JP6396157B2 - Frequency information detection device and high frequency power supply device - Google Patents

Description

  The present invention relates to a frequency information detection device for detecting frequency information of an analog sine wave signal and a high frequency power supply device using the frequency information detection device.

  The frequency information detection apparatus can be used in a high frequency power source that supplies power to a load such as a plasma processing apparatus that performs plasma etching and plasma CVD, for example.

FIG. 6 is a schematic configuration example of a high-frequency power supply system.
The first high-frequency power source 110 and the second high-frequency power source 120 amplify a high-frequency signal output from the common oscillator 100 by a traveling wave power output unit (not shown) and output high-frequency power. The high-frequency power output from the first high-frequency power source 110 and the second high-frequency power source 120 is supplied to two locations of the electrodes (131, 132) in the plasma processing apparatus 130 serving as a load. 6 shows an example in which high-frequency power is supplied to each of the electrode 131 and the electrode 132. For example, as shown in FIG. 7, high-frequency power is supplied to two locations of the upper electrode 131. Is also possible.

  The high frequency power directed from the first high frequency power supply 110 and the second high frequency power supply 120 to the plasma processing apparatus 130 is referred to as traveling wave power, and the high frequency power reflected by the plasma processing apparatus 130 and returning to the high frequency power supply side is reflected wave power. That's it.

  In the plasma processing apparatus 130, the plasma 133 is generated using the high-frequency power supplied from the first high-frequency power source 110 and the second high-frequency power source 120, and etching is performed.

  An impedance matching device that matches the impedances of the first high frequency power supply 110 and the plasma processing apparatus 130 may be used between the first high frequency power supply 110 and the plasma processing apparatus 130. Similarly, an impedance matching device may be used between the second high-frequency power source 120 and the plasma processing apparatus 130.

  In the high frequency power supply system of FIGS. 6 and 7, the first high frequency power supply 110 and the second high frequency power supply 120 are controlled by separate control circuits. If the control circuits are different, the output frequencies of the first high frequency power supply 110 and the second high frequency power supply 120 may be slightly different even if a high frequency signal is given from the common oscillator 100. As this cause, for example, an error due to a difference in the control clock may be considered. In particular, if the first high-frequency power source 110 and the second high-frequency power source 120 are from different manufacturers, a slight difference may occur.

In the high frequency power supply system as shown in FIGS. 6 and 7, when the output frequencies of the two high frequency power supplies 110 and 120 are slightly different, the electrodes (131, 132) are supplied with high frequency power having slightly different frequencies. Mixed. That is, since the frequencies of the two types of high-frequency voltages applied to the electrodes (131, 132) are slightly different, the amplitude of the voltage waveform generated by overlapping the two types of high-frequency voltages is periodically changed as if modulated. fluctuate. For example, if the frequencies of two types of high-frequency voltages differ by 1 Hz in the vicinity of 13.56 MHz, the amplitude varies with a period of about 1 s. As a result, the potential of the plasma generated in the plasma processing apparatus 130 also varies periodically, which has an adverse effect.
For example, when the peak of one high-frequency voltage waveform and the peak of the other high-frequency voltage waveform are in the same phase, the waveform of the overlapping voltage is the maximum value, but the peak of one high-frequency voltage waveform and the valley of the other high-frequency voltage waveform When the two have the same phase, the waveform of the voltage generated by overlapping becomes the minimum value. Since the difference between the maximum value and the minimum value is large, a waveform of a voltage generated by overlapping two types of high-frequency voltages periodically varies with a large change in amplitude.

  Therefore, the output frequencies of the first high frequency power supply 110 and the second high frequency power supply 120 need to be the same. For this purpose, the above problem can be solved by detecting the output frequency of one high-frequency power supply and matching the output frequency of the other high-frequency power supply with the detected frequency. Therefore, also in the field of the high frequency power supply system, a frequency information detection device for detecting the frequency is necessary. Moreover, the use of monitoring the output frequency of a high frequency power supply etc. can be considered.

JP 63-66472 A

  Conventionally, as a frequency information detection device in a high frequency region, for example, a device as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 63-66472) has been proposed. However, in this patent document 1, although the frequency can be detected, the phase information cannot be detected. Therefore, even if a conventional frequency information detection device is used, the frequency and phase of the traveling wave voltage output from the first high frequency power supply 110 and the traveling wave voltage output from the second high frequency power supply 120 (another high frequency power supply) are matched. I can't.

  It is an object of the present invention to provide a frequency information detection device capable of matching the frequency and phase of traveling wave voltages output from two high frequency power supplies, and a high frequency power supply device including the frequency information detection device. It is said.

The frequency information detection apparatus provided by the first invention is
A frequency information detecting apparatus for detecting the frequency information of the analog sine wave signal V _in,
A sine wave signal V _in analog, (the reciprocal of the sampling frequency f _s: 1 / f _s) a predetermined sampling period by the instantaneous value V of the input signal V _in at the time [t] obtained by converting a digital signal an A / D converter that converts _in [t] sequentially into a sine wave signal composed of a plurality of sampling data;
A first estimated phase information output unit that outputs the estimated value of the phase information of the input signal V _in at the time [t] as a first estimated phase information,
A first estimated frequency information output unit that outputs the estimated value of the frequency information of the input signal V _in at the time [t] as a first estimated frequency information,
Frequency information obtained by adding the correction frequency information to the set frequency information of the input signal V _in when the synchronizing frequency information, and the sine wave signal generator for generating a sine wave signal based on the synchronization frequency information,
A second estimated phase information output unit that outputs an estimated value of phase information of the sine wave signal output from the sine wave signal generation unit at time [t] as second estimated phase information;
A second estimated frequency information output unit that outputs an estimated value of frequency information of the sine wave signal output from the sine wave signal generation unit at time [t] as second estimated frequency information;
An error frequency information output unit that calculates a moving average value of an error (error frequency information) of the second estimated frequency information with respect to the first estimated frequency information at time [t], and outputs the error frequency moving average value information;
An error phase information output unit that calculates a moving average value of an error (error phase information) of the second estimated phase information with respect to the first estimated phase information at time [t], and outputs the error phase moving average value information;
If the error frequency moving average value information is outside a predetermined range, the correction frequency information is determined and output so that the error frequency moving average value information is small, and the error frequency moving average value information is predetermined. If within the range, a frequency correction unit that determines and outputs the correction frequency information so that the error phase moving average value information is small; and
It has.

