JP4157270B2 - Inverter system for hybrid vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inverter system used in a hybrid vehicle that uses an internal combustion engine such as a gasoline engine or a diesel engine and an electric drive using a secondary battery such as a storage battery as an energy source. The present invention relates to an inverter system for a hybrid vehicle that realizes noise reduction of an AC machine.
[0002]
[Prior art]
Recently, as a measure to improve air pollution caused by exhaust gas from automobiles using internal combustion engines such as gasoline engines and diesel engines, vehicles are driven by three-phase alternators using secondary batteries such as storage batteries as energy sources instead of internal combustion engines. The popularization of so-called electric vehicles has been called worldwide.
[0003]
However, this electric vehicle has problems such as a short mileage in one fuel filling and the need to spread fuel supply facilities.
[0004]
Therefore, recently, in order to solve such a problem, a hybrid vehicle using electric drive has been attracting attention.
[0005]
In a hybrid vehicle using this type of electric drive together, the drive unit is configured by directly connecting a three-phase AC machine to the internal combustion engine, and drives the wheels via a transmission.
[0006]
In addition, a three-phase AC machine is controlled by an inverter to perform torque assist, energy regeneration, start of an internal combustion engine, electric braking, and use a secondary battery as a power source and an energy source.
[0007]
That is, at the time of start acceleration, the exhaust gas of the internal combustion engine is reduced by controlling the three-phase AC machine by the inverter so that the internal combustion engine is torque-assisted by the stored energy of the secondary battery.
[0008]
Further, at the time of stop braking, the three-phase AC machine is regeneratively operated under the control of the inverter, and the inertial energy of the vehicle is stored in the secondary battery.
[0009]
As a result, energy saving and energy balance are maintained, and emission pollution is reduced and fuel consumption is improved.
[0010]
FIG. 8 is a schematic diagram showing a basic configuration example of a drive unit of this type of hybrid vehicle.
[0011]
In FIG. 8, the drive unit of the hybrid vehicle is composed of an internal combustion engine 1 such as a gasoline engine or a diesel engine, and a three-phase AC machine 2 directly connected to the internal combustion engine 1 so as to drive wheels via the transmission 3. I have to.
[0012]
The three-phase AC machine 2 is controlled by an inverter 4 to perform torque assist, energy regeneration, start of the internal combustion engine 1 and electric braking, and use a secondary battery 5 such as a storage battery as a power source and an energy source.
[0013]
FIG. 9 is a circuit diagram showing a configuration example of a conventional inverter system used in this type of hybrid vehicle, and the same elements as those in FIG. 8 are denoted by the same reference numerals.
[0014]
9, the hybrid vehicle inverter system includes a three-phase AC machine 2 coupled to the internal combustion engine 1, a secondary battery 5 such as a chargeable / dischargeable storage battery, and an output voltage of the secondary battery 5 as a switch 6. And an inverter 4 that is driven by supplying this AC voltage to the three-phase AC machine 2.
[0015]
The inverter 4 includes an inverter circuit 40 in which a plurality of semiconductor elements 41 to 46 are bridge-connected, a smoothing DC capacitor 47, and a control circuit 48 that controls the inverter circuit 40.
[0016]
Then, the three-phase AC machine 2 is controlled by the inverter circuit 40 so that the internal combustion engine 1 is torque-assisted with the stored energy of the secondary battery 5 when the hybrid vehicle starts.
[0017]
By the way, in recent years, in such an inverter system for a hybrid vehicle, there is a need to increase the capacity of the system, and it is necessary to improve the driving power and the regenerative power of the three-phase AC machine 2.
[0018]
The conventional three-phase alternator 2 is a three-phase alternator having a rated voltage of 200 VAC. However, the current increases as the capacity increases, and the outer shape of the three-phase alternator 2 increases, so the current is increased. In order to increase the capacity, a method of using a voltage of AC400V system is adopted.
[0019]
In general, the inverter is PWM controlled to control the current of the three-phase AC machine 2, but in order to output AC 400V, the DC voltage needs to be about 600V.
[0020]
However, in order to obtain a DC voltage of 600V by the secondary battery 5, it is necessary to connect about 50 12V batteries in series, and space and weight when mounted on a vehicle are problematic.
