JP2011188594A - Polyphase ac power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyphase AC power generation system which is excellent in responsiveness to fluctuations in voltage and frequency of a polyphase AC power generator with a simple circuit structure and capable of reducing a ripple. <P>SOLUTION: In the polyphase AC power generation system including the polyphase AC power generator and a voltage controller, the polyphase AC power generator is structured to output an AC voltage from each phase of polyphase independently, and the voltage controller has square waveform circuits which are each connected independently to each independent phase and corresponds to each phase. The square waveform circuit has a single-phase bridge rectifier circuit, a step-down chopper circuit, and a duty control oscillation circuit. The duty control oscillation circuit controls duty in such a way that the duty given to a semiconductor switch of the step-down chopper circuit becomes proportional to an input instantaneous voltage. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a multiphase AC power generator, and more particularly to a multiphase AC power generator that includes a multiphase AC generator and a voltage control device and can obtain an output voltage with low ripple.

  Generally, in a three-phase AC generator, a three-phase output that is Δ-connected or Y-connected is converted into direct current by a three-phase bridge rectifier circuit. When a load is connected to this three-phase bridge rectifier circuit, the rotational torque of the alternator fluctuates, causing vibrations and noise in the alternator.

  More specifically, in the three-phase bridge rectifier circuit, when a three-phase AC power (sine wave) having a phase difference (2π / 3) is input, only the phase with the maximum instantaneous voltage is T / 6 (T: period ) Change the output step by step. For this reason, the three-phase bridge rectifier circuit repeatedly outputs only the sine wave peak portion, so that a ripple (fluctuation component) is generated in the output voltage. When the output voltage fluctuates in this way, the output and input (mechanical power = rotational speed × rotational torque) fluctuate, and mechanical vibration is generated due to torque fluctuation.

  As a technique for reducing the ripple, there is a technique using a smoothing circuit (a capacitor, a coil, or the like). Although this smoothing circuit can reduce the ripple of the output voltage, it stores the energy at the peak voltage in the capacitor and releases it at the low voltage, so the ripple of the input current increases on the contrary, and the input power (rotation speed x rotational torque) Fluctuation increases. That is, the output characteristics are improved, but the input characteristics are deteriorated, and the torque fluctuation increases, so that the vibration and noise of the AC generator increase.

Conventionally, there is a method of improving the input characteristics by using a high-efficiency converter circuit so that the power supply current of each phase becomes a sine wave having a power factor of 1 (current waveform proportional to voltage). By this control, the input power of the entire three phases (rotational speed corresponding to mechanical input × rotational torque value) is made constant. By using this high-efficiency converter circuit, it is possible to solve the vibration and noise generation of the AC generator.
However, the high-efficiency converter circuit has a complicated circuit configuration, and there is a limit to the responsiveness of the AC generator voltage and frequency fluctuation.

  As an example of a technology that reduces ripples (prevents vibration and noise) and improves the responsiveness of AC generator voltage and frequency fluctuations with a simple circuit configuration, each phase of a three-phase AC generator is taken out with six wires. A simple control circuit may be used to reduce ripples and improve responsiveness to voltage and frequency fluctuations.

  As a technology related to this, the technology disclosed in Patent Document 1 is that each phase (A phase coil, B phase coil and C phase coil) of a three-phase AC generator is independently taken out with 6 wires, and each phase is single-phase. This is a technology connected to an H-bridge rectifier circuit (full-wave rectifier circuit).

  The technique disclosed in Patent Document 1 includes a regenerative control signal generation unit that supplies an output signal to a single-phase H-bridge rectifier circuit (transistor control terminal), and the regenerative control signal generation unit includes AC phase sensors. Based on the output, the output signal supplied to each rectifier circuit (transistor control terminal) is adjusted to “H level” or “L level”.

  However, in the technique disclosed in Patent Document 1, power is efficiently recovered from the A-phase to B-phase coils by setting the “H level” interval to a symmetrical interval centered on the peak of the sensor output waveform. It is not intended to reduce ripple.

JP 2008-92789 A

  In view of the above problems, the problems to be solved by the present invention are excellent in responsiveness of voltage and frequency fluctuation of a multiphase AC generator with a simple circuit configuration, can reduce ripples, and the power supply current of each phase Provided is a multi-phase AC power generator that can reduce vibration and noise of a multi-phase AC generator by controlling the input power of the entire three phases to be constant so that it becomes a sine wave with a power factor of 1. It is.

