# US 12,191,775 B2 · Three-level rectification DC/DC converter

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- Number: US 12,191,775 B2
- Document ID: US12191775B2
- Status: Granted
- Kind: B2
- Application number: 17/574,004
- Filed: 2022-01-12
- Published: 2023-06-08
- Granted: 2025-01-07
- Earliest claimed: 2021-12-02
- Assignees: Delta Electronics (Shanghai) Co., Ltd.
- Applicants: Delta Electronics (Shanghai) Co., Ltd.
- Inventors: Chi Zhang; Minli Jia; Hao Sun; Jinfa Zhang; Peter Mantovanelli Barbosa
- Web page: https://patentgrep.com/patent/US12191775B2

## CPC

- H02M 3/33592: {having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer}
- H02M 1/0009: {Devices or circuits for detecting current in a converter}
- H02M 1/0025: {Arrangements for modifying reference values, feedback values or error values in the control loop of a converter}
- H02M 1/083: {for the ignition at the zero crossing of the voltage or the current}
- H02M 3/33584: {Bidirectional converters}
- H03B 5/08: with frequency-determining element comprising lumped inductance and capacitance
- 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
- 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)
- H03B: GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS (generators adapted for electrophonic musical instruments G10H; masers or lasers H01S; generation of oscillations in plasma H05H)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

The present disclosure provides a three-level rectification DC/DC converter including primary and secondary circuits and a resonant tank circuit. A voltage between two primary terminals is a first voltage. The secondary circuit includes two clamping switches, a switch bridge arm, and a capacitor bridge arm. The switch bridge arm includes four switches serially connected. The two clamping switches are connected in series between a node between the first and second switches and a node between the third and fourth switches. Two secondary terminals are respectively connected between the second and third switches and connected between two output capacitors of the capacitor bridge arm. A node between the two clamping switches is connected between the two output capacitors. The second and third switches are at least in an on state for a preset time length after falling and rising edges in a period of the first voltage respectively.

## Claims

### Claim 1

A three-level rectification DC/DC converter, comprising:
a primary circuit receiving an input voltage and comprising a plurality of primary switches;
a resonant tank circuit comprising a resonant inductor, a resonant capacitor, and a transformer, wherein a first primary terminal and a second primary terminal of the resonant tank circuit are coupled to the primary circuit, a primary winding of the transformer is coupled between the first and second primary terminals, a secondary winding of the transformer is coupled between a first secondary terminal and a second secondary terminal of the resonant tank circuit, a voltage between the first and second primary terminals is a first voltage, a voltage between the first and second secondary terminals is a second voltage; and
a secondary circuit comprising two clamping switches, a switch bridge arm, and a capacitor bridge arm, wherein the switch bridge arm comprises a first secondary switch, a second secondary switch, a third secondary switch, and a fourth secondary switch sequentially connected in series, the two clamping switches are connected in series between a node between the first and second secondary switches and a node between the third and fourth secondary switches, a node between the second and third secondary switches is connected to the first secondary terminal, the capacitor bridge arm comprises a first output capacitor and a second output capacitor connected in series, a node between the first and second output capacitors is connected to a node between the two clamping switches and the second secondary terminal, two terminals of the capacitor bridge arm are connected to two terminals of the switch bridge arm, and a voltage between the two terminals of the capacitor bridge arm is an output voltage,
wherein the second secondary switch is at least in an on state for a preset time length after a falling edge in a period of the first voltage, and the third secondary switch is at least in the on state for the preset time length after a rising edge in the period of the first voltage,
wherein the three-level rectification DC/DC converter operates in a continuous current mode,
wherein if the first secondary switch and the fourth secondary switches are kept in an off state, the second secondary switch is switched from the off state to the on state at the falling edge in the period of the first voltage and is in the on state for the preset time length after the falling edge, and the third secondary switch is switched from the off state to the on state at the rising edge in the period of the first voltage and is in the on state for the preset time length after the rising edge.

### Claim 2 (depends on 1)

The three-level rectification DC/DC converter according to claim 1, wherein phases of the second and third secondary switches are out of phase by 180 degrees with respect to each other.

### Claim 3 (depends on 1)

The three-level rectification DC/DC converter according to claim 1, wherein a switching frequency of the second and third secondary switches is equal to a frequency of the first voltage.

### Claim 4 (depends on 1)

The three-level rectification DC/DC converter according to claim 1, wherein if the first and fourth secondary switches are not kept in the off state, the first, second, third, and fourth secondary switches are in the on state during all durations within a duration of currents flowing reversely through the first, second, third, and fourth secondary switches respectively.

