VICOR VI-HAM-MM, VI-HAM-IM, VI-HAM-EM, VI-HAM-CM Datasheet

121-800-735-6200

VI-HAM

Harmonic Attenuator

Modules

Features

■Unity Power Factor

■Safety Agency Approvals: UL, CSA, TÜV, BABT

■Meets IEC 6100-3-2 for Line Current Harmonic Content

■Reduces Peak and RMS Line Currents

■Universal Input: 85-264Vac: 50/60 Hz

■Up to 600W of Power

■Power Density Up to100W/in3

■Adaptive Output Voltage Control

■Short-Circuit Protection

■Input Surge Current Limiting

■Converter Enable

■Power OK Output

■Size: 4.6" x 2.4" x 0.5" (116,8mm x 61,0mm x 12,7mm)

■Efficiency: 90-94% Typical

■CE Marked

Unity Power Factor

Conventional capacitive-input front ends draw energy from the AC line in short bursts of current at the peaks of the line voltage waveform. These current bursts are characterized by high peak currents and high harmonic content. The effect of the distorted line current can be appreciated by measuring the rms line current drawn by a conventional front end: the product of the measured rms current and the rms line voltage — the "apparent power" being delivered by the line

— will be significantly greater (typically 1.6X) than the DC power delivered by the front end. The "extra" rms current at the input is circulating harmonic currents which deliver no power to the load but which flow in the delivery system and contribute to losses. Only the fundamental component of the line current contributes to "real" power flow. Power factor — the ratio of "real" to "apparent" power — is a measure of the effectiveness with which an AC load can extract usable power from an AC source.

The VI-HAM (see Fig. 2) consists of a

full-wave rectifier, a proprietary high-frequency zerocurrent switching (ZCS) boost regulator (patents applied for), active inrush, short-circuit protection, control and housekeeping circuitry. The incoming AC line is rectified and fed to the ZCS boost converter. The control circuitry varies the operating frequency of the ZCS boost converter so as to simultaneously maintain the output voltage of the HAM at a DC voltage value above the peak of the incoming line, while forcing the input current to the ZCS converter to follow the waveshape of the rectified line. By this means, the AC input current follows the AC voltage waveform and a power factor better than 0.99 is achieved. Operating efficiency of the ZCS boost converter is optimized at any incoming line voltage by a patented adaptive output voltage control scheme.

The HAM also includes active circuitry which controls inrush currents when power is applied and active short circuit protection circuitry — features not normally found in conventional power factor correctors.

Housekeeping circuitry provides two signals of use to the system designer (see Fig. 2): Module Enable and Power OK. Referencing the timing diagram (see Fig. 3), the Module Enable signal, which is connected to the Gate In inputs of the Vicor DCDC converters powered by the HAM, will come high and enable the DC-DC converters when the HAM output voltage exceeds 240Vdc. The DC-DC converter voltage outputs will be up approximately 10 ms after Module Enable goes high. Typically, 20 ms after Module Enable goes high the HAM Power OK signal, which can be used by the system designer to enable circuitry powered by the DC-DC converter modules, goes low. On loss of power or brownout, the Power OK signal will go high when the HAM DC output voltage drops below 230V, signaling an impending loss of input power to the converter modules. When the DC output dips below 195V, the Module Enable signal will toggle low, disabling the converter modules and unloading the HAM.

The HAM will provide at least 16 ms of ride-through or holdup time, and at least 5 ms of AC fail warning time with a 1000 µF output capacitor.

Figure 1a.

Figure 1b.

Above: Oscilloscope photos showing input voltage and current without power factor correction (A) and with power factor correction as provided by the VI-HAM (B).

			ZCS	Inrush	+
	AC	Recti-		& Short	DC
			Boost
	Line	fier		Circuit	Out
			Converter
				Protection	–
			Current
			Sense	High Frequency	Note:
					Non-Isolat
				Control
		Voltage			Output
				Output Voltage
		Waveform	Control
			& House-	Module Enable
			keeping	Power OK
			Circuitry

	Gate In	Aux. Supply
	Gate Out

NOTE: No input to output isolation.