The frequency information detection apparatus provided by the second invention is
The first estimated phase information output unit is
Time cosine value obtained by differentiating the instantaneous value _V in [t] of the input signal _{V in} in [t] (cos (α [ t])) an estimate of the instantaneous value of the input signal _{V in} at the time [t-1] A cosine value estimator that uses V _in [t−1], an instantaneous value V _in [t + 1] of the input signal V _in at time [t + 1], and a known value;
Time the instantaneous value _V in [t] of the input signal _{V in} at the [t] and a sine component (sin component), the cosine value at time [t] estimated by the cosine value estimating section (cos (alpha [t]) ) As a cosine element (cos element), the phase α [t] of the cosine value (cos (α [t])) at time [t] is calculated using an arctangent function (tan ⁻¹ ), and the calculated phase is calculated. a phase estimation unit that outputs α [t] as first estimated phase information;
The first estimated frequency information output unit includes:
Based on the phase α [t−1] at time [t−1] and the phase α [t] at time [t] calculated by the phase estimation unit, the phase displacement amount Δα [t] at time [t] is calculated. A phase displacement amount calculation unit to be calculated;
On the basis of the phase shift amount [Delta] [alpha] [t] in the calculated time in the phase shift amount calculation unit [t], calculates the estimated frequency information of the input signal V _in at the time [t], the calculation was estimated frequency information 1 a frequency estimator for outputting as estimated frequency information;
It is characterized by having.

The frequency information detection apparatus provided by the third invention is
Characterized in that said cosine value estimating unit for calculating the constants are calculated using the set frequency information of the input signal V _in is taken as K, the cosine value (cos (α [t]) ) by the formula It is said.
cos (α [t]) = K · {V _in [t + 1] −V _in [t−1]}

The frequency information detection apparatus provided by the fourth invention is
The constant K is calculated by the following equation. However, the set frequency information is “F _set ”.
K = 1 / {2 sin (2π · (F _set / f _s ) [t])}
It is characterized by that.

The high frequency power supply device provided by the fifth invention provides:
The traveling wave voltage is output based on the sine wave signal output from the sine wave signal generation unit according to any one of the first to fourth inventions .

In the present invention, the frequency and phase of the sine wave signal output from the sine wave signal generation unit provided in the frequency information detection device converge so as to approach the frequency and phase of the input signal. by using the sine wave signal output from the parts, it is possible to match the other high-frequency power source output frequency and phase to the frequency and phase of the input signal V _in.

It is a block diagram which shows the example of a detection of a high frequency voltage. 1 is a configuration example of a frequency information detection device 1. 3 is a diagram illustrating a configuration example of a sine wave signal generation unit 40. FIG. If the frequency _{f in} of the input signal _{V in} is assumed to have shifted from the set frequency _{f The set,} the moving average value _{f Dif_ave} estimate _{f dif} difference frequency output from the moving average unit 71 [t] [t] This is a simulation result. If the frequency _{f in} of the input signal _{V in} is assumed to have shifted from the set frequency _{f The set,} the moving average value _{f Dif_ave} estimate _{f dif} difference frequency output from the moving average unit 71 [t] [t] This is a simulation result. It is an example of schematic structure of a high frequency electric power supply system. It is another schematic structural example of a high frequency electric power supply system.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or similar structure as the past.

FIG. 1 is a block diagram illustrating an example of detecting a high-frequency voltage.
The first high-frequency power supply 110 is a device for amplifying a high-frequency signal output from the oscillator 100, outputting traveling wave power PF having an output frequency in a radio frequency band, and supplying the traveling wave power PF to a plasma processing apparatus 130 serving as a load. . The traveling wave power PF output from the high frequency power supply 110 is supplied to the plasma processing apparatus 130 via the transmission line 140. In general, this type of high-frequency power supply outputs traveling wave power PF having a frequency in a radio frequency band of several hundred kHz or more (for example, a frequency of 13 MHz, 40 MHz, etc.).

  The plasma processing apparatus 130 serving as a load is an apparatus for processing (etching, CVD, etc.) a workpiece such as a wafer and a liquid crystal substrate that is provided with a processing section and is carried into the processing section. Note that an electrode (see FIGS. 6 and 7) is provided in the processing portion. When a plasma discharge gas is introduced into the processed portion and the traveling wave power PF output from the high frequency power supply 110 is supplied to the electrode, discharge occurs and plasma is generated. The plasma processing apparatus 130 processes the workpiece using this plasma.

The directional coupler 150 is inserted between the first high frequency power supply 110 and the plasma processing apparatus 130 to detect a traveling wave voltage VF from the high frequency power supply 110 to the plasma processing apparatus 130 and detect the detected signal as a traveling wave detection. Output as signal _Vf . The directional coupler 150 also has a function of detecting the reflected wave voltage reflected by the load, but is omitted because it is not necessary in this example.

The filter 160 is a low-pass filter or a band-pass filter, removes harmonic components from the traveling wave detection signal V _f output from the directional coupler 150, and passes the fundamental frequency component. As a result, the signal output from the filter 160 becomes a sine wave signal and is sent to the frequency information detection apparatus 1. In this specification, a signal output from the filter 160 is an input signal V _in to the frequency information detection device 1.
The input signal V _in is because it is an analog voltage signal, the output frequency f, and time t, the phase offset theta, when the angular frequency is ω (= 2π · f), the input signal V _in is of the formula It can be expressed as (1). It should be noted that, here, is set to "1", the amplitude of the input signal V _in.
V _in = sin (2π · f · t + θ)
= Sin (ω · t + θ) (1)

  Further, a level conversion circuit for converting the signal level so as to be suitable for the input range of the A / D conversion unit 10 to be described later may be provided at the subsequent stage of the filter 160, but this is omitted in FIG.

  FIG. 2 is a configuration example of the frequency information detection apparatus 1. As shown in FIG. 2, the frequency information detection apparatus 1 includes an A / D conversion unit 10, a first estimated phase information output unit 20, a first estimated frequency information output unit 30, a sine wave signal generation unit 40, and a second estimated phase. An information output unit 50, a second estimated frequency information output unit 60, an error frequency information output unit 70, an error phase information output unit 80, and a frequency correction unit 90 are provided.

<A/D converter 10>
A / D converter 10, a predetermined sampling period the input signal _{V in} analog output from the filter 160 (the reciprocal of the sampling frequency _{f s:} 1 / _{f s)} to convert into a digital signal. The A / D converted sampling data is sequentially output as an instantaneous value V _in [t] of the input signal V _in at time [t]. Thereby, the alternating analog signal waveform is converted into a digital signal waveform composed of a plurality of sampling data. Note that if the input signal V _in outputted from the filter 160 is a sine wave signal, a digital signal waveform output from the A / D converter 10 is also a sine wave signal.
The A / D converter 10 includes an A / D converter and performs the A / D conversion as described above. Further, a low-pass filter or a band-pass filter may be provided at the subsequent stage of the A / D converter so as to pass the fundamental frequency component.

