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EP-4740295-A1 - A CLOSED-LOOP CONTROL METHOD FOR ZERO VOLTAGE SWITCHING CONVERTERS

EP4740295A1EP 4740295 A1EP4740295 A1EP 4740295A1EP-4740295-A1

Abstract

Herein is disclosed a controller for an auxiliary resonant commutated pole (ARCP) converter, the controller comprising: a sensor section comprising: a ZVD sensor configured to measure a voltage across a switch of the converter, and detect when the voltage across the switch equals zero; a dv/dt sensor configured to measure a change in the voltage over time across the switch, and detect a voltage transition across the switch; and a gate sensor configured to measure a gate-source voltage of the switch, and detect when the gate-source voltage is sufficient for the switch to transition between OFF and ON; and a control section configured to: receive measurements from the ZVD sensor, the dv/dt sensor, and the gate sensor; and generate a control signal for the switch based at least in part on the measurements received from the ZVD sensor, the dv/dt sensor, and the gate sensor.

Inventors

  • AMINI, Jalal
  • BERGER, ARI
  • HAMOND, JAMES
  • HENGSTENBERGER, HARALD

Assignees

  • Hillcrest Energy Technologies Ltd.

Dates

Publication Date
20260513
Application Date
20240705

Claims (20)

  1. 1 . A controller for an auxiliary resonant commutated pole (ARCP) converter, the controller comprising: a sensor section comprising: a ZVD sensor configured to measure a voltage across a switch of the converter, and detect when the voltage across the switch equals zero; a dv/dt sensor configured to measure a change in the voltage over time across the switch, and detect a voltage transition across the switch; and a gate sensor configured to measure a gate-source voltage of the switch, and detect when the gate-source voltage is sufficient for the switch to transition between OFF and ON; and a control section configured to: receive measurements from the ZVD sensor, the dv/dt sensor, and the gate sensor; and generate a control signal for the switch based at least in part on the measurements received from the ZVD sensor, the dv/dt sensor, and the gate sensor.
  2. 2. The controller according to claim 1 , wherein the control section is further configured to receive a load current, a first DC link voltage VC1 , and a second DC link voltage VC2, wherein one or both of VC1 and VC2 can be measured directly or indirectly, and generate the control signal for the switch based at least in part on one or more of the load current, VC1 , and VC2.
  3. 3. The controller according to claim 2, wherein the controller is configured to determine one of VC1 and VC2 from a DC voltage.
  4. 4. The controller according to any one of claims 1 to 3, wherein the switch is a main switch of the converter.
  5. 5. The controller according to any one of claims 1 to 3, wherein the switch is an auxiliary switch of the converter.
  6. 6. The controller according to any one of claims 1 to 5, wherein the control section is further configured to: determine a resonance time of the converter; and generate the control signal based at least in part on the resonance time.
  7. 7. The controller according to any one of claims 1 to 6, wherein the control section further comprises a feed-forward section, and control section is further configured to: determine an ideal switch signal for the switch with the feed-forward section; and generate the control signal based at least in part on the ideal switch signal.
  8. 8. The controller according to claim 7, wherein the sensor section further comprises a Delink voltage sensor and a load current sensor, and determining the ideal switch signal for the switch comprises determining the ideal switch signal at least based in part on a Delink voltage measured with the DC-link voltage sensor and a load current measured with the load current sensor.
  9. 9. The controller according to either of claims 7 and 8, wherein determining the ideal switch signal comprises determining the ideal switch signal based at least in part on one or more nominal values of one or more electrical components of the converter.
  10. 10. The controller according to any one of claims 1 to 9, wherein generating the control signal for the switch comprises determining a charging time for the switch, and generating the control signal comprises generating the control signal based at least in part on the charging time.
  11. 1 1. The controller according to any one of claims 1 to 10, wherein generating the control signal for the switch comprises determining a dead time for the switch, and generating the control signal comprises generating the control signal based at least in part on the dead time.
  12. 12. A controller for an auxiliary resonant commutated pole (ARCP) converter, the controller comprising: a sensor section comprising: a first ZVD sensor configured to measure a voltage across a first switch of the converter, and detect when the voltage across the first switch equals zero; a first dv/dt sensor configured to measure a change in the voltage over time across the first switch, and detect a voltage transition across the first switch; and a first gate sensor configured to measure a gate-source voltage of the first switch, and detect when the gate-source voltage is sufficient for the first switch to transition between OFF and ON; a second ZVD sensor configured to measure a voltage across a second switch of the converter, and detect when the voltage across the second switch equals zero; a second dv/dt sensor configured to measure a change in the voltage over time across the second switch, and detect a voltage transition across the second switch; and a second gate sensor configured to measure a gate-source voltage of the second switch, and detect when the gate-source voltage is sufficient for the second switch to transition between OFF and ON; and a control section configured to: receive measurements from the first ZVD sensor, the second ZVD sensor, the first dv/dt sensor, the second dv/dt sensor, the first gate sensor, and the second gate sensor; generate a first control signal for the first switch based at least in part on the measurements received from one or more of: the first ZVD sensor, the second ZVD sensor, the first dv/dt sensor, the second dv/dt sensor, the first gate sensor, and the second gate sensor; and generate a second control signal for the second switch based at least in part on the measurements received from one or more of: the first control signal, the first ZVD sensor, the second ZVD sensor, the first dv/dt sensor, the second dv/dt sensor, the first gate sensor, and the second gate sensor.
  13. 13. The controller according to claim 12, wherein the first switch is one of a first main switch of the converter and a first auxiliary switch of the converter.
  14. 14. The controller according to either of claims 12 and 13, wherein the second switch is one of a second main switch of the converter and a second auxiliary switch of the converter.
  15. 15. A method for controlling an auxiliary resonant commutated pole (ARCP) converter, the method comprising: receiving a ZVD sensor signal from a ZVD sensor, wherein the ZVD sensor signal represents a voltage across a switch of the ARCP converter; receiving a dv/dt sensor signal from a dv/dt sensor, wherein the dv/dt sensor signal represents a change in the voltage over time across the switch; receiving a gate sensor signal from a gate sensor, wherein the gate sensor signal represents a gate-source voltage of the switch; and generating a control signal for the switch based at least in part on the ZVD sensor signal, the dv/dt sensor signal, and the gate sensor signal.
  16. 16. The method according to claim 15, wherein the ZVD sensor signal indicates when the voltage across the switch equals zero.
  17. 17. The method according to either of claims 15 and 16, wherein the dv/dt sensor signal indicates when a voltage transition across the switch occurs.
  18. 18. The method according to any one of claims 15 to 17, wherein the gate sensor signal indicates when the voltage is sufficient for the switch to transition between OFF and ON.
  19. 19. The method according to any one of claims 15 to 18, wherein the switch is a main switch of the converter.
  20. 20. The method according to any one of claims 15 to 18, wherein the switch is an auxiliary switch of the converter.

