JP7086016B2 - Power converter, motor drive, refrigeration cycle device, blower, air conditioner, refrigeration equipment - Google Patents

Description

The present invention relates to a power conversion device that converts AC power supplied from an AC power source into DC power and supplies it to a load, a motor drive device provided with the power conversion device, a blower and a compressor provided with the motor drive device, and the like. In addition, the present invention relates to the blower or the air conditioner equipped with the compressor.

In the power conversion device, one of the problems is to suppress the loss on the circuit through which the current flows to improve the efficiency. As a power conversion device for the purpose of improving efficiency, in the power conversion device described in Patent Document 1 below, two of the four diodes are replaced with MOSFETs (Metal-Oxide-Semiconductor Field Field-Effective Transistor). A rectifier having a different configuration is disclosed. In the rectifier, two diodes and two MOSFETs are bridge-connected to form a bridge circuit.

In the power conversion device of Patent Document 1, the conduction loss is reduced by controlling the MOSFET in synchronization with the timing when the current starts to flow in the bridge circuit and the timing when the current flowing in the bridge circuit changes to zero. This technique is called synchronous rectification.

Japanese Unexamined Patent Publication No. 2012-143154

In addition to the above background, in recent years, in order to correspond to a wider operating area, there has been a problem that it is desired to suppress the flow current and improve the efficiency of the system, especially in the high load operating area.

The present invention has been made to solve the above-mentioned problems, and in a rectifier having a configuration in which a part of a rectifier circuit is replaced with a MOSFET, the loss as a system is smaller and it corresponds to a wide drive range. The purpose is to obtain a power conversion device that can be used.

The power conversion device according to the present invention includes a plurality of legs consisting of an upper arm and a lower arm composed of a semiconductor switch or a diode, a bridge circuit that rectifies the AC power of the AC power supply into DC power, and smoothes the DC power. An integrated magnetic component having a capacitor and one end connected to one end of an AC power supply and the other end connected to a connection point between the upper arm and the lower arm, and a current correlated with the current of the AC power supply or the current of the AC power supply. The control unit includes a current detection unit for detecting, a voltage detection unit for detecting the voltage of the DC power or a voltage correlated with the voltage of the DC power, and a control unit for controlling the opening and closing of the semiconductor switch. The conduction mode of the semiconductor switch is switched based on one or two of the detection value of the current detection unit and the detection value of the voltage detection unit, and the current pattern flowing through the integrated magnetic component is changed . It is characterized in that the determination of switching based on the detection value of the current detection unit is changed according to the detection value of the voltage detection unit .

According to the power conversion device according to the present invention, since the switching operation can be switched and flexibly controlled, there is an effect that efficiency can be improved and boosting performance can be improved in a wide operating range.

(1) Configuration example of the power conversion device according to the first embodiment, (2) Example of integrated magnetic component used in the power conversion device Configuration example of the power conversion device according to the first embodiment (when the motor drive unit is connected to the load side) Example of diode loss characteristics according to the first embodiment and loss characteristics when the switching element is turned on. Example of current path in load supply mode of the power converter according to the first embodiment (operating region when the current is relatively small) Example of current path in load supply mode of the power converter according to the first embodiment (operating region when the current is relatively large) Example of current path in power supply short-circuit mode of the power converter according to the first embodiment (operating region when the current is relatively small) Example of current path in power supply short-circuit mode of the power converter according to the first embodiment (operating region when the current is relatively large) Example of current path in blend mode of the power converter according to the first embodiment (operating region when the current is relatively small) Current path example 1 of the blend mode of the power converter according to the first embodiment (operating region when the current is relatively large) Current path example 2 of the blend mode of the power converter according to the first embodiment (operating region when the current is relatively large) (1) Setting example of the mode switching area of the power converter according to the first embodiment (3 areas) (2) Setting example of the mode switching area of the power converter according to the first embodiment (4 areas) (3) Implementation Setting example of the mode switching area of the power converter according to the first form (4 areas) Example of the power converter according to the first embodiment in which a part of the converter (AC / DC converter) is configured by a diode. Example of applying the power conversion device according to the first embodiment to an air conditioner

The power conversion device, the motor drive device, the blower, the compressor, and the air conditioner according to the embodiment of the present invention will be described below with reference to the accompanying drawings. The present invention is not limited to the embodiments shown below. Further, in the following, the electrical connection will be described simply as "connection".