Here, frequency _{f in} of the input signal _{V in,} the sampling frequency _{f s,} the phase offset theta ', when the relative angular frequency is _{ω in = 2π · (f in} / f s), the input at time [t] The instantaneous value V _in [t] of the signal V _in can be expressed as shown in Equation (2). It should be noted that, here, is set to "1", the amplitude of the input signal V _in. The time data “t” is a variable that is incremented every sampling period.
V _in [t] = sin (2π · (f _in / f _s ) [t] + θ ′)
= Sin (ω _in [t] + θ ′) (2)

<First Estimated Phase Information Output Unit 20>
The first estimated phase information output unit 20 outputs the estimated value α [t] of the phase information of the input signal Vin at time [t] as the first estimated phase information. The first estimated phase information output unit 20 includes a cosine value estimation unit 21 and a phase estimation unit 22.

[Cosine value estimation unit 21]
The cosine value estimation unit 21 obtains the estimated value of the cosine value “cos (ω _in [t] + θ ′)” obtained by differentiating the instantaneous value V _in [t] of the input signal V _{in at} the time [t] at the time [t− 1] instantaneous value _V in of the input signal _{V in} at the [t-1], is calculated using the instantaneous value _V in [t + 1] and the known values of the input signal _{V in} at the time [t + 1]. The estimated cosine value “cos (ω _in [t] + θ ′)” is sent to the phase estimation unit 22. This will be specifically described below.

When “α [t] = ω _in [t] + θ ′ = 2π · (f _in / f _s ) [t] + θ ′”, the cosine value (cos (α [t])) at time [t] is It can be expressed by equation (3).
cos (α [t])
= {(2 sin (ω _in [t]) · cos (α [t])} / (2 sin (ω _in [t]))
= {Sin (α [t] + ω _in [t]) − sin (α [t] −ω _in [t])} / (2 sin (ω _in [t]))
= {Sin (2ω _in [t] + θ ′) − sin (θ ′)} / (2 sin (ω _in [t])) (3)

Referring to equation (2), because the time [t] instantaneous value _V in [t] of the input signal _{V in} in is a _{"sin (ω in [t] +} θ ') ", the frequency _{f in} of the input signal _{V in} If does not change, the displacement amount of the relative angular frequency ω _in for each sampling period (1 / f _s ) is constant at “ω _in [t]”. Thus, molecules of formula (3), the time from the instantaneous value _V in of the input signal _{V in} at the [t + 1] [t + 1], time instantaneous value _V in of the input signal _{V in} at the [t-1] [t- 1] Represents subtracting.

In addition, “sin (ω _in [t])” of the denominator of Expression (3) is obtained by omitting the phase offset θ ′ from the instantaneous value V _in [t] of the input signal V _in at time [t]. Yes.

Therefore, the cosine value (cos (α [t])) at time [t] is the instantaneous value V _in [t−1] of the three input signals V _in at time [t−1], [t] and [t + 1]. ], V _in [t] and V _in [t + 1].

However, as described above, “sin (ω _in [t])” is obtained by omitting the phase offset θ ′ from the instantaneous value V _in [t] of the input signal V _in at time [t]. An error occurs in the denominator of Equation (3). Here, since the value of the sine function (the value of sin) changes within a range of ± 1 centering on 0, the error may be positive or negative.

As will be described later, after estimating the cosine value (cos (α [t])) at time [t], the phase α [t] is calculated, and the phase displacement amount Δα for each sampling period of the phase α [t]. It calculates an estimate _{f est} of the frequency of the input signal _{V in} on the basis of the [t] [t] or estimate omega _est of the angular frequency [t]. After that, since the moving average value of the calculated frequency estimated value f _est [t] or the angular frequency estimated value ω _est [t] is calculated, the denominator error in the equation (3) is almost canceled.

Therefore, even if the frequency f _in of the input signal V _in constituting the denominator of the equation (3) having an error is replaced with the set frequency f _set as in the equation (4), there is almost no influence. Here, the setting frequency _{f set,} because it is setting the frequency of the input signal _{V in,} the error is small. For example, in the examples of FIGS. 6 and 7, the frequency of the high-frequency signal output from the oscillator 100. Since this set frequency f _set is known in advance, it may be input to the cosine value estimation unit 21, for example. Of course, the set angular frequency ω _set (= 2π · f _in ) may be used.
2 sin (ω _in [t]) = 2 sin (2π · (f _in / f _s ) [t])
→ 2 sin (2π · (f _set / f _s ) [t]) (4)

In this specification, the set frequency f _set and the set angular frequency ω _set are collectively referred to as “set frequency information F _set ”.

Here, all the elements constituting the formula (4) are all known values. Therefore, when “1 / {2 sin (2π · (f _set / f _s )] [t])}” is expressed by a constant K, Equation (3) can be transformed into Equation (5). Therefore, originally, when estimating the cosine value (cos (α [t])) at time [t], it is necessary to use the equation (3), and thus a complicated calculation is required. By using (5), the calculation formula can be simplified and the calculation load can be reduced.
cos (α [t]) = K · {sin (2ω _in [t] + θ ′) − sin (θ ′)}
= K · {V _in [t + 1] −V _in [t−1]} (5)

As described above, the cosine value estimating unit 21, the cosine value at time [t] by using the data of a plurality of input signal _{V in} which a digital signal by the A / D converter 10 (cos (α [t] ) ) Is calculated. For this reason, the cosine value estimation unit 21 has a memory (not shown) and sequentially stores the instantaneous value V _in [t] of the input signal V _in output from the A / D conversion unit 10 _in the memory.

Incidentally, as described above, the cosine value estimating unit 21, a time [t-1] and the instantaneous value _V in of the input signal _{V in} [t-1] at time [t + 1] instantaneous value V of the input signal _{V in} at _in [t + 1] is used, but the instantaneous value V _in [t] of the input signal V _in at time [t] is not used. However, since the instantaneous value V _in [t] of the input signal V _{in at} the time [t] is used for the calculation performed by the phase estimation unit 22 as described later, at least the instantaneous value V _in [t−1] is stored in the memory. , Three consecutive data of the instantaneous value V _in [t] and the instantaneous value V _in [t + 1] are stored.

In the above example, after the instantaneous value V _in [t + 1] of the input signal V _in at time [t + 1] is input to the cosine value estimation unit 21, the cosine value (cos (α [t] at time [t] is )) Can be computed.

[Phase estimation unit 22]
The phase estimation unit 22 uses the instantaneous value V _in [t] of the input signal V _in at time [t] as a sine element (sin element), and uses the cosine value (cos (α [t])) at time [t] as a cosine. As an element (cos element), the phase α [t] of the cosine value (cos (α [t])) at time [t] is calculated using an arctangent function (tan ⁻¹ ) as shown in Expression (6). Calculate. The phase α [t] is calculated within a range of ± π [unit: rad]. The calculated phase α [t] is sent to the phase displacement amount calculation unit 31.
α [t] = tan ⁻¹ (V _in [t] / cos (α [t])) (6)

As described above, after the instantaneous value V _in [t + 1] of the input signal V _{in at} the time [t + 1] is input to the cosine value estimation unit 21, the cosine value (cos (α [t] at the time [t]) is input. because)) is calculated, phase alpha [t] is also time instantaneous value _V in of the input signal _{V in} at the [t + 1] [t + 1] is calculated after being input to the cosine value estimating unit 21. Further, the instantaneous value V _in [t] of the input signal V _{in at} the time [t] necessary for the calculation of the phase α [t] may be read from the memory provided in the cosine value estimation unit 21.