[0021]
Therefore, a method which has been recently proposed is a method of providing a boost chopper circuit as disclosed in, for example, “JP-A-6-245332”.
[0022]
By such a method, the secondary battery 5 voltage, that is, a desired DC voltage can be obtained without increasing the number of batteries.
[0023]
In order to increase the driving power and regenerative power of the three-phase AC machine 2, specifically, it has a function of boosting the voltage of the secondary battery 5 and a function of stepping down the DC voltage to the voltage of the secondary battery 5. A method of providing a step-up / down chopper circuit is effective.
[0024]
[Problems to be solved by the invention]
However, the provision of the step-up / step-down chopper circuit can achieve the purpose of improving the driving power and regenerative power of the three-phase AC machine 2, but in the minimum standby operation state of the internal combustion engine 1, that is, in the idling state. However, since the boost chopper of the step-up / step-down chopper circuit is operated, the loss of the semiconductor element of the step-up / step-down chopper circuit is large, and when the DC voltage is high, the switching loss of the inverter circuit 40 is large, and the entire inverter This will cause a decrease in efficiency.
[0025]
In addition, when the inverter circuit 40 is PWM-controlled with a high voltage, the loss of the three-phase AC machine 2 is also larger than when the PWM control is operated with a low voltage.
[0026]
Further, the magnetic noise of the three-phase AC machine 2 corresponding to the PWM control frequency of the inverter circuit 40 becomes large, and there arises a problem that the magnetic noise that is different from the engine sound of the vehicle becomes annoying.
[0027]
An object of the present invention is to provide a highly reliable inverter system for a hybrid vehicle capable of improving the efficiency of an inverter and reducing the noise of a three-phase AC machine.
[0028]
[Means for Solving the Problems]
  To achieve the above objective,An inverter system for a hybrid vehicle corresponding to the present invention includes a three-phase AC machine coupled to an internal combustion engine, a secondary battery, and an output voltage from the secondary battery to a desired DC voltage via an energy absorption reactor. A step-up / step-down chopper circuit for stepping up or stepping down a DC voltage to the secondary battery voltage and a semiconductor element are bridge-connected, and an output voltage from the step-up / step-down chopper circuit is converted to alternating current, and the alternating voltage is converted to the three-way voltage. An inverter circuit that is supplied to and driven by the phase alternator, and a control circuit that controls the step-up / step-down chopper circuit and the inverter circuit, and the control circuit stores the energy stored in the secondary battery during acceleration When the three-phase AC machine is controlled by the inverter circuit so as to assist the internal combustion engine with torque, and the three-phase AC machine is below a predetermined speed, The boosting operation of the step-up / down chopper circuit is stopped, the DC voltage is made substantially equal to the secondary battery voltage and the inverter circuit is controlled to perform PWM control operation, and the PWM control frequency of the inverter circuit is set to a predetermined frequency. The range is modulated in a sine wave shape with a predetermined period.
[0046]
As described above, it is possible to improve the efficiency of the inverter and reduce the noise of the three-phase AC machine, and to obtain a highly reliable inverter system for a hybrid vehicle.
[0047]
DETAILED DESCRIPTION OF THE INVENTION
The present invention controls the step-up / step-down chopper circuit to stop the boost operation when the three-phase AC machine is below a predetermined speed, and control the inverter circuit to perform PWM control operation with the DC voltage substantially equal to the secondary battery voltage. Or,
Alternatively, when the internal combustion engine is operating at the lowest speed idling operation, the boosting operation of the step-up / down chopper circuit is stopped, the DC voltage is made substantially equal to the secondary battery voltage, and the inverter circuit is When the control is performed so that the PWM control operation is performed, or when the internal combustion engine is in the idling operation state at the minimum speed, the boosting operation of the step-up / step-down chopper is stopped, and the PWM control frequency of the inverter circuit is set to a frequency corresponding to the idling operation speed. Control to lower and operate PWM
In this way, the efficiency of the inverter is improved and the noise of the three-phase AC machine is reduced.
[0048]
Hereinafter, embodiments of the present invention based on the above-described concept will be described in detail with reference to the drawings.
[0049]
(First embodiment)
FIG. 1 is a circuit diagram showing a configuration example of an inverter system for a hybrid vehicle according to the present embodiment, in which the same elements as those in FIG. 9 are denoted by the same reference numerals.