Embodiment 1.
FIG. 1 (1) is a circuit diagram showing the configuration of the power conversion device 101 according to the first embodiment. The power conversion device 101 according to the first embodiment is a device that converts an AC voltage supplied from a single-phase AC power supply 1 into a DC voltage and supplies it to a load 7. As shown in FIG. 1 (1), the power conversion device 101 according to the first embodiment includes an integrated magnetic component 3, a converter 40 (a plurality of switching elements 4a to 4f, and a diode connected in antiparallel to these switching elements). (Consists of 5a to 5f), a smoothing capacitor 6, a current sensor 2, a current detection unit 41, a DC voltage detection unit 31, and a control device 11. Further, the integrated magnetic component 3 is configured by winding a DC winding 3c and a plurality of coupling windings 3a to 3b around one magnetic material.

In FIG. 1 (1), the example of the load 7 is composed of a motor built in a blower, a compressor, or an air conditioner (these are referred to as actuators), an inverter for driving these actuators, and the like.

FIG. 1 (2) shows a configuration example of the integrated coupling component 3.
The integrated magnetic component 3 is mainly composed of a core and windings, and particularly for windings, it is composed of a DC winding 3c and a plurality of coupling windings 3a and 3b connected in series. As the core shape of the integrated magnetic component 3, for example, a shape having a tripod such as an EE type or an EI type is used. FIG. 1 (2) shows an example of the EE type, but the present invention is not limited to this. Here, with respect to the windings 3a and 3b, a coupled reactor can be formed by winding the windings 3a and 3b around the side legs of each winding so as to cancel each other's DC magnetic flux. Further, the winding 3c can form a DC reactor by winding the windings 3a and 3b around the center leg of the core in a direction in which the magnetic fluxes of the windings 3a and 3b are strengthened. As a result, the integrated magnetic component 3 has an inductance of self-inductance, mutual inductance, and leakage inductance, and it is possible to configure a compact, highly efficient, and highly boosted system by devising a method of energizing the winding. ..
One end of the DC winding 3c is connected to the AC power supply 1, and the other end is connected to the coupling winding side. Each end on the other side of the coupling winding side is connected to each intermediate connection point between the switching element 4c / 4d (diode 5c / 5d) and the switching element 4e / 4f (diode 5e / 5f). That is, the magnetic flux generated by the current flowing through the DC winding and the coupling winding merges in the same direction.

Next, in FIG. 1, the converter 40 will be described. First, the switching elements constituting the converter 40 are formally described as follows. That is, the switching element 4a and the diode 5a connected in antiparallel to the switching element 4a are used as the first upper arm element. The switching element 4b and the diode 5b connected in antiparallel to the switching element 4b are used as the first lower arm element.
The switching element 4c and the diode 5c connected in antiparallel to the switching element 4c are used as the second upper arm element. The switching element 4d and the diode 5d connected in antiparallel to the switching element 4d are used as the second lower arm element.
The switching element 4e and the diode 5e connected in antiparallel to the switching element 4e are used as the third upper arm element. The switching element 4f and the diode 5f connected in antiparallel to the switching element 4f are used as the third lower arm element.

In FIG. 1 (1), the use of a metal oxide semiconductor field effect transistor (Metal Oxide Semiconductor Field Effect Transistor: MOSFET) is exemplified for each of the switching elements used for the first to third upper and lower arms, but the MOSFET is used. Not limited. A MOSFET is a switching element capable of passing a current in both directions between a drain and a source. Any switching element may be used as long as it is a switching element capable of bidirectionally flowing a current between the first terminal corresponding to the drain and the second terminal corresponding to the source, that is, a bidirectional switching element.

Further, antiparallel means that the first terminal corresponding to the drain of the MOSFET and the cathode of the diode are connected, and the second terminal corresponding to the source of the MOSFET and the anode of the diode are connected. As the diode, a parasitic diode contained in the MOSFET itself may be used. Parasitic diodes are also called body diodes.

Further, at least one of the switching elements used for the first to third upper and lower arms is not limited to the MOSFET formed of the silicon-based material, and is made of a wide bandgap semiconductor such as silicon carbide, gallium nitride-based material, or diamond. It may be a formed MOSFET.

In general, wide bandgap semiconductors have higher withstand voltage and heat resistance than silicon semiconductors. Therefore, by using a wide bandgap semiconductor for at least one of the switching elements used for the first to third upper and lower arms, the withstand voltage resistance and the allowable current density of the switching element are increased, and the semiconductor incorporating the switching element. The module can be miniaturized.

