JP3814454B2 - Inverter device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to power supply control of an inverter device that drives a load such as an electric motor for a compressor in a refrigerator, for example.
[0002]
[Prior art]
In recent years, in an inverter device used for a refrigerator or the like, the applied voltage is changed depending on the operation state of the compressor, and the operation efficiency during low-speed rotation of the compressor is improved.
[0003]
A conventional inverter device is disclosed in Japanese Patent Application Laid-Open No. 11-32498.
[0004]
Hereinafter, the conventional inverter device will be described with reference to the drawings.
[0005]
FIG. 6 is a configuration diagram of a conventional inverter device. The conventional inverter device has the following seven components.
[0006]
(1) An AC power source (commercial 100V) 1 is rectified and smoothed by a converter 10 and then switched by a three-phase bridge-connected semiconductor switch (transistor) or the like to armature windings of a three-phase brushless motor 4 Inverter circuit 3 to be applied to
(2) The semiconductor switches (transistors) Ua, Va, Wa, X, Y, and Z of the inverter circuit 3 are turned on and off by a signal output from the control circuit 11 based on the position detection signal from the position detection circuit 5 Drive circuit 7 to be driven,
(3) Converter 10 having a full-wave rectifier circuit 2a, a voltage doubler circuit 2b, a smoothing capacitor 2c, and a mode switching circuit 10a that disables the voltage doubler operation between the full-wave rectifier circuit 2a and the voltage doubler circuit 2b. ,
(4) A rotation speed calculation unit 11a that calculates the rotation speed of the brushless motor 4 based on a position detection signal from the position detection circuit 5, and whether to switch to the voltage doublerless mode of the voltage doubler circuit 2b based on this rotation speed. A mode determination unit 11b for determining whether
(5) A mode switching unit 11c that controls the mode switching circuit according to this mode determination, and issues a variable instruction of the duty of PWM chopping;
(6) A timer 11d for prohibiting mode switching for a certain period of time, a duty setting unit 11e for changing the on-time width of PWM chopping in accordance with the duty variable instruction, and a drive signal in which chopping is superimposed on the energization timing A control circuit (microcomputer) 11 having a waveform generator 11f for generating;
(7) A driver 12 that drives the mode switching circuit 10 by a control signal from the control circuit 11 is provided.
[0007]
About the inverter apparatus comprised as mentioned above, the operation | movement is demonstrated below.
[0008]
First, AC 100V AC power from a commercial power source is rectified and smoothed by the converter 10, and these form a voltage doubler rectifier circuit by turning on the mode switching circuit 10a, and form a full-wave rectifier circuit by turning it off. The DC voltage applied to the inverter circuit 3 is about 280V when the mode switching circuit 10a is ON and no more than 140V when the mode switching circuit 10a is OFF when there is no load.
[0009]
This DC voltage is supplied to the inverter circuit 3 and chopped with a PWM signal of several KHz to several tens of KHz to supply required power to the brushless motor 4. A PWM signal for controlling on / off of a semiconductor switch which is a component of the inverter circuit 3 is generated by a control circuit 11 including a microcomputer or the like.
[0010]
Further, the voltage applied to the inverter circuit 3 is increased by turning on the mode switching circuit 10a during high-speed rotation, and the voltage applied to the inverter circuit 3 is decreased by turning off the mode switching circuit 10a during low-speed rotation.
[0011]
[Problems to be solved by the invention]
However, in the above conventional configuration, since the mode switching circuit 10a switches from the full-wave rectifier circuit to the voltage doubler rectifier circuit in an instant, the voltage applied to the inverter circuit 3 changes abruptly. However, there is a drawback that the mode switching circuit 10a flows to increase the size and cost of the mode switching circuit 10a.
[0012]
The present invention solves the conventional problems, and an object of the present invention is to provide an inverter device that can be smoothly transformed when the applied voltage is changed.
[0013]
In addition, as described above, since the voltage applied to the inverter circuit 3 changes sharply, when the voltage is stepped down, the applied voltage is stepped down faster than the voltage applied to the motor, and thus a reverse current is generated. There were drawbacks.