  The invention according to claim 1 is a multiphase AC power generator comprising a multiphase AC generator and a voltage control device that converts an AC voltage of the multiphase AC generator into a DC voltage and outputs the DC voltage. The AC generator is configured to make the polyphase independent for each phase and output an AC voltage for each independent phase, and the voltage control device is connected independently for each independent phase, A square (voltage) waveform circuit corresponding to a phase, the square waveform circuit being connected to the corresponding phase and rectifying an AC voltage of the phase; and a single-phase bridge rectifier circuit A step-down chopper circuit connected to the output side for converting an input voltage waveform inputted from the single-phase bridge rectifier circuit and outputting an output voltage waveform; and a step-down chopper circuit connected to the output side of the single-phase bridge rectifier circuit, Dedicated to the semiconductor switch of the circuit A duty control oscillation circuit for controlling a duty ratio, wherein the duty control oscillation circuit monitors an input instantaneous voltage input to the step-down chopper circuit from the single-phase bridge rectifier circuit and supplies the voltage to a semiconductor switch of the step-down chopper circuit A multi-phase AC power generator for controlling the duty ratio to be proportional to the input instantaneous voltage, wherein the square waveform circuit of each phase is connected in series on the output side of the step-down chopper circuit About.

  According to a second aspect of the present invention, the square waveform circuit is connected to the output side of the single-phase bridge rectifier circuit and has a power supply circuit that supplies power to the duty control oscillation circuit and the step-down chopper circuit. The present invention relates to a multiphase AC power generator according to claim 1.

According to the first aspect of the present invention, in the multiphase AC generator, comprising: a multiphase AC generator; and a voltage control device that converts the AC voltage of the multiphase AC generator into a DC voltage and outputs the DC voltage. The polyphase AC generator is configured to make the polyphase independent for each phase and output an AC voltage for each independent phase, and the voltage control device is connected independently for each independent phase. A square waveform circuit corresponding to each phase, wherein the square waveform circuit is connected to the corresponding phase and rectifies the AC voltage of the phase, and an output of the single phase bridge rectifier circuit And a step-down chopper circuit that converts an input voltage waveform input from the single-phase bridge rectifier circuit and outputs an output voltage waveform; and a step-down chopper circuit connected to the output side of the single-phase bridge rectifier circuit Du to give to semiconductor switch A duty control oscillation circuit for controlling a tee ratio, wherein the duty control oscillation circuit monitors an input instantaneous voltage input to the step-down chopper circuit from the single-phase bridge rectifier circuit and supplies the voltage to a semiconductor switch of the step-down chopper circuit The duty ratio is controlled to be proportional to the input instantaneous voltage, and the square waveform circuit of each phase is connected in series on the output side of the step-down chopper circuit. Rectified by a phase bridge rectifier circuit to form a “蒲 鉾 -shaped pulsation waveform: input instantaneous voltage”, and this “蒲 鉾 -shaped pulsation waveform” is monitored by a duty-controlled oscillation circuit. Based on this monitoring, the semiconductor switch of the step-down chopper circuit The duty ratio given to is controlled.
The duty control oscillation circuit controls the duty ratio given to the semiconductor switch of the step-down chopper circuit to be proportional to the input instantaneous voltage, thereby converting the saddle-shaped pulsation waveform into a square sine waveform (or a double cosine waveform). To do.
The duty control oscillation circuit includes a voltage dividing circuit, a variable gain amplification circuit, a peak voltage detection circuit, and a voltage-pulse width conversion oscillation circuit. The voltage dividing circuit divides a high voltage input signal to generate a small signal voltage proportional to the input voltage. The variable gain amplifier circuit amplifies a signal voltage by arbitrarily setting a voltage gain (amplification factor) by a gain adjustment signal. The peak voltage detection circuit monitors the maximum value of the signal voltage which is a “蒲 鉾 -shaped pulsation waveform” and generates a signal voltage proportional to the maximum value. The voltage-pulse width conversion oscillation circuit generates a rectangular wave pulse signal having a duty ratio proportional to the signal voltage by making the pulse width proportional to the signal voltage with a constant frequency.
Here, since the duty ratio does not exceed 1 (100%), the pulse width cannot be longer than the oscillation period. Therefore, the input signal voltage necessary for the duty ratio to be 1 is determined as the maximum value of the signal voltage, and the gain of the variable gain amplifier circuit is adjusted so that the maximum value (peak voltage) of the input signal does not exceed the maximum. The signal voltage that is the output of the variable gain amplifier circuit is monitored, the peak voltage is detected, and feedback control is performed to supply the gain adjustment signal voltage to the variable gain amplifier circuit based on the detected peak voltage.
In the range where the amplitude of the input voltage (maximum value of the input voltage waveform) is small, the variable gain amplifier circuit operates at the maximum gain to amplify the signal voltage. -Supply to pulse width conversion oscillator. At this time, the maximum value of the duty ratio increases in proportion to the amplitude of the input voltage. When the input voltage increases and the variable gain amplifier circuit operates at the maximum gain, and the signal voltage exceeds the specified maximum value, the peak voltage detection circuit detects the peak voltage and decreases the gain. Operate. As a result, it is possible to generate a signal voltage waveform in which the maximum value of the signal voltage always becomes a predetermined maximum value, and the maximum value of the duty ratio is constant (approximately 1) regardless of the amplitude of the input voltage.
When the amplitude of the input voltage is large and the maximum value of the duty ratio is controlled to be 1, the waveform of the AC instantaneous voltage of each phase is 1/2 (V _m / 2) of the maximum value amplitude V _m. It becomes a cosine waveform that vibrates at a double frequency in the range of 0 to Vm as the center. When the step-down chopper circuit of the square waveform circuit corresponding to each phase is connected in series, the output voltage output from the step-down chopper circuit is summed, so that all the amplitude components of the trigonometric function are canceled and V _0ut = (n / 2) · V _m and a DC voltage proportional to the amplitude of the input voltage is output (n = number of phases of the AC generator). When the amplitude of the input voltage is small and the maximum value of the duty ratio is less than 1, assuming that the proportionality factor of the duty ratio to the input instantaneous voltage is k, V _0ut = (n / 2) · k · (V _m ) ² A DC voltage proportional to the square of the input voltage is output.
As a result, a DC voltage that cancels all the amplitude components of the trigonometric function can be obtained, so that a DC voltage with less ripple is obtained and the input power (rotation speed × rotation torque) is always constant. Reduces vibration and noise.
Secondly, a higher voltage can be obtained compared to a three-phase bridge rectifier circuit (the three-phase bridge rectifier circuit has a maximum V _m , and the multi-phase AC power generation according to the present invention is applied to a three-phase AC generator. If the maximum value of the duty ratio is controlled to be 1, the 3/2 times the 1.5V _m).
Third, the circuit configuration is simpler than that of the high efficiency converter circuit, and a quick response to the voltage amplitude and frequency fluctuation of the generator is possible.

