Bidirectional insulating DC-DC converter, control apparatus therefor, and operating method thereof

Patent metadata

Field	Value
Publication number	US-11870360-B2
Application number	US-202117551819-A
Country	US
Kind code	B2
Filing date	Dec 15, 2021
Priority date	Dec 15, 2020
Publication date	Jan 9, 2024
Grant date	Jan 9, 2024

Abstract

The bidirectional insulating DC-DC converter shares high/low voltage terminals, a cooling passage, a housing, and a control board, and two independent step-down circuit ( 10 ) and step-up circuit ( 20 ) are formed in parallel to perform a bidirectional DC power conversion. A high voltage applied from a high voltage battery HV is stepped down through the step-down circuit ( 10 ) and output to a low voltage battery LV. On the other hand, a low voltage applied from the low voltage battery LV is stepped up through the step-up circuit ( 20 ) and output to the high voltage battery HV. The step-down circuit ( 10 ) is formed as an active clamp forward converter circuit, and the step-up circuit ( 20 ) is formed as an active clamp flyback converter circuit.

First claim

What is claimed is:

1. A bidirectional insulating DC-DC converter comprising:
a first battery and a second battery, a discharge voltage of the first battery being relatively higher than that of the second battery;
a step-down circuit configured to step down a voltage applied from the first battery and output the stepped-down voltage to the second battery; and
a step-up circuit connected in parallel to the step-down circuit and configured to step up a voltage applied from the second battery and output the stepped-up voltage to the first battery,
wherein the step-down circuit includes an active clamp forward converter circuit, and the step-up circuit includes an active clamp flyback converter circuit, and
wherein the step-down circuit comprises:
a current transformer configured to convert a current value into a voltage and detect the current value for current control of a first voltage stage which is an input part of the step-down circuit;
a semiconductor switch element in the first voltage stage configured to alternately switch the voltage of the first battery so as to perform a function of the active clamp forward converter;
a transformer configured to step down the voltage switched by the semiconductor switch element in the first voltage stage, transfer the stepped-down voltage to a second voltage stage, and electrically insulate the first voltage stage from the second voltage stage; and
semiconductor switch elements in the second voltage stage configured to rectify a voltage output from the transformer.

2. The bidirectional insulating DC-DC converter of claim 1 , further comprising:
a first current sensor connected in common to the step-down circuit and the step-up circuit and configured to detect a current flowing between the first battery, the step-down circuit, and the step-up circuit;
a second current sensor connected in common to the step-down circuit and the step-up circuit and configured to detect a current flowing between the second battery, the step-down circuit, and the step-up circuit; and
a bidirectional back-to-back semiconductor switch element connected in common to the step-down circuit and the step-up circuit and configured to separate the second battery from the step-down circuit and the step-up circuit.

3. The bidirectional insulating DC-DC converter of claim 1 , wherein the transformer comprises a primary winding connected to the semiconductor switch element in the first voltage stage, a secondary winding connected to one of the semiconductor switch elements in the second voltage stage, and a tertiary winding connected to the other one of the semiconductor switch elements in the second voltage stage.

4. The bidirectional insulating DC-DC converter of claim 1 , wherein the step-up circuit comprises:
a semiconductor switch element in a second voltage stage configured to alternately switch a voltage of the second battery so as to perform a function of the active clamp forward converter;
a transformer configured to step up the voltage switched by the semiconductor switch element in the second voltage stage, transfer the stepped-up voltage to a first voltage stage, and electrically insulate the second voltage stage from the first voltage stage; and
a rectifying element configured to rectify a voltage output from the transformer and transfer the rectified voltage to the first battery.

5. The bidirectional insulating DC-DC converter of claim 4 , wherein the transformer comprises a primary winding connected to the semiconductor switch element in the second voltage stage and a secondary winding connected to the rectifying element.