[0014]
Another object of the present invention is to smoothly reduce the applied voltage so that no reverse current is generated during operation of the motor.
[0015]
Further, as described above, since the voltage applied to the inverter circuit 3 changes abruptly, when the voltage is increased during operation of the motor, there is a drawback that noise is generated because the rotational speed of the motor is disturbed.
[0016]
Another object of the present invention is to smoothly increase the applied voltage so that the rotational speed is not disturbed during motor operation.
[0017]
In addition, when smoothly transforming as described above, if it is controlled at a constant transformation speed regardless of the rotation speed of the motor, it takes excessive time even when the rotation speed needs to be changed quickly. There may be a drawback.
[0018]
Another object of the present invention is to adjust the voltage transformation time in accordance with the rotation speed of the electric motor and control the voltage transformation speed of the applied voltage in the minimum necessary time.
[0019]
In addition, when performing a smooth voltage transformation as described above, when a switch that generates heat when turned on is used, a switch with a high yield strength is required, which may cause a disadvantage that the switch is increased in size and cost.
[0020]
Another object of the present invention is to suppress heat generation when the switch is ON.
[0021]
[Means for Solving the Problems]
  In order to achieve this object, the present invention provides a rectification / smoothing circuit that converts input AC power having a constant voltage into DC power, and converts the DC power converted by the rectification / smoothing circuit into required power and supplies it to a load. In the inverter device having a load power supply module for driving and a drive means for driving the load power supply module, the voltage applied to the load power supply module is doubled from full-wave rectification depending on the magnitude of the power (load). When changing in the range of voltage rectification (about 140 to about 280 V at no load), using the zero cross detection circuit of the input AC voltage and the switch means driven by phase control based on the detection signal, Change applied voltage smoothlyAnd, the transformation speed control is performed to adjust the transformation time according to the rotation speed of the electric motor.It is characterized by that.
[0022]
  Thereby, the voltage applied to the load power supply module can be smoothly transformed.Also, during low-speed operation (including when stopped) where noise and the like are not a problem, it is possible to respond quickly even when, for example, rapid freezing is required by relatively shortening the transformation time.
[0023]
Further, the present invention relates to the input AC voltage of the phase control drive signal for turning on the switch means in order to step down the voltage applied to the load power supply module so that the rotational speed of the motor during operation is lower. It is characterized in that the applied voltage is smoothly stepped down by performing phase control so that the phase progress gradually increases in the direction from the quarter cycle to the half cycle of the input AC voltage.
[0024]
As a result, the voltage applied to the load power supply module does not step down faster than the voltage applied to the motor, and the occurrence of reverse current can be prevented.
[0025]
Further, the present invention relates to the input AC voltage of the phase control drive signal for turning on the switch means in order to boost the voltage applied to the load power supply module so as to increase the rotational speed of the motor during operation. It is characterized in that the applied voltage is smoothly boosted by performing phase control so that the degree of phase progression gradually decreases from the half cycle of the input AC voltage to the quarter cycle.
[0026]
Thereby, the rotation speed of the motor during operation is not disturbed, and noise generated by the motor can be suppressed.
[0029]
Further, the present invention is characterized in that the voltage applied to the load power supply module is changed by using two types of switch means having different calorific values.
[0030]
As a result, it is possible to suppress the temperature rise of the switch that generates a large amount of heat when turned on.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
  The invention according to claim 1 of the present invention includes a rectifying / smoothing circuit that converts input AC power having a constant voltage into DC power, and the DC power converted by the rectifying / smoothing circuit is converted into required power for compression. A voltage applied to the load power supply module by the power (load) in an inverter device having a load power supply module that supplies a load such as a motor for a machine and a drive unit that drives the load power supply module Is changed in the range of full-wave rectification to voltage doubler rectification (about 140 to about 280 V when no load is applied), and a zero cross detection circuit for input AC voltage and switch means driven by phase control based on the detection signal The applied voltage is changed smoothly usingAnd, the transformation speed control is performed to adjust the transformation time according to the rotation speed of the electric motor.In order to gently change the voltage applied to the switch means, the current flowing through the switch means can be suppressed, and the switch means can be reduced in size and cost can be reduced.Further, by performing transformation at an optimum time with respect to the rotation speed of the motor during operation, for example, rapid refrigeration during low-speed operation (including when the motor is stopped) in which noise generated by the motor is not a significant problem. When a request is received, it has the effect of being able to respond quickly by performing transformation in a relatively short time.