The first upper arm element 4a in the first leg, the second upper arm element 4c in the second leg, and the third upper arm element 4e side in the third leg are connected to the DC bus on the high potential side. ing. One end of the smoothing capacitor 6 is connected to the DC bus on the high potential side. The first lower arm element 4b in the first leg, the second lower arm element 4d in the second leg, and the third lower arm element 4f side in the third leg are connected to the DC bus on the low potential side. Has been done. The other end of the smoothing capacitor 6 is connected to the DC bus on the low potential side.

The output of the bridge circuit composed of the above three legs is applied to both ends of the smoothing capacitor 6. The smoothing capacitor 6 smoothes the output voltage of the bridge circuit. The smoothing capacitor 6 is connected to the DC bus on the high potential side and the low potential side. The voltage smoothed by the smoothing capacitor 6 is called "bus voltage". The bus voltage may be referred to as a "second voltage" or a "DC voltage". The bus voltage is also the voltage applied to the load 7.

The current detector 2 detects the alternating current flowing between the alternating current power supply 1 and the converter 40 (bridge circuit), and outputs the alternating current to the current detection unit 41. Then, the AC current detection value Is is output from the current detection unit 41 to the control unit 11. An example of the current detector 6 is a current transformer (CT). The alternating current flowing between the alternating current power supply 1 and the bridge circuit is appropriately referred to as "power supply current". The current detection unit 41 detects the current of the AC power supply or the current correlated with the current of the AC power supply.

The voltage detection unit 31 detects the bus voltage and outputs the detection value Vdc of the bus voltage to the control unit 11. The voltage detection unit 31 detects the voltage of the DC power or the voltage correlated with the voltage of the DC power.

The control unit 11 controls the control signals S1 to S6 for controlling each switching element constituting the converter 40 (bridge circuit) based on the detection value Is of the current detection unit 41, the detection value Vdc of the voltage detector 31, and the like. To generate. Although not specified here, depending on the type of converter control (control related to AC / DC conversion), a means for detecting the power supply voltage may be provided.
The control signal S1 is a control signal for controlling the switching element 4a. Similarly, the control signal S2 is a control signal for controlling the switching element 4b, the control signal S3 is a control signal for controlling the switching element 4c, and the control signal S4 controls the switching element 4d. The control signal S5 is a control signal for controlling the switching element 4e, and the control signal S6 is a control signal for controlling the switching element 4f. The control signals S1 to S6 generated by the control unit 11 are output as drive signals S11 to S16 of each switching element via the gate drive unit 51.

For example, an inverter motor or the like may be connected to the load 7.
An example is shown in FIG. In FIG. 2, based on the power conversion device 101 of FIG. 1 (1), an inverter 500a (composed of switching elements 8a to 8f and diodes 9a to 9f connected in antiparallel to each switching element) and a motor 500b. Is a motor drive device that drives the motor by converting the DC power output from the power conversion device 101 into AC power.
Here, the control signals S21 to S26 of the inverter 500a (AC / DC conversion unit) generated by the control unit 11 are output as drive signals S31 to S36 of each switching element via the gate drive unit 52.
The control signal S21 is a control signal for controlling the switching element 8a. Similarly, the control signal S22 is a control signal for controlling the switching element 8b, the control signal S23 is a control signal for controlling the switching element 8c, and the control signal S24 controls the switching element 8d. The control signal S25 is a control signal for controlling the switching element 8e, and the control signal S26 is a control signal for controlling the switching element 8f. The control signals S21 to S26 generated by the control unit 11 are output as drive signals S31 to S36 of each switching element via the gate drive unit 51.

A motor 500b is connected to the output side of the inverter 500a. The inverter 500a drives the motor 500b by inputting DC power output from the power conversion device 101, converting it into AC power, and supplying it to the motor 500b.

Further, the application of the motor 500b can be applied to products such as a blower, a compressor and an air conditioner.

Next, the operation of the main part of the power conversion device 101 according to the first embodiment will be described with reference to the drawings.

In driving the power conversion device 101, by considering the characteristics of the switching element, more efficient operation can be performed and the loss is small, so that the operation range can be expanded even when the load is high on the load side.

FIG. 3 shows an example of the loss characteristic of the diode and the loss characteristic when the switching element is turned on. When an element having the characteristics shown in FIG. 3 is used, the diode loss is larger than the switching element loss in the region A where the current is smaller than the current value I0. By utilizing this characteristic and using the synchronous rectification control in which the switching element connected in antiparallel to the diode is turned on and the reverse conduction is performed in accordance with the timing when the current flows through the diode, the device can be operated with high efficiency. ..