[0050]
In FIG. 1, an inverter system for a hybrid vehicle according to the present embodiment includes a three-phase AC machine 2 coupled to an internal combustion engine 1 such as a gasoline engine or a diesel engine, a secondary battery 5 such as a chargeable / dischargeable storage battery, A step-up / step-down chopper circuit 49 for stepping up the output voltage from the secondary battery 5 to a desired DC voltage via the switch 6 and the energy absorption step-up / down reactor 7, and stepping down the DC voltage to the secondary battery 5 voltage; A DC capacitor 47 for smoothing the output voltage from the step-up / step-down chopper circuit 49; an inverter circuit 40 for converting the voltage smoothed by the DC capacitor 47 into AC and supplying the AC voltage to the three-phase AC machine 2 for driving; The step-up / step-down chopper circuit 49 and the control circuit 48 for controlling the inverter circuit 40 are included.
[0051]
The inverter 4 is composed of the inverter circuit 40, the DC capacitor 47, the control circuit 48, and the step-up / step-down chopper circuit 49.
[0052]
Here, the step-up / step-down chopper circuit 49 is formed by connecting a plurality of upper and lower semiconductor elements 49a and 49b in series.
[0053]
Further, the inverter circuit 40 is formed by bridge-connecting a plurality of semiconductor elements 41 to 46.
[0054]
Further, the control circuit 48
A function of controlling the inverter circuit 40 to control the three-phase alternator 2 so that the internal combustion engine 1 is torque-assisted with the stored energy of the secondary battery 5 at the time of starting acceleration of the hybrid vehicle;
When the three-phase AC machine 2 is below a predetermined speed, the step-up / step-down chopper circuit 49 stops the boosting operation, that is, the chopping operation is stopped and only the upper arm semiconductor element is continuously conducted, so that the DC voltage is reduced. The inverter circuit 40 has a function of controlling the inverter circuit 40 to perform a PWM control operation substantially equal to the voltage of the secondary battery 5.
[0055]
Next, the operation of the hybrid vehicle inverter system according to the present embodiment configured as described above will be described with reference to the time chart shown in FIG.
[0056]
Now, when a start command is input at time to in FIG. 2, the switch 6 is turned on, and gate signals are output from the control circuit 48 to the semiconductor elements 41 to 46 of the inverter circuit 40 in accordance with the speed reference signal. 4 drives the three-phase AC machine 2 as a load at a predetermined output frequency (f-INV).
[0057]
At this stage, the step-up / step-down chopper circuit 49 turns on only the upper semiconductor element 49a and supplies power from the secondary battery 5 to the three-phase AC machine 2 that is a load.
[0058]
Therefore, a voltage substantially equal to the secondary battery 5 voltage is supplied to the inverter circuit 40 as the DC voltage.
[0059]
Next, at time t1 in FIG. 2, when the magnitude of the speed reference signal becomes equal to or higher than a predetermined level (L1 in FIG. 2), the upper and lower semiconductor elements 49a and 49b of the buck-boost chopper circuit 49 are switched. The inverter circuit 40 is controlled to operate and boost the DC voltage.
[0060]
For example, assuming that the rated voltage of the three-phase AC machine 2 is AC400V, it is necessary to perform PWM control with a DC voltage of about 600V, but even when the secondary battery 5 voltage is 300V, the voltage is not boosted and the output is about 50% AC200V can do.
[0061]
Therefore, it is not necessary to operate the step-up / step-down chopper circuit 49 to a speed of about 50%, so that the loss of the inverter 4 can be reduced.
[0062]
Furthermore, since the peak value of the PWM voltage waveform is 50%, the magnetic sound of the three-phase AC machine 2 can also be reduced.
[0063]
As described above, in the inverter system for a hybrid vehicle according to the present embodiment, when the three-phase AC machine 2 is below a predetermined speed, the boost chopper operation of the step-up / down chopper circuit 49 is stopped. Therefore, the loss of the inverter 4 can be reduced and the efficiency can be improved, and at the same time, the noise (magnetic sound) of the three-phase AC machine 2 can be reduced.