[0032]
According to a second aspect of the present invention, in the first aspect of the present invention, when the voltage applied to the load power supply module is changed in the range from full-wave rectification to voltage doubler rectification depending on the size of the load, In order to lower the applied voltage so as to lower the rotation speed of the input AC voltage, the phase control drive signal for turning on the switch means gradually changes in phase with respect to the input AC voltage from the quarter cycle of the input AC voltage to the half cycle. The phase control is performed so that the applied voltage is smoothly stepped down, and the voltage applied to the load power supply module is gently stepped down so that the stepping down speed is the voltage applied to the motor. Since it is slower than the step-down speed, it has the effect of preventing the occurrence of reverse current.
[0033]
In the invention of claim 3, in the invention of claim 1, when the voltage applied to the load power supply module is changed in the range of full-wave rectification to voltage doubler rectification depending on the size of the load, In order to increase the applied voltage so as to increase the rotation speed of the motor, the phase control drive signal for turning on the switch means is shifted in phase from the half cycle of the input AC voltage to the quarter cycle. By performing phase control so that the voltage gradually decreases, the applied voltage is smoothly boosted. In order to gently boost the voltage applied to the motor during operation, the rotational speed of the motor is not disturbed, and the motor It has the effect | action that the noise which generate | occur | produces can be suppressed.
[0035]
  Claim4In the invention described in claim 1, in the invention described in claim 1, when the double voltage is continuously applied to the load power supply module, the applied voltage is changed by using two kinds of switch means having different heat generation amounts. When the voltage after voltage doubler rectification is continuously applied to the load power supply module, the switch means having a large calorific value is switched to the switch means having a small calorific value to suppress the temperature rise. Have.
[0036]
Hereinafter, embodiments of an inverter device according to the present invention will be described with reference to the drawings.
[0037]
FIG. 1 is a configuration diagram of an inverter device according to an embodiment of the present invention.
[0038]
In FIG. 1, reference numeral 21 denotes a rectifier circuit, which is composed of four rectifier diodes, rectifies input AC power having a constant voltage and outputs the rectified circuit to the smoothing circuit 23.
[0039]
Reference numeral 22 denotes a switch means, which is composed of a triac and a relay connected in parallel. The ON / OFF is switched by a signal output from the controller 29, and the voltage output to the smoothing circuit 23 is a peak value at no load. The voltage is changed in the range of 140V to 280V (in this embodiment, the voltage value of the input AC power is AC100V).
[0040]
A smoothing circuit 23 is composed of two smoothing capacitors connected in series, and smoothes the voltage rectified by the rectifier circuit 21 and outputs it as DC power to the load power supply module 24.
[0041]
Reference numeral 24 denotes a load power supply module, in which a semiconductor switch (transistor) is connected in a three-phase bridge, and a diode is connected to each transistor in parallel and in the reverse direction. The DC power output from the smoothing circuit 23 is converted into required power and supplied to the load (electric motor 25).
[0042]
Reference numeral 25 denotes an electric motor, which is operated at a required rotational speed by the output of the load power supply module 24.
[0043]
Reference numeral 26 denotes a zero-cross detection circuit, which is composed of an integrated circuit (op-amp) or the like, and detects when the voltage value of the input AC power becomes 0 V and outputs an appropriate phase control drive signal to the triac drive circuit 27. The input AC zero cross signal is output to the controller 29.
[0044]
Reference numeral 27 denotes a triac drive circuit, which appropriately turns on / off the triac according to the phase control drive signal output from the controller 29.
[0045]
An applied voltage detection circuit 28 detects a voltage applied to the load power supply module 24 and outputs an applied voltage detection signal to the controller 29.
[0046]
Reference numeral 29 denotes a controller, which is a microcomputer, the load power supply module 24.