  According to the second aspect of the present invention, the square waveform circuit includes a power supply circuit that is connected to the output side of the single-phase bridge rectifier circuit and supplies power to the duty control oscillation circuit and the step-down chopper circuit. Therefore, the power supply circuit can obtain power from the output side of the single-phase bridge rectifier circuit, and can apply drive power to the duty control oscillation circuit and the step-down chopper circuit.

1 is a schematic circuit diagram of a multiphase AC power generator according to the present invention. It is a circuit diagram which shows the structure of the square waveform circuit in FIG. It is a figure which shows the sine waveform of the alternating current instantaneous voltage output from one phase of the three-phase alternating current generator in FIG. It is a figure which shows the output waveform (saddle-shaped pulsation waveform) of the single phase bridge rectifier circuit in FIG. FIG. 3 is a diagram showing an input voltage waveform (a saddle-shaped pulsation waveform) monitored by a duty control oscillation circuit in FIG. 2 and an output voltage waveform (a double angle cosine waveform) of a step-down chopper circuit. FIG. 3 is a diagram showing a relationship between input and output voltage waveforms in the three-phase AC generator, duty control oscillation circuit, and step-down chopper circuit of FIG. 2. It is a voltage (V) -time (t) relationship figure in the input waveform of a single phase sine wave voltage, a rectification waveform, and a square output waveform. It is a relationship figure of voltage (V) -time (t) in the square output waveform of each phase which concerns on this invention, and the three-phase DC voltage waveform. FIG. 7 is a circuit diagram showing a configuration of a duty control oscillation circuit in FIGS. 5 and 6. FIG. 10 is a relationship diagram of voltage gain (voltage amplification factor) (Av) −input voltage amplitude (maximum value of input voltage waveform) (Vm) of the variable gain amplifier in FIG. 9. FIG. 6 is a relationship diagram of a maximum value of duty ratio (αmax) −input voltage amplitude (maximum value of input voltage) (Vm) in a duty control oscillation circuit. It is a relationship figure of the rotation speed (f) -DC output voltage (Vout) of the generator of a three-phase alternating current power generator as an Example of this invention.

