# US 11,116,068 B2 · High voltage generator and control methods thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,116,068 B2 - Document ID: US11116068B2 - Status: Granted - Kind: B2 - Application number: 16/235,186 - Filed: 2018-12-28 - Published: 2019-06-27 - Granted: 2021-09-07 - Earliest claimed: 2017-11-03 - Assignees: Shanghai Unted Imaging Healthcare Co., Ltd.; Shanghai Advanced Research Institute, Chinese Academy of Sciences - Applicants: Shanghai United Imaging Healthcare Co., Ltd.; Shanghai Advanced Research Institute, Chinese Academy of Sciences - Inventors: Guoping Zhu; Xu Chu - Web page: https://patentgrep.com/patent/US11116068B2 ## CPC - H05G 1/12: with DC or rectified single-phase AC {or double-phase} - H02M 1/081: {wherein the phase of the control voltage is adjustable with reference to the AC source} - H02M 3/01: {Resonant DC/DC converters} - H02M 3/33573: {Full-bridge at primary side of an isolation transformer} - H02M 3/3376: {with automatic control of output voltage or current} - H02M 1/0009: {Devices or circuits for detecting current in a converter} - H02M 1/0058: {by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero (using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826)} - H02M 1/346: {Passive non-dissipative snubbers} - Y02B 70/10: Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes - H05G: X-RAY TECHNIQUE (investigating or analysing materials by the use of X-rays G01N23/00; apparatus for X-ray photography G03B42/02; X-ray tubes H01J35/00; TV systems having X-ray input H04N5/321) - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract A high voltage generator is provided. The high voltage generator includes an inverter circuit coupled to receive a direct-current (DC) input voltage, a resonant circuit coupled to the inverter circuit, a transformer coupled to the resonant circuit and also coupled to provide a high voltage output to a high voltage device, and a phase control circuit coupled to receive a voltage across and a current through the resonant circuit and also coupled to the inverter circuit. The phase control circuit generates control signals to drive the inverter circuit. The control signals drive the inverter circuit to keep the resonant circuit operating in an inductive region. ## Claims ### Claim 1 A high voltage generator, comprising: an inverter bridge including a first bridge leg and a second bridge leg, the first bridge leg or the second bridge leg including at least two switch transistors distributed in series; a first resonant branch coupled in series to the first bridge leg; a transformer coupled in series between the first resonant branch and the second bridge leg; a second resonant branch coupled in parallel with the transformer, wherein the second resonant branch includes a capacitor and an inductor, a first end of the capacitor is connected to a first end of the inductor, a second end of the capacitor is connected to a first end of the transformer, and a second end of the inductor is connected to a second end of the transformer; and a rectifier circuit coupled with the transformer for providing an output voltage to an X-ray source. ### Claim 2 (depends on 1) The high voltage generator of claim 1, wherein the first resonant branch comprises a series resonant branch comprising capacitors and/or inductors. ### Claim 3 (depends on 1) The high voltage generator of claim 1, wherein the second resonant branch is coupled in parallel with the primary side or the secondary side of the transformer. ### Claim 4 (depends on 1) The high voltage generator of claim 1, wherein the switch transistor comprises an IGBT transistor, the IGBT transistor is operated between a first switching frequency and a second switching frequency, the first switching frequency is determined based on the first resonant branch and the second resonant branch, the second switching frequency is determined by the second resonant branch. ### Claim 5 (depends on 1) The high voltage generator of claim 1, further comprising a control circuit, the control circuit comprising a first control branch, a second control branch, and a modulator, and both the first control branch and the second control branch being coupled to the modulator; wherein the first control branch is operable to obtain an output current and a bridge leg voltage of the inverter bridge, and to produce a first control signal based on the output current and the bridge leg voltage of the inverter bridge; wherein the second control branch is operable to receive a voltage feedback signal from the rectifier circuit or the X-ray generating device, and to produce a second control signal based on the voltage feedback signal. ### Claim 6 (depends on 5) The high voltage generator of claim 5, wherein the second control branch comprises: an adder, an input of the adder being coupled with an output of the rectifier circuit or an output of the X-ray generating device; a regulator coupled with an output of the adder; a limiter, an input of the limiter being coupled with an output of the regulator, and an output of the limiter being coupled with an input of the modulator. ### Claim 7 A high voltage generator comprising: an inverter bridge including a first bridge leg and a second bridge leg, at least one of the first bridge leg or the second bridge leg including at least two switch transistors distributed in series; a first resonant branch coupled in series to the first bridge leg; a transformer coupled in series between the first resonant branch and the second bridge leg; a second resonant branch coupled in parallel with the transformer; a rectifier circuit coupled with the transformer for providing an output voltage to an X-ray source; and a control circuit, the control circuit comprising a first control branch, a second control branch, and a modulator, and both the first control branch and the second control branch being coupled to the modulator, wherein the first control branch is operable to obtain an output current and a bridge leg voltage of the inverter bridge, and to produce a first control signal based on the output current and the bridge leg voltage of the inverter bridge, wherein the second control branch is operable to receive a voltage feedback signal from the rectifier circuit or the X-ray generating device, and to produce a second control signal based on the voltage feedback signal, wherein the first control branch comprises: a first zero-crossing comparator, an input of the first zero-crossing comparator being coupled with the output of the first bridge leg; a second zero-crossing comparator, an input of the second zero-crossing comparator being coupled with the output of the inverter bridge; a phase delay coupled in series to the first zero-crossing comparator; a phase comparator, an output of the phase delay and the output of the second zero-crossing comparator being coupled with an input of phase