The motor 25 is based on the above-described input / output of various signals, the relay drive signal output to the relay drive circuit 30, and the signal output from the position detection circuit 31. Rotational speed monitoring is performed.
[0047]
A relay drive circuit 30 is composed of a semiconductor switch or the like, and appropriately controls ON / OFF of the relay by a relay drive signal output from the controller 29.
[0048]
A position detection circuit 31 detects the position of the rotor of the electric motor 25 and outputs it to the controller 29.
[0049]
About the inverter apparatus comprised as mentioned above, the operation | movement is demonstrated below.
[0050]
In a device such as a refrigerator having an inverter device, the voltage applied to the load power supply module 24 is changed according to the load state such as the speed of the electric motor 25 in order to operate the load such as the electric motor more efficiently. For example, the electric motor 25 is switched to a double voltage when the motor is operating at high speed, and is switched to approximately half the voltage when operating at a low speed including when it is stopped.
[0051]
In this case, in general, the DC voltage is switched instantaneously by a switch such as a relay regardless of the operation state of the electric motor 25 and the voltage switching direction (step-down direction or step-up direction). The DC voltage switching method in the present embodiment is performed as follows. First, based on the input AC zero-cross signal output from the zero-cross detection circuit 26 and the applied voltage detection signal output from the applied voltage detection circuit 28, the value of the voltage applied to the load power supply module 24 is greater than the value of the voltage applied to the load power supply module 24. The controller 29 outputs a phase control drive signal to the triac drive circuit 27 so that the triac is ignited at a phase position where the peak value of the voltage of the input AC power slightly increases.
[0052]
By repeating this, the voltage applied to the load power supply module 24 is transformed. When the applied voltage is stepped down, the applied voltage is transformed such that the triac is ignited at a phase position where the peak value of the voltage of the input AC power is slightly reduced.
[0053]
Therefore, the voltage applied to the load power supply module 24 can be smoothly transformed, and the inrush current flowing through the switch means 22 becomes very small, so that the switch can be downsized and the cost can be reduced.
[0054]
FIG. 2 is a diagram schematically showing the relationship between voltage and signal when the voltage applied to the load power supply module 24 during operation of the electric motor 25 is reduced smoothly. The voltage is reduced from about 280V when there is no load as commercial voltage 100V to about half of that (equivalent to 140V when there is no load as commercial input voltage 100V).
[0055]
In FIG. 2, the zero cross point is a point at which the input AC voltage becomes 0 V, and exists every half cycle of the input AC voltage waveform. The voltage after rectification is a voltage after the input AC power is rectified by the rectifier circuit 21, and the voltage waveform is generated every half cycle of the input AC voltage.
[0056]
Considering each zero cross point as a reference for this voltage waveform after rectification, the voltage after rectification becomes the maximum after the time corresponding to the quarter cycle of the input AC voltage waveform, and the time until the next zero cross point corresponds to the half cycle of the input AC voltage. Can be interpreted. That is, the time t when the voltage after rectification becomes maximum_D1Is a quarter cycle after the previous zero crossing point and the time t_D2, T_D3, T_D4, T_D5Is between a quarter cycle and the next zero crossing point or half cycle, and t_D2, T_D3, T_D4, T_D5Can be interpreted as approaching from the quarter period to the half period.
[0057]
The step-down method of the applied voltage in this embodiment is performed as follows. First, the controller 29 outputs a phase control drive signal as shown on the left in the figure, and gradually shifts the time when the triac is fired from the quarter cycle of the input AC voltage waveform to the half cycle for each zero cross point. Phase control the triac.
[0058]
Therefore, the conduction time of the triac is gradually shortened, whereby the voltage applied to the load power supply module 24 is stepped down slower than the voltage drop rate applied to the electric motor 25, thereby preventing reverse current. The circuit reliability can be improved.
[0059]
FIG. 3 is a diagram schematically showing a relationship between a voltage and a signal when the voltage applied to the load power supply module 24 during operation of the electric motor 25 is smoothly increased. In this embodiment, half of the double voltage is shown. The voltage is boosted from a voltage of about (equivalent to 140V when the input voltage is commercial 100V and no load) to a double voltage (equivalent to 280V when the input voltage is commercial 100V and no load).