A multiphase AC power generator according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic circuit diagram of a multiphase AC power generator according to the present invention. FIG. 2 is a circuit diagram showing the configuration of the square waveform circuit in FIG. FIG. 3 is a diagram showing a sine waveform of an AC voltage output from one phase of the three-phase AC generator in FIG. FIG. 4 is a diagram showing an output waveform (a saddle-shaped pulsation waveform) of the single-phase bridge rectifier circuit in FIG. FIG. 5 is a diagram showing an input voltage waveform (a saddle-shaped pulsation waveform) monitored by the duty control oscillation circuit in FIG. 2 and an output voltage waveform (double angle cosine waveform) of the step-down chopper circuit. FIG. 6 is a diagram showing the relationship between input and output waveforms in the three-phase AC generator, duty control oscillation circuit, and step-down chopper circuit of FIG. FIG. 7 is a relationship diagram of voltage (V) -time (t) in an input waveform, a rectified waveform, and a square output waveform of a single-phase sine wave voltage. FIG. 8 is a relationship diagram of voltage (V) -time (t) in the square output waveform of each phase and the three-phase DC voltage waveform according to the present invention. FIG. 9 is a circuit diagram showing a configuration of the duty control oscillation circuit in FIGS. FIG. 10 is a relationship diagram of voltage gain (voltage amplification factor) (Av) −input voltage amplitude (maximum value of input voltage waveform) (Vm) of the variable gain amplifier in FIG. 9. FIG. 11 is a relationship diagram of duty ratio maximum value (αmax) −input voltage amplitude (maximum value of input voltage) (Vm) in the duty control oscillation circuit. FIG. 12 is a graph showing the relationship between the rotational speed (f) of the generator of the three-phase AC generator and the DC output voltage (Vout) as an embodiment of the present invention.

  First, a schematic circuit configuration of a multiphase AC power generator (1) according to the present invention will be described with reference to FIG.

  In FIG. 1, the multiphase AC power generator (1) is composed of a multiphase AC generator (2) and a voltage control device (3).

  As shown in FIG. 1, the multiphase AC generator (2) is a three-phase AC generator (hereinafter referred to as “three-phase AC generator (2)”). As shown in FIG. 1, the three-phase AC generator (2) has a three-phase electromagnetic coil (3) arranged in a Δ type (delta type), and the three-phase electromagnetic coil (3) is a one-phase electromagnetic It consists of a coil (5), a two-phase electromagnetic coil (6) and a three-phase electromagnetic coil (7). Hereinafter, these are simply referred to as a one-phase coil (5), a two-phase coil (6), and a three-phase coil (7).

As shown in FIG. 1, the one-phase coil (5) takes out the two wires (a1) and (a2) at both ends of the coil (5) from the three-phase AC generator (2). Moreover, as shown in FIG. 1, the two-phase coil (6) takes out the two wires (b1) and (b2) at both ends of the coil (6) from the three-phase AC generator (2). As shown in FIG. 1, the three-phase coil (7) also takes out the two wires (c1) and (c2) at both ends of the coil (7) from the three-phase AC generator (2).
Thereby, as shown in FIG. 1, a three-phase alternating current generator (2) makes a three-phase coil independent for every 1-phase coil (5), 2 phase coil (6), and 3 phase coil (7), The AC voltage is output for each of the independent 1-phase to 3-phase coils (5), (6), and (7).

As shown in FIG. 1, the voltage control device (3) is connected to each of the one-phase coil (5), the two-phase coil (6), and the three-phase coil (7) in which the three phases are independent. A plurality of square waveform circuits (A1), (B1), and (C1) corresponding to the three-phase coils (5), (6), and (7) are provided.
That is, the two wires (a1) and (a2) of the one-phase coil (5) are connected to the input side of the one-phase square waveform circuit (A1) as shown in FIG. 2 lines (b1) and (b2) are connected to the input side of the two-phase square waveform circuit (B1) as shown in FIG. Further, the two wires (c1) and (c2) of the three-phase coil are also connected to the input side of the three-phase square waveform circuit (C1) as shown in FIG.
As a result, the one-phase coil (5), the two-phase coil (6), and the three-phase coil (7) are, as shown in FIG. ) And (C1) are connected to the input side.

As shown in FIG. 1, the one-phase square waveform circuit (A1) has an output-side positive electrode connected to a load (10), and an output-side negative electrode connected to the output side of the two-phase square waveform circuit (B1). Is connected to the positive electrode. As shown in FIG. 1, in the two-phase square waveform circuit (B1), the negative electrode on the output side is connected to the positive electrode of the three-phase square waveform circuit (C1). Further, as shown in FIG. 1, the three-phase square waveform circuit (C1) has an output-side negative electrode connected to a load (10).
As a result, the square waveform circuits (A1), (B1), and (C1) of each phase are converted into a one-phase square waveform circuit (A1), a two-phase square waveform circuit (B1), and The three-phase square waveform circuit (C1) is connected in series in this order.

  Next, specific circuit configurations of the square waveform circuits (A1), (B1), and (C1) corresponding to the respective phases will be described with reference to FIG. Since the square waveform circuits (A1), (B1), and (C1) of each phase have the same configuration, the one-phase square waveform circuit (A1) will be described.

