency-synchronized with the reference frequency source 105, which can be achieved relatively easily. On the other hand, a common motor control signal is a PWM signal. In order to non-contactly transmit the information necessary to realize high-accuracy and high-speed PWM driving with low delay, the transmission system becomes complicated, and this becomes the main factor that limits the upper limit of speeding up.

FIG. 4 shows the measurement results of input and output voltages obtained by measuring the voltage applied to the motor 400 with respect to the output voltage of the power supply 104. The horizontal axis is the output voltage of the power supply 104, ie, the input voltage, and the vertical axis is the voltage applied to the motor 400, ie, the output voltage. The output voltage was switched between a positive voltage and a negative voltage using the phase shift function of the phase shift circuit 102, and measurements were performed on both potentials. FIG. 4 also depicts an ideal curve when the input and output voltages match. The switching frequency is 4 MHz, and a 3 mH inductor is connected as a pseudo load in place of the motor 400. Any voltage from 0V to 30V can be wirelessly supplied. There are parts where the output voltage is lower than the ideal curve. This part can be corrected by correcting the command value of the output voltage amplitude from the controller 103 to the power supply 104 so as to increase the output voltage of the power supply 104 by the voltage drop based on the measurement results in FIG. 4, or by using the phase shift circuit 102. By adjusting the amount of phase shift, it is possible to approximate the ideal curve. This result demonstrated the practicality of the wireless device 300.

The wireless device 300 can realize faster motor control and a smaller and lighter movable circuit in a motor drive circuit that wirelessly supplies power.

(Second embodiment)
The second embodiment describes a wireless device 300 that satisfies the operating principle of the first embodiment while arbitrarily setting the switching frequency and the frequency of the reference frequency source used for wireless power transmission.

FIG. 5A is a diagram illustrating a configuration example of a wireless device 300 according to the second embodiment. FIG. 5A shows a configuration in which the reference frequency source 202 is removed from FIG. 2, and PLL (Phase Locked Loop) circuits 107, 207 and a phase shift circuit 208 are added. f1 to f3 in FIG. 5(a) indicate the frequencies of signals in each part.

The switching frequency used for wireless power transmission can take various values depending on the antenna shape, transmitted power, and input voltage. Further, the switching frequency needs to be adjusted with an accuracy of 10 to 100 kHz. A crystal resonator, a MEMS oscillator, or the like is used as the reference frequency source 105, but these devices are manufactured with discrete frequencies and are not suitable for applications where the output frequency is varied with fine precision. To solve such problems, PLL (Phase Locked Loop) circuits 107 and 207 are used.

In the second embodiment, a crystal resonator or the like is used as the reference frequency source 105. PLL circuit 107 in power transmitting section 100 and PLL circuit 207 in power receiving section 200 share the output signal of reference frequency source 105. By commonly setting the output frequency f2 of the two PLL circuits 107 and 207 as a value suitable for wireless power transmission, flexible design according to the environment is possible. The output signal of the PLL circuit 107 is input to the phase shift circuit 102, and the output signal of the PLL circuit 207 is input to the phase shift circuit 208.

In FIG. 5A, a phase shift circuit 208 is also added to the power receiving unit 200, compared to FIG. The phase shift circuit 208 of the power reception unit 200 performs the same processing as the phase shift circuit 102 of the power transmission unit 100. The output signal of the phase shift circuit 208 is input to the gate drive circuit 205. The phase shift circuit 208 is useful when attempting to acquire the voltage or current waveform that the power receiving unit 200 is receiving, detect θ in [Equation 5], and adjust it to a desired value.

Reference frequency source 105 outputs a reference frequency signal. PLL circuit 107 inputs a reference frequency signal and outputs a signal to phase shift circuit 102 . The PLL circuit 207 inputs the reference frequency signal. A phase shift circuit 208 shifts the phase of the output signal of the PLL circuit 207. Gate drive circuit 205 outputs a second switching signal to rectifier circuit 206 based on the output signal of phase shift circuit 208 .