<First Estimated Frequency Information Output Unit 30>
The first estimated frequency information output unit 30 outputs the estimated value of the frequency information of the input signal Vin at time [t] as first estimated frequency information F _est [t]. The first estimated frequency information output unit 30 includes a phase displacement amount calculation unit 31 and a frequency estimation unit 32.

[Phase displacement calculation unit 31]
The phase displacement amount calculation unit 31 is based on the phase α [t−1] at time [t−1] and the phase α [t] at time [t] calculated by the phase estimation unit 22 at time [t]. The phase displacement amount Δα [t] is calculated. The calculated phase displacement amount Δα [t] is sent to the frequency estimation unit 32.

Here, the phase displacement amount calculation unit 31 calculates the phase displacement amount Δα [t] generated during the sampling period from time [t−1] to time [t]. Since the phase α [t] of the cosine value (cos (α [t])) at the time [t] is calculated in the range of ± π [unit: rad] as described above, {“α [t ] −α [t−1]} is positive, the phase displacement amount Δα [t] is calculated using Expression (7), and {“α [t] −α [t−1]} is negative. In this case, the phase displacement amount Δα [t] is calculated using Expression (8).
Δα [t] = α [t] −α [t−1] (7)
Δα [t] = (α [t] −α [t−1]) + 2π (8)

  As described above, the phase displacement amount calculation unit 31 uses the phase α [t−1] at time [t−1] and the phase α [t] at time [t] calculated by the phase estimation unit 22. Since the phase displacement amount Δα [t] at time [t] is calculated, the phase displacement amount calculation unit 31 has a memory (not shown), and the phase α [t] output from the phase estimation unit 22 is stored in the memory. It memorizes sequentially. This memory stores at least the phase α [t−1] at time [t−1] and the phase α [t] at time [t].

Further, as described above, after the instantaneous value V _in [t + 1] of the input signal V _in at time [t + 1] is input to the cosine value estimation unit 21, the phase α [t] at time [t] is calculated. Therefore, the phase displacement amount Δα [t] is also calculated after the instantaneous value V _in [t + 1] of the input signal V _in at time [t + 1] is input to the cosine value estimation unit 21.

[Frequency estimation unit 32]
Frequency estimation unit 32, based on the phase shift amount [Delta] [alpha] [t] in the calculated time in the phase shift amount calculation unit 31 [t], the time estimate of the angular frequency of the input signal V _in at the [t] ω _est [ t] or the estimated frequency f _est [t]. Estimate omega _est of the angular frequency of the operation input signal _{V in} [t] or frequency estimate _{f est} [t] is sent to the error frequency information output section 70.
Incidentally, the estimated value of the frequency of the input signal V _in (detection value) by moving average estimated frequency information F _est outputted from the frequency estimation unit 32 _[t], to reduce the error, good frequency information accurate Can be obtained. Therefore, it is possible to moving average portion downstream of the frequency estimation unit 32 provided with a (not shown), the estimate of the frequency of the input signal V _in the output of the moving average unit (not shown) (detected value).

Here, since the phase displacement amount Δα [t] is a phase displacement amount generated during the sampling period, as shown in the equation (9), when the phase displacement amount Δα [t] is multiplied by the sampling frequency f _s. The amount of phase displacement that occurs in one second can be determined. That is, the time estimate of the angular frequency of the input signal _{V in} at the _{[t] ω est [t]} [ Unit: rad / s] can be calculated. Further, as shown in the equation (10), the phase displacement amount Δα [t] at the time [t] is multiplied by the sampling frequency f _s and divided by “2π” to obtain the estimated value of the frequency at the time [t]. f _est [t] [unit: Hz] can be calculated.
ω _est [t] = Δα · f _s (9)
f _est [t] = Δα · f _s / (2π) (10)

Further, the estimated angular frequency value ω _dif [t] between the estimated angular frequency value ω _est [t] and the set angular frequency ω _set can be calculated as in Expression (11). The set angular frequency ω _set is “2π · f _set ”. Moreover, the estimated frequency f _dif [t] of the difference frequency between the estimated frequency f _est [t] and the set frequency f _set can be calculated as in Expression (12). Therefore, the frequency estimation unit 32 can also output an estimated value ω _dif [t] of the difference angular frequency and an estimated value f _dif [t] of the difference frequency. In this case, for example, the set frequency f _set may be input to the frequency estimation unit 32. Of course, the set angular frequency ω _set may be input to the frequency estimation unit 32. Also it may be calculated to set angular frequency omega _{The set} from the set frequency _{f The set,} and vice versa, may be calculated set frequency _{f The set} of setting angular frequency omega _{The set.}
ω _dif [t] = ω _est [t] −ω _set [t] (11)
f _dif [t] = f _est [t] −f _set [t] (12)

In this specification, the estimated value omega _est of the angular frequency of the input signal _{V in} [t], the estimate _f est of the frequency [t], the estimated value omega _dif difference angular frequency [t] and the estimated value of the frequency f _dif [t] of the input signal _{V in} at the time [t] are collectively referred to as "estimated frequency information _{F est} [t]".

Also, the estimated value omega _est of the angular frequency of the input signal _{V in} [t], the estimate _f est of the frequency [t], the estimated value omega _dif difference angular frequency [t] and the estimated value _f dif difference frequency [t] May output any one of them, but may output a plurality of them.

Incidentally, as described above, the time phase displacement of [Delta] [alpha] [t] in the [t], the time [t + 1] instantaneous value _V in of the input signal _{V in} at the [t + 1] is operation after being input to the cosine value estimating unit 21 since the time estimated frequency information _{F est} [t] of the input signal _{V in} at the [t] is also time instantaneous value _V in of the input signal _{V in} at the [t + 1] [t + 1] is input to the cosine value estimating unit 21 It is calculated after.

<Sine Wave Signal Generator 40>
The sine wave signal generation unit 40 uses the synchronization frequency information F _syc [t] _obtained by adding correction frequency information F _rev [t] described later to the _set frequency information F _set as a command value, and is the same as the synchronization frequency information F _syc [t]. A sine wave signal V _out [t] having a frequency (which may be expressed by an angular frequency) is generated and output.
Note that the instantaneous value of the sine wave signal V _out output from the internal oscillator 41 (see FIG. 3) at time [t] is V _out [t].

