JP2011072149A - Power supply regenerative control method and power supply regenerative control device for power supply regenerative converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply regeneration function equivalent to that of a conventional power supply regenerative converter while reducing costs and achieving a simple circuit by eliminating the need for a circuit to detect a peak value of an AC power supply that is required by the conventional power supply regenerative converter. <P>SOLUTION: A power supply regenerative converter includes: a phase detecting means for detecting a voltage phase of an AC power supply; a DC power supply output voltage detecting means for detecting a DC power supply output voltage being output of the power supply regenerative converter; a regenerative transistor for executing power supply regeneration operation to the AC power supply by switching the DC power supply output voltage; and a regenerative-signal generating means for generating an on/off drive signal of the regenerative transistor on the basis of a detection signal detected by the AC power supply voltage phase detecting means and a detection signal detected by the DC power supply output voltage detecting means. The DC power supply output voltage is detected and a voltage of the AC power supply is estimated so as to execute power supply regeneration when estimated that the voltage on the side of the AC power supply is in a low state. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

        The present invention relates to a power regenerative converter that regenerates regenerative energy generated during motor deceleration or the like to a power source, and in particular, a power source for a power regenerative converter that realizes an inexpensive power regenerative converter by monitoring the state of a DC power output voltage. The present invention relates to a regeneration control method and a power regeneration control device.

        The power regenerative converter is placed between the inverter that controls the motor at a variable speed and the AC power supply. When the motor decelerates or is used for applications that support heavy objects, the motor moves down and stops. It is a device that regenerates the regenerative energy generated when the power is being used.

        The conventional power regenerative converter is an inverter power source that drives the motor when the voltage of the AC power source is lower than the DC power source output voltage that is the DC voltage output of the power source regenerative converter 1 in FIG. In order to perform power regeneration, it is necessary to detect the voltage on the AC power supply side, and in order to regenerate regenerative energy in synchronization with the phase, the AC voltage phase / waveform detector 8 in FIG. 2 is necessary. The AC voltage phase / waveform detection unit 8 required a circuit for detecting a zero-cross point where the AC voltage was 0 V and a circuit for detecting the peak value of the AC power supply. (For example, see Patent Document 1)

Japanese Patent No. 4116112

        Of the AC voltage phase / waveform detector 8 shown in FIG. 2, which is required for a conventional power regeneration converter, a circuit for detecting the peak value of the AC power supply is not required, the circuit is simplified, and the cost is reduced. The power regeneration function is equivalent to the power regeneration converter.

        In order to achieve the above object, a power regeneration converter according to the present invention is disposed between an inverter device for variable speed control of a motor and an AC power supply, and includes a phase detection means for detecting a voltage phase of the AC power supply, and a motor. This is the terminal voltage of the smoothing capacitor that stores the regenerative energy generated when the motor is moving down and stopping when used for applications such as decelerating or supporting heavy objects. DC power supply output voltage detection means for detecting a DC power supply output voltage that is also a voltage output, a regenerative transistor that switches the DC power supply output voltage to perform a power regeneration operation on the AC power supply, and detects a voltage phase of the AC power supply Based on the detection signal detected by the phase detection means and the detection signal detected by the DC power supply output voltage detection means In a power regeneration converter comprising regeneration signal generating means for generating an on / off drive signal for a raw transistor, the DC power supply output voltage is detected, the voltage of the AC power supply is estimated, and the voltage on the AC power supply side is low It is characterized by performing power regeneration when estimated to be.

        According to the present invention, a circuit for detecting the peak value of an AC power supply is unnecessary, the circuit is simplified, and it is possible to provide a power regeneration function equivalent to that of a conventional power regeneration converter while reducing the cost. .

The block diagram of the motor drive device using the Example of the power regeneration converter by this invention Example of a motor drive device using a conventional power regeneration converter Flowchart for detecting DC power supply output voltage and performing power regeneration operation according to the detected voltage Flow chart for obtaining the threshold value for power regeneration operation Detailed flowchart of S611 to S614 in FIG.

        Examples of the present invention will be described below.

        FIG. 1 is a block diagram showing a configuration example of a power regeneration converter to which the present invention is applied. As shown in FIG. 1, the power regeneration converter 1 is disposed between an inverter device 4 that controls the motor at a variable speed and an AC power source 2.