The phase shift circuit 102 and the phase shift circuit 208 can be realized by an analog circuit system combining a CR low-pass filter and a waveform shaping circuit, or by changing the output tap position of a shift register driven by a high-speed clock. It can also be achieved by When a shift register is used for the phase shift circuit 102 and the phase shift circuit 208, there is a concern about jitter in the output signal. Therefore, the phase shift circuit 102 and the phase shift circuit 208 are configured so that the driving clock of the shift register is sufficiently faster than the power transmission frequency (several tens of MHz to several GHz), or is an integral multiple of the power transmission frequency and is phase-synchronized. It is desirable that

As the circuit topology of the switch circuit 106, a full bridge type, a half bridge type, or a push-pull type is adopted. The output signal of the phase shift circuit 102 needs to be appropriately changed to a form suitable for driving each of the above-mentioned circuit topologies. For example, when driving a half-bridge type, it is necessary to insert dead time. FIG. 5B shows the relationship between the output signal of the phase shift circuit 102 and the drive signal into which a dead time is inserted for driving the half-bridge switch circuit 106. As can be seen from FIG. 5(b), even if a dead time is inserted, the period of the drive signal of the switch circuit 106 is kept consistent with the period of the phase shift circuit 102, so the drive signal of the switch circuit 106 The drive signals of the rectifier circuit 206 and the rectifier circuit 206 can be synchronized in frequency. Note that the constants of the switch circuit 106 may be designed so that the switch circuit 106 performs ZCS (Zero Current Switching) operation or ZVS (Zero Voltage Switching) operation for the purpose of improving power conversion efficiency.

(Third embodiment)
FIG. 6 is a diagram illustrating a configuration example of a wireless device 300 according to the third embodiment. In the third embodiment, the functions of the configuration shown in FIG. 5(a) are further expanded to further improve design flexibility and incorporate built-in functions of general integrated circuits (microcontrollers and FPGAs). Describe suitable techniques to use. Specifically, in FIG. 6, frequency division/phase shift circuits 108, 109, 203, and 209 are added to FIG. Set the ratio or phase shift amount.

Frequency divider/phase shift circuits 108 and 209 are provided in place of phase shift circuits 102 and 208 in FIG. 5(a), respectively. The output signal of reference frequency source 105 is output to PLL circuit 107 via frequency divider/phase shift circuit 109 . Further, the output signal of the reference frequency source 105 is output to the PLL circuit 207 via the frequency division/phase shift circuit 203.

Reference frequency source 202 outputs a reference frequency signal. Frequency division/phase shift circuit 109 frequency divides and phase shifts the reference frequency signal. Frequency division/phase shift circuit 203 frequency divides and phase shifts the reference frequency signal. PLL circuit 107 receives the output signal of frequency divider/phase shift circuit 109 as input. The PLL circuit 207 receives the output signal of the frequency division/phase shift circuit 203 as input. Frequency division/phase shift circuit 209 frequency divides and phase shifts the output signal of PLL circuit 207. Gate drive circuit 205 outputs a second switching signal to rectifier circuit 206 based on the output signal of frequency divider/phase shift circuit 209 . The frequency division/phase shift circuit 108 outputs a signal obtained by frequency dividing and phase shifting the output signal of the PLL circuit 107 to the switch circuit 106 as a first switching signal.

Similarly to the first embodiment, the operating condition of the third embodiment is that the switching signal of the switch circuit 106 and the gate drive signal of the rectifier circuit 206 are synchronized in frequency. Therefore, it is sufficient that the sum of the frequency multiplication ratio by the PLL circuit and the frequency division ratio by the frequency divider circuit is the same in the power transmitting section 100 and the power receiving section 200. Note that the frequency dividing/phase shifting circuits 203 and 209 and the PLL circuit 207 do not necessarily have to be physically placed in the power receiving unit 200, but it is advantageous that they are placed in the power transmitting unit 100, such as easier control. If there is, it may be placed within the power transmission unit 100. Or, on the contrary, the frequency dividing circuit and the PLL circuit may be integrated within the power receiving unit 200.

The practical frequency relationship of FIG. 6 is shown. The output frequency f3 of the reference frequency source 105 is suitably from several tens of kHz to several tens of MHz. This signal of frequency f3 is appropriately frequency-divided by frequency dividing/phase shifting circuits 109 and 203 according to the specifications of PLL circuits 107 and 207, and is input to PLL circuits 107 and 207.