The operation mode of the power conversion device 101 utilizes the fact that the load supply mode for supplying the power supply current to the load, the power supply short-circuit mode for storing energy in the reactor by short-circuiting the power supply, and the integrated magnetic component 3 having three terminals. It can be divided into blend modes that combine the above modes. By combining these modes and selecting and operating the operation mode according to the load conditions, it is possible to configure a compact, highly efficient, and highly boosted system.

Hereinafter, the operation of each mode will be described with reference to FIGS. 4 to 10.
4 to 10 show the current flow of the switching element of the power conversion device 101 of the first embodiment shown in FIG. 1 (1).

In the above drawings, the case where the AC input voltage has a negative electrode property will be described as a representative, but the case where the AC input voltage has a positive electrode property can also be controlled by the same concept.
The dotted line in the figure shows the current path when the AC input voltage is the negative electrode.

First, the load supply mode will be described.
FIG. 4 shows a current path when the AC input voltage of the circuit of the power conversion device 101 of the first embodiment shown in FIG. 1 (1) is a negative electrode (dotted line arrow in the figure).

The current from the AC voltage source 1 enters the integrated magnetic component 3, passes through the DC winding 3c, and is output from the coupling windings 3a and 3b.

Here, by turning on the switching elements 4c and 4e, the flow is divided into the switching elements 4c and 4e, enters the smoothing capacitor 6, and is supplied to the load 7.
Further, by turning on the switching element 4b on the side returning to the power supply, the switching element 4b returns to the AC voltage source 1. The other switching elements are turned off.

Here, the voltage between the winding 3c and the winding 3a is V1e (between A and C in FIG. 1 (1)), and the voltage between the winding 3c and the winding 3b is V2e (between FIG. 1 (1)). Assuming that the on-voltages (source-drain voltage) of the switching elements 4b, 4c, and 4e (between A and D) are Vsd, the voltages of (Equation 1) and (Equation 2) are applied to V1e and V2e, respectively. It becomes.
V1e = Vin-Vout-2 × Vsd (Equation 1)
V2e = Vin-Vout-2 × Vsd (Equation 2)

The three elements of the switching element are in the reverse conduction mode, and especially in the region A (low current region) of FIG. 3, the flow of each switching element is performed with less voltage drop than the diodes 5b, 5c, and 5e, so that it is in the conduction path. Loss can be reduced and high-efficiency operation is possible.
In other words, if the on-voltage (forward voltage) of the diodes 5b, 5c, and 5e is Vf, Vsd is smaller than Vf, so the power loss of each element determined by the product of the current and voltage is each switching. It can be made smaller by passing through the element.

On the other hand, in the region B (medium / high current region) of FIG. 3, high-efficiency operation is possible by setting the mode as shown in FIG. 5 (switching elements 4c, 4e, and 4b are turned off). The other switching elements are turned off.

In this case, the current is output from the coupling windings 3a and 3b, then enters the smoothing capacitor 6 via the diodes 5c and 5e, respectively, and is supplied to the load 7. After that, it returns to the AC voltage source 1 via the diode 5b on the side returning to the power supply.

Here, assuming that the on voltage (forward voltage) of the diodes 5b, 5c, and 5e is Vf, the voltages of (Equation 3) and (Equation 4) are applied to V1e and V2e, respectively.
V1e = Vin-Vout-2 × Vf (Equation 3)
V2e = Vin-Vout-2 × Vf (Equation 4)

In the B region (medium and high current region) of FIG. 3, the on-voltage of the diodes 5b, 5c, and 5e can be lower than the on-voltage of the switching elements 4b, 4c, and 4e, and the flow of each diode is higher than that of the switching element. As a result, the loss in the conduction path can be reduced and high-efficiency operation becomes possible because the operation can be performed with less voltage drop.
In other words, when comparing the on-voltage (source-drain voltage) Vsd and Vf of the switching elements 4b, 4c, and 4e, Vf is smaller than Vsd, so the power of each element determined by the product of the current and voltage. The loss can be reduced by passing through each diode.

Next, the power short circuit mode will be described.
Further, FIGS. 6 to 7 show a power supply short-circuit mode in which the power supply is short-circuited and energy is stored in the reactor.
In the case of FIG. 6, after being output from the coupling windings 3a and 3b, the switching elements 4d and 4f and 4b are turned on to pass through the switching elements 4d and 4f, and then the switching element 4b is connected from the low voltage side of the DC bus. It returns to the AC voltage source 1 via. The other switching elements are turned off.