Figure 2 • VI-HAM Block Diagram

121-800-735-6200
			Vicor varies the output voltage of the HAM as							VI-HAM Protection Features
AC			a function of incoming AC line voltage
Mains										Overtemperature Shutdown
120V			(see Fig. 4, patent applied for). On a nominal
RMS			120Vac line the output voltage of the HAM is							The HAM incorporates overtemperature
		230	260Vdc — well within the input operating							shut-down, and is designed to shut down when
DC	240	Vdc	voltage range of standard Vicor converters.							the temperature of the baseplate exceeds
		195
	Boost Voltage
Output	Vdc	Vdc	As input line increases, so does the HAM							90–100°C. It is not safe to run the HAM for
of HAM			output voltage; at 220Vac the delivered voltage							extended periods above its maximum operating
	Rectified Line
			will be about 350V. For any given input line							temperature of 85°C.
Module		Off at	voltage, the HAM maintains enough headroom							Short Circuit Protection
			between the output voltage and peak input
Enable		195								The HAM contains a short circuit shutdown
		Vdc	voltage to ensure high quality active power
										function. Operation of this function does not
			factor correction without unnecessarily
	25 ms									clear the input fuse and the output will resume
			sacrificing operating efficiency.
		Off at								normal operation after removal of the short. A
Power OK		230								small period of time may be required to allow
		Vdc
										for cooling of an internal PTC. Overcurrent
	10 ms		400 Vdc				250 Vac			protection is provided by the Vicor DC-DC
Outputs										converters.
VI-200			350 Vdc
DC-DC										Output Overvoltage Protection
Converter(s)			300 Vdc		260 Vdc				Output Voltage
			250 Vdc
				80 Vac	152 Vac			46V	as a Function	The HAM contains output overvoltage
								Boost	of Input Voltage
			200 Vdc		85 Vac					protection. In the event the output voltage
Figure 3 • Functional Timing Diagram			150 Vdc
										exceeds approximately 420Vdc, the boost will
			100 Vdc	Vin x 2
Active power factor correctors incorporate a									264	decrease to maintain 420Vdc on the output.
			50 Vdc
						Operating Region			Vac
boost regulator which must operate over a range				50	100	150	200	250	300	When the peak of the AC line exceeds 420V
of incoming AC line voltages. Conventionally,										(approximately 293Vac) the boost will have
the output voltage of the boost regulator is set				25	75	125	175	225	275	been reduced to zero. Beyond this the protection
						Vac			296
to a value greater than the maximum anticipated										circuit will be enabled and the output voltage
peak value of the incoming AC line.			Figure 4 • Input Voltage vs. Output Voltage							will decrease.

Pin Function Description

• L1 and L2/N (VI-HAM):

These pins are to be connected to the AC mains output of a suitable EMI/RFI filter (Vicor

P/N 07818 or equivalent). Do not connect an X capacitor across these pins as power factor correction will be slightly degraded.

• +IN, –IN (VI-HAMD, VI-BAMD):

These pins are connected to the output of the external bridge rectifier.

• Gate Input (VI-HAM):

This pin disables the boost converter only. Rectified line current may still be present on the output. This pin does not provide the same function as the gate input pin of VI-200/VI-J00 modules. The user should not make any connection to this pin.

• Gate Input (VI-HAMD):

This pin serves as a rectified AC following pin for power factor correction synchronization to line. This connection must be made through the synchronization diodes between the line filter and bridge rectifier (see

Fig. 10, page 84).

• Gate Input (VI-BAMD):

The Gate Input pin is an interface pin to the Gate Out pin of a VI-HAM, VI-HAMD or VI-BAMD depending on configuration. The user should not make any other connection to this pin.

• Gate Output:

The Gate Output pin is an interface pin to BAMDs; the user should not make any other connection to this pin.

• +Output and -Output and Holdup Capacitor:

These outputs should be connected to the respective inputs of Vicor DC/DC converters. In addition, an external holdup capacitor of 1000 µF with a minimum voltage rating of 450Vdc, is required across the output for 16 ms ride through time at 600W (500 µF for 300W, etc). Do not exceed 3000 µF of total

output capacitance. Lower values of capacitance may be used for reduced holdup requirements, but not less than 330 µF. Lower capacitance values may degrade power factor specifications.

• Auxiliary Supply (A/S):

The VI-HAM and VI-BAMD contain an internal low voltage output (A/S) that may be used to power primary side logic. This output is 19-23Vdc, referenced to -OUT, at 3 mA max. Do not overload or short this output as the HAM will fail. A typical use for A/S is to power an optical coupler that isolates the Power OK signal.

This provides sufficient time for the converters to turn on and their outputs to stabilize prior to P/OK being asserted. When the AC mains is removed and the output of the HAM drops below 230V, P/OK goes to an open circuit state. When the output voltage drops below 195V the converters are disabled via Module Enable. P/OK will provide power fail warning at least 1 ms prior to converter shutdown.

P/OK

	D
LOGIC	S
	G

-OUT

+	A/S
19 - 23V	≤ 3mA
–	-OUT

"Power OK" Status

Low = OK

+ OUT

P/OK

E/O 18 kΩ , 1/4W

A/S

– OUT

Figure 5 • Auxiliary Supply (A/S)

• Power OK (P/OK)

P/OK is a monitor signal that indicates the status of the AC mains and the DC output voltage of the HAM. P/OK, during normal operation, is an active low

(see Fig. 6). In the event AC mains or DC output fails, this pin goes to an open circuit state. P/OK is asserted when the output bus voltage is within normal operating range and 20-25 ms after DC-DC converters are enabled by the Module Enable output of the HAM.

Figure 6 • Power OK (P/OK)

• Module Enable (E/O)

The Module Enable output is used to disable the DC-DC converters until there is sufficient energy in the holdup capacitor (240V) to support normal operation, while limiting inrush current. Module Enable must be connected to the Gate Input of all driver DC-DC converters. It is not necessary to connect this pin to boosters as they are controlled by their respective driver. If the AC mains fail, Module Enable goes low when the DC output of the HAM drops below 195V. Failure to connect Module Enable may result in the output of the HAM latching low during turn-on.

E/O

	D
LOGIC	S
G	-OUT

Figure 7 • Enable/Output (E/O)