  In FIG. 2, the one-phase square waveform circuit (A1) includes a single-phase bridge rectifier circuit (15), a step-down chopper circuit (16), a duty control oscillation circuit (17), and a power supply circuit (18). Yes.

  As shown in FIG. 2, the single-phase bridge rectifier circuit (15) is a full-wave rectifier circuit, and is connected to the one-phase coil (5) of the three-phase AC generator (2). Is rectified to output a DC voltage.

As shown in FIG. 2, the step-down chopper circuit (16) is connected to the output side of the single-phase bridge rectifier circuit (15), and is input as an input voltage from the single-phase bridge rectifier circuit (15). The step-down chopper circuit (16) has a semiconductor switch (not shown) such as a transistor.
The step-down chopper circuit (16) performs switching (ON / OFF) of the semiconductor switch based on an ON / OFF control pulse (duty ratio (α)) input to the semiconductor switch (not shown). (V _i ) is converted into a predetermined output voltage.

As shown in FIG. 2, the duty control oscillation circuit (17) is connected to the output side of the single-phase bridge rectifier circuit (15) and the input side of the step-down chopper circuit (16), respectively, and the step-down chopper circuit (16). The duty ratio (α) given to the semiconductor switch (not shown) is controlled.
As shown in FIG. 2, the duty control oscillation circuit (17) monitors the input instantaneous voltage (V _i ) input to the step-down chopper circuit (16) and supplies it to the semiconductor switch of the step-down chopper circuit (16). The duty ratio (α) is controlled to be proportional to the input instantaneous voltage (V _i ).

  As shown in FIG. 2, the power supply circuit (18) is connected to the output side of the single-phase bridge rectifier circuit (15), and converts the power output from the rectifier circuit (15) to the duty control oscillation circuit (17) and the step-down circuit. Supply to the chopper circuit (16). Thereby, the duty control oscillation circuit (17) and the step-down chopper circuit (16) can be driven by power supply from the power supply circuit (18) as shown in FIG.

The step-down chopper circuits (16) of the square waveform circuits (A1), (B1), and (C1) corresponding to the one-phase coil (5), the two-phase coil (6), and the three-phase coil (7) are connected in series. ing.
Specifically, as shown in FIG. 1, the corresponding step-down chopper circuit (16) of the one-phase coil (5) has an output side positive electrode (+) connected to a load (10) and an output side negative electrode. (−) Is connected to the positive electrode (+) on the output side of the step-down chopper circuit (16) corresponding to the two-phase coil (6). As shown in FIG. 2, the step-down chopper circuit (16) corresponding to the two-phase coil (6) has an output side negative electrode (-) on the output side of the step-down chopper circuit (16) corresponding to the three-phase coil (7). Connected to the positive electrode (+). Further, in the step-down chopper circuit (16) corresponding to the three-phase coil (7), the negative electrode (−) on the output side is connected to the load (10) as shown in FIG.

Next, operation | movement of a polyphase alternating current power generator (1) is demonstrated with reference to FIGS.
The operations of the one-phase coil (5) and the one-phase square waveform circuit (A1) of the three-phase AC generator will be described. The two-phase coil (6), the three-phase coil (7), the two-phase square waveform circuit (B1), and the three-phase square waveform circuit (C1) are composed of a one-phase coil (5) and a one-phase square waveform circuit ( Since it has the same operation as A1), its description is omitted.

As shown in FIG. 2, the multiphase AC power generator (1) according to the present invention has a single phase coil (5) of the three phase AC generator (2) and a single phase of the one phase square waveform circuit (A1). It is connected to the bridge rectifier circuit (15).
As a result, the output waveform of the one-phase coil (5) becomes the sine waveform shown in FIG. 3, and when this is rectified by the single-phase bridge rectifier circuit (15), the “sag-shaped pulsation waveform: V _i = | V _m sin (ωt) | ”. V _{i is} the input voltage of the step-down chopper circuit (16), and V _m is the maximum voltage. Further, the “蒲 鉾 -shaped pulsation waveform (see FIG. 4)” refers to a waveform obtained by folding the minus side of the sine waveform shown in FIG.
The multiphase AC power generator (1) according to the present invention is shown in FIG. 4 without reducing the “saddle-shaped pulsation waveform (see FIG. 4)” obtained by the single-phase bridge rectifier circuit (15) with a smoothing circuit. The pulsation waveform is intentionally used as it is.