[0060]
In FIG. 3, the same interpretation as in FIG. 2 can be made. That is, the time t when the voltage after rectification becomes maximum_U5Is a quarter cycle after the previous zero crossing point and the time t_U1, T_U2, T_U3, T_U4Is between a quarter cycle and the next zero crossing point or half cycle, and t_U1, T_U2, T_U3, T_U4This can be interpreted as approaching from half to quarter.
[0061]
The boosting method of the applied voltage in this embodiment is performed as follows. First, the controller 29 outputs a phase control drive signal as shown on the left in the figure, and gradually shifts the time when the triac is fired from the half cycle of the input AC voltage waveform to the quarter cycle for each zero cross point. Phase control the triac.
[0062]
Therefore, the conduction time of the triac is gradually increased, whereby the voltage applied to the load power supply module 24 is smoothly boosted, and the disturbance of the rotation speed in the electric motor 25 that cannot be followed by the controller 29 can be prevented. 25 can suppress noise generated.
[0063]
FIG. 4 is a flowchart relating to the transformation speed control of the voltage applied to the load supply module 24. Here, the control in the previous stage of the transformation speed control will be described a little. As described in the above-described prior art, the applied voltage is determined by the operating speed condition of the electric motor 25. Therefore, before starting the transformation speed control, it is supplemented that the operation speed of the electric motor 25 at that time is known.
[0064]
Hereinafter, the transformation speed control of the applied voltage applied to the load power supply module 24 according to the present embodiment will be described in detail with reference to FIG. First, based on the signal output from the position detection circuit 31, the rotational speed of the electric motor 25 calculated by the controller 29 is an arbitrary rotational speed, for example, 30 s.^-1It is determined whether it is slower than (30 rps) (step ST1).
[0065]
If it is slow, the mode of the transformation speed is determined as the short time mode (step ST2). Here, the transformation time in this mode is assumed to be 2 seconds. Then, the controller 29 outputs a phase control drive signal to the triac drive circuit 27 so that the transformation to the target voltage is completed in 2 seconds (step ST3), and the applied voltage of the load power supply module 24 is set to the target voltage. (Step ST6).
[0066]
On the other hand, the determination result of step ST1 is 30s.^-1If it is faster than (30 rps), the transformation speed mode is determined to be the long-time mode (step ST4). Here, the transformation time in this mode is assumed to be 5 seconds. Then, the controller 29 outputs a phase control drive signal to the triac drive circuit 27 so that the transformation to the target voltage is completed in 5 seconds (step ST5), and the target voltage is reached as in the case of the short time mode. Transform (step ST6).
[0067]
Here, I will explain in more detail using specific numerical values. Now, suppose the input AC voltage is commercial 100V, frequency 50Hz, and the motor 25 is 29s.^-1Consider that the voltage applied to the load power supply module 24 is transformed during operation at (29 rps). Rotation speed is 29s^-1Therefore, the mode of the transformation speed is a short-time mode, and the TRIAC is phase-controlled so that the transformation is completed in 2 seconds.
[0068]
As described above, since the phase control is performed by firing the triac every half cycle of the input AC voltage waveform, when the frequency of the input AC voltage is 50 Hz, the triac is fired to complete the transformation in 2 seconds. It will be done 200 times.
[0069]
On the other hand, the rotation speed is 31 s.^-1In the case of (31 rps), the transformation speed mode is the long-time mode, and the TRIAC is phase-controlled so that the transformation is completed in 5 seconds. Since it is the same as in the short-time mode, the triac is fired 500 times to complete the transformation in 5 seconds.
[0070]
That is, the number of firings is increased in the long-time mode than in the short-time mode, resulting in smoother voltage transformation. Now, the transformer will be described in more detail as a step-up from 140V to 280V. To increase the voltage from 140 V to 280 V means to increase the conduction angle of the triac from about 30 degrees to about 90 degrees.