Here, the voltage between the winding 3c and the winding 3a is V1e (between A and C in FIG. 1 (1)), and the voltage between the winding 3c and the winding 3b is V2e (between FIG. 1 (1)). (A-D), switching element 4b on-voltage (source-drain voltage) is Vsd, 4c, 4e on-voltage (drain-source voltage) is Vds, respectively, V1e and V2e are (Equation 5), The voltage of (Equation 6) will be applied.
V1e = Vin-Vds-Vsd (Equation 5)
V2e = Vin-Vds-Vsd (Equation 6)

One element (switching element 4b) of the switching element is in the reverse conduction mode, and can be made lower than the on voltage of the diode especially in the A region (low current region) of FIG. 3, so that the loss in the conduction path is small. It is possible and highly efficient operation is possible. This is also based on the comparison of the power loss of each element as described above.

On the other hand, in the B region (medium / high current region) of FIG. 3, high-efficiency operation is possible by setting the mode as shown in FIG. 7 (switching elements 4d and 4f are turned on and 4b is turned off).

In this case, after the current is output from the coupling windings 3a and 3b, the switching elements 4d and 4f are turned on to pass through the switching elements 4d and 4f, and then alternating current from the low voltage side of the DC bus via the diode 5b. Return to the voltage source 1. The other switching elements are turned off.

Here, the voltage between the winding 3c and the winding 3a is V1e (between A and C in FIG. 1 (1)), and the voltage between the winding 3c and the winding 3b is V2e (between FIG. 1 (1)). (Between AD) and the on voltage (forward voltage) of the diode 5b is Vf, the voltages of (Equation 7) and (Equation 8) are applied to V1e and V2e.
V1e = Vin-Vout-Vds-Vf (Equation 7)
V2e = Vin-Vout-Vds-Vf (Equation 8)

In the region B (medium / high current region) of FIG. 3, the diode 5b can be made lower than the on voltage (source-drain voltage) of the switching element 4b, so that the loss in the conduction path can be reduced and high-efficiency operation can be performed. It is possible. This is also due to the reason for comparing the power loss of each element described above.

Finally, the blend mode will be described.
The blend mode utilizes the fact that the integrated magnetic component has three terminals, and forms a short-circuit mode on one side of the coupling winding and a load supply mode on the other side by combining the on / off of each switch element. This is the operating mode.

FIG. 8 shows an example of a current path when this mode is implemented.
A short-circuit mode is formed in the current path output from the coupling winding 3a, and a load supply mode is formed in the current path output from the coupling winding 3b. Although an example is shown in this example, a load supply mode may be formed in the current path output from the coupling winding 3a, and a short-circuit mode may be formed in the current path output from the coupling winding 3b.

In the case of FIG. 8, after the current is output from the coupling winding 3a, the switching elements 4d and 4b are turned on to pass through the switching element 4d and then the AC voltage from the low voltage side of the DC bus via the switching element 4b. Return to source 1.

On the other hand, after the current is output from the coupling winding 3b, the switching element 4e is turned on so that the current flows into the smoothing capacitor 6 and is supplied to the load 7.
Further, by turning on the switching element 4b on the side returning to the power supply, the switching element 4b returns to the AC voltage source 1. The other switching elements are turned off.

Here, the voltage between the winding 3c and the winding 3a is V1e (between A and C in FIG. 1 (1)), and the voltage between the winding 3c and the winding 3b is V2e (between FIG. 1 (1)). (A-D), the on-voltage (source-drain voltage) of the switching element 4b is Vsd, the on-voltage of 4d (drain-source voltage) is Vds, and the on-voltage of 4e (source-drain voltage) is Vsd. Then, the voltages of (Equation 8) and (Equation 9) are applied to V1e and V2e.
V1e = Vin-Vds-Vsd (Equation 9)
V2e = Vin-2 × Vsd (Equation 10)

Here, the two elements (switching elements 4b and 4e) of the switching element are in the reverse conduction mode, and in particular, in the region A (low current region) of FIG. 3, the voltage can be lower than the on voltage of the diode, so that the voltage is within the conduction path. Loss can be reduced and high-efficiency operation is possible.
That is, when the on-voltage (forward voltage) of the diode 5e is Vf, the on-voltage Vsd of the switching elements 4b and 4e is smaller than Vf, so that the power loss of each element determined by the product of the current and voltage is It can be made smaller by passing through each switching element.