6. A control apparatus for a bidirectional insulating DC-DC converter comprising:
a step-down circuit including an active clamp forward converter circuit and configured to step down a voltage applied from a first battery and output the stepped-down voltage to a second battery, a discharge voltage of the first battery being relatively higher than that of the second battery, and a step-up circuit including an active clamp flyback converter circuit, connected in parallel to the step-down circuit and configured to step up a voltage applied from the second battery and output the stepped-up voltage to the first battery, the control apparatus comprising:
a step-down circuit controller configured to control the step-down circuit in a peak current mode control method; and
a step-up circuit controller configured to control the step-up circuit in an average current mode control method,
wherein the step-down circuit controller comprises a pulse width modulation (PWM) control integrated circuit (IC) configured to output a PWM signal for PWM switching control of a semiconductor switch element of the step-down circuit, and a microcomputer configured to provide a control signal to the PWM control IC, and
the step-up circuit controller comprises a PWM control IC configured to output a PWM signal for PWM switching control of a semiconductor switch element of the step-down circuit, and a microcomputer configured to provide a control signal to the PWM control IC.

7. The control apparatus of claim 6 , wherein the step-down circuit controller: converts a current value of a first voltage stage of the step-down circuit into a voltage to input a current (IHSBU) detected in a current transformer to be detected to a current sense amplifier input terminal of the PWM control IC; adds a reference voltage signal (ML-VREF_BU) from the microcomputer to a voltage of the second battery of the bidirectional insulating DC-DC converter to generate an added voltage, and inputs the added voltage to a feedback voltage input terminal of the PWM control IC; and adds a reference current signal (ML-IREFBU) from the microcomputer to a current value (ILS) detected in a current sensor in a second voltage stage of the bidirectional insulating DC-DC converter to input the added current to a threshold setting terminal of the PWM control IC so that the PWM control IC generates the PWM signal for controlling the semiconductor element of the step-down circuit.

8. The control apparatus of claim 6 , wherein the step-up circuit controller:
adds a reference voltage signal (ML-VREF_BO) from the microcomputer to a voltage (V_HS) of the first battery of the bidirectional insulating DC-DC converter and adds a current value (I_LS) detected by a current sensor in a second voltage stage of the bidirectional insulating DC-DC converter again to input the added signal to a feedback voltage input terminal of the PWM control IC; and
adds a reference current signal (ML-IREF_BO) from the microcomputer to a current value (I_HS) detected by a current sensor in a first voltage stage of the bidirectional insulating DC-DC converter to input the added signal to a threshold setting terminal of the PWM control IC so that the PWM control IC generates the PWM signal for controlling the semiconductor element of the step-up circuit.

9. The control apparatus of claim 6 , wherein the step-down circuit controller is configured to input a signal (ML-VC_BU) output from an error amplifier output terminal of the PWM control IC to the microcomputer to provide feedback on whether the step-down circuit of the bidirectional insulating DC-DC converter is in normal operating state.

10. The control apparatus of claim 6 , wherein the step-up circuit controller is configured to input a signal (ML-VC_BO) output from an error amplifier output terminal of the PWM control IC to the microcomputer to provide feedback on whether the step-up circuit of the bidirectional insulating DC-DC converter is in normal operating state.

11. An operating method of a bidirectional insulating DC-DC converter comprising a step-down circuit configured to step down

Assignees

• Hyundai Mobis Co Ltd

Inventors

• Kim Du Ho
• Choi Deok Kwan
• Heo Min
• Kim Kang Min
• Jeon Soo Min
• Lee A Ra
• Kim Won Gon
• Park Ji Hoon
• Shim Hyun Woo
• Bang Tae Ho

Classifications

• H02J7/90

  Regulation of charging or discharging current or voltage · CPC title

• H02M3/33584 Primary

  Bidirectional converters · CPC title

• H02J7/007

  Electricity · mapped topic

• H02M1/0009

  Devices or circuits for detecting current in a converter · CPC title

• B60L53/20

  characterised by converters located in the vehicle · CPC title