As shown in FIG. 5, the duty control oscillation circuit (17) monitors the input instantaneous voltage (V _i ) output from the single-phase bridge rectifier circuit (15) and input to the step-down chopper circuit (16). . The input instantaneous voltage (V _i ) is a “蒲 鉾 -shaped pulsation waveform” shown in FIG.
As shown in FIG. 5, the duty control oscillation circuit (17) is a semiconductor switch (illustrated) in the step-down chopper circuit (16) so that the duty ratio α (= kV _i ) is proportional to the input instantaneous voltage (V _i ). ON / OFF control pulse is output.
That is, as shown in FIG. 5, the duty control oscillation circuit (17) monitors the “蒲 鉾 -shaped pulsation waveform” of the input instantaneous voltage (V _i ) so that the duty ratio is proportional to the increase / decrease of the pulsation waveform. The ON / OFF control pulse given to the semiconductor switch of the step-down chopper circuit (16) is controlled.

As shown in FIG. 5, the step-down chopper circuit (16) turns the semiconductor switch ON / OFF based on the ON / OFF control pulse from the duty control oscillation circuit (17).
As a result, the output instantaneous voltage (V _O1 ) of the step-down chopper circuit (16) becomes a square waveform (V _O = kV _m ² · sin ² ωt) of the input instantaneous voltage (V _i ) as shown in FIG. Thus, a sine waveform (double angle cosine waveform) voltage is obtained.

That is, when the duty ratio α is set, the relationship between the input instantaneous voltage (V _i ) and the output instantaneous voltage (V _O ) of the step-down chopper circuit (16) is V _O = V _i × α. Since the duty control oscillation circuit (17) shown in FIG. 5 controls the duty ratio α to be proportional to the input instantaneous voltage (V _i ), the duty ratio α = k × V _i . When this duty α is substituted into V _O = V _i × α, the output instantaneous voltage (V _O ) of the step-down chopper circuit (16) is V _O = k × V on the positive voltage side as shown in FIG. _i ² = k × (V _m · sin ωt) ² = k × V _m ² · sin ² ωt = k × V _m ² · (1 + cos 2ωt) / 2.
As a result, the output instantaneous voltage (V _O ) of the step-down chopper circuit (16) can be a square sine waveform (or a double angle cosine waveform).

The same applies to the two-phase coil (6) and the two-phase square waveform circuit (B1), the three-phase coil (7) and the three-phase square waveform circuit (C1), and the instantaneous output of the step-down chopper circuit (16). The voltages (V _O2 ) and (V _O3 ) also have a square waveform of the input instantaneous voltage (V _i ).
Since the step-down chopper circuits (16) of the square waveform circuits (A1), (B1), and (C1) of each phase are connected in series as shown in FIG. 2, each step-down chopper circuit (16) The output voltage is synthesized as follows: V _O = V _O1 + V _O2 + V _O3 .

As described above, in the multiphase AC generator according to the present invention, as shown in FIG. 6, the “sine waveform” of each phase coil (5), (6), (7) of the three-phase AC generator is simply set. A “bridge-shaped pulsating waveform” is formed by the phase bridge rectifier circuit (15), and the “蒲 鉾 -shaped pulsating waveform” is converted into a “square sine waveform” by the duty control oscillation circuit (17) and the step-down chopper circuit (16). It is.
In order to obtain this square sine waveform, a duty proportional to the input instantaneous voltage (V _i ) is intentionally used without using a smoothing circuit, and a “蒲 鉾 -shaped pulsation waveform: input instantaneous voltage (V _i )” is used. The ratio α (ON / OFF control pulse) is given to the semiconductor switch of the step-down chopper circuit (16).

  The operation theory (theoretical calculation) of the multiphase AC power generator (1) according to the present invention will be described with reference to FIGS.

Input instantaneous voltage of step-down chopper circuit: V _i
Output instantaneous voltage of step-down chopper circuit: V _o
Duty ratio: α
Then, the output instantaneous voltage (V _o ) is proportional to the duty ratio (α) and the input instantaneous voltage (V _i ).

V _o = α · V _i (Equation 1)

When the duty control oscillation circuit (17) shown in FIG. 2 controls the duty ratio (α) applied to the semiconductor switch of the step-down chopper circuit (16) to be proportional to the input instantaneous voltage (V _i ),
Ie

α = k · V _i ··············································

Then, the output instantaneous voltage (V _o ) of the step-down chopper circuit (16) is expressed by (Equation 1) and (Equation 2):

V _o = k · V _i ² (Equation 3)

Thus, the waveform of the square of the input instantaneous voltage V _i is obtained.

Here, as shown in FIG. 7, the input voltage to the step-down chopper circuit (16) is a sine wave voltage indicated by a dotted line, and the output of the single-phase bridge rectifier circuit (15: full wave rectifier circuit) is a negative voltage. It becomes like the broken line in FIG.
this is,

V _i = | V _m · sin ωt | (Equation 4)

It can be expressed as

At this time, the square output waveform is expressed by (Equation 3) and (Equation 4).