On the other hand, in the region B (medium / high current region) of FIG. 3, high-efficiency operation is possible by setting the mode as shown in FIG. 9 (switching elements 4d and 4e are turned on and 4b is turned off). The other switching elements are turned off.

In this case, after the current is output from the coupling winding 3a, the switching element 4d is turned on to pass through the switching element 4d and then return to the AC voltage source 1 from the low voltage side of the DC bus via the diode 5b.
Further, after being output from the coupling winding 3b, by turning on the switching element 4e, after passing through the switching element 4e, the voltage returns to the AC voltage source 1 from the low voltage side of the DC bus via the diode 5b.

Here, assuming that the on-voltage (drain-source voltage) of the switching element 4d is Vds, the on-voltage of the switching element 4e (source-drain voltage) is Vsd, and the on-voltage of the diode 5b (forward voltage) is Vf, V1e and The voltages of (Equation 11) and (Equation 12) are applied to V2e.
V1e = Vin-Vout-Vds-Vf (Equation 11)
V2e = Vin-Vout-Vsd-Vf (Equation 12)

In the region B (medium and high current region) of FIG. 3, the diode 5b can be made lower than the on voltage (source-drain voltage) of the switching element 4b, so that the loss in the conduction path can be reduced and high-efficiency operation can be performed. It is possible. This is also for the reason mentioned above.

Further, depending on the diversion ratio of the coupling windings 3a and 3b, the switching element 4e may also have a lower loss when it is passed through the diode 5e side. In that case, the mode as shown in FIG. 10 (switching element 4d is turned on, 4b, 4e is turned off) may be set. The other switching elements are turned off.

The operation of the three modes has been described above. By creating a switching pattern by combining the three modes, the voltage applied to each winding can be changed and the magnetic flux can be changed. Therefore, the load conditions are combined with the miniaturization of the reactor. It is possible to obtain the desired efficiency and boosting performance according to the above.

Further, using these three modes, various boost control is constructed based on the detection value Is of the current detection unit 41, the detection value Vdc of the DC voltage detection unit 31, and the like, and the drive for controlling each switching element. The signals S1 to S6 may be generated.

The mode may be flexibly switched according to the operating conditions.
For example, when boosting operation is not required, it is not necessary to use the power short circuit mode or the blend mode, so only the load supply mode may be used. Alternatively, in the case of usage conditions in which the split flow ratios of the coupled windings are substantially the same, it is not necessary to actively use the blend mode.
That is, the operation mode may be set up so that it can be appropriately switched according to the usage conditions and the specifications required by the user.

Further, the reverse conduction mode of the switching element may not need to be positively used according to the load, the usage environment, and the required specifications even during light load operation. Therefore, the selection of the reverse conduction mode may be flexibly constructed according to the operating conditions, usage conditions, and the like.

11 (1) to 11 (3) show an example of switching.
The mode is switched according to the magnitude of the detection value Is detected by the current detection unit 41 or the detection value pressure Vdc detected by the DC voltage detection unit 31.
Here, the power supply current is used for Is, but any current that correlates with Is may be used.
That is, for example, a current flowing in the DC winding, a current flowing in at least one of the coupling windings, a DC current (current flowing in the DC bus side), a current flowing in the motor winding, or the like may be used. Similarly, for Vdc, a DC voltage is used here, but any voltage that correlates with Vdc may be used. That is, the voltage detected by dividing the DC voltage, the correlation with the power supply voltage, or the like may be used instead.

FIG. 11 (1) shows an example in the case where the switching area is three areas.
For example, when Is is smaller than I1, the use of the reverse conduction mode is permitted (A region in FIG. 11 (1)). In the A region, the reverse conduction mode may be used, or may not be used depending on the usage environment and required specifications.

When Is is larger than I1, the use of the reverse conduction mode is prohibited (FIG. 11 (1) B region).

For example, when Vdc is larger than Vdc1, the use of the operation mode (power short-circuit mode or blend mode) for boosting is permitted (C region in FIG. 11 (1)). In the C region, the power supply short-circuit mode or the blend mode may be used, or may not be used depending on the usage environment and required specifications.
Here, a DC voltage is used for Vdc, but a power supply voltage or the like that correlates with Vdc may be used.