[0064]
(Second Embodiment)
The circuit configuration of the hybrid vehicle inverter system of the present embodiment is the same as that of FIG. 1, and the functions of the control circuit 48 are partially different.
[0065]
That is, the control circuit 48
When the above-described three-phase AC machine 2 is at a predetermined speed or less, the step-up / step-down chopper circuit 49 stops the boosting operation, and the inverter circuit 40 is PWM-controlled by making the DC voltage substantially equal to the secondary battery 5 voltage. Instead of the ability to control
When the internal combustion engine 1 is in the idling operation state at the lowest speed and the three-phase AC machine 2 is operated, the boosting operation of the step-up / step-down chopper circuit 49 is stopped, that is, the chopping operation is stopped and only the upper arm semiconductor element is continuously operated. Therefore, the inverter circuit 40 is controlled to perform a PWM control operation by making the DC voltage substantially equal to the secondary battery 5 voltage.
[0066]
Next, the operation of the hybrid vehicle inverter system according to the present embodiment configured as described above will be described with reference to the time chart shown in FIG.
[0067]
Note that the description of the operation of the same portion as the operation of the first embodiment is omitted, and only the operation of the different portion will be described here.
[0068]
That is, as shown in FIG. 3, by controlling so that the boost chopper operation is stopped only when the internal combustion engine 1 is in the minimum speed state and the idling operation state of the internal combustion engine 1, the vehicle is stopped. Loss of the inverter 4 in the idling state can be reduced.
[0069]
Further, high-frequency magnetic sound unique to the inverter 4 that performs PWM control operation can also be reduced.
[0070]
As described above, in the hybrid vehicle inverter system according to the present embodiment, the boost chopper of the step-up / down chopper circuit 49 is used when the internal combustion engine 1 is operated in the idling operation state at the lowest speed. Since the operation is stopped, it is possible to improve the efficiency by reducing the loss of the inverter 4 when the vehicle is in an idling state while the vehicle is stopped, and at the same time, reduce the high-frequency magnetic sound unique to the inverter 4. Is possible.
[0071]
(Third embodiment)
The circuit configuration of the hybrid vehicle inverter system of the present embodiment is the same as that of FIG. 1, and the functions of the control circuit 48 are partially different.
[0072]
That is, the control circuit 48
When the above-described three-phase AC machine 2 is at a predetermined speed or less, the step-up / step-down chopper circuit 49 stops the boosting operation, and the inverter circuit 40 is PWM-controlled by making the DC voltage substantially equal to the secondary battery 5 voltage. Instead of the ability to control
When the internal combustion engine is in the idling operation state at the lowest speed, the boosting operation of the step-up / step-down chopper is stopped, and the PWM control frequency of the inverter circuit is lowered to a frequency corresponding to the idling operation speed to perform the PWM operation. It is supposed to be.
[0073]
Next, the operation of the hybrid vehicle inverter system according to the present embodiment configured as described above will be described with reference to the time chart shown in FIG.
[0074]
Note that the description of the operation of the same portion as the operation of the first embodiment is omitted, and only the operation of the different portion will be described here.
[0075]
That is, as shown in FIG. 4, the switching frequency (p-INV) of the inverter 4 is lowered to a constant frequency at a speed equal to or lower than the idle operation state, and when the speed is equal to or higher than the idle operation state, By controlling so as to increase the efficiency, it is possible to reduce the loss of the inverter 4 at a speed equal to or lower than the idling operation state and improve the efficiency.
[0076]
As described above, in the hybrid vehicle inverter system according to the present embodiment, when the internal combustion engine 1 is in the idling operation state at the lowest speed, the step-up / step-down chopper boosting operation of the step-up / step-down chopper circuit 49 is stopped, and the inverter circuit Since the PWM operation is performed by lowering the PWM control frequency of 40 to a frequency corresponding to the idling operation speed, it is possible to reduce the loss of the inverter 4 at the speed below the idling operation state and improve the efficiency. .
[0077]
(Fourth embodiment)
The circuit configuration of the hybrid vehicle inverter system of the present embodiment is the same as that of FIG. 1, and the functions of the control circuit 48 are partially different.
[0078]
That is, the control circuit 48
In addition to the functions of the first embodiment,
The inverter circuit 40 has a function of modulating the PWM control frequency in a predetermined frequency range in a sine wave shape with a predetermined period.