V _o = k · | V _m · sin ωt | ²

= KV _m ² · sin ² ωt

= (1/2) k · V _m ² (1-cos 2ωt) (5)

It becomes.
This, as shown by the solid line in FIG. 7, a cosine waveform amplitude at twice the frequency from 0 to V _m around the V m _{/ 2.}

Connect the same circuit to all three phases. Since the voltage of each phase of the three-phase alternating current is shifted by 1/3 period,

V ₁ = V _m · sin ωt (6)

V ₂ = V _m · sin [ωt + 2π / 3] (Equation 7)

V ₃ = V _m · sin [ωt + 4π / 3] (Equation 8)

It is represented by

The output of the square waveform circuit connected to each of the 1st to 3rd phases

V _o1 = (1/2) kV _m ² [1-cos 2ωt] (Equation 9)

V _o2 = (1/2) kV _m ² [1-cos (2ωt + 4π / 3)]

= (1/2) kV _m ² [1- (cos2ωt · cos4π / 3
-Sin2ωt · sin4π / 3)]

= (1/2) kV _m ² [1-{(− 1/2) cos2ωt
+ (√3 / 2) sin2ωt}] (Equation 10)

V _o3 = (1/2) kV _m ² [1-cos (2ωt + 8π / 3)]

= (1/2) kV _m ² [1- (cos2ωt · cos2π / 3
-Sin2ωt · sin2π / 3)]

= (1/2) kV _m ² [1-{(− 1/2) cos2ωt
+ (√3 / 2) sin2ωt}] (Equation 11)

It becomes.

When these are illustrated, the dotted line waveforms in FIG. 8 are obtained, and when all are connected in series, the voltage becomes the sum, so all the amplitude components of the trigonometric function are canceled,
V _out = V _o1 + V _o2 + V _o3

= (3/2) kV _m ²

Thus, a DC voltage is output.

  Next, a specific configuration and operation of the duty control oscillation circuit (17) will be described with reference to FIGS.

  As shown in FIG. 9, the duty control oscillation circuit (17) includes a voltage dividing circuit (51), a variable gain amplification circuit (52), a peak voltage detection circuit (53), and a voltage-pulse width conversion oscillation circuit (54). Consists of

In duty control oscillation circuit (17) shown in FIG. 9, the voltage dividing circuit (51) generates a 1 / d times the voltage waveform of the input voltage dividing input voltage V _i, also the variable gain amplifier circuit (52) Vs = Av · V _i / d is obtained as the signal voltage by outputting the input voltage by Av times (the value of Av is adjusted by the gain adjustment signal voltage). The voltage-pulse width conversion oscillating circuit (54) generates a pulse voltage waveform having a length (time) proportional to the signal voltage Vs at a constant frequency, that is, every constant period T.

In FIG. 9, since the duty ratio (α) cannot exceed 1 (100%) in the pulse voltage waveform generated from the duty control oscillation circuit (17), the pulse width cannot be longer than the oscillation period T of oscillation. . Therefore, the input signal voltage necessary for the duty ratio (α) to be 1 is determined as the maximum value V _T of the signal voltage, and the maximum value Vsmax = Av · V _m / d of the signal voltage when the input voltage is the maximum value Vm. The gain Av of the variable gain amplifier circuit (52) is adjusted so that does not exceed the maximum value V _T. The signal voltage Vs that is the output of the variable gain amplifier circuit (52) is monitored to detect the peak voltage Vsmax, and a signal voltage for adjusting the gain of the variable gain amplifier circuit (52) is supplied based on the detected peak voltage. To do.

If the amplitude Vm of the input voltage V _i (the maximum value of the input voltage waveform) is small, the variable gain amplifier circuit (52) as shown in Figure 10 amplifies the signal voltage operates at a constant maximum gain Avmax, voltage - pulse This is supplied to the width conversion oscillation circuit (54). In this case the duty ratio (alpha) is proportional to the input voltage V _i, the maximum value αmax of the duty ratio (alpha) as illustrated in FIG. 11 is proportional to the input voltage amplitude Vm. The proportional coefficient k of the duty ratio with respect to the input voltage is constant. Since the output voltage is V _out = (3/2) kV _m ² and k is constant, the output voltage increases in proportion to the square of the input voltage amplitude.

When the input voltage amplitude Vm increases and the variable gain amplifier circuit (52) operates at the maximum gain Avmax, if the signal voltage Vs tries to exceed the predetermined maximum value V _T , the peak voltage detection circuit (53) The maximum value of the voltage is detected, and the gain Av is decreased in inverse proportion to the increase of the input voltage amplitude Vm as shown in FIG. As a result, it is possible to generate a signal voltage waveform such that the maximum value of the signal voltage Vs always becomes a predetermined maximum value V _T, and the maximum value αmax of the duty ratio (α) is the input voltage amplitude as shown in FIG. It operates so as to be 1 regardless of the magnitude of Vm. Therefore, since αmax = k · Vm = 1, the output voltage V _out = (3/2) kV _m ² = (3/2) V _m , and the output voltage is proportional to the input voltage amplitude.