Further, in FIG. 11 (1), in the operation mode for boosting as in the region C, the permission or prohibition of the use of the reverse conduction mode may be switched. That is, a new region D may be added as shown in FIG. 11 (2).
When adding the area D, the reverse conduction mode is switched between the area C and the area D.
For example, in the region C, the reverse conduction mode is used together in the power supply short-circuit mode and the blend mode. On the other hand, in the region D, the power short-circuit mode and the blend mode may be switched by setting not to use the reverse conduction mode together.
The differences between the regions C and D will be described by taking FIGS. 8 and 10, which are similar switching patterns, as an example.
In the region C, the operation of conducting the switching element as shown in FIG. 8 is performed, and in the region D, as shown in FIG. 10, the switching pattern is such that the diode is conducted in the blend mode. As a result, it is possible to realize a wide range of high-efficiency operation according to the magnitude relationship of the switching element on-voltage (drain-source voltage) Vds and Vsd and the diode on-voltage (forward voltage) Vf as in the regions A and B. It is possible.

Although FIGS. 8 and 10 have been described above as typical examples, they may be applied to other switching patterns such as switching between FIGS. 8 and 9 and switching in a power short circuit mode such as a combination of FIGS. 6 and 7. good. Further, in FIG. 11 (2), the boundary between the area C and the area D is the same as the boundary between the area A and the area B, but as shown in FIG. 11 (3), it is set as a different boundary (I2 in FIG. 11 (3)). There is no problem.
Also in this case, as described above, the setting of the reverse conduction mode may be switched between the regions C and D.
Further, in addition to setting the area according to the magnitude relationship between the two parameters Vdc and Is as shown in FIGS. 11 (1) to 11 (3), the area is set by using three or more parameters in combination. There is no problem.

Further, in the description so far, the description is limited to the polarity in which the current conducts from the coupling winding 3a and 3b side to the current sensor 2 side, but the polarity of the AC power supply is switched, that is, the coupling winding from the current sensor 2 side. When a current flows to the 3a and 3b sides, the current path and switching pattern as shown in FIGS. 4 to 11 (3) change. However, even when the polarity of the AC power supply is switched, it is possible to realize high-efficiency operation by switching the switching operation as shown in FIGS. 4 to 11 (3), that is, switching the conduction to the switching element or the conduction to the diode. There is no problem if it is a certain switching pattern.

By doing so, it is possible to support various applications.

In addition, there are cases where it is desired to change the switching element to a diode according to the required specifications. In that case, a circuit may be configured in which a part of the AC / DC converter is replaced with a diode.

For example, FIG. 12 shows an example in which the upper arm of the three legs is composed of a diode and the lower arm is composed of a switching element in the AC / DC conversion unit.

In this case, since the switching element is three elements, the drive signal in the AC / DC conversion unit may be three signals.
Here, the control signals S1 to S3 generated by the control unit 11 are output as drive signals S11 to S13 of each switching element via the gate drive unit 51.

Even if a switching element is not provided in each part, the conduction path of the above three modes can be secured due to the presence of the diode.

Therefore, by omitting the reverse conduction mode implemented in each switching element of the upper arm of the leg, that is, by setting the drive signal of these switches to off, etc., it is relatively possible to make a relatively control change. It is possible to build an inexpensive system.

Embodiment 2.
FIG. 13 is a diagram showing an example of an air conditioner equipped with the power conversion device 101 according to the second embodiment.
A motor 500b is connected to the output side of the power conversion device 101, and the motor 500b is connected to the compression element 504. The compressor 505 includes a motor 500b and a compression element 504. The refrigeration cycle unit 506 is configured to include a four-way valve 506a, an indoor heat exchanger 506b, an expansion valve 506c, and an outdoor heat exchanger 506d.

The flow path of the refrigerant circulating inside the air conditioner is from the compression element 504 via the four-way valve 506a, the indoor heat exchanger 506b, the expansion valve 506c, the outdoor heat exchanger 506d, and again via the four-way valve 506a. , It is configured to return to the compression element 504. The motor drive device 101 receives AC power from the AC power source 1 and rotates the motor 500b. The compression element 504 can execute the compression operation of the refrigerant by rotating the motor 500b, and can circulate the refrigerant inside the refrigeration cycle unit 506.

As a result, the effects described in the first embodiment can be enjoyed in the products such as the compressor and the air conditioner to which the motor drive device according to the second embodiment is applied. Further, this motor drive device may be used for driving a blower. Further, the refrigerator may be configured by using the above refrigeration cycle.