[0079]
Next, the operation of the hybrid vehicle inverter system according to the present embodiment configured as described above will be described with reference to the time chart shown in FIG.
[0080]
Note that the description of the operation of the same portion as the operation of the first embodiment is omitted, and only the operation of the different portion will be described here.
[0081]
That is, as shown in FIG. 5, by changing the switching frequency (p-INV) of the inverter 4 with a sine wave having a certain period, the switching frequency is changed and the electromagnetic noise of the three-phase AC machine 2 is reduced. can do.
[0082]
As described above, in the inverter system for a hybrid vehicle according to the present embodiment, the PWM control frequency of the inverter circuit 40 is modulated in a sine wave shape with a predetermined period within a predetermined frequency range, so that the switching frequency is changed. Thus, electromagnetic noise of the three-phase AC machine 2 can be reduced.
[0083]
(Fifth embodiment)
The circuit configuration of the hybrid vehicle inverter system of the present embodiment is the same as that of FIG. 1, and the functions of the control circuit 48 are partially different.
[0084]
That is, the control circuit 48
In addition to the functions of the first embodiment,
The inverter circuit 40 has a function of randomly modulating the PWM control frequency in a predetermined frequency range.
[0085]
Next, the operation of the hybrid vehicle inverter system according to the present embodiment configured as described above will be described with reference to the time chart shown in FIG.
[0086]
Note that the description of the operation of the same portion as the operation of the first embodiment is omitted, and only the operation of the different portion will be described here.
[0087]
That is, as shown in FIG. 6, the electromagnetic noise of the three-phase AC machine 2 can be reduced by changing the switching frequency (p-INV) of the inverter 4 with a random number (without regularity). it can.
[0088]
In this case, especially by using random numbers, the rate of change of switching becomes larger than that in the case of changing at a constant cycle as in the fourth embodiment, and the electromagnetic noise of the three-phase AC machine 2 is further reduced. can do.
[0089]
As described above, in the hybrid vehicle inverter system according to the present embodiment, the PWM control frequency of the inverter circuit 40 is randomly modulated in a predetermined frequency range. The electromagnetic noise of the phase alternator 2 can be further reduced.
[0090]
(Sixth embodiment)
The circuit configuration of the hybrid vehicle inverter system according to the present embodiment is a hybrid vehicle inverter system according to any one of the first to fifth embodiments, in which a rotational speed detector that detects the rotational speed of the internal combustion engine 1 is provided. Add
Furthermore, the control circuit 48
In addition to the functions of any of the first to fifth embodiments,
Based on the output signal from the rotation speed detector, when it is determined that the three-phase AC machine 2 is below a predetermined speed or is in an idling operation state, control is performed so that the step-up / step-down chopper circuit 49 stops the step-up operation. It has functions.
[0091]
Next, the operation of the hybrid vehicle inverter system according to the present embodiment configured as described above will be described.
[0092]
Note that the description of the operation of the same portion as the operation of the first embodiment is omitted, and only the operation of the different portion will be described here.
[0093]
That is, an output signal from a detector that detects the number of revolutions of the internal combustion engine 1 is taken into the control circuit 48, and it is determined that the three-phase AC machine 2 is below a predetermined speed or in an idling operation state. By performing control so as to stop the step-up operation of 49, highly accurate matching with the internal combustion engine 1 can be performed.
[0094]
As described above, in the hybrid vehicle inverter system according to the present embodiment, the rotational speed of the internal combustion engine 1 is detected, and based on this rotational speed, the three-phase AC machine 2 is below a predetermined speed or in an idling operation state. Is determined, the boosting operation of the step-up / step-down chopper circuit 49 is stopped, so that highly accurate matching with the internal combustion engine 1 can be performed.
[0095]
(Seventh embodiment)
The circuit configuration of the hybrid vehicle inverter system of the present embodiment is the same as that of FIG. 1, and the functions of the control circuit 48 are partially different.
[0096]
  That is, in addition to the function of the fourth embodiment, the control circuit 48 increases the speed of the three-phase AC machine 2 when modulating the PWM control frequency of the inverter circuit 40 in a predetermined frequency range with a predetermined period. WithFrequency rangeIt has a function of modulating so that the width is narrowed.