        The AC power supply 2 is connected to the power regeneration converter 1 via the reactor 5. A DC power supply output voltage that is a DC voltage output of the power regeneration converter 1 is connected to the inverter device 4.

        In the power regenerative converter 1, regenerative transistors Tr1 to Tr6 through which a current flows during power regeneration are arranged and connected as shown in FIG. These regenerative transistors are arranged and connected as shown in FIG. 1 with diodes D1 to D6 through which current flows when the AC power supply voltage during power running is rectified or by a back electromotive voltage generated in switching of the regenerative transistor.

Further, the smoothing capacitor C is arranged and connected as shown in FIG. 1, and smoothes the AC power supply voltage during power running rectified by the diodes D1 to D6. It also plays a role in accumulating regenerative energy that is generated when the motor decelerates or when the motor is moving down or stopped when it is used to support heavy objects.
Both ends of the smoothing capacitor C are connected to the DC power supply output voltage detector 7, and the output terminal of the DC power supply output voltage detector 7 is connected to the regenerative signal generator 6.

        An AC voltage phase detection unit 8 is connected to a terminal to which the reactor 5 and the power regeneration converter 1 are connected, and an output terminal of the AC voltage phase detection unit 8 is connected to the regeneration signal generation unit 6. The six output terminals of the regenerative signal generator 6 are connected to corresponding base terminals of the six regenerative transistors Tr1 to Tr6.

        In the above configuration, the regenerative transistor may be replaced with a semiconductor such as a thyristor, a GTO thyristor (Gate Turn Off Thyristor), a MOS FET (Field Effect Transistor), or an IGBT (Insulated Gate Bipolar Transistor).

        In the above configuration, the present invention will be described with reference to FIGS. In the present invention, the circuit for detecting the peak value of the AC power supply, which has been conventionally required, is unnecessary, and the power supply is regenerated by estimating the voltage of the AC power supply. FIG. 3 is a flowchart for sampling the DC power supply output voltage by the DC power supply output voltage detector 7 of FIG. 1 and determining whether or not to perform the power regeneration operation based on the voltage.

        First, the DC power supply output voltage detection unit 7 samples the DC power supply output voltage at a constant cycle, and the value is set as PNFFB_NOW. Compare the PNVFB_NOW with the threshold value (PNVFB_FIR + Vrf) for determining whether to perform power regeneration operation. Output.

        PNFFB_FIR of PNFFB_FIR + Vrf, which is the threshold value of the power regeneration operation, indicates the peak value of the estimated AC power supply voltage, and uses a constant value (for example, set by a parameter) when the motor drive device is powered on. Thereafter, when the motor drive device starts to be driven, the value is updated by being estimated from the DC power supply output voltage sequentially sampled by the DC power supply output voltage detection unit 7. The updating method will be described later.

        Vrf is a value for setting the voltage at which power regeneration starts, and can also be set with a parameter. Normally, PNFFB_FIR + Vrf is used by the power regeneration converter 1 with PNFFB_FIR as the initial constant value. It is sufficient to set a constant value that will not break. For example, if PNFFB_FIR is the peak value of AC voltage 282V (200V x √2) and the maximum rated voltage value of the part is 400V, then 95% of the maximum rated voltage value of the part is used and 400V x 0.95-282V becomes Vrf. Set Vrf = 98V.

        Next, a method for updating the PNFFB_FIR will be described. As described above, a constant value is used (initialization) when the motor drive device is powered on. (S610 in FIG. 4) Next, averaging is performed using the DC power supply output voltage PNFFB_NOW eight times sampled by the power supply output voltage detector 7, and the average value is stored in the PNFFB_AVL1 register. (S611 in FIG. 4) The sampling cycle should be performed at a constant interval as short as possible, but is determined in consideration of cost, motor drive device protection, and the like.

        Here, the averaging process is to calculate the average value by ignoring the largest and smallest values of the 8 sampled values and adding all the remaining 6 values and dividing by 6. Various methods can be considered, such as simply obtaining all 8 values and dividing by 8. Also, the number of times of sampling is not 8 times, but various times such as 4 times and 16 times can be considered, and an optimum method may be used for each.