Further, the configuration shown in the above-described embodiment shows an example of the content of the present invention, can be combined with another known technique, and is configured without departing from the gist of the present invention. It is also possible to omit or change a part of.

1 AC power supply, 2 current sensor, 3 (3a to 3c) integrated magnetic component, 4a to 4f semiconductor switch, 5a to 5f diode (built-in diode), 6 capacitor, 7 load, 8a to 8f semiconductor switch (DC AC conversion side) , 9a-9f diode (DC / AC conversion side), 11 controller, 12 conduction mode switching means, 31 DC voltage detection unit, 40 converter (AC / DC conversion unit), 41 current detection unit, 51 drive unit, 52 drive unit, 101 Power converter, 500a inverter (DC AC converter), 500b motor, 504 compression element, 505 compressor, 506 refrigeration cycle section, 506a four-way valve, 506b indoor heat exchanger, 506c expansion valve, 506d outdoor heat exchanger

Claims (18)

A bridge circuit that has multiple legs consisting of an upper arm and a lower arm composed of a semiconductor switch or diode and rectifies the AC power of the AC power supply to DC power.
An integrated magnetic component that smoothes the DC power, one end is connected to one end of the AC power supply, and the other end is connected to the connection point between the upper arm and the lower arm.
A current detector that detects the current of the AC power supply or the current that correlates with the current of the AC power supply,
A voltage detector that detects the voltage of the DC power or the voltage that correlates with the voltage of the DC power,
A control unit that controls the opening and closing of the semiconductor switch is provided.
The control unit switches the conduction mode of the semiconductor switch based on any one or two of the detection value of the current detection unit and the detection value of the voltage detection unit, and the current flowing through the integrated magnetic component. A power conversion device characterized in that the pattern is changed and the determination of switching based on the detection value of the current detection unit is changed according to the detection value of the voltage detection unit . The winding of the integrated magnetic component is divided into a DC winding and a coupling winding, one end connected to the AC power supply is the DC winding side, and the side connected to the connection point between the upper arm and the lower arm is the coupling winding. The power conversion device according to claim 1, wherein the power conversion device is on the wire side, and the coupling winding side is composed of at least two terminals. The control unit controls a plurality of types of power conversion modes by switching a plurality of the semiconductor switches.
As the power conversion mode, a load supply mode in which the current after conversion to direct current is supplied to the load, a power short circuit mode in which the AC power supply is short-circuited in the bridge circuit and power is stored in the integrated magnetic component, and a direct current mode are used. One of the blend modes in which the operation of supplying the converted current to the load and the operation of short-circuiting the AC power supply in the bridge circuit and storing the electric power in the integrated magnetic component are performed in parallel, or The power conversion device according to claim 1 or 2 , wherein any two or all of them are performed. The third aspect of claim 3, wherein the control unit switches the power conversion mode based on either one or two of the detection value of the current detection unit and the detection value of the voltage detection unit. Power converter. The power conversion device according to any one of claims 1 to 4, wherein a diode is connected to the semiconductor switch in antiparallel. The invention according to any one of claims 1 to 5, wherein the conduction mode is a forward mode in which a current flows in the forward direction of a semiconductor switch and a reverse mode in which a current flows in the reverse direction. Power converter. The power conversion device according to any one of claims 1 to 6 , wherein the conduction mode is individually switched for each semiconductor switch. The power conversion device according to any one of claims 1 to 7, wherein the conduction mode is switched by an electric current. The current according to any one of claims 1 to 8, wherein the current is a power supply current, a current flowing through a DC winding, a current flowing through at least one of the coupling windings, or a current equivalent thereto. The power converter described. The power conversion device according to any one of claims 1 to 9, wherein the conduction mode is set to the reverse direction mode when the current is a predetermined value or more. The power conversion device according to any one of claims 1 to 10, further comprising at least one leg including a semiconductor switch configured in series. The power conversion device according to any one of claims 1 to 11, further comprising at least one leg configured by connecting a semiconductor switch and a diode in series. The power conversion device according to any one of claims 1 to 12, wherein a wide bandgap semiconductor is used for the semiconductor switch or diode. A motor drive device comprising the power conversion device according to any one of claims 1 to 13. A refrigeration cycle device comprising the motor drive device according to claim 14. A blower comprising the motor driving device according to claim 14 . An air conditioner comprising the motor driving device according to claim 14 . A freezing device comprising the motor driving device according to claim 14 .

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