[0097]
Next, the operation of the hybrid vehicle inverter system according to the present embodiment configured as described above will be described with reference to the time chart shown in FIG.
[0098]
Note that the description of the operation of the same part as that of the fourth embodiment is omitted, and only the operation of the different part will be described here.
[0099]
  That is, as shown in FIG. 7, as the rotational speed of the internal combustion engine 1 increases, the switching frequencyWidth of(PH-PL)By making it narrow, the switching frequency in the high-speed rotation region can be increased, and the control stability can be improved.
[0100]
In this case, since the noise of the internal combustion engine is loud in the high-speed rotation region, the noise of the three-phase AC machine 2 is small, so there is no particular problem even if the fluctuation range of the switching frequency is small.
[0101]
  As described above, in the hybrid vehicle inverter system according to the present embodiment, when the PWM control frequency of the inverter circuit 40 is modulated in a predetermined frequency range with a predetermined period, the speed of the three-phase AC machine 2 increases. TheFrequency rangeSince the width is narrowed, it is possible to increase the switching frequency in the high-speed rotation region to be modulated and improve the control stability.
[0102]
(Eighth embodiment)
The circuit configuration of the hybrid vehicle inverter system according to the present embodiment is the same as that shown in FIG. 1, and an induction motor or a synchronous motor is used as the three-phase AC machine 2 coupled to the internal combustion engine 1.
[0103]
Next, in the inverter system for a hybrid vehicle according to the present embodiment configured as described above, an induction motor or a synchronous motor is used as the three-phase AC machine 2 coupled to the internal combustion engine 1, so that a three-phase Corresponding to the case where an induction motor or a synchronous motor is used for the AC machine 2, the same operation as in the above-described embodiments can be achieved.
[0104]
As described above, in the hybrid vehicle inverter system according to the present embodiment, the induction motor or the synchronous motor is used as the three-phase AC machine 2 coupled to the internal combustion engine 1. The above-described effects can be achieved by smoothly responding to either the induction motor or the synchronous motor.
[0105]
(Ninth embodiment)
The circuit configuration of the hybrid vehicle inverter system of the present embodiment is the same as that of FIG. 1, and the functions of the control circuit 48 are partially different.
[0106]
That is, the control circuit 48
In addition to the functions of the first embodiment,
Assuming that the inverter circuit 40 has a function of controlling the inverter circuit 40 to perform any one of the power running operation, the regenerative operation, and the excitation operation when the inverter circuit 40 is PWM-controlled to supply power to the three-phase AC machine 2. Yes.
[0107]
Next, in the inverter system for a hybrid vehicle according to the present embodiment configured as described above, when the inverter circuit 40 is PWM-controlled to supply power to the three-phase AC machine 2, the inverter circuit 40 is operated by power running, By controlling either the regenerative operation or the excitation operation, the inverter circuit 40 becomes one of the operation modes of the power running operation, the regenerative operation, or the excitation operation, and torque assist is performed in the power running operation mode. In the regenerative operation mode, charging can be performed, and in the excitation operation mode, the response can be improved by preliminary excitation.
[0108]
Thereby, since the operation performance of the whole system can be improved, the efficiency of the whole system can be further improved as a result.
[0109]
As described above, in the inverter system for a hybrid vehicle according to the present embodiment, when the inverter circuit 40 is PWM-controlled to supply power to the three-phase AC machine 2, the inverter circuit 40 is operated by power running, regenerative operation, or excitation. Since any one of the operations is controlled, the inverter circuit 40 is in any one of the power running operation mode, the regenerative operation mode, and the excitation mode mode, and the overall system performance can be improved. It is possible to further increase the efficiency of the.
[0110]
【The invention's effect】
As described above, according to the hybrid vehicle inverter system of the present invention, when the three-phase AC machine is at a predetermined speed or less, the boosting operation of the step-up / down chopper circuit is stopped, and the DC voltage is changed to the secondary battery voltage. The inverter circuit is controlled so as to perform PWM control operation at approximately the same level, or when the internal combustion engine is operating at the lowest speed idling operation state, the step-up / step-down chopper circuit boost operation is stopped. , The DC voltage is made substantially equal to the secondary battery voltage and the inverter circuit is controlled to perform PWM control operation, or when the internal combustion engine is in the idling operation state at the lowest speed, the boosting operation of the step-up / down chopper is stopped, The PWM control frequency of the inverter circuit is lowered to a frequency commensurate with the idling operation speed so that the PWM operation is performed. , It is possible to achieve a noise reduction of efficiency and the three-phase alternator of the inverter.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing first to ninth embodiments of an inverter system for a hybrid vehicle according to the present invention.
