Convert BusVolt ControlConfig Attrib

These are the bus voltage control configuration attributes associated with a regenerative converter.

Bus Voltage Droop Control Mode

When Droop Control is selected as the Bus Voltage Reference Source, this Bus Voltage Droop Control Mode attribute establishes the relationship between the Bus Voltage Reference and the Active Current Reference for the Bus Voltage Droop Control function. In general, the Bus Voltage Droop Control function decreases the Bus Voltage Reference as the Active Current Reference increases.

Linear Mode operation applies a linear relationship between the Bus Voltage Reference and the Active Current Reference.

Nonlinear Mode operation applies a nonlinear relationship between the Bus Voltage Reference and the Active Current Reference to further optimize load sharing.

Bus Voltage Droop Gain Full Load

Bus Voltage Droop Gain Full Load sets the full load droop gain for the Bus Voltage Droop Control function. This gain is used when the absolute value of the active output current is greater than the value specified in the Bus Voltage Droop Transition Current attribute. The units for this gain value are defined as the percent increase in Bus Voltage Reference over the positive output current range (zero load to full

Bus Voltage Droop Gain No Load

Bus Voltage Droop Gain No Load sets the no load droop gain for the Bus Voltage Droop Control function. This gain is used when the absolute value of the active current is less than the value specified in the Bus Voltage Droop Transition Current attribute. The units for this gain value are defined as the percent increase in Bus Voltage Reference over the positive output current range (zero load

Bus Voltage Droop Minimum Bus Voltage

Bus Voltage Droop Minimum Bus Voltage sets the Minimum Bus Voltage that, when operative, serves as the baseline voltage used by the Bus Voltage Droop Control function when motoring at full rated current. As the Active Current Reference decreases, the Bus Voltage Droop Control function increases the Bus Voltage Reference according to the configured Bus Voltage Droop Gain attributes.

This attribute can be used to improve current sharing between regenerative converters that have unequal input voltages. In the case where converters use equal AC line voltages, this attribute can improve current sharing when there are differences between transformers and cabling.

For this attribute to be operative, its value must be higher than the minimum Bus Voltage Reference level established by the Automatic Bus Voltage Reference Source function. The Bus Voltage Droop Control function applies the higher of these two voltage levels to the Bus Voltage Reference when the converter supplies full rated current to the DC bus.

Bus Voltage Droop Transition Current

Bus Voltage Droop Transition Current sets the transition current level used by the Bus Voltage Droop Control function to define the transition point where the droop gain changes from the Bus Voltage Droop Gain No Load attribute to the Bus Voltage Droop Gain Full Load attribute setting.

Bus Voltage Set Point

The Bus Voltage Set Point attribute sets the reference voltage used to actively regulate the DC Bus Voltage of the converter when in the Running state and the Bus Voltage Reference Source is set to Manual.

Bus Voltage Reference Source

The Bus Voltage Reference Source attribute selects between Automatic and Manual source for the Bus Voltage Reference. Other source selections for the Bus Voltage Reference that are tailored to specific applications may be optionally supported by the converter.

Automatic (default) selection allows converter to optimize the Bus Voltage Reference for best converter performance. In this case the Bus Voltage Reference is automatically adjusted based on the AC Line Voltage, e.g. 102% of AC Line Voltage

With the Manual selection, the converter uses the user configured Bus Voltage Set Point value for the Bus Voltage Reference signal.

Bus Voltage Loop Bandwidth

The Bus Voltage Loop Bandwidth attribute value determines the proportional gain, Kbp, of the bus voltage loop that multiplies the Bus Voltage Error signal. This value represents the unity gain bandwidth of the bus voltage loop.

Bus Voltage Integrator Bandwidth

The Bus Voltage Integrator Bandwidth attribute value determines the bus voltage loop integral gain, Kbi, which together with the Kbp, multiplies the integrated Bus Voltage Error signal. This value represents the bandwidth of the bus voltage integrator beyond which the integrator is ineffective. A value of 0 for this attribute disables the integrator.

Bus Voltage Rate Limit

The Bus Voltage Rate Limit attribute sets the DC Bus rate limit for the Bus Voltage Set Point that becomes the DC Bus Reference signal when the Bus Voltage Reference Source is set to Manual.

Bus Voltage Error Tolerance

The Bus Voltage Error Tolerance attribute determines the absolute maximum Bus Voltage Error value that can be tolerated without causing an Excessive Bus Voltage Error exception.

Bus Voltage Error Tolerance Time

The Bus Voltage Error Tolerance Time attribute determines the maximum amount of time that the Bus Voltage Error Tolerance can be exceeded without generating an exception.

Bus Observer Configuration

The Bus Observer Configuration attribute enumerated value configures the operation of the Bus Observer. The Bus Observer dynamically measures the active current applied to the DC Bus for the purpose of bus impedance compensation. Selecting the Voltage Estimate configures the observer to dynamically estimate voltage based on an internal model of the DC Bus. When Voltage Estimate is selected, this signal is applied to the voltage loop to provide superior control loop performance. The Voltage Estimate may be used in combination with the Bus Observer by selecting Bus Observer with Voltage Estimate.

Bus Observer Bandwidth

The Bus Observer Bandwidth attribute value determines the proportional gain, Kbop, of the Bus Observer. This value represents the unity gain bandwidth of the Bus Observer.

Bus Observer Integrator Bandwidth

The Bus Observer Integrator Bandwidth attribute value determines the Bus Observer integral gain, Kboi, that together with the Kbop, multiplies the integrated error signal within the observer. This value represents the bandwidth of the integrator beyond which the integrator is ineffective. A value of 0 for this attribute disables the integrator.

When configured for Nonlinear Mode, the piece-wise linear k1 and k2 segments shown in Figure 3-20 that define the relationship between the Bus Voltage Reference, Vdc_ref, and the Active Current Reference, Iq, are smoothed into a non-linear curve. The Bus Voltage Droop Gain No Load attribute still tends to dictate the slope of the curve for lower currents levels, while Bus Voltage Droop Gain Full Load establishes the k2 segment tends to dictate the slope of the curve for higher current levels. The transition current level between the k1 and k2 segments is still determined by the Bus Voltage Droop Transition Current attribute.