        The same processing as S611 in FIG. 4 is performed three times (four times including S611 in FIG. 4). Store in the register (see S614 in FIG. 4). Next, compare the PNFFB_AVL1 register to PNFFB_AVL4 register with PNFFB_FIR ± Vof, and if all the registers are outside the range of PNFFB_FIR ± Vof (less than PNFFB_FIR−Vof or greater than PNFFB_FIR + Vof), The average value of the PNFFB_AVL4 register is obtained, PNFFB_FIR is replaced with the average value, and the process returns to S611 in FIG. If all the registers are within the range of PNFFB_FIR ± Vof (PNVFB_FIR−Vof or more and PNFFB_FIR + Vof or less), nothing is done and the process returns to S611 in FIG. (See Figure 4)

        Vof is a value indicating an allowable range for comparing each register of the PNFFB_AVL1 register to the PNFFB_AVL4 register and PNFFB_FIR, and can be set by a parameter, but normally a constant value should be set. For example, 5% of PNFFB_FIR

        Here, the average value is obtained using four registers, PNFFB_AVL1 to PNFFB_AVL4. However, instead of four registers, various numbers such as two or six can be considered, and the optimum method should be used for each. . The contents of FIG. 4 are repeatedly executed except for the initialization of S610 PNFFB_FIR.

        Through the above processing, the AC voltage phase / waveform detection unit 8 shown in FIG. 2 which is required for a conventional power regeneration converter can be estimated accurately without alternating with a momentary change such as noise. Among them, a circuit for detecting the peak value of the AC power supply is unnecessary, the circuit is simplified, and the power regeneration function equivalent to the conventional power regeneration converter can be provided while reducing the cost.

1 Power regeneration converter
2 AC power supply
3 Motor
4 Inverter device
5 Reactor
6 Regenerative signal generator
7 DC power supply output voltage detector
8 AC voltage phase detector
108 AC voltage phase / waveform detector

Claims (3)

In a power regeneration converter that is placed between an AC drive and an inverter that controls the motor at a variable speed,
Phase detection means for detecting the voltage phase of the AC power supply;
This is the terminal voltage of the smoothing capacitor that stores the regenerative energy generated when the motor decelerates or when the motor is used for supporting heavy loads when the motor is moving down and stopping. DC power supply output voltage detection means for detecting a DC power supply output voltage which is also a DC voltage output of
A regenerative transistor that switches the DC power supply output voltage to perform a power regeneration operation on the AC power supply;
Regenerative signal generation for generating an on / off drive signal for the regenerative transistor based on a detection signal detected by the phase detection means for detecting a voltage phase of the AC power supply and a detection signal detected by the DC power supply output voltage detection means Means,
A power regeneration control for a power regeneration converter that detects the DC power supply output voltage, estimates the voltage of the AC power supply, and performs power regeneration when it is estimated that the voltage on the AC power supply side is low. Method.
In a power regeneration converter that is placed between an AC drive and an inverter that controls the motor at a variable speed,
A phase detector for detecting the voltage phase of the AC power supply;
This is the terminal voltage of the smoothing capacitor that stores the regenerative energy generated when the motor decelerates or when the motor is used for supporting heavy loads when the motor is moving down and stopping. A DC power supply output voltage detector that detects a DC power supply output voltage that is also a DC voltage output of
A regenerative transistor that switches the DC power supply output voltage to perform a power regeneration operation on the AC power supply;
Regenerative signal generation for generating an ON / OFF drive signal for the regenerative transistor based on a detection signal detected by the phase detection unit for detecting a voltage phase of the AC power supply and a detection signal detected by the DC power supply output voltage detection unit With
A power regeneration control for a power regeneration converter that detects the DC power supply output voltage, estimates the voltage of the AC power supply, and performs power regeneration when it is estimated that the voltage on the AC power supply side is low. apparatus.
      3. The power supply of the power regeneration converter according to claim 2, wherein a CPU (Central Processing Unit), FPGA (Field Programmable Logic Device), and CPLD (Complex Programmable Logic Device) are used in the regeneration signal generator according to claim 2. Regenerative control device.

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