Radio-frequency isolated gate driver for power semiconductors

Patent metadata

Field	Value
Publication number	US-10659036-B2
Application number	US-201916287058-A
Country	US
Kind code	B2
Filing date	Feb 27, 2019
Priority date	Feb 27, 2018
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

A gate driver for power semiconductors is disclosed. The gate driver includes modulation to modulate signals from a controller to a radio frequency (RF) range that is much higher than frequencies associated with conducted EMI. The gate driver also includes RF transformer and tank circuit to that couples the modulated signals, filters EMI, and provides galvanic isolation. The gate driver further includes a RF demodulator and unfolder circuit for converting the RF signal into a signal appropriate for controlling the gate of a power semiconductor for switching. Additionally, the disclosed gate driver provides active gate control using programmable waveforms with values that can range over a continuous range of voltages.

First claim

The invention claimed is:

1. A radio frequency (RF) isolated gate driver, comprising
an RF modulator that receives a control signal from a controller and outputs a carrier frequency that is modulated by the control signal from the controller, wherein the carrier frequency is higher than frequencies corresponding to conducted electromagnetic interference (EMI);
an RF transformer tuned to the carrier frequency and connected at a primary side to the RF modulator, wherein the RF transformer spatially couples energy from the primary side to a secondary side, and wherein the RF transformer filters the frequencies corresponding to conducted EMI, and wherein the RF transformer provides galvanic isolation between the primary side and the secondary side;
an RF demodulator connected to the secondary side of the RF transformer that receives the modulated carrier frequency and outputs a demodulated control signal; and
an unfolder circuit connected to the RF demodulator that receives the demodulated control signal and outputs a gate signal for driving a gate of a power semiconductor.

2. The RF isolated gate driver according to claim 1 , further comprising a resonant tank circuit.

3. The RF isolated gate driver according to claim 2 , wherein the resonant tank circuit connected between the RF modulator and the primary side of the RF transformer.

4. The RF isolated gate driver according to claim 2 , wherein the resonant tank circuit is part of the RF transformer.

5. The RF isolated gate driver according to claim 1 , wherein the carrier frequency and the frequencies corresponding to the conducted EMI are separated by more than 100 megahertz.

6. The RF isolated gate driver according to claim 1 , wherein the RF modulator comprises a voltage controlled oscillator.

7. The RF isolated gate driver according to claim 6 , wherein:
the control signal from the controller comprises an analog signal that describes an on/off profile, and wherein
the voltage controlled oscillator outputs the carrier frequency modulated by the control signal describing the on/off profile.

8. The RF isolated gate driver according to claim 6 , wherein:
the control signal from the controller comprise a multibit digital signal that describes an active gating profile, and wherein:
the RF modulator further comprises a digital to analog converter (DAC) that converts the multibit digital signal into an analog signal that describes an active gating profile, and wherein:
the voltage controlled oscillator outputs the carrier frequency modulated by the analog signal describing the active gating profile.

9. The RF isolated gate driver according to claim 1 , wherein the unfolder circuit includes amplification and level shifting.

10. The RF isolated gate driver according to claim 1 , wherein the conducted EMI corresponds to transients or ringing from switching the power semiconductor.

11. A power electronics system comprising:
a controller configured to output a control signal for controlling a power semiconductor;
a power semiconductor configured to switch high power according to a gate signal applied to a gate of the power semiconductor; and
a radio-frequency (RF) isolated gate driver, comprising:
an RF modulator that receives the control signal from the controller and outputs a carrier frequency that is modulated by the control signal from the controller, wherein the carrier frequency is higher than frequencies corresponding to conducted electromagnetic interference (EMI);
an RF transformer tuned to the carrier frequency and connected at a primary side to the RF modulator, wherein the RF transformer spatially couples energy from the primary side to a secondary side, and wherein the RF transformer filters the frequencies corresponding to EMI, and wherein the RF transformer provides galvanic isolation between the primary side and the secondary side;
an RF demodulator connected to the secondary side of the RF transformer that receives the modulated carrier frequency and outputs a demodulated control signal; and
an unfolder circuit connected to the RF demodulator that receives the demodulated control signal and outputs the gate signal for driving the gate of the power semiconductor.

12. The power electronics system according to claim 11 , further comprising a resonant tank circuit.

13. The power electronics system to claim 12 , wherein the resonant tank circuit connected between the RF modulator and the primary side of the RF transformer.

14. The power electronics system according to claim 12 , wherein the resonant tank circuit is part of the RF transformer.

15. The power electronics system according to claim 11 , wherein the carrier frequency and the frequencies corresponding to the conducted EMI are separated by more than 100 megahertz.

16. The power electronics system according to claim 11 , wherein the RF modulator comprises a voltage controlled oscillator.

17. The power electronics system according to claim 16 , wherein:
the control signal from the controller comprises an analog signal that describes an on/off profile, and wherein
the voltage controlled oscillator outputs the carrier frequency modulated by the analog signal describing the on/off profile.

18. The power electronics system according to claim 16 , wherein:
the control signal from the controller comprises a multibit digital signal that describes an active gating profile, and wherein:
the RF modulator further comprises a digital to analog converter (DAC) that converts the multibit digital signal into an analog signal that describes an active gating profile, and wherein:
the voltage controlled oscillator outputs the carrier frequency modulated by the analog signal describing the active gating profile.

19. The power electronics system according to claim 11 , wherein the unfolder circuit includes amplification and level shifting.

20. The power electronics system according to claim 11 , wherein the conducted EMI corresponds to transients or ringing from switching the power semiconductor.

21. A method of driving power electronics, the method comprising:
providing a power semiconductor configured to switch high power according to a gate signal applied to a gate of the power semiconductor;
providing a controller configured to output a control signal for controlling the power semiconductor;
modulating the control signal from the controller to a frequency higher than conducted electromagnetic interference (EMI);
using an RF transformer to pass the modulated control signal, filter the conducted EMI, and provide galvanic isolation;
demodulating the modulated control signal passed by the RF transformer;
unfolding the demodulated control signal to create a gate signal; and
applying the gate signal to the gate of the power semiconductor.

Assignees

• Univ Florida State Res Found Inc

Inventors

• Li Hui
• Shi Yanjun

Classifications

• H02M1/08 Primary

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title

• H03K17/162 Primary

  without feedback from the output circuit to the control circuit · CPC title

• H03K2217/0081

  Power supply means, e.g. to the switch driver · CPC title

• H03K17/0822

  in field-effect transistor switches · CPC title

• H03K17/691

  using transformer coupling · CPC title