Inverter for electric vehicle

• US 8,461,791 B2
• Filed: 06/15/2011
• Issued: 06/11/2013
• Est. Priority Date: 07/02/2010
• Status: Active Grant

• Current Assignee: LSIS Co. Ltd. (LS Corporation)
• Original Assignee: LSIS Co. Ltd. (LS Corporation)
• Inventors: Hong, Chan Ook
• Primary Examiner(s): Ip, Paul
• Application Number:
  US13/161,398
• Publication Number:
  US 20120001578A1
• Time in Patent Office: 727 Days
• Field of Search: 318/446, 318/778, 318/400.34, 123/350, 123/399, 123/436, 701/102, 701/103, 701/93
• US Class Current: 318/446
• CPC Class Codes: B60L 15/025 using field orientation; Vector control; Direct Torque Control [DTC]
• CPC Class Codes: B60L 15/2009 for braking
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: H02P 21/08 Indirect field-oriented control; Rotor flux feed-forward control
• CPC Class Codes: H02P 27/047 V/F converter, wherein the voltage is controlled proportionally with the frequency
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

An inverter for an electric vehicle includes a speed instruction generating unit, a frequency voltage converting unit, an integrator and a 2-to-3 phase converter. The speed instruction generating unit outputs a speed instruction for changing the rotational frequency of an electric motor based on the on/off of a signal outputted from the accelerator pedal. The frequency voltage converting unit outputs a voltage instruction based on the frequency of the speed instruction. The integrator outputs a rotational angle by performing integration on the frequency of the speed instruction. The 2-to-3 phase converter receives the voltage instruction and the rotational angle and converts the received voltage instruction and rotational angle into three-phase voltage instructions.

Claims

1. An inverter for an electric vehicle, the inverter comprising:

a speed instruction generating unit connected to an accelerator pedal so as to output a speed instruction for changing the rotational frequency of an electric motor based on the on/off of a signal outputted from the accelerator pedal;

a frequency voltage converting unit configured to output a voltage instruction based on the frequency of the speed instruction;

an integrator configured to output a rotational angle by performing integration on the frequency of the speed instruction; and

a 2-to-3 phase converter configured to receive the voltage instruction and the rotational angle and convert the received voltage instruction and the received rotational angle into three-phase voltage instructions.

2. The inverter of claim 1, further comprising a voltage regulating unit configured to receive the three-phase voltage instructions from the 2-to-3 phase converter and output three-phase output voltages to the electric motor using pulse width modulation (PWM).

3. The inverter of claim 1, wherein the speed instruction generating unit comprises:

a storage in which a maximum frequency at which the electric motor is rotated, a frequency increment and a frequency decrement are stored; and

a control unit configured to increase the frequency of the speed instruction by the frequency increment when the accelerator pedal is on, and decrease the frequency of the speed instruction by the frequency decrement when the accelerator pedal is off.

4. The inverter of claim 3, wherein the control unit regulates the frequency of the speed instruction within a range from a minimum frequency to the maximum frequency.

5. The inverter of claim 4, wherein, when the accelerator pedal is on, the control unit outputs the increased frequency of the speed instruction when the increased frequency of the speed instruction is smaller than the maximum frequency, and outputs the maximum frequency when the increased frequency of the speed instruction is greater than the maximum frequency.

6. The inverter of claim 4, wherein, when the accelerator pedal is off, the control unit outputs the decreased frequency of the speed instruction when the decreased frequency of the speed instruction is greater than the minimum frequency, and outputs the minimum frequency when the decreased frequency of the speed instruction is smaller than the minimum frequency.

7. The inverter of claim 1, wherein the frequency voltage converting unit outputs a voltage instruction of the electric motor, obtained by multiplying the frequency of the speed instruction by a ratio of rated voltage/rated frequency.