The PLL circuits 107 and 207 generate reference frequency signals (f2t and f2r in FIG. 6) of several tens to several GHz based on the frequency-divided reference signal. This reference frequency signal is frequency-divided and phase-shifted by frequency divider/phase shift circuits 108 and 209 to obtain a frequency-synchronized switching signal f1. Switching signal f1 is input to switch circuit 106 and rectifier circuit 206. The frequencies f2t and f2r are several tens to several GHz, and by passing through a process of frequency division, it is possible to eliminate the concern about jitter generation described in the second embodiment. The above functions are provided as built-in functions of general microcontrollers and FPGAs. By using these, it is possible to reduce the number of parts used, reduce size and cost, and enjoy expandability that allows parameters to be flexibly changed by programming.

The PLL circuit and the phase shift circuit can be configured using a timer function of a microcontroller or an FPGA. Further, the PLL circuit and the phase shift circuit can be configured by a counter logic circuit or a frequency dividing circuit.

(Fourth embodiment)
In the fourth embodiment, an example is shown in which the PLL circuit is arranged only in either the power transmitting section 100 or the power receiving section 200. FIG. 7 is a configuration diagram when the PLL circuit 107 is arranged only in the power transmission section 100. 7 , the frequency dividing/phase shifting circuits 203 and 209 and the PLL circuit 207 of the power receiving unit 200 are deleted from the power receiving unit 200 and the frequency dividing/phase shifting circuit 110 is added to the power transmitting unit 100 in contrast to FIG. 6 . The frequency division/phase shift circuit 110 inputs the output signal of the PLL circuit 107 and outputs the frequency-divided and phase-shifted signal to the gate drive circuit 205 .

Reference frequency source 105 outputs a reference frequency signal. Frequency division/phase shift circuit 109 frequency divides and phase shifts the reference frequency signal. PLL circuit 107 receives the output signal of frequency divider/phase shift circuit 109 as input. Frequency division/phase shift circuit 110 frequency divides and phase shifts the output signal of PLL circuit 107. Gate drive circuit 205 outputs a second switching signal to rectifier circuit 206 based on the output signal of frequency divider/phase shift circuit 110 . The frequency division/phase shift circuit 108 outputs a signal obtained by frequency dividing and phase shifting the output signal of the PLL circuit 107 to the switch circuit 106 as a first switching signal.

Similarly to the first embodiment, the operating condition of the fourth embodiment is that the switching signal of the switch circuit 106 and the gate drive signal of the rectifier circuit 206 are synchronized in frequency. The fourth embodiment has the advantage of facilitating design (control software design) because control signal generation can be unified into one integrated circuit. On the other hand, if it is desired to change the amount of phase shift of power receiving section 200, it is necessary to feed back the state of power receiving section 200 to power transmitting section 100 and then request a change in the amount of phase shift. This is useful when this feedback delay is not a problem or when it is easy to provide a means for providing feedback.

According to the first to fourth embodiments, the wireless device 300 can wirelessly supply power and drive the motor 400. Since the wireless device 300 does not require transmission of control signals, it is possible to increase the speed of controlling the motor 400 and to reduce the size and weight of the movable side circuit. The wireless device 300 eliminates the influence of transmission delay of control signals, which was a factor that hinders speeding up, and can achieve high-speed control of the motor 400.

Note that the above embodiments are merely examples of implementation of the present invention, and the technical scope of the present invention should not be interpreted to be limited by these embodiments. That is, the present invention can be implemented in various forms without departing from its technical idea or main features.