[0071]
In other words, since the frequency of the input AC voltage is 50 Hz, the conduction time is extended from about 1.67 ms to about 5 ms. This expansion of about 60 degrees (about 3.33 ms for conduction time) is divided into 200 firing times (2 seconds boosting time) in the short-time mode, and firing times in the long-time mode. Since it is divided into 500 times (5 seconds for boosting time), the phase control is finer in the long-time mode, so smoother boosting can be achieved, and the short-time mode can transform quickly. Can be completed.
[0072]
Therefore, the TRIAC can be phase-controlled so as to realize an optimum transformation speed according to the number of rotations of the electric motor 25 during operation. Even when freezing is required, a quick response is possible.
[0073]
In addition to FIG. 4, the simplest control method having only two branches after the determination condition of step ST <b> 1 has been described here, but the rotation speed, the transformation direction (step-up or step-down), and the transformation. More suitable transformation speed control can be realized by increasing the number of branches after the determination according to conditions such as the size and the change rate of the conduction angle.
[0074]
As a specific example, for example, the rotational speed is in a stopped state 0 s.^-1In the case of (0 rps), it is conceivable to perform a transformation speed control such that when the voltage is boosted, the transformation time is 1 second, and when the voltage is lowered, the voltage is transformed instantaneously.
[0075]
Even in such a case, the basic control flow is almost the same as the flow of the above-described method, and the number of branches increases due to the increase of the determination condition of step ST1, and the number of steps increases accordingly. Only.
[0076]
FIG. 5 is a timing chart of the applied voltage of the load power supply module 24, the phase control drive signal output to the triac drive circuit 27, and the relay drive signal output to the relay drive circuit 30. Hereinafter, a method for suppressing the temperature rise of the switch means 22 in this embodiment will be described with reference to FIG.
[0077]
In FIG. 5, t₁Is the voltage boost start time applied to the load power supply module 24, t₂Is the boost completion time, t_ThreeIs the pressure drop start time, t_FourIs the completion time of step-down. First, when a phase control drive signal is output from the controller 29 to the triac drive circuit 27 and phase control of the triac is started, the applied voltage of the load power supply module 24 is changed to the time t.₁Then, the voltage starts to be boosted from the full-wave rectified voltage (a voltage that is about half of the double voltage). This state is, for example, a state such as “during the low speed operation, the refrigerator internal temperature becomes higher than the required temperature and the electric motor 25 needs to be operated at a higher speed”.
[0078]
And time t₂When the voltage is boosted to a voltage doubled, the TRIAC is completely turned on by the phase control drive signal (the conduction angle is 180 degrees, that is, the state where the conduction is 100%), and immediately after that time t_{twenty one}Then, a relay drive signal is output from the controller 29 to the relay drive circuit 30, the relay is also turned on, and a time t immediately thereafter_{twenty two}The phase control drive signal is stopped to make the triac non-conductive. That is, time t₂To t_{twenty two}During this period, the switch means 22 is switched from the triac to the relay.
[0079]
Further, since the triac is in a complete conduction state during this period, the number of times that the commutator repeats commutation increases and the temperature also increases as the period increases. On the other hand, the applied voltage is stepped down at time t._ThreeStarting from. This state is, for example, a state such as “switch to low speed operation because the refrigerator internal temperature has dropped to a required temperature”. Similarly to the step-up, the applied voltage is stepped down by TRIAC phase control. Therefore, the switch means 22 needs to be switched from the relay to the TRIAC before starting step-down.
[0080]
Therefore, time t₃₂At time t immediately after the TRIAC is completely turned on by the phase control drive signal.₃₃At time t immediately after the relay is turned off by the relay drive signal at_ThreeIn addition, the triac is phase-controlled by the phase control drive signal to start the step-down of the applied voltage.
[0081]
And time t_FourIn addition, the applied voltage is stepped down to the full-wave rectified voltage and the phase control drive signal is stopped, thereby making the triac non-conductive. Summarizing such operations, the switch means 22 is switched such that the triac is driven when transforming and the relay is driven when not transforming.