Next, an embodiment of the multiphase AC power generator according to the present invention will be described.
The output voltage amplitude of the AC generator, that is, the input voltage amplitude to the circuit, increases in proportion to the rotational speed f of the generator. In the embodiment of FIG. 12, the rotational speed f is 50 r. p. m. When the power supply circuit starts operating and an output voltage is generated, and when the rotation speed f is small and the value of V _m is small, the output voltage Vo increases in proportion to the rotation speed, that is, the square of the input voltage amplitude, and the rotation speed f is constant. It is confirmed that the output voltage Vo increases in direct proportion to the rotation speed f, that is, the input voltage amplitude, when the value exceeds 140m (140 rpm) in the embodiment.

In the multiphase AC generator according to the present invention, when the duty ratio (α) given to the step-down chopper circuit (semiconductor switch) is controlled to be proportional to the input instantaneous voltage (V _i ), the input instantaneous voltage (V _i ) can be converted into an instantaneous voltage output proportional to the square of 2).
As a result, a DC voltage with less ripple can be obtained, the input power (rotation speed × rotation torque) is always constant, and the vibration and noise of the multiphase AC generator are small.

Further, a higher voltage can be obtained as compared with the three-phase bridge rectifier circuit. That is, in the three-phase bridge rectifier circuit, as shown in FIG. 8, the maximum is V _m , and in the multiphase AC power generator according to the present invention, it is 1.5 V _m that is 3/2 times as shown in FIG. (However, _Vm is a sinusoidal voltage amplitude).

  Furthermore, in the multiphase AC power generator according to the present invention, the circuit configuration is simpler than that of the conventional high efficiency converter, and a quick response to the voltage and frequency fluctuations of the generator is possible.

  In the multiphase AC generator according to the present invention, a three-phase AC generator has been described. However, the present invention is not limited to this, and a multiphase including two phases (phases shifted by a quarter cycle) and four or more phases is provided. It may be applied to the AC generator. In this case, an AC voltage is output independently for each phase, and a square waveform circuit corresponding to each phase is connected.

  Further, in the multiphase AC generator according to the present invention, the duty control oscillation circuit is controlled so that the output voltage becomes higher as the number of revolutions of the generator increases as in the conventional bridge rectifier circuit. In order to match the characteristics, it is also possible to perform duty control so that the output voltage Vo becomes constant regardless of the rotational speed f of the generator.

  The present invention is suitably used for voltage control of a multiphase AC generator.

DESCRIPTION OF SYMBOLS 1 Multiphase alternating current generator 2 Multiphase alternating current generator 3 Voltage control apparatus 5 1 phase electromagnetic coil 6 2 phase electromagnetic coil 7 3 phase electromagnetic coil 15 Single phase bridge rectifier circuit 16 Step-down chopper circuit 17 Duty control oscillation circuit 18 Power supply circuit A1 1-phase square waveform circuit B1 2-phase square waveform circuit C1 3-phase square waveform circuit

Claims (2)

In a polyphase AC generator, and a polyphase AC generator comprising a voltage control device that converts an AC voltage of the multiphase AC generator into a DC voltage and outputs the DC voltage,
The multi-phase AC generator is
The polyphase is made independent for each phase, and an AC voltage is output for each independent phase.
The voltage controller is
It is connected independently for each independent phase, and has a square waveform circuit corresponding to each phase,
The square wave circuit is
A single-phase bridge rectifier circuit connected to the corresponding phase and rectifying an alternating voltage of the phase;
A step-down chopper circuit that is connected to the output side of the single-phase bridge rectifier circuit, converts an input voltage waveform input from the single-phase bridge rectifier circuit, and outputs an output voltage waveform;
A duty control oscillation circuit that is connected to an output side of the single-phase bridge rectifier circuit and controls a duty ratio applied to a semiconductor switch of the step-down chopper circuit;
The duty control oscillation circuit includes:
Monitoring the input instantaneous voltage input to the step-down chopper circuit from the single-phase bridge rectifier circuit, and controlling the duty ratio applied to the semiconductor switch of the step-down chopper circuit to be proportional to the input instantaneous voltage;
The multiphase AC power generator according to claim 1, wherein the square waveform circuit of each phase is connected in series on the output side of the step-down chopper circuit.   2. The square wave circuit includes a power supply circuit that is connected to an output side of the single-phase bridge rectifier circuit and supplies power to the duty control oscillation circuit and the step-down chopper circuit. The multiphase AC power generator described in 1.

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