Electric power converter

Patent metadata

Field	Value
Publication number	US-9762126-B2
Application number	US-201514933505-A
Country	US
Kind code	B2
Filing date	Nov 5, 2015
Priority date	Nov 6, 2014
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

An electric power conversion unit of an electric power converter establishes two converter circuits including four switching elements and two batteries and carries out electric power conversion in a parallel mode in which the batteries are connected in parallel with each other. A controller is configured to set a control signal for each of the switching elements, identify a target switching element of which a temperature is suppressed, determine a state having a maximum loss value in correspondence with input-output data, and execute phase control for suppressing the maximum loss value.

First claim

What is claimed is:

1. An electric power converter comprising:
a first battery;
a second battery;
a plurality of switching elements; and
a controller configured to execute ON-OFF control over the plurality of switching elements, wherein
the electric power converter has a parallel mode and a series mode, the electric power converter is able to switch between the parallel mode and the series mode,
in the parallel mode, electric power conversion between the first battery and an output power line and electric power conversion between the second battery and the output power line are individually carried out and the two electric power conversions are carried out in parallel with each other,
in the series mode, electric power conversion between both the first battery and the second battery and the output power line is carried out while the first battery and the second battery are connected in series with each other, and wherein
the controller is configured to:
(i) in the parallel mode, control the electric power conversion between the first battery and the output power line with the use of a first PWM signal, control the electric power conversion between the second battery and the output power line with the use of a second PWM signal, determine an ON-OFF state of each of the plurality of switching elements based on a combination of a first signal, which is the first PWM signal or an inversion signal of the first PWM signal, and a second signal, which is the second PWM signal or an inversion signal of the second PWM signal, and set each of the switching elements in the ON state when the corresponding first signal or the corresponding second signal is in an ON state;
(ii) determine a specific one of the plurality of switching elements, of which the number of switching times is suppressed;
(iii) set a control phase of the first signal and a control phase of the second signal; and
(iv) when the electric power converter operates in the parallel mode, set a phase difference between the first signal and the second signal for the specific switching element such that the second signal enters the ON state in a period in which the first signal is in the ON state or set the phase difference between the first signal and the second signal for the specific switching element such that the first signal enters the ON state in a period in which the second signal is in the ON state.

2. The electric power converter according to claim 1 , wherein
the controller is configured to:
(i) in the specific switching element, identify switching timing of a signal, at which a maximum switching loss arises, among switching losses that arise as a result of switching of the signal, that is, the switching between ON-OFF states of the first signal or the switching between ON-OFF states of the second signal; and
(ii) set the phase difference such that switching timing between the ON-OFF states of the specific switching element does not overlap with the switching timing of the signal at which the maximum switching loss arises.

3. The electric power converter according to claim 2 , wherein
the controller is configured to determine the switching loss based on a voltage value of the first battery, a voltage value of the second battery, a current flowing through each battery, and an output voltage of a load.

4. The electric power converter according to claim 2 , wherein
the controller is configured to, when each of the switching timing between the ON-OFF states of the first signal and the switching timing between the ON-OFF states of the second signal is such that the switching timing of the signal, at which the maximum switching loss arises, is falling timing, determine whether the switching timing at which the maximum switching loss arises is the falling timing of the first signal or the falling timing of the second signal.

5. The electric power converter according to claim 1 , wherein
the controller is configured to, when the sum of the period in which the first signal is in the ON state and the period in which the second signal is in the ON state is longer than one period of the PWM control, cause the specific switching element not to turn on or off over one period of the PWM control by setting the phase difference for the specific switching element such that a rising edge and falling edge of the first signal arise in the period in which the second signal is in the ON state or setting the phase difference such that a rising edge and falling edge of the second signal arise in the period in which the first signal is in the ON state.

6. The electric power converter according to claim 1 , wherein
the controller is configured to, when the electric power converter is configured such that a step-up ratio in the electric power conversion between the first battery and the output power line and a step-up ratio in the electric power conversion between the second battery and the output power line are determined in advance, set the phase difference between the first signal and the second signal to a phase difference within an applicable phase difference range under the step-up ratios determined in advance.

Assignees

• Toyota Motor Co Ltd

Inventors

• Ide Akihiko
• Hamada Hidetsugu
• Shinohara Masatoshi
• Sunahara Shohei

Classifications

• H02J7/575

  Parallel/serial switching of connection of batteries to charge or load circuit · CPC title

• H02M3/158 Primary

  including plural semiconductor devices as final control devices for a single load · CPC title

• H02J7/0024

  Electricity · mapped topic

• Y02T10/7055

  Cross-Sectional Technologies · mapped topic

• Y02T10/70

  Energy storage systems for electromobility, e.g. batteries · CPC title