The sine wave signal V _out [t] output from the sine wave signal generation unit 40 is a signal synchronized with the input signal V _in [t]. That is, the frequency and phase of the sine wave signal V _out to be output from the internal oscillator 41 as described later, it converges to be closer to the frequency and phase of the input signal V _in. As a result, the sine wave signal _{V out} to be output from the internal oscillator 41 is a signal synchronized with the input signal _{V in.}

FIG. 3 is a diagram illustrating a configuration example of the sine wave signal generation unit 40. As shown in FIG. 3, the sine wave signal generation unit 40 may have a configuration example as shown in FIGS. 3A to 3B, for example. In any case, the sine wave signal generation unit 40 includes: For example, an oscillator 41 composed of a direct digital synthesizer (DDS) is provided.
The oscillator 41 functions as an oscillator of another high-frequency power source (for example, the second high-frequency power source 120 shown in FIGS. 6 and 7). Note that the "other" and "the other high-frequency power source", that other high-frequency power to the source is a high frequency power source (first high frequency power supply 110 shown in FIG. 1 in this embodiment) of the input signal V _in Meaning. In FIG. 3, the other high frequency power supply 43 is indicated.

(1) The sine wave signal generation unit 40 in FIG. 3A includes an oscillator 41 and an A / D conversion unit 42. In this example, the output of the oscillator 41 is sent to another high-frequency power source 43 to cause the other high-frequency power source 43 to output a traveling wave power PF having a frequency in the radio frequency band, and the sine wave signal V _out output from the oscillator 41. Is sent to the second estimated phase information output unit 50 via the A / D conversion unit 42.

Here, when the frequency of the sine wave signal V _out output from the oscillator 41 is f _out , the time is t, the phase offset is θ ″, and the angular frequency is ω (= 2π · f), the sine output from the oscillator 41. The wave signal V _out can be expressed as shown in Expression 13. Here, the amplitude of the sine wave signal V _out is “1”.
V _out = sin (2π · f _out · t + θ ″)
= Sin (ω · t + θ ″) (13)

A / D converter 42, similarly to the A / D converter 10, (the reciprocal of the sampling frequency _{f s:} 1 / _{f s)} sinusoidal signal _{V out} of the predetermined sampling period which is output from the oscillator 41 in digital Convert to signal. The A / D converted sampling data is sequentially output as an instantaneous value V _out [t] of the sine wave signal V _out at time [t]. Thereby, the alternating analog signal waveform is converted into a digital signal waveform composed of a plurality of sampling data. If the sine wave signal _Vout output from the oscillator 41 is a sine wave signal, the digital signal waveform output from the A / D converter 42 is also a sine wave signal.
The A / D converter 42 includes an A / D converter and performs the A / D conversion as described above. Further, a low-pass filter or a band-pass filter may be provided at the subsequent stage of the A / D converter so as to pass the fundamental frequency component.

Here, when the frequency of the sine wave signal V _out is f _out , the sampling frequency is f _s , the phase offset is θ ″, and the relative angular frequency is ω _out = 2π · (f _out / f _s ), at time [t] instantaneous value _{V out} [t] of the sine wave signal _{V out} can be represented by the equation (14). here, is "1" and the amplitude of the sine wave signal _{V out.} The time data “t” is a variable that is incremented every sampling period.
V _out [t] = sin (2π · (f _out / f _s ) [t] + θ ″)
= Sin (ω _out [t] + θ ″) (14)

(2) The sine wave signal generation unit 40 in FIG. 3B amplifies the output of the oscillator 41 with another high frequency power supply 43 and detects the traveling wave voltage VF ₂ that is the output with the directional coupler 44. Then, the traveling wave detection signal V _f2 that is the detection signal is sent to the second estimated phase information output unit 50 via the filter 45 and the A / D conversion unit 46.
The directional coupler 44, the filter 45, and the A / D converter 46 have the same functions as the directional coupler 150, the filter 160, and the A / D converter 10 shown in FIG. Therefore, detailed description is omitted. In FIG. 3B, the output of the filter 45 is a sine wave signal V _{out ′} and the output of the A / D converter 46 is a sine wave signal V _{out ′} [t]. In order to simplify the description, the reference numerals of the oscillators 41 are the same in FIGS. 3A and 3B.

Even in the case of FIG. 3B, since the traveling wave voltage VF ₂ is output from the other high frequency power supply 43 based on the sine wave signal V _out output from the oscillator 41, the sine wave signal V _out and the traveling wave voltage VF are output. ₂ is synchronized in frequency and phase. Therefore, the directional coupler 44 in a subsequent stage, the sine wave signal _{V out '[t]} be the input signal _{V in} to be sent to the second estimated phase information output unit 50 through the filter 45 and the A / D converter 46 It becomes a signal to synchronize.

The frequency of the sine wave signal V _out [t] output from the sine wave signal generation unit 40 shown in FIGS. 2 and 3 is synchronous frequency information F _syc [t]. Since the synchronization frequency information F _syc [t] represents the frequency of the traveling wave voltage VF from the first high frequency power supply 110 to the plasma processing apparatus 130, the synchronization frequency information F _{syc is used} as a command signal for the oscillator 41 for the other high frequency power supply. By using [t], the output frequency of the first high-frequency power supply 110 can be matched (synchronized) with the output frequency of another high-frequency power supply.

<Second Estimated Phase Information Output Unit 50>
The second estimated phase information output unit 50 has the same configuration as the first estimated phase information output unit 20, but the first estimated phase information output unit 20 receives the input signal Vin at time [t] as an input signal. While the phase α [t] of Vin is output, the second estimated phase information output unit 50 receives the sine wave signal V _out [t] output from the sine wave signal generation unit 40 at time [t]. And the phase α ₂ [t] of the sine wave signal V _out [t] is output. Since others are the same as the 1st estimated phase information output part 20, description is abbreviate | omitted.

<Second Estimated Frequency Information Output Unit 60>
The second estimated frequency information output unit 60 has the same configuration as the first estimated frequency information output unit 30, but the first estimated frequency information output unit 30 outputs an input signal output from the first estimated phase information output unit 20. The phase α [t] of Vin is input and the estimated value of the frequency information of the input signal Vin at time [t] is output as the first estimated frequency information F _est [t], whereas the second estimated frequency information output part 60 inputs the phase alpha ₂ [t] of the sine wave signal _{V out} [t] at time [t] output from the second estimated phase information output unit 50, the sine wave signal _{V out} at the time [t] The difference is that an estimated value of frequency information of [t] is output as second estimated frequency information F _est2 [t]. Since others are the same as that of the 1st estimated frequency information output part 30, description is abbreviate | omitted.

<Error frequency information output unit 70>
The error frequency information output unit 70 calculates the error of the second estimated frequency information F _est2 [t] with respect to the first estimated frequency information F _est [t] at time [t], and the error frequency information F _err [t] at time [t]. ] Is output. The error frequency information output unit 70 includes a moving average unit 71 that calculates a moving average value of the error frequency information F _err [t].

