RF band power supply device and pulse width modulation control method

Patent metadata

Field	Value
Publication number	US-12323074-B2
Application number	US-202118281023-A
Country	US
Kind code	B2
Filing date	Dec 17, 2021
Priority date	Mar 9, 2021
Publication date	Jun 3, 2025
Grant date	Jun 3, 2025

Abstract

The pulse width modulation control method and RF band power supply device according to the present invention are a pulse width modulation (PWM) control of a single phase PWM inverter in which the modulated wave frequency fs of a modulated wave is set in the RF band. The present control includes each of (a) a frequency synchronization control in which the carrier wave frequency fc of the carrier wave is set to even N times the modulated wave frequency fs, (b) an odd function control in which the modulated wave is set to a sine wave of an odd function and the carrier wave is set to a triangle wave of an odd function, and (c) a phase synchronization control in which the carrier wave is synchronized in phase with the modulated wave in each cycle of the modulated wave.

First claim

The invention claimed is:

1. An RF band power supply device, comprising:
a DC power source;
a single-phase PWM inverter that comprises a single-phase full-bridge circuit formed by parallel-connecting two legs having switching elements on upper and lower arms between a positive end and a negative end of the DC power source, and convert a DC input supplied from the DC power source into an AC output by an ON/OFF operation of each switching element; and
an inverter controller that compares a modulation wave with a carrier wave to generate a gate signal, and turns on and off the switching element by using the gate signal as a PWM pulse signal, so as to perform pulse width modulation (PWM) control on the single-phase PWM inverter,
wherein the inverter controller comprises:
a PWM control unit and a modulation wave/carrier wave generation unit for generating the gate signal,
the modulation wave/carrier wave generation unit sets a modulation wave frequency fs of the modulation wave as a frequency in an RF band,
wherein the modulation wave/carrier wave generation unit further comprises:
a frequency synchronization unit that makes a carrier wave frequency fc of the carrier wave to be even-number N times higher than the modulation wave frequency fs;
an odd function control unit that controls the modulation wave to be a sine wave of an odd function and the carrier wave to be a triangular wave of an odd function; and
a phase synchronization unit that synchronizes a phase of the carrier wave with a phase of the modulation wave in each period of the modulation wave.

2. The RF band power supply device according to claim 1 , wherein the frequency synchronization unit makes the carrier wave to be point symmetry in which positive and negative of the carrier wave are reversed at a phase time point as a reference time point of a half period a in one period 2π of the modulation wave.

3. The RF band power supply device according to claim 1 or 2 , wherein the odd function control unit alternates a time-series pattern of a gate signal in an anterior half period of the modulation wave and a time-series pattern of a gate signal in a posterior half period of the modulation wave for each half period π of the modulation wave in each one period 2π of the modulation wave for each leg, so as to generate a gate signal having alternation at the phase time point in the half period π as the reference time point.

4. The RF band power supply device according to claim 3 , wherein the power supply device has two modulation waves having opposite phases, and
the odd function control unit is configured to:
generate a gate signal with a first time-series pattern in which the time-series patterns are identical with each other for driving a switching element of one of the legs in the anterior half period of the modulation wave while driving a switching element of the other leg in the posterior half period of the modulation wave by comparing one of the modulation waves having the opposite phases with the carrier wave;
generate a gate signal with a second time-series pattern in which the time-series patterns are identical with each other for driving a switching element of the one of the legs in the posterior half period of the modulation wave while driving a switching element of the other leg in the anterior half period of the modulation wave by comparing the other modulation wave which is out of phase by π with respect to the one of the modulation waves;
provide the alternation at a phase time point in the half period π as a reference time point in the one period of the modulation wave to two gate signals, in which the order is altered between the gate signal with the first time-series pattern and the gate signal with the second time-series pattern at the phase time point in the half period π of the modulation wave as the reference time point; and
perform drive control on each switching element of each leg in the one period of the modulation wave by switching the gate signal with the first time-series pattern and the gate signal with the second time-series pattern for each half period, so as to convert the DC input into the AC output by the pulse width modulation (PWM).

5. The RF band power supply device according to claim 3 , wherein the power supply device has two modulation waves having opposite phases, and
the odd function control unit is configured to:
generate a gate signal with a first time-series pattern in which the time-series patterns are identical with each other for driving a switching element of one of the legs in the anterior half period of the modulation wave while driving a switching element of the other leg in the posterior half period of the modulation wave by comparing one of the modulation waves having the opposite phases with the carrier wave;
generate a gate signal with a second time-series pattern in which the time-series patterns are identical with each other for driving a switching element of the one of the legs in the posterior half period of the modulation wave while driving a switching element of the other leg in the anterior half period of the modulation wave by comparing the other modulation wave which is out of phase by π with respect to the one of the modulation waves;
provide the symmetry at a phase time point in the quarter-period as a reference time point in the half period between the gate signal with the first time-series pattern and an inverted signal of the gate signal with the second time-series pattern in the half period of the modulation wave; and
perform drive control on each switching element of each leg in the one period of the modulation wave by switching the gate signal with the first time-series pattern and the gate signal with the second time-series pattern for each half period, so as to convert the DC input into the AC output by the pulse width modulation (PWM).

6. The RF band power supply device according to claim 4 , wherein the PWM control unit comprises two comparison circuits,
one of the two comparison circuits comparing one of modulation waves S having opposite phases with a carrier wave C to generate a gate signal for driving the switching element of one of the two legs,
the other comparison circuit of the two comparison circuits comparing the other modulation wave S having the opposite phase with the carrier wave C to generate a gate signal for driving the switching element of the other leg of the two legs.

7. The RF band power supply device according to claim 1 , wherein the odd function control unit reverses a time-series pattern of a gate signal in an anterior quarter-period and a time-series pattern of a gate signal in a posterior quarter-period of the modulation wave in each half period π of the modulation wave at a point π/2 of a quarter-period of the modulation wave for each leg, so as to generate a gate signal that is symmetrical at a phase time point of the quarter-period π/2 as a reference time point.

8. A pulse width modulation control method for a single-phase PWM inverter that generates a gate signal based on a comparison between a modulation wave in an RF band and a carrier wave, and performs pulse width modulation (PWM) control on the single-phase PWM inverter by using the generated gate signal as a PWM pulse signal to output a sine wave in the RF band,
defining a modulation wave frequency fs of the modulation wave as a frequency in the RF band,
the pulse width modulation control method comprising:
a frequency synchronization control step for defining a carrier wave frequency fc of the carrier wave to be even-number N times higher than the modulation wave frequency fs;
an odd function control step for controlling the modulation wave to be a sine wave of an odd function and the carrier wave to be a triangular wave

Assignees

• Kyosan Electric Mfg

Inventors

• Yuzurihara Itsuo
• Yoneyama Tomohiro
• Kobayashi Shohei
• Hosoyamada Yu

Classifications

• H02M7/53871

  with automatic control of output voltage or current · CPC title

• H02M1/12

  Arrangements for reducing harmonics from AC input or output · CPC title

• H02M1/0025

  Arrangements for modifying reference values, feedback values or error values in the control loop of a converter · CPC title

• H01J37/32174

  Circuits specially adapted for controlling the RF discharge · CPC title

• H02M7/5387 Primary

  in a bridge configuration · CPC title