Description

A CLOSED-LOOP CONTROL METHOD FOR ZERO VOLTAGE SWITCHING CONVERTERS Cross-Reference to Related Applications [1] This application claims priority from application No. 63/524,976, filed 5 July 2023. For purposes of the United States, this application claims the benefit under 35 U.S.C. §1 19 of application No. 63/524,976, filed 5 July 2023, and entitled Closed-loop Control Method for Zero Voltage Switching Converters, which is hereby incorporated herein by reference for all purposes. Technical Field [2] This disclosure is directed to systems and methods for control of zero voltage switching converters. More particularly, the present disclosure is directed to systems and methods for closed-loop control of zero voltage switching converters. Background [3] Power converters play an important role in various industries such as transportation, entertainment, energy and food chains, as well as in applications like electrical drives, electric vehicles (EVs), renewable energy harvesting, power conditioning, and the like. In recent years, with increased attention to carbon-emission reduction and renewable energy harvesting, their penetration in power systems has been increasing. [4] Because of converter switches’ non-idealities, they generate losses which can be divided into two parts, conduction losses and switching losses. These losses appear as heat on the switches. This heat reduces the lifetime of the switches, and efficiency and the reliability of the converter. In addition to causing heat, the switching losses limit the maximum switching frequency that the converter can run at. The limited switching frequency also hinders the converter’s ability to achieve better output power quality, higher power density, and lower cost. Increasing switching frequency leads to better power quality, smaller passive component values and consequently to a more compact and cost-effective converter. [5] One way to reach higher switching frequency is to reduce the switching losses thereby lowering junction temperature of the switching devices. Lower losses also help to save energy and reduce carbon emissions, thereby making the power system more environmentally friendly. Therefore, reducing losses is of great interest. Besides, considering an increasing number of sensitive loads in a power grid like data processing system, and the like, the electromagnetic compatibility (EMC) of power converters is also an important issue that needs attention. [6] Switching losses in a power semiconductor device arise as a result of the overlapping of rising and falling edges of the voltage across the device with falling and rising edges of the current flowing through the device, respectively. [7] One way to reduce the switching losses is by shortening the overlapping time via increasing rising and falling rates of the current and the voltage. To do so, wide-bandgap devices have been introduced to the market. Although wide-bandgap devices have lower losses compared to silicon-based devices, their utilization involves dealing with problems like electromagnetic interference (EMI) challenges and problems related to rapid changes in voltage over time (referred to as “dv/dt”) which may damage some loads like motors. [8] Another way of reducing the switching losses is adapting a zero voltage switching scheme based on a resonance circuit. A resonance circuit brings the voltage over the switching device to zero before a switching event and eliminates the overlap between transition edges of voltage and current, which leads to zero switching losses. This can be known as “soft-switching”. [9] Several soft-switching methods have been proposed to reduce switching losses in DC/DC, AC/DC, and DC/AC converters. However, many of these methods, which may be referred to as “open-loop control”, use the nominal value of the components and known working points in calculating proper switching times to provide zero voltage switching, while components not only have tolerances in their values but also their values depend on their working conditions like temperature, voltage, and the like. Furthermore, actual components have parasitic parameters such as output capacitance of the switches, parasitic inductance, and the like, that are also working-condition dependant in nature. Furthermore, these is some deviation on working point because of change in temperature, the nature of a load powered by the converter, and source conditions. Therefore, such open-loop control suffers from partial hard switching and losses induced by incorrect switching times due to the above-referenced deviations. [10] There is a need for an improved method of zero voltage switching. Furthermore, there is a need for and improved method of zero voltage switching able to at least partially compensate for errors introduced by non-idealities, component tolerances, dynamically-changing behaviors, and the like. Summary [11] According to a part of the disclosure, there is provided a closed-loop zero voltage sw