FIG. 2 is a time chart for explaining the operation of the hybrid vehicle inverter system according to the first embodiment of the present invention;
FIG. 3 is a time chart for explaining the operation of the hybrid vehicle inverter system according to the second embodiment of the present invention.
FIG. 4 is a time chart for explaining the operation in the hybrid vehicle inverter system of the third embodiment according to the present invention;
FIG. 5 is a time chart for explaining the operation in the hybrid vehicle inverter system of the fourth embodiment according to the present invention;
FIG. 6 is a time chart for explaining the operation of the hybrid vehicle inverter system according to the fifth embodiment of the present invention.
FIG. 7 is a time chart for explaining the operation of the inverter system for a hybrid vehicle according to the seventh embodiment of the present invention.
FIG. 8 is a schematic diagram illustrating a configuration example of a drive unit of a hybrid vehicle.
FIG. 9 is a circuit diagram showing a configuration example of a conventional inverter system for a hybrid vehicle.
[Explanation of symbols]
1 ... an internal combustion engine,
2. Three-phase AC machine,
3 ... Transmission,
4 ... Inverter,
40: Inverter circuit,
41 ... Semiconductor element,
42 ... Semiconductor element,
43. Semiconductor element,
44. Semiconductor element,
45. Semiconductor element,
46: Semiconductor element,
47 ... DC capacitor,
48 ... control circuit,
49. Buck-boost chopper circuit,
49a ... Semiconductor element,
49b ... semiconductor element,
5 ... Secondary battery,
6 ... switch,
7: A step-up / down reactor.

Claims (5)

A three-phase alternator coupled to an internal combustion engine;
A secondary battery,
A step-up / step-down chopper circuit that boosts the output voltage from the secondary battery to a desired DC voltage via an energy absorption reactor, or steps down the DC voltage to the secondary battery voltage;
An inverter circuit that bridges semiconductor elements, converts the output voltage from the step-up / step-down chopper circuit to alternating current, and supplies the alternating voltage to the three-phase alternating current machine for driving;
A control circuit that controls the step-up / down chopper circuit and the inverter circuit;
The control circuit includes:
At the time of starting acceleration, the inverter circuit controls the three-phase AC machine so as to torque assist the internal combustion engine with the energy stored in the secondary battery,
When the three-phase AC machine is below a predetermined speed, the boosting operation of the step-up / step-down chopper circuit is stopped, and the inverter circuit is controlled to perform PWM control operation with the DC voltage substantially equal to the secondary battery voltage. And
A hybrid vehicle inverter system, wherein the PWM control frequency of the inverter circuit is modulated in a sine wave shape with a predetermined period within a predetermined frequency range. The hybrid vehicle inverter system according to claim 1,
Adding a rotation speed detecting means for detecting the rotation speed of the internal combustion engine;
When the control circuit determines that the three-phase AC machine is below a predetermined speed or in an idling operation state based on an output signal from the rotation speed detection means, the control circuit performs a boosting operation of the step-up / down chopper circuit. A hybrid vehicle inverter system characterized by being stopped . The hybrid vehicle inverter system according to claim 1 ,
When the PWM control frequency of the inverter circuit is modulated in a predetermined frequency range, the hybrid is modulated so that the width of the frequency range is narrowed as the speed of the three-phase AC machine increases. Inverter system for cars. In the hybrid vehicle inverter system according to any one of claims 1 to 3 ,
The three-phase AC machine uses an induction motor or a synchronous motor, and is an inverter system for a hybrid vehicle. In the hybrid vehicle inverter system according to any one of claims 1 to 4,
The control circuit controls the inverter circuit to perform any one of a power running operation, a regenerative operation, and an excitation operation when the inverter circuit is PWM-controlled to supply power to the three-phase AC machine. This is an inverter system for hybrid vehicles.

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