Apparatus to realize fast battery charging and motor driving for electric vehicles using one AC/DC converter

Patent metadata

Field	Value
Publication number	US-10686385-B2
Application number	US-201815915400-A
Country	US
Kind code	B2
Filing date	Mar 8, 2018
Priority date	Mar 23, 2017
Publication date	Jun 16, 2020
Grant date	Jun 16, 2020

Abstract

An apparatus includes a controller, a switching block, and a three-phase bidirectional AC/DC converter. The switching block has a first interface connected to a power grid, a second interface connected to an electric motor, and a third interface connected to the three-phase bidirectional AC/DC converter that includes first, second, and third single-phase AC/DC conversion modules, and which have inputs and outputs joined at an output node, and a respective transformer configured to provide electrical isolation. In a first mode of operation, the switching block connects the power grid to the AC/DC converter for charging a battery connected to the output node and disconnects the electric motor. In a second mode of operation, the switching block disconnects the power grid and connects the electric motor to the AC/DC converter which is controlled to convert DC power drawn from the battery to energize the electric motor.

First claim

What is claimed is:

1. An electric power conversion apparatus, comprising:
an electronic controller including a processor and a memory;
a switching block controlled by said controller and having a first interface configured to be connected to a power grid source for receiving a first AC signal having first, second, and third phases, said switching block having a second interface configured to be connected to an electric motor;
a three-phase bidirectional AC/DC converter configured to be connected to a third interface of said switching block and including first, second, and third single-phase AC/DC conversion modules each connected to and controlled by said controller, said AC/DC conversion modules having respective inputs, respective outputs joined at an output node, and a respective transformer configured to provide electrical isolation;
wherein in a first mode of operation, said controller controls said switching block to assume a first condition that (i) connects said first and third interfaces so that said power grid is connected to said three-phase AC/DC converter which is controlled to convert said first AC signal to an output signal having a DC component at said output node for charging a battery, and (ii) disconnects said second and third interfaces to thereby disconnect said electric motor;
wherein in a second mode of operation, said controller controls said switching block to assume a second condition that (i) disconnects said first and third interfaces so as to disconnect said power grid, and (ii) connects said second and third interfaces to connect said electric motor to said three-phase bidirectional AC/DC converter which is controlled to convert DC power drawn from said battery to a second AC signal for energizing said electric motor; and
wherein each AC/DC conversion module respectively comprises (i) a rectifier stage for converting a respective phase of said first AC signal into a DC signal, and (ii) a dual-active-bridge (DAB) stage configured to convert said DC signal into said output signal having said DC component, wherein each dual-active-bridge (DAB) stage includes:
(i) a first full bridge coupled to said rectifier stage including a plurality of DC to AC switches,
(ii) said transformer having a respective primary winding coupled to said first full bridge, said transformer having an electrically isolated and magnetically coupled secondary winding, and
(iii) a second full bridge between said secondary winding and said output node and including a plurality of AC to DC switches.

2. The apparatus of claim 1 further comprising operating mode control logic stored in said memory which when executed by said controller is configured to control said switching block to assume (i) said first condition when predetermined battery charging criteria are satisfied and (ii) said second condition when predetermined motor driving criteria are satisfied.

3. The apparatus of claim 1 further comprising main control logic stored in said memory which when executed by said controller is configured, when in said first mode of operation, to control operation of said three-phase bidirectional AC/DC converter so as to achieve power factor correction (PFC) and zero voltage switching (ZVS) while charging said battery.

4. The apparatus of claim 1 wherein operation of said first, second, and third AC/DC conversion modules in said first mode of operation produce respective AC components thereof that cancel each other out.

5. The apparatus of claim 1 wherein each rectifier stage is coupled to a respective one of said first, second, and third phases of said first AC signal and is configured to produce a respective DC signal, each rectifier stage including a respective plurality of rectifier switches arranged in a full bridge arrangement.

6. The apparatus of claim 5 wherein said controller includes rectifier logic stored in said memory, said rectifier logic when executed by said controller being configured to generate a first set of switch control signals corresponding to gate drive signals for said plurality of rectifier switches.

7. The apparatus of claim 6 further comprising a grid voltage sensor in sensing relation to said first AC signal from said power grid source configured to generate a grid voltage signal indicative of said first AC signal voltage.

8. The apparatus of claim 7 wherein said rectifier logic, in said first mode of operation, is responsive to said grid voltage signal in generating said first set of switch control signals so as to provide synchronous rectification of said first AC signal.

9. The apparatus of claim 1 further including a coupling inductor in series between said first full bridge and said primary winding of said transformer.

10. The apparatus of claim 1 wherein said first AC signal has a first frequency, said first full bridge is configured, in said first mode of operation, to convert said first DC signal into a third AC signal, said third AC signal having a second frequency that is greater than said first frequency, said main control logic, when executed by said controller in said first mode of operation, being configured to generate (i) a second set of switch control signals corresponding to gate drive signals for said plurality of DC to AC switches and (ii) a third set of switch control signals corresponding to gate drive signals for said AC to DC switches.

11. The apparatus of claim 10 wherein said main control logic includes power factor correction (PFC) logic which, when executed by said controller in said first mode, is configured to generate said second and third sets of switch control signals so as to increase a power factor associated with power drawn from said power grid source towards one.

12. The apparatus of claim 11 wherein said PFC logic is configured to vary a phase difference in gate drive signals associated with respective DAB stages.

13. The apparatus of claim 1 wherein said main control logic includes motor control logic stored in said memory, said motor control logic, when executed by said controller in said second mode of operation, being configured to control operation of said first, second, and third AC/DC conversion modules based on a motor control command signal to produce said second AC signal to drive said electric motor.

14. The apparatus of claim 1 wherein said switching block comprises electrically-actuated relays.

15. The apparatus of claim 1 further comprising main control logic stored in said memory which when executed by said controller is configured, when in said second mode of operation, to control operation of said three-phase bidirectional AC/DC converter so as to achieve zero voltage switching (ZVS) while driving said motor.

Assignees

• Hella Gmbh & Co Kgaa

Inventors

• Brown Alan Wayne
• Bai Hua

Classifications

• H02J2105/37

  exchanging power with electric vehicles [EV] or with hybrid electric vehicles [HEV] · CPC title

• H02J7/865

  Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence) · CPC title

• H02J7/02 Primary

  for charging batteries from AC mains by converters · CPC title

• H02M3/33584 Primary

  Bidirectional converters · CPC title

• H02M1/0058

  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) · CPC title