### Claim 5 (depends on 4)

The three-level rectification DC/DC converter according to claim 4, wherein driving signals of the second and third secondary switches are complementary.

### Claim 6 (depends on 1)

The three-level rectification DC/DC converter according to claim 1, wherein the preset time length is obtained based on the input voltage and the output voltage.

### Claim 7 (depends on 1)

The three-level rectification DC/DC converter according to claim 1, wherein all the primary and secondary switches are turned on with zero voltage switching.

### Claim 8 (depends on 1)

The three-level rectification DC/DC converter according to claim 1, wherein the first voltage is a square wave which is at a high level in one-half period and at a low level in the other half period.

### Claim 9 (depends on 1)

The three-level rectification DC/DC converter according to claim 1, wherein the first and fourth secondary switches are active switches.

### Claim 10 (depends on 1)

The three-level rectification DC/DC converter according to claim 1, wherein the first and fourth secondary switches are a first diode and a second diode respectively, an anode and a cathode of the first diode are coupled to the second secondary switch and the first output capacitor respectively, and an anode and a cathode of the second diode are coupled to the second output capacitor and the third secondary switch respectively.

### Claim 11 (depends on 1)

The three-level rectification DC/DC converter according to claim 1, wherein the two clamping switches are active switches.

### Claim 12 (depends on 1)

The three-level rectification DC/DC converter according to claim 1, wherein the two clamping switches are a third diode and a fourth diode, an anode and a cathode of the third diode are coupled a cathode of the fourth diode and a node between the first and second secondary switches respectively, and an anode of the fourth diode is coupled to a node between the third and fourth secondary switches.

### Claim 13 (depends on 1)

The three-level rectification DC/DC converter according to claim 1, wherein the primary circuit comprises an input capacitor, a first bridge arm, and a second bridge arm connected to each other in parallel, a voltage on the input capacitor is the input voltage, the first bridge arm comprises a first primary switch and a second primary switch connected in series, a node between the first and second primary switches is connected to the second primary terminal, the second bridge arm comprises a third primary switch and a fourth primary switch, and a node between the third and fourth primary switches is connected to the first primary terminal.

### Claim 14 (depends on 1)

The three-level rectification DC/DC converter according to claim 1, wherein the primary circuit comprises two primary clamping switches, a first bridge arm, and a second bridge arm, a voltage between two terminals of the first bridge arm is the input voltage, the two terminals of the first bridge arm are connected to two terminals of the second bridge arm respectively, the first bridge arm comprises a first input capacitor and a second input capacitor connected in series, the second bridge arm comprises a first primary switch, a second primary switch, a third primary switch, and a fourth primary switch sequentially connected in series, the two primary clamping switches are connected in series between a node between the first and second primary switches and a node between the third and fourth primary switches, a node between the second and third primary switches is connected to the first primary terminal, and a node between the first and second input capacitors is connected to a node between the two primary clamping switches and the second primary terminal.

### Claim 15 (depends on 1)

The three-level rectification DC/DC converter according to claim 1, wherein in the resonant tank circuit, the resonant inductor, the primary winding, and the resonant capacitor are connected in series between the first and second primary terminals.

### Claim 16 (depends on 1)

The three-level rectification DC/DC converter according to claim 1, further comprising a control module, wherein the control module is configured to acquire an input voltage signal, an output voltage signal, and an output current signal reflecting the input voltage, the output voltage, and an output current respectively through detection and to control the operation of all the primary and secondary switches, the control module comprises a regulator, and the regulator generates a regulating signal according to the output voltage signal, the output current signal, an output reference voltage, and an output reference current.

### Claim 17 (depends on 16)

The three-level rectification DC/DC converter according to claim 16, wherein the control module further comprises a voltage-controlled oscillator and a controller, the voltage-controlled oscillator is coupled to the regulator and generates a switching frequency of the plurality of primary switches according to the regulating signal, the controller is coupled to the voltage-controlled oscillator, and the controller generates an on-time of all the secondary switches according to the input voltage signal, the output voltage signal and the switching frequency of the plurality of primary switches.

### Claim 18 (depends on 16)

The three-level rectification DC/DC converter according to claim 16, wherein the control module further comprises a PWM controller coupled to the regulator, and the PWM controller generates driving signals of all the primary and secondary switches according to the regulating signal.

### Claim 19 (depends on 18)

The three-level rectification DC/DC converter according to claim 18, wherein a switching frequency of the plurality of primary switches is fixed and is larger than a resonant frequency of the resonant tank circuit.