101 power transmission coil, 102 phase shift circuit, 103 controller, 104 power supply, 105 reference frequency source, 106 switch circuit, 201 power reception coil, 202 reference frequency source, 204 power reception circuit, 205 gate drive circuit, 206 rectifier circuit, 400 motor

Claims (12)

A power transmission coil that wirelessly transmits power;
a power receiving coil that wirelessly receives power from the power transmitting coil;
a switch circuit that applies voltage to the power transmission coil based on a first switching signal;
a rectifier circuit that rectifies the voltage output from the power receiving coil based on a second switching signal and applies the rectified voltage to a load;
a first phase shift circuit that provides a phase difference between the first switching signal and the second switching signal ;
The wireless device , wherein the first phase shift circuit phase-shifts the reference frequency signal and outputs at least one of the first switching signal and the second switching signal . The wireless device according to claim 1, wherein the first switching signal and the second switching signal have the same period. The wireless device according to claim 1 or 2, wherein the rectifier circuit includes a plurality of bidirectional switches. 4. The wireless device according to claim 3, wherein the drive signals for the plurality of bidirectional switches are provided with a dead time for preventing through current. The wireless device according to claim 1, wherein the switch circuit is of a full-bridge type, a half-bridge type, or a push-pull type. The wireless device according to claim 1, wherein the switch circuit operates in a ZCS (Zero Current Switching) operation or a ZVS (Zero Voltage Switching) operation. The wireless device according to any one of claims 1 to 6, further comprising a resonant circuit provided between the power receiving coil and the rectifier circuit.
. a first reference frequency source that outputs a reference frequency signal to the first phase shift circuit;
a drive circuit that drives the rectifier circuit using the second switching signal;
8. The driving circuit according to claim 1, further comprising a second reference frequency source that is synchronized in frequency with the first reference frequency source and outputs a reference frequency signal to the drive circuit. Radio equipment. a reference frequency source that outputs a reference frequency signal;
a first PLL circuit that inputs the reference frequency signal and outputs a signal to the first phase shift circuit;
a second PLL circuit inputting the reference frequency signal;
a second phase shift circuit that shifts the phase of the output signal of the second PLL circuit;
According to any one of claims 1 to 7, further comprising a drive circuit that outputs the second switching signal to the rectifier circuit based on the output signal of the second phase shift circuit. radio equipment. A power transmission coil that wirelessly transmits power;
a power receiving coil that wirelessly receives power from the power transmitting coil;
a switch circuit that applies voltage to the power transmission coil based on a first switching signal;
a rectifier circuit that rectifies the voltage output from the power receiving coil based on a second switching signal and applies the rectified voltage to a load;
a first phase shift circuit that provides a phase difference between the first switching signal and the second switching signal;
a reference frequency source that outputs a reference frequency signal;
a first frequency divider/phase shift circuit that frequency divides and phase shifts the reference frequency signal;
a second frequency divider/phase shift circuit that frequency divides and phase shifts the reference frequency signal;
a first PLL circuit inputting the output signal of the first frequency dividing/phase shifting circuit;
a second PLL circuit inputting the output signal of the second frequency dividing/phase shifting circuit;
a third frequency divider/phase shift circuit that frequency divides and phase shifts the output signal of the second PLL circuit;
further comprising a drive circuit that outputs the second switching signal to the rectifier circuit based on the output signal of the third frequency dividing/phase shifting circuit,
The wireless device is characterized in that the first phase shift circuit outputs a signal obtained by frequency-dividing and phase-shifting the output signal of the first PLL circuit as the first switching signal. A power transmission coil that wirelessly transmits power;
a power receiving coil that wirelessly receives power from the power transmitting coil;
a switch circuit that applies voltage to the power transmission coil based on a first switching signal;
a rectifier circuit that rectifies the voltage output from the power receiving coil based on a second switching signal and applies the rectified voltage to a load;
a first phase shift circuit that provides a phase difference between the first switching signal and the second switching signal;
a reference frequency source that outputs a reference frequency signal;
a first frequency divider/phase shift circuit that frequency divides and phase shifts the reference frequency signal;
a first PLL circuit inputting the output signal of the first frequency dividing/phase shifting circuit;
a second frequency divider/phase shift circuit that frequency divides and phase shifts the output signal of the first PLL circuit;
further comprising a drive circuit that outputs the second switching signal to the rectifier circuit based on the output signal of the second frequency divider/phase shift circuit,
The wireless device is characterized in that the first phase shift circuit outputs a signal obtained by frequency-dividing and phase-shifting the output signal of the first PLL circuit as the first switching signal. The wireless device according to claim 1 , wherein the load is a motor.

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