comparator; and a carrier generator, an input of the carrier generator being coupled with an output of the phase comparator, and an output of the carrier generator being coupled with the input of the modulator. ### Claim 8 A method for controlling a high voltage generator, the high voltage generator comprising: an inverter bridge, the inverter bridge comprising a first bridge leg and a second bridge leg, the first bridge leg and the second bridge leg being coupled in parallel, and the first bridge leg or the second bridge leg comprising two or more switch transistors distributed in series; a first resonant branch, the first resonant branch being coupled with the first bridge leg; a transformer comprising a primary side winding and a secondary side winding, the primary side winding and the first resonant branch being coupled in series, and the primary side winding being coupled with the second bridge leg; a second resonant branch, the second resonant branch being coupled in parallel to the primary side winding or the secondary side winding of the transformer, wherein the second resonant branch includes a capacitor and an inductor, a first end of the capacitor is connected to a first end of the inductor, a second end of the capacitor is connected to a first end of the transformer, and a second end of the inductor is connected to a second end of the transformer; a rectifier circuit, the rectifier circuit being coupled with the secondary side winding of the transformer for providing output voltage to an X-ray generating device; the method comprising: controlling the phase relationship between the bridge leg voltage and the output current of the inverter bridge to control a frequency of a driving signal of the switch transistors of the inverter bridge. ### Claim 9 (depends on 8) The method of claim 8, wherein controlling the phase relationship between the bridge leg voltage and the output current of the inverter bridge to control the frequency of the driving signal of the switch transistors of the inverter bridge comprises: obtaining an output current and a bridge leg voltage of the inverter bridge; generating a phase signal based on the bridge leg voltage and the output current, and generating a first control signal based on the phase signal; obtaining an output voltage of the rectifier circuit, and producing a second control signal based on the output voltage of the rectifier circuit; and generating a driving signal for the switch transistors for driving the switch transistors to operate based on the first control signal and the second control signal. ### Claim 10 (depends on 8) The method of claim 8, wherein the phase of the bridge leg voltage is ahead of the phase of the output current of the inverter bridge. ### Claim 11 (depends on 8) The method of claim 8, wherein the first bridge leg is configured to couple to the anode of an X-ray generation device, the second bridge leg is configured to couple to the cathode of the X-ray generating device. ### Claim 12 (depends on 8) The method of claim 8, wherein the first bridge leg or the second bridge leg comprises a plurality of IGBT transistors, the plurality of IGBT transistors are operated between a first switching frequency and a second switching frequency, the first switching frequency is determined based on the first resonant branch and the second resonant branch, the second switching frequency is determined by the second resonant branch. ### Claim 13 A high voltage generator, comprising: an inverter circuit coupled to receive a direct-current (DC) input voltage, wherein the inverter circuit includes a first bridge leg and a second bridge leg, the first bridge leg or the second bridge leg including at least two switch transistors distributed in series; a resonant circuit coupled to the inverter circuit, wherein the resonant circuit includes a first resonant branch coupled in series to the first bridge leg and a second resonant branch coupled in parallel with a transformer; the transformer coupled in series between the first resonant branch and the second bridge leg, and also coupled to a rectifier circuit, wherein the rectifier circuit is configured to provide a high voltage output to an X-ray source, wherein the second resonant branch includes a second capacitor and a second inductor, a first end of the second capacitor is connected to a first end of the second inductor, a second end of the second capacitor is connected to a first end of the transformer, and a second end of the second inductor is connected to a second end of the transformer; and a phase control circuit coupled to receive a voltage across and a current through the resonant circuit and also coupled to the inverter circuit, wherein the phase control circuit generates control signals to drive the inverter circuit, and wherein the control signals drive the inverter circuit to keep the resonant circuit operating in an inductive region. ### Claim 14 (depends on 13) The high voltage generator of claim 13, wherein the control signals drives the inverter circuit working at frequency higher than an upper resonance peak, based on a phase delay between the voltage and the current, and the upper resonance peak is corresponding to a first resonant frequency. ### Claim 15 (depends on 14) The high voltage generator of claim 14, further comprising an amplitude limiting circuit coupled to the rectifier circuit, the control signals drives the inverter circuit to work at frequency lower than a lower resonant peak based on a selection of the amplitude limiting circuit, and the lower resonant peak is corresponding to a second resonant frequency. ### Claim 16 (depends on 13) The high voltage generator of claim 13, wherein the first resonant branch includes a first inductor serially connected to a first capacitor. ### Claim 17 (depends on 13) The high voltage generator of claim 13, wherein the second resonant branch is coupled in parallel to the secondary windings of the transformer. ### Claim 18 (depends on 13) The high voltage generator of claim 13, wherein the second resonant branch is coupled in parallel to the primary windings of the transformer. ### Claim 19 (depends on 13) The high voltage generator of claim 13, wherein the first resonant branch includes a first inductor, wherein a first end of the first inductor is connected to the first bridge leg and a second end of the first inductor is connected to the second resonant branch. ### Claim 20 (depends on 13) The high voltage generator of claim 13, wherein the first bridge leg or the second bridge leg comprises a plurality of IGBT transistors, the plurality of IGBT transistors are operated between a first switching frequency and a second switching frequency, the first switching frequency is determined based on the first resonant branch and the second resonant branch, the second switching frequency is determined by the second resonant branch.