The first estimated frequency information F _est [t] and the second estimated frequency information F _est2 [t] must be compared with the same type of information. For example, the first estimated frequency information F _est [t] In this case, the second estimated frequency information F _est2 [t] also needs to be expressed in frequency. The same applies to an angular frequency, a difference frequency, or a difference angular frequency.

[Moving average unit 71]
The moving average unit 71 calculates a moving average value of the error frequency information F _err [t], and outputs it as error frequency moving average value information F _{err_ave} [t] (it can also be output outside the frequency information detection device 1). ). The moving average value is calculated using a predetermined number of data.

As described above, the moving average unit 71 calculates a moving average value of a predetermined number of data based on the error frequency information F _err [t] at the time [t] where the error is calculated. Has a memory (not shown) and sequentially stores the error frequency information F _err [t] in the memory. This memory stores at least a predetermined number of data necessary for calculating the moving average value.

Further, as described above, the time after the instantaneous value _V in of the input signal _{V in} at the [t + 1] [t + 1] is input to the cosine value estimating unit 21, the estimated frequency information F of the input signal _{V in} at the time [t] since _est [t] is computed, the moving average value omega _ave of the angular frequency [t], the moving average value _{f ave} frequency [t] is also instantaneous value _V in of the input signal _{V in} at the time [t + 1] [t + 1 ] Is input to the cosine value estimation unit 21 and then calculated. Therefore, the corresponding error frequency information _{F err} [t] is also time instantaneous value _V in of the input signal _{V in} at the [t + 1] [t + 1] is calculated after being input to the cosine value estimating unit 21.

Further, immediately after starting sampling of data, a predetermined number of data necessary for calculating the moving average value is not stored in the memory. Therefore, while the predetermined number of data is not stored in the memory, the moving average value may be calculated using data smaller than the predetermined number. Alternatively, the moving average value may be calculated after a predetermined number of data is stored in the memory. How to calculate the moving average value may be determined in advance.

<Reasons for calculating the moving average value>
As described above, since the cosine value (cos (α [t])) at time [t] includes an error, the phase α [t] also includes an error. Of course, the cosine value (cos (α) [t−1]) and the phase α [t−1] at time [t−1] also include errors. As a result, the phase displacement amount Δα [t] also includes an error. Therefore, also included an error in the time estimated frequency information _{F est} of the input signal _{V in} at the [t] [t].

That is, the error included _in the estimated frequency information F _est [t] of the input signal Vin at time [t] is due to the cosine value (cos (α [t])) at time [t].
Error of the cosine value in this time [t] (cos (α [ t])) , so also be negative if also become positive, as described above, the input signal V _in at the time [t] The error of the estimated frequency information F _est [t] may be positive or negative. Therefore, if the moving average unit 71 performs a moving average of a plurality of data, the error is canceled out, so that the error can be reduced and accurate frequency information can be obtained.

The moving average in the error frequency information output unit 70 is not performed on the first estimated frequency information F _est [t], but is performed on the error frequency information F _err [t] at time [t]. At this time, since the second estimated frequency information F _est2 [t] also includes an error, the moving average effect can be obtained in the same manner as described above.

As described above, it is preferable to perform the moving average by providing the moving average unit 71. However, if the error between the first estimated frequency information F _est [t] and the second estimated frequency information F _est2 [t] is small, it can be omitted. There is also.

<Error phase information output unit 80>
The error phase information output unit 80 calculates the error of the second estimated phase information α ₂ [t] with respect to the first estimated phase information phase α [t] at time [t], and the error phase information α _err [t] at time [t]. ] Is output. The error phase information output unit 80 includes a moving average unit 81 that calculates a moving average value of the error phase information α _err [t].

[Moving average unit 81]
The moving average unit 81 calculates a moving average value of the error phase information α _err [t], and outputs it as error phase moving average value information α _{err_ave} [t] (can be output outside the frequency information detection apparatus 1). ). The moving average value is calculated using a predetermined number of data.
Although the moving average unit 71 calculates the moving average value of the error frequency information F _err [t], the moving average unit 81 is different in that the moving average value of the error phase information α _err [t] is calculated. Since others are the same, description is abbreviate | omitted.

<Frequency correction unit 90>
When the error frequency moving average value information F _{err_ave} [t]) at time [t] is outside a predetermined range, the frequency correction unit 90 sets the time so that the error frequency moving average value information F _{err_ave} [t] becomes small. The correction frequency information F _rev [t] at [t] is determined and output. The time when the in the range of error frequency moving average value information _{F err_ave} [t] is predetermined in [t], the correction frequency information so that the error phase moving average information _α err_ave [t] is small _{F rev} [ t] is determined and output. Hereinafter, the frequency correction unit 90 will be further described.

As described above, there may be an error between the set frequency information F _set and the frequency of the traveling wave voltage VF from the first high frequency power supply 110 toward the plasma processing apparatus 130. For that purpose, by detecting the frequency of the actual traveling wave voltage VF and making the frequency information the command signal of the oscillator of another high frequency power source (for example, the second high frequency power source 120 shown in FIGS. 6 and 7), The output frequency of the first high frequency power supply 110 and the output frequency of another high frequency power supply can be matched (synchronized).

Note that the frequency of the traveling wave voltage VF is obtained from the estimated frequency information F _est [t] output from the frequency estimation unit 32. In addition, a moving average unit is provided in the subsequent stage of the frequency estimation unit 32 in order to reduce the error and obtain an accurate estimated value of the frequency information.

However, only the estimated frequency information F _est [t] output from the frequency estimation unit 32 cannot obtain the phase information of the traveling wave voltage VF.
Therefore, a sine wave signal generator generates a sine wave signal V _out for synchronizing with a traveling wave detection signal V _f (more specifically, an input signal V _in that has passed through the filter 160), which is a detection signal of the traveling wave voltage VF. 40. Further, control is performed to bring the frequency and phase of the sine wave signal V _out output from the sine wave signal generator 40 to the frequency and phase of the input signal V _in.
Then, close to the frequency and phase of the sine wave signal V _out of _the frequency and phase of the input signal V _in, that both the error is sufficiently small, the output frequency of the first high frequency power supply 110 other high frequency power source and The phases can be matched (synchronized).

Therefore, the error frequency information output unit 70 _obtains an error of the second estimated frequency information F _est2 [t] with respect to the first estimated frequency information F _est [t] at time [t]. This error is output as error frequency information F _err [t], and error frequency moving average value information F _{err_ave} [t] is input to the frequency correction unit 90 via the moving average unit 71.