[0082]
Therefore, at time t₂To t_ThreeIt was necessary to continue the complete conduction state for a long period of time until the applied voltage remains at the double voltage and is not transformed.₂To t_{twenty two}And t₃₂To t_ThreeIt is possible to reduce the temperature rise in the switch means 22 significantly by significantly reducing the commutation repetition time of the triac (commutator). In FIG. 5, the time t_ThreeIf the relay is driven immediately before and the triac is turned off immediately after that, the time t_ThreeTo t₃₂Since the complete conduction state can be eliminated, further temperature rise suppression can be realized.
[0083]
【The invention's effect】
  As explained aboveBookThe invention smoothly reduces the voltage applied to the load power supply module, thereby reducing the inrush current flowing through the switch means used for the transformation, and reducing the size and cost of the switch means.. Also,By controlling the transformation speed to adjust the transformation time of the applied voltage and controlling the transformation speed so that it becomes the optimal time with respect to the rotation speed of the motor, for example, noise generated by the motor does not matter much. When a rapid freezing request is received during low-speed operation (including when stopped), a quick response can be made by performing transformation in a relatively short time.
[0084]
  In addition, if the applied voltage is stepped down smoothly during operation of the motor in the above configuration, it is possible to step down slower than the step-down speed of the motor and prevent reverse current generation, thereby improving circuit reliability, If the applied voltage is increased smoothly during operation of the electric motor, the disturbance of the rotational speed that cannot be followed by the controller can be prevented, so that noise generated by the electric motor can be suppressed. Also,When the voltage after voltage doubler rectification is continuously applied to the load power supply module, the temperature rise can be suppressed by switching from the switch means having a large heat generation amount to the switch means having a small heat generation amount.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an inverter device according to an embodiment of the present invention.
FIG. 2 is a characteristic diagram of an inverter device according to an embodiment of the present invention.
FIG. 3 is a characteristic diagram of an inverter device according to an embodiment of the present invention.
FIG. 4 is a flowchart of the inverter device in the embodiment of the present invention.
FIG. 5 is a time chart of an inverter device according to an embodiment of the present invention.
FIG. 6 is a configuration diagram of a conventional inverter device.
[Explanation of symbols]
21 ... Rectifier circuit
22 ... Switch means
23. Smoothing circuit
24 ... Load power supply module
25 ... Electric motor
26: Zero cross detection circuit
27. Triac drive circuit
28 ... Applied voltage detection circuit
29 ... Controller
30 ... Relay drive circuit
31 ... Position detection circuit

Claims (4)

Rectifying / smoothing circuit that converts input AC power of a constant voltage into DC power, and load power that converts the DC power converted by the rectifying / smoothing circuit into required power and supplies it to a load such as a compressor motor In an inverter device having a supply module and a driving means for driving the load power supply module, the voltage applied to the load power supply module by the power (load) is changed from full-wave rectification to voltage doubler rectification (when no load is applied). When the input voltage is changed in the range of about 140 to about 280 V, the applied voltage is smoothly changed by using a zero-crossing detection circuit for the input AC voltage and switch means driven by phase control based on the detection signal. And an inverter device that performs a transformation speed control for adjusting a transformation time according to the number of rotations of the electric motor .   When changing the voltage applied to the load power supply module depending on the size of the load in the range of full-wave rectification to voltage doubler rectification, in order to lower the applied voltage so that the rotation speed of the motor during operation becomes lower, The applied voltage is smoothed by performing phase control so that the phase of the phase control drive signal for turning on the switching means gradually increases in phase with respect to the input AC voltage from the quarter cycle to the half cycle of the input AC voltage. The inverter device according to claim 1, wherein step-down control is performed.   When changing the voltage applied to the load power supply module depending on the size of the load in the range of full-wave rectification to voltage doubler rectification, in order to increase the applied voltage so that the rotation speed of the motor during operation becomes higher, The applied voltage is smoothed by controlling the phase so that the phase of the phase control drive signal for turning on the switching means gradually decreases in the direction from the half cycle of the input AC voltage to the quarter cycle. The inverter device according to claim 1, wherein step-up control is performed.   2. The inverter device according to claim 1, wherein when the double voltage is continuously applied to the load power supply module, the applied voltage is changed by using two types of switch means having different heat generation amounts.

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