On the other hand, regarding the phase information, the error phase information output unit 80 obtains an error of the second estimated phase information α ₂ [t] with respect to the first estimated phase information phase α [t] at time [t]. This error is output as error phase information α _err [t], and error phase moving average value information α _{err_ave} [t] is input to the frequency correction unit 90 via the moving average unit 81.

As described above, in the frequency correction unit 90, when the error frequency moving average value information F _{err_ave} [t] at _time [t] is outside the predetermined range, the error frequency moving average value information F _{err_ave} [t] The correction frequency information F _rev [t] at time [t] is determined and output so that becomes smaller.
That is, when the first estimated frequency information F _est [t] is larger (the frequency is higher) than the second estimated frequency information F _est2 [t], the synchronization that is a command value to the sine wave signal generation unit 40 Positive (plus) correction frequency information F _rev [t] is output so that the frequency information F _syc [t] is large (the frequency is high). On the other hand, when the first estimated frequency information F _est [t] is smaller (frequency is lower) than the second estimated frequency information F _est2 [t], the negative (minus) corrected frequency information F _rev [t] ] Is output.

Note that the magnitude of the error between the first estimated frequency information F _est [t] and the second estimated frequency information F _est2 [t] (more specifically, the magnitude of the error frequency moving average value information F _{err_ave} [t]). Correspondingly, the correction frequency information F _rev [t] is determined, but it is preferable to adjust the coefficient (K _f ) to be multiplied by the error because the control becomes easy.

By performing the control as described above, it is possible to make the frequency of the sine wave signal V _out output from the sine wave signal generator 40 to the frequency of the input signal V _in.

Then, the time when the error frequency moving average value information _{F err_ave} [t] is within a predetermined range in the [t], the frequency of the sine wave signal _{V out} output from the sine wave signal generation section 40 of the input signal _{V in} it is determined that close to the frequency shifts to a control to bring the phase of the sine wave signal V _out output from the sine wave signal generation section 40 to the phase of the input signal V _in.

At this time, in the frequency correction unit 90, when the error frequency moving average value information F _{err_ave} [t] at _time [t] is within a predetermined range, the correction frequency is set so that the error phase information α _err [t] becomes small. Information F _rev [t] is determined and output.
That is, when the first estimated phase information phase α [t] is larger than the second estimated phase information α ₂ [t], the synchronization frequency information F _syc [which is a command value to the sine wave signal generation unit 40 is _used . Positive (plus) correction frequency information F _rev [t] is output so that t] is large (frequency is high). Conversely, if the first estimated phase information phase α [t] is smaller than the second estimated phase information α ₂ [t], negative (minus) corrected frequency information F _rev [t] is output.

Note that the magnitude of the error between the first estimated phase information phase α [t] and the second estimated phase information α ₂ [t] (more specifically, the magnitude of the error phase moving average value information α _{err_ave} [t]). Correspondingly, the correction frequency information F _rev [t] is determined. However, it is preferable that the coefficient (K _α ) to be multiplied by the error can be adjusted because control is facilitated.

When the correction frequency information F _rev [t] is output from the frequency correction unit 90, the frequency of the sine wave signal V _out output from the sine wave signal generation unit 40 changes, and thus the first estimated phase information phase α [t ], The relationship of the second estimated phase information α ₂ [t] changes, and the error phase information α _err [t] decreases.

Then, it is determined if falls within a range error phase information alpha _{err [t]} is a predetermined, and the phase of the sine wave signal V _out output from the sine wave signal generation section 40 is close to the phase of the input signal V _in.
By performing the control as described above, it is possible to make the phase of the sine wave signal V _out output from the sine wave signal generation section 40 to the phase of the input signal V _in.

Incidentally, when performing control to bring the phase of the sine wave signal V _out output from the sine wave signal generation section 40 to the phase of the input signal V _in, since by changing the frequency of the sine wave signal V _out, the error frequency It is conceivable that the moving average value information F _{err_ave} [t] is outside a predetermined range. Therefore, the frequency correction unit 90 confirms again whether or not the error frequency moving average value information F _{err_ave} [t] at _time [t] is out of a predetermined range, and repeats the above control. Run.

Thus, the frequency and phase of the sine wave signal V _out is, converges to be closer to the frequency and phase of the input signal V _in. Then, the frequency correction unit 90 has the error frequency moving average value information F _{err_ave} [t]) at time [t] within a predetermined range and the error phase moving average value information α _{err_ave} [t] is determined in advance. When it falls within the specified range, it is determined that it has converged. When it is determined that the signal has converged, a convergence signal S _con indicating that may be output to the outside.

<Simulation results>
As described above, the frequency of the traveling wave voltage VF can be obtained by moving average the estimated frequency information F _est [t] output from the frequency estimation unit 32. Therefore, a simulation result in the case where a moving average unit is provided in the subsequent stage of the frequency estimation unit 32 is shown.

4, when the frequency _{f in} of the input signal _{V in} is assumed to have shifted from the set frequency _{f The set,} the moving average value f of the estimated value _{f dif} difference frequency output from the moving average unit 71 [t] It is a simulation result of _{dif_ave} [t]. Figure 4 (a) is a simulation result of the estimated value _{f dif} difference frequency of the input signal _{V in} [t], FIG. 4 (b), the estimated value _f dif difference frequency of the input signal _{V in} [t] FIG. 4C is a partially enlarged view of FIG. 4B. FIG. 4C is a simulation result of the moving average value f _{dif_ave} [t] of FIG. 4A and 4B show data for about 150 to 160 μs after the start of sampling, and FIG. 4C shows data for about 159 to 160 μs after the start of sampling.

The simulation conditions are as follows.
(1) Sampling frequency f _s : 50 MHz
(2) Setting frequency f _set : 13.56 MHz
(3) of the input signal _{V in} frequency _f in: 13.563MHz
(Assuming that the _set frequency f _set is shifted by 3,000 Hz)
(4) Number of data used for calculating the moving average value: 500 (moving average value of 10 μs)

5, when the frequency _{f in} of the input signal _{V in} is assumed to have shifted from the set frequency _{f The set,} the moving average value f of the estimated value _{f dif} difference frequency output from the moving average unit 71 [t] It is another simulation result of _{dif_ave} [t]. Figure 5 (a) is a simulation result of the estimated value _{f dif} difference frequency of the input signal _{V in} [t], FIG. 5 (b), the estimated value _f dif difference frequency of the input signal _{V in} [t] FIG. 5C is a partially enlarged view of FIG. 5B. FIG. 5C is a simulation result of the moving average value f _{dif_ave} [t] of FIG.
Incidentally, FIG. 5, except that the frequency _{f in} of the input signal _{V in} is 13.5603MHz (assuming are shifted by setting the frequency _{f The set} and 300 Hz), is the result of simulation under the same conditions as FIG. 4 .

As shown in FIG. 4 (a), the input signal _V when the frequency of the _in is assumed to have shifted 3,000Hz the set frequency _f set (13.56MHz), the estimated value f of the difference between the frequency of the input signal _{V in dif} [t] varies within a range of about ± 400 Hz with respect to the frequency to be detected (3,000 Hz), but as shown in FIGS. 4B and 4C, the estimated value of the difference frequency f _dif [t] moving average _{f dif_ave} [t] of, it is seen that within the range of about ± 0.6 Hz for the frequency to be detected (3,000 Hz).
As described above, even when the frequency of the input signal V _in is significantly deviated from the set frequency f _set , the moving average of the estimated value f _dif [t] of the difference frequency output from the moving average unit 71 is obtained. The value f _{dif_ave} [t] has a small error with respect to the frequency to be detected.

Further, as shown in FIG. 5 (a), the case where the frequency _{f in} of the input signal _{V in} is assumed to have shifted 300Hz the set frequency _f set (13.56MHz), estimation of the difference frequency of the input signal _{V in} The value f _dif [t] varies in a range of about ± 40 Hz with respect to the frequency to be detected (300 Hz), but as shown in FIGS. 5B and 5C, the estimated value of the difference frequency. f _dif [t] moving average _{f dif_ave} [t] of, it is seen that within the range of about ± 0.05 Hz for the frequency to be detected (300 Hz). Therefore, it can be seen that can detect frequency accurately the input signal V _in.

That is, as the error between the frequency _{f in} of the input signal _{V in} and the set frequency _{f The set} is small, it can be seen that can detect a frequency of more accurately the input signal _{V in.}
In the above embodiment, the frequency of the sine wave signal V _out is, since the controlled so as to approach the frequency of the input signal V _in, as performs control, that can detect the frequency of the more accurately the input signal V _in Show.

The frequency information detection apparatus of this embodiment, the sine wave signal V _in analog, (the reciprocal of the sampling frequency f _s: 1 / f _s) a predetermined sampling period by A / D-converted digital signal This is a frequency information detection device that detects frequency information of the obtained digital sine wave signal, and its application is not particularly limited. Therefore, although the example which uses a frequency information detection apparatus for a high frequency electric power supply system like FIG.6 and FIG.7, for example was shown above, it is not limited to this. For example, it can be applied even in a commercial frequency band (50 Hz to 60 Hz).

DESCRIPTION OF SYMBOLS 1 Frequency information detection apparatus 10 A / D conversion part 20 1st estimated phase information output part 21 Cosine value estimation part 22 Phase estimation part 30 1st estimated frequency information output part 31 Phase displacement amount calculation part 32 Frequency estimation part 40 Moving average part 50 Second estimated phase information output unit 50
60 Second estimated frequency information output unit 60
70 Error frequency information output unit 80 Error phase information output unit 80
90 Frequency correction unit 100 Oscillator 110 First high frequency power source 120 Second high frequency power source 130 Plasma processing apparatus (load)
131 Electrode 132 Electrode 133 Plasma 140 Transmission Line 150 Directional Coupler 160 Filter

Claims (5)

A frequency information detecting apparatus for detecting the frequency information of the analog sine wave signal V _in,
A sine wave signal V _in analog, (the reciprocal of the sampling frequency f _s: 1 / f _s) a predetermined sampling period by the instantaneous value V of the input signal V _in at the time [t] obtained by converting a digital signal an A / D converter that converts _in [t] sequentially into a sine wave signal composed of a plurality of sampling data;
A first estimated phase information output unit that outputs the estimated value of the phase information of the input signal V _in at the time [t] as a first estimated phase information,
A first estimated frequency information output unit that outputs the estimated value of the frequency information of the input signal V _in at the time [t] as a first estimated frequency information,
Frequency information obtained by adding the correction frequency information to the set frequency information of the input signal V _in when the synchronizing frequency information, and the sine wave signal generator for generating a sine wave signal based on the synchronization frequency information,
A second estimated phase information output unit that outputs an estimated value of phase information of the sine wave signal output from the sine wave signal generation unit at time [t] as second estimated phase information;
A second estimated frequency information output unit that outputs an estimated value of frequency information of the sine wave signal output from the sine wave signal generation unit at time [t] as second estimated frequency information;
An error frequency information output unit that calculates a moving average value of an error (error frequency information) of the second estimated frequency information with respect to the first estimated frequency information at time [t], and outputs the error frequency moving average value information;
An error phase information output unit that calculates a moving average value of an error (error phase information) of the second estimated phase information with respect to the first estimated phase information at time [t], and outputs the error phase moving average value information;
If the error frequency moving average value information is outside a predetermined range, the correction frequency information is determined and output so that the error frequency moving average value information is small, and the error frequency moving average value information is predetermined. If within the range, a frequency correction unit that determines and outputs the correction frequency information so that the error phase moving average value information is small; and
A frequency information detection apparatus comprising: The first estimated phase information output unit includes:
Time cosine value obtained by differentiating the instantaneous value _V in [t] of the input signal _{V in} in [t] (cos (α [ t])) an estimate of the instantaneous value of the input signal _{V in} at the time [t-1] A cosine value estimator that uses V _in [t−1], an instantaneous value V _in [t + 1] of the input signal V _in at time [t + 1], and a known value;
Time the instantaneous value _V in [t] of the input signal _{V in} at the [t] and a sine component (sin component), the cosine value at time [t] estimated by the cosine value estimating section (cos (alpha [t]) ) As a cosine element (cos element), the phase α [t] of the cosine value (cos (α [t])) at time [t] is calculated using an arctangent function (tan ⁻¹ ), and the calculated phase is calculated. a phase estimation unit that outputs α [t] as first estimated phase information;
The first estimated frequency information output unit includes:
Based on the phase α [t−1] at time [t−1] and the phase α [t] at time [t] calculated by the phase estimation unit, the phase displacement amount Δα [t] at time [t] is calculated. A phase displacement amount calculation unit to be calculated;
On the basis of the phase shift amount [Delta] [alpha] [t] in the calculated time in the phase shift amount calculation unit [t], calculates the estimated frequency information of the input signal V _in at the time [t], the calculation was estimated frequency information 1 a frequency estimator for outputting as estimated frequency information;
The frequency information detection apparatus according to claim 1, wherein The cosine value estimation unit, the input signal V _in setting constant is calculated using the frequency information is taken as K, the cosine value (cos (alpha [t])) to be calculated by the formula (1) The frequency information detection apparatus according to claim 2, wherein:
cos (α [t]) = K · {V _in [t + 1] −V _in [t−1]} (1) The frequency information detection apparatus according to claim 3, wherein the constant K is calculated according to Equation (2). However, the set frequency information is “F _set ”.
K = 1 / {2 sin (2π · (F _set / f _s ) [t])} (2) A high frequency power supply device that outputs a traveling wave voltage based on the sine wave signal output from the sine wave signal